제어로봇시스템학회:학술대회논문집
Institute of Control, Robotics and Systems (ICROS)
- 기타
Domain
- Machinery > Robot/Automated Machinery
1997.10a
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This paper presents a muzzle velocity measuring equipment(MVME) for the AN/UPQ6 model using doppler signals, which are generated from the difference of the transmitter signals and the receiver signals. It describes the principles of a velocity measurement, a ballistic analysis program and the accuracy of the MVME. With a comparison between the existence velocity meter and this system, the accuracy and the usefulness of this equipment is validates.
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When we use Hadamard transform spectrometers (HTS), we can increase signal to noise ratio(SNR) by multiplexing which is done by masks. But if the mask has a single defective element, output-SNR decreases. In this paper the effect of a single defective element on the output-SNR is investigated. And a method of compensating for the defective mask element is presented.
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In recent years, the metal industry has become increasingly aware of an unwanted component in metal scrap-radioactive material. Worldwide, there have 38 instances where radioactive sources were unintentionally smelted in the course of recycling metal scrap. In some cases contaminated metal consumer products were distributed internationally. U.S. mill that have smelted a radioactive source face costs resulting from decontamination, waste disposal, and lost profits that range from 7 to 23 million U.S. dollars for each case. Despite radiation monitoring system does not provide 100% protection, POSCO has developed the system for the first time in the steel industry of KOREA.
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This paper describes the grenade counting system developed for DPICM submunition analysis using the infrared video streams, and its some video stream processing technique. The video stream data processing procedure consists of four sequences; Analog infrared video stream recording, video stream capture, video stream pre-processing, and video stream analysis including the grenade counting. Some applications of this algorithms to real bursting test has shown the possibility of automation for submunition counting.
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원자력 발전소용 증기발생기의 수위제어에 기존의 경우 주로 PI제어기를 이용하는데 반해 본 논문에서는 기타의 주급수유량에 대한 주증기 유량의 변화를 2-자유도 PID제어기를 이용해 제어하는 문제를 연구하였다. 2-자유도 PID제어기의 파라메터 .alpha..betha..gamma.를 외란에 대해 가인하도록 하고 설정치변화에 대해서는 기존의 PID 파라메터가 부담하도록 함으로서 외란 및 설정치 모두에 대해 고찰한 결과 기존의 PI제어기에 비해 성능이 우수함을 나타내었다.
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Refuse incineration plant operations involve many kinds of uncertain factors, such as the variable physical properties of refuse as fuel and the complexity of the burning phenomenon. That makes it very difficult to apply conventional control methods to the combustion control of the refuse. In this paper, an adaptive fuzzy model predictive controller is proposed for the combustion control of the refuse. And computer simulation was carried out to evaluate performance of the proposed controller.
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A periodic disturbance canceler is proposed to compensate the periodic disturbance due to cutting process in a CNC machining center. For precision cutting, the combination of a disturbance observer and a periodic disturbance canceler is desirable in order to compensate both the frictional force and the periodic disturbance. This method is implemented in a position control system of a CNC machining center in cutting process and the experimental results are described to show its effectiveness.
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This paper describes the quick and precise controlling method for home-applied refrigerator. The proposed controller is based on the fuzzy logic control method and is designed for better performance in maintaining the constant temperature of the refrigerator. The temperature of the refrigerator is controlled by the cooling air blowing fan motor which is put on, off according to fuzzy logic controller. Finally, I study the performance of the proposed controller through the computer simulation about the approximated model of the refrigerator.
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A recent development in the Flat Panel Display(FPD) industry requires an auto-alignment system which is operated in high speed and high precision. In the FPD production process, aligning photo-mask with respect to guide mark printed in the glass should be accomplished in the accuracy of sub-micron order. So the system has high bandwidth and needs a dedicated control system which is fast and robust enough to control linear motors in precise manner. Proposed auto-alignment system structure in this presentation which consists of the master controller board, the DSP position controller board which controls 3 axis precision linear motors, the servo system and the man machine interface software. Designed and tuned under repeated experiments, the proposed system showed a reasonable performance in the aspect of rise time and steady state error.
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In this paper, we described an approach to design of precision optical system for visual inspection of solder joint defects of SMC(surface mount components) on PCBs(Printed Circuit Board). The illumination system, consisting of three tiered LED lamps and one main camera and four side view camera, is implemented to generated iso-contour on the solder joint according to gradient of the soldered surface. We analyze LED design parameter such as incident angle, diameter of LED ring, and so on to acquire uniform illumination.
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This paper presents a 3D object recognition method for generation of 3D environmental map or obstacle recognition of mobile robots. An active light source projects a stripe pattern of light onto the object surface, while the camera observes the projected pattern from its offset point. The system consists of a laser unit and a camera on a pan/tilt device. The line segment in 2D camera image implies an object surface plane. The scaling, filtering, edge extraction, object extraction and line thinning are used for the enhancement of the light stripe image. We can get faithful depth informations of the object surface from the line segment interpretation. The performance of the proposed method has demonstrated in detail through the experiments for varies type objects. Experimental results show that the method has a good position accuracy, effectively eliminates optical noises in the image, greatly reduces memory requirement, and also greatly cut down the image processing time for the 3D object recognition compared to the conventional object recognition.
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Building a reliable mobile robot - one that can navigate without failures for long periods of time - requires that the uncertainty which results from control and sensing is bounded. This paper proposes a new mobile robot localization method using artificial landmarks. For a mobile robot localization, the proposed method uses a camera calibration(only extrinsic parameters). We use the FANUC arc mate to estimate the posture error, and the result shows that the position error is less than 1 cm and the orientation error less than 1 degrees.
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This paper presents the algorithm of FIC inspection in chip mounter. When device is mounted on the PCB, it is impossible to get zero defects since there are many problems which can not be predicted. Of these problems, devices with bent corner leads due to mis-handling and which are not placed at a given point measured along the axis are principal problem in SMT(Surface Mounting Technology). In this paper, we proposed a new algorithm based on the Radon transform which uses a projection to inspect the FIC(Flat Integrated Circuit) device and compared this method with other algorithms. We measured the position error and applied this algorithm to our image processing board which is characterized by line scan camera. We compared speed and accuracy in our board.
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This paper discusses an automatic visual-servoing system, in which a laser and a CCD camera are used for imaging the pattern of joint groove. The algorithm used here is simple and robust to find out the gap width and gap center. As a consequence, the speed of algorithm is very fast and optimized. A feature of this system is that it processes only by summing the vertical line and horizontal line of screen without any image preprocessing in order to get the energy information of lines alternatively. It is practical and useful for the system requiring a fast process time of vision.
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Vision system is mainly consist of three parts of perception, action. One of these parts, perception system detects visual target in surrounding environment. Block-based motion estimation with compensation is one of the popular approaches without accuracy. The hierarchical method the optical flow with gradient is used to improve optical flow time delay.
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Designing fuzzy controller, there are difficulties that we have to determine fuzzy rules and shapes of membership functions which are usually obtained by the amount of trial-and-error or experiences from the experts. In this paper, to overcome these defects, genetic algorithms which is probabilistic search method based on genetics and evolution theory are used to determine fuzzy rules and fuzzy membership functions. We design a series compensation fuzzy controller, then determine basic structures, input-output variables, fuzzy inference methods and defuzzification methods for fuzzy controllers. We develop genetic algorithms which may search more accurate optimal solutions. For evaluating the fuzzy controller performances through experiments upon an actual system, we design the fuzzy controllers for the speed control of a DC series motor with nonlinear characteristics and show good output responses to reference inputs.
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溜is paper is concerned with the controllers for time-delay systems which has an integrator. It is known that high performance can be obtained for the systems response and load disturbance rejection by adjusting the only three parameters of the modified Smith predictor. In the case of the time-delay systems with repeated poles, good performance cannot be obtained with the modified Smith predictor. But superior performance can be obtained through the intentional delay parameters mismatch. The calculating method for the approximation delay parameter values is proposed. Simulation results show the improved response characteristics with the proposed delay parameter values.
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A universal controller is designed using a DSP (digital signal processor). The design objectives of the system are to implement control algorithms that require a lot of calculations and to develop a convenient user-interface environment. To demonstrate the efficiency of the system, the time delay control algorithm is implemented for the 2 D.O.F.SCARA type robot and the experimental results are presented.
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The temperature control system for semiconductor test handler is designed. We controlled the temperature of chamber using 3-wire RTD sensor and MVME EMbedded controller. VxWorks that is a real-time operating system is used and heater is controlled by PWM. Temperature fluctuation of chamber is decreased within 0.3.deg. C, which is about one-half of that of commercial controller.
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In this paper presented is a temperature controller for a semiconductor test handler. Using ARMAX model and least square method, the chamber model for the design of a controller is identified through experiment. With the identified model an LQG/LTR controller is designed. Experiment with a real test handler demonstrated good performance in that its overshoot is small and response time is fast.
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This paper studies an active noise controller in a communication headset. The system is a two inputs(communication signal and noise signal) and single output(error signal) system. The problem is to reduce noise level sufficiently lower than communication signal to receive the communication signal clearly. The approach to this problem is in two steps. In the first step, we solve the noise rejection problem without communication signals. In this step, the problem is transformed to the robust H
$_{\infty}$ regulating problem and solved using Linear Matrix Inequalities. In the second step, communication signal is introduced to the system, To verify the performance of the designed controller, a couple of experiments are performed.. -
Fieldbus is the real-time communication network for process control and manufacturing automation systems. IEC/ISA fieldbus was proposed as an international standard of fieldbus network. This protocol is operated on the basis of token-passing and scheduling mechanism. In this paper, we analyze the performance characteristics of the 1996 version of IEC/ISA fieldbus systems.
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The objective of this paper is to provide an alternative framework for the integration of process planning and scheduling in cellular manufacturing. The concept of an integrated cellular manufacturing system is defined and the system architecture is presented. In an integrated cellular manufacturing system, there are three modules : the process planning module, the manufacturing-cell design module, and the cell-scheduling module. For each module, the tasks and their activities are explained.
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The paper suggests a guide of designing and implementing automation systems using industrial communication networks.
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Fieldbuses are used as the lowest level communication network for real-time communication in factory automation and process control systems. Data generated from field devices can be divided into three categories: sporadic real-time, periodic real-time and non real-time data. Since these data share one fieldbus network medium, it needs a method that allocate the limited bandwidth of fieldbus network to the sporadic real-time, periodic real-time and non real-time traffic. This paper introduces an implementation method of bandwidth allocation scheme introduced in [51 on PROFIBUS. Using the modified PROFIBUS FDL(Fieldbus Data Link layer), the bandwidth allocation scheme introduced in [51 is verified by the experiments.
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In this paper, we deal with a quadratic stabilization by
$H^{\infty}$ output feedback controllers with adjustable parameters. The designed controller contains a contractive time-varying gain which can be used to adjust the responses of the resulting closed-loop system. The free parameter expressed as time-varying gain is chosen so that a Lyapunov function of the closed-loop system descends as fast as possible. A numerical example is given to show the validity of proposed method.. -
This paper proposes a new approach of balanced model reduction using matrix pencil. The algorithm presented in this paper is to convert full-rank high-order system into rank-deficient system using perturbation made by matrix pencil method. Then the system can be truncated to a low-order system that we want via balanced realization. We discuss the comparison with other methods and the various observations by simulations.
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In this note, we investigate a noniterative design method of an observer-based robust H
$\_$ 2/ controller in the presence of structured real parameter uncertainty by applying Riccati approach based on the guaranteed cost function. Motivated by the numerical difficulty of the problem, we try to develop a simple design method named as block-diagonal approach, which can be solved by the LMIs method. By assuming the block-diagonal structure of Riccati solution, the original problem can be derived into two sequentially decoupled optimization problems as LQG control problem. The proposed method seems to be numerically efficient in obtaining a feasible compensator. -
In this paper, we present a robust
$H^{\infty}$ controller design method for parameter uncertain time-varying systems with disturbance and that have time-varying delays in both state and control. It is found that the problem shares the same formulation with the$H^{\infty}$ control problem for systems without uncertainty. Through a certain differential Riccati inequality approach, a class of stabilizing continuous controller is proposed. For parameter uncertainties, disturbance and time varying delays, proposed controllers the plant and guarantee an$H^{\infty}$ norm bound constraint on disturbance attenuation for all admissible uncertainties. Finally a numerical example is given to demonstrate the validity of the results.ts. -
We consider the control design for nonlinear uncertain systems. The uncertainty is mismatched and possibly fast time-varying. Within the suitable range of the uncertainty the control is valid. No statistical information on uncertainty is imposed. Only the possible bound of the uncertain parameter is known and the control design is based on Lyapunov approach.
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This paper presents models of fuzzy inference systems that can be built from a set of input-output training data pairs through hybrid structure-parameter learning. Fuzzy inference systems has the difficulty of parameter learning. Here we develop a coding format to determine a fuzzy neural network(FNN) model by chromosome in a genetic algorithm(GA) and present systematic approach to identify the parameters and structure of FNN. The proposed FNN can automatically identify the fuzzy rules and tune the membership functions by modifying the connection weights of the networks using the GA and the back-propagation learning algorithm. In order to show effectiveness of it we simulate and compare with conventional methods.
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In this paper, we propose a method of cooperative control based on immune system in distributed autonomous robotic system(DARS). Immune system is living body's self-protection and self-maintenance system. Thus these features can be applied to decision making of optimal swarm behavior in dynamically changing environment. For the purpose of applying immune system to DARS, a robot is regarded as a B lymphocyte(B cell), each environmental condition as an antigen, and a behavior strategy as an antibody respectively. The executing process of proposed method is as follows. When the environmental condition changes, a robot selects an appropriate behavior strategy. And its behavior strategy is simulated and suppressed by other robot using communication. Finally much simulated strategy is adopted as a swarm behavior strategy. This control scheme is based on clonal selection and idiotopic network hypothesis. And it is used for decision making of optimal swarm strategy.
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In the paper a problem of search for a moving robot by another moving robot is considered. The problem is formalized as minmax and maxmin task also as a game.
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This paper presents a new approach to the design of intelligent control system for track vehicle system using fuzzy logic based on neural network. The proposed control scheme uses a Gaussian function as a unit function in the neural network-fuzzy, and back propagation algorithm to train the fuzzy-neural network controller in the framework of the specialized learning architecture. It is proposed a learning controller consisting of two neural network-fuzzy based on independent reasoning and a connection net with fixed weights to simply the neural networks-fuzzy. The performance of the proposed controller is illustrated by simulation for trajectory tracking of track vehicle speed.
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In this paper, Tuning method of the parameter P.I.D of the 2DOG-PID controller for having a required response to the disturbance and the setpoint is studied by the neural network. This algorithms is simulated in the level control of the steam generator and the flow control system, and resulting represents than the conventional PID controller.
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In this paper, a robust controller is proposed to achieve an accurate tracking for an uncertain nonlinear plant with actuator dynamics. The extent of parameter uncertainty can be quantified by using linear parameterization technique. A switching controller is proposed to guarantee the global asymptotic stability of the plant. In order to eliminate the chattering caused by the switching controller, a smoothing controller is designed using the boundary layer technique around the sliding surface and guarantees the uniform ultimate boundedness of the tracking error.
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In this paper, we propose a fuzzy-supervised nonlinear H
$_{\infty}$ controller which guarantees the robustness and has exact tracking performance for robot manipulator with system parameter uncertainty and exogenous disturbance, The proposed controller which is based on robotic H$_{\infty}$ controller has fuzzy supervisor which decides the optimal control input weighting value through fuzzy making-decision process. Owing to the fuzzy supervisor, The proposed controller can take the optimal control input. Then, we will apply the proposed controller to rigid robot manipulator to verify the performance of our controller.r. -
In the study, we consider chua's circuit which is a paradigmatic chaotic system belonging to Lur'e form. It is shown that the dynamic behavior of such a system can be influenced in such a way as to obtain out of chaotic behavior a desired periodic orbit corresponding to an unstable periodic trajectory which exists in the system. This kind of control can be achieved via injection of a single continuous time signal representing the output of the system associated with an unstable periodic orbit embedded in the chaotic attractor We investigate the case when this signal is sampled, i.e. we supply to the system the control signal at discrete time moments only.
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An open loop vibrational control of underactuated mechanical systems with amplitude and frequency modulations is investigated. The underactuated systems considered in the paper are assumed to have free joints with no brake. The active joints are positioned first by a linearizing control, and then periodic oscillatory inputs are applied to them to move the remaining free joints to their desired states. A systematic way of obtaining averaged systems for the underactuated systems with oscillatory vibrations is developed. A complete solution to the open loop control strategy in terms of determining amplitudes and frequencies for general system is still under investigation. However, a specific control design for 2R manipulator which is obtained the averaging system is demonstrated.
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In this paper, we present new results concerning the relationship between the input-output and Lyapunov stability of nonlinear system possessing a periodic orbit. Definition of small-signal finite-gain L
$\sub$ p/ stability around periodic orbit is introduced. We show L$\sub$ p/ stability of exponentially stable periodic orbit using quadratic Lyapunov functions for the periodic orbit. The L$\sub$ 2/ gain analysis is presented with Hamiltonian-Jacobi inequality along with an example. -
This paper describes robust stabilization of nonlinear single-input uncertain systems without matching conditions. We consider nonlinear systems with a vector of unknown constant parameters perturbed about a known value. The approach utilizes the generalized controller canonical form to lump the unmatched uncertainties recursively into the matched ones. This can be achieved via nonlinear coordinate transformations which depend not only on the states of the nonlinear system but also on the control input. Then the dynamic robust control law is derived and the stability result is also presented.
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In order to shorten head-way time on existing railway lines without any change of signal block length between stations, it is a realistic optional way to change the control method of train signal, i.e. to modernize the cab signal using transponder. A new signalling system of operation pattern control technique is suggested as new model to increase the railway traffic efficiency. Through the computer simulation of this model, the train head-way time by the fixed signalling system and the new pattern control system is analyzed.
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In this paper, the mathematical model of the hydraulic control valve is formulated, that is, this dynamic modeling which includes the motion equations and continuity equations can analyze the dynamic characteristics of the hydraulic control valve. The control valve for the transmission has the Over Speed Protection to protect a hydraulic travel motor. Therefore, this simulation shows the over speed protection and researches the main design parameters. The results of the computer simulation were assured through the experiment. From the comparison between both results, it is shown that this simulation program is useful and effective.
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This study was carried out to obtain an analytical expression for the specifications of the Stewart Platform that minimize the maximum force acting on the hydraulic cylinder. The position and orientation of the platform were calculated by means of the inverse kinematic analysis. The maximum force to be exerted on a cylinder was calculated using the Newton's second law for the case when the platform is moved along a horizontal axis with 0.6 g, the maximum translational acceleration possible. This paper suggests a mathematical model to minimize the maximum actuating force using radius and angle ratios as design variables. Finally, a fuzzy set for the minimum actuating force is proposed for this dynamic optimal design problem.
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In a training simulator for power plant, operator's action in the MCR(Main Control Room) are given to plant process and computer system model as an inputs, and the same response as in real power plant is provided in real time. Inter-process communication and synchronization are especially important among various inputs. In the plant simulator, to simulate the digital control system such as FOXBORO SPEC-200 Micro control system, modification and adaptation of control card(CCC) and its continuous display station(CDS) is necessary. This paper describes the modeling and simulation of FOXBORO SPEC-200 Micro control system applied to Younggwang nuclear power plant unit #3 & 4, and its integration process to the full-scope replica type training simulator. In a simulator, display station like CDS of FOXBORO SPEC-200 Micro control system is classified as ITI(Intelligent Type Instrument), which has a micro processor inside to process information and the corresponding alphanumeric display, and the stimulation of ITI limits the important functions in a training simulator such as backtrack, replay, freeze and IC reset. Therefore, to achieve the better performance of the simulator, modification of CDS and special firmware is developed to simulate the FOXBORO SPEC-200 Micro control system. Each control function inside control card is modeled and simulated in generic approach to accept the plant data and control parameter conveniently, and debugging algorithms are applied for massive coding developed in short period.
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This paper presents the new MR rotary brake with a permanent magnet, based on the shear operating mode. Due to the permanent magnet, the MR rotary brake can give the nominal resistance to the external disturbance and give the fail safe capacity to the system even when the power supply is accidentally cut off. As we apply the positive or negative current to the electric magnet coil, the resistance torque of the MR rotary brake can be reduced to the value less than the nominal resistance or increased up to the magnetic saturation point.
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In the past few years, many researchers are interesting of control of mobile robot with nonholonomic constraints. And tracking problems is important as well as regulation in nonholonomic system control. Some researchers have investigated the stable tracking control law for mobile robot. But, few results showed the globally asymptotically stable control method simply. So, we address the design of globally asymptotically stable tracking control law for mobile robot with nonholonomic velocity constraints using simple method. The stabilizability of the controller is derived by Lyapunov direct method. And we analyze the system responses according to the variation of control parameters in line tracking problem. It is derived that the responses represent no overshoot property in line tracking. Examples are two-wheeled mobile robot and car-like mobile robot and the simulation results represent the effectiveness of our method.
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Passive, semi-active and active dampers have been used to dissipate energy in mechanical systems. Semi-active dampers have higher performance than passive dampers and require lower power to operate than active dampers. Its damping characteristics can be changed appropriately for varying conditions. In this paper, we developed a semi-active damper based on Magnetorheological(MR) fluid. MR fluid has a variable damping characteristics proportional for the magnetic field intensity. It has several advantages such as high strength, low viscosity, robustness in impurities and wide temperature range of operational stability. We designed a constrained rotary MR damper base on valve mode which can dissipate more energy per unit volume. The system with Bingham characteristics is obtained and proved by the experiment.
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This paper proposes the effective compensation method of the rotor time constant of induction motor. An indirect vector control method is highly dependent on the motor parameters. To solve the problem of performance degradation due to parameter variation in an indirect vector control of induction motor, we compensate the rotor time constant by current error feedback. The proposed method is a simple on-line rotor time constant compensation method using the information from terminal voltages and currents. As the current error, difference between current command and estimated current, approaches to zero, the value of rotor time constant in an indirect vector controller follows the real value of induction motor. This scheme is valid transient region as well as steady state region regardless of low or high speed. This method is verified by computer simulation. For this, we constructed the simulation model of induction motor, indirect vector controller and current regulated PWM (CRPWM) voltage source inverter (VSI) using SIMULINK in MATLAB.
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In this paper, a novel disturbance observer is proposed in order to regulate the disturbance in motor systems. The proposed observer does not require the implementation of ideal derivative of the state since the inverse of the nominal model is not used in the design of the observer. The transfer gain from a disturbance to the output of the disturbance observer is one. So, there is no time-delay in the response due to the dynamics of the observer.
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DC servo motors are widely used in many industrial fields as actuator of robot and driving power motors of electrical vehicle. Usually in the speed control systems, of motors, speed sensors are required and this fact results in the increased price and operating cost and the limited application of the motors. In this paper, a new speed control method for DC servo motor is proposed. In the scheme, the rotational speed is estimated by the measurement values of the armature voltage and current, instead of measurement by sensor. Optimal control theory is applied to design of the controller in construction of real system. This paper also report on the results of experiments to prove the validity of the proposed method.
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In this paper, a hierarchical fuzzy controller for stabilization of the inverted pendulum system is proposed. The facility of this hierarchical fuzzy controller which has a swing-up control mode and a stabilization one, moves a pendulum in an initial natural stable equilibrium point and a cart in arbitrary position to an unstable equilibrium point and a center of rail. Specially, the virtual equilibrium point (.PHI.
$_{VEq}$ ) which describes functionally considers the interactive dynamics between a position of cart and a angle of inverted pendulum is introduced. And comparing with the convention optimal controller, the proposed hierarchical fuzzy inference made substantially the inverted pendulum system robust and stable.e. -
This paper applies fuzzy self-tuning PID controller in DS/CDMA cellular system. Power control is essential in DS/CDMA to compensate for the differing received powers due to both the slowly varying long-term and fast varying short-term fading processes and co-channel interference. The controller proposed is adaptable for the variations of the system dynamics and especially for the variable time delay which exists in mobile radio systems. Accordingly the results is the smaller power control error, that is, the smaller average transmitting power of mobile compared with the conventional control schemes. Because interferences to the other mobiles are reduced, the capacity of CDMA can be increased.
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A dynamic back-propagation neural network is addressed for adaptive neural control system to approximate non-linear control system rather than static networks. It has the capability to represent the approximation of nonlinear system without mathematical analysis and to carry out the on-line learning algorithm for real time application. The simulated results show fast tracking capability and adaptive response by using dynamic back-propagation neurons.
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Due to the unpredictability and irregularity, the behaviors of chaotic systems are considered as undesirable phenomena to be avoided or controlled. Thus in this paper, to control systems showing chaotic behaviors, a direct adaptive control method using a radial basis function network (RBFN) as an excellent alternative of multi-layered feed-forward networks is presented. Compared with an indirect scheme, a direct one does not need the estimation of the controlled process and gives fast control effects. Through simulations on the two representative continuous-time chaotic systems, Duffing and Lorenz systems, validity of the proposed control scheme is shown.
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Usually, the Evolutionary Algorithms(EAs) are considered more efficient for optimal, system design because EAs can provide higher opportunity for obtaining the global optimal solution. This paper presents a mechanism of co-evolution consists of the two genetic algorithms(GAs). This mechanism includes host populations and parasite populations. These two populations are closely related to each other, and the parasite populations plays an important role of searching for useful schema in host populations. Host population represented by feedforward neural network and the result of co-evolution we will find the optimal structure of the neural network. We used the genetic algorithm that search the structure of the feedforward neural network, and evolution strategies which train the weight of neuron, and optimize the net structure. The validity and effectiveness of the proposed method is exemplified on the stabilization and position control of the inverted-pendulum system.
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In this paper, robot navigation experiments with a new navigation algorithm are carried out in real environments. The authors already proposed a reactive navigation algorithm for mobile robots using optimal via-point selection method. At each sampling time, a number of via-point candidates is constructed with various candidates of heading angles and velocities. The robot detects surrounding obstacles, and the proposed algorithm utilizes fuzzy multi-attribute decision making in selecting the optimal via-point the robot would proceed at next step. Fuzzy decision making allows the robot to choose the most qualified via-point even when the two navigation goals-obstacle avoidance and target point reaching-conflict each other. The experimental result shows the successful navigation can be achieved with the proposed navigation algorithm for real environments.
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We propose the hybrid control for the path control of wheeled mobile robot system. To develop the hybrid control of mobile robot, the continuous dynamics of mobile robot are modeled by the switched systems. The abstract model and digital automata for the path control are developed. This hybrid control system has the 3-layered hierachical structure : digital automata as the higher process, mobile robot system as the lower process, and the interface as the interaction process between the continuous dynamics and the discrete dynamics. The control of following the desired-paths with edges are investigated as the applications by the computer simulation.
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The design of underwater inspection robot system is presented. This robot system is designed for wall inspection in the nuclear plant facility. This paper describes the major components of the robot and its structures. This robot system is consisted of three parts : mechanical electrical and sensing pail. The main problem of designing mechanical part is to select the mechanism of driving. In this system the propeller driving mechanism is selected which can be move the robot continuously. For reducing the size of robot, we designed the CPU and motor controller board. The sensor system is consisted of two parts. One is environment monitoring part and the other is robot localization system.
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A dead reckoning navigation system is developed for autonomous mobile robot localization. The navigation system was implemented by novel sensor fusion using a Kalman filter. A differential encoder and the gyroscope error models are developed for the filter. An indirect Kalman filter scheme is adopted to reduce the computational burden and to enhance the navigation system reliability. The filter mutually compensates the encoder errors and the gyroscope errors. The experimental results show that the proposed mobile . robot navigation algorithm provides the reliable position and heading angle of the mobile robot without any help of the external positioning systems.
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The control modes used in teleoperation are position control mode, and rate control mode. This paper presents the problems of the conventional control modes, through simulation, proposes an intelligent mixed control mode that converts the operation mode between the position mode and the rate mode intelligently by judging the operator's intention using the real-time measurement data. The effectiveness of the proposed intelligent mixed control mode is demonstrated and compared to other typical control modes through simulation and actual experiment.
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In this paper the sway-control problem of a container crane is investigated in the perspective of controlling an underactuated mechanical system. For fast loading/unloading of containers from the ship, quick suppression of the remaining swing motion of the container at the end of each trolley stroke is crucial. Known nonlinearities are fully incorporated by feedback linearization. Robustness is enhanced by variable structure control. Compared with the linear LQ control, much better performance can be obtained.
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This paper proposes a control strategy of position and force control in the same direction based on hybrid position/force control. In order to control position and force in the same direction, a weighting matrix is introduced instead of a selection matrix suggested by Raibert and Craig. The major part of the controller output comes from the position controller when a position control error is large, from the force controller when a position control error is large. The proposed algorithm is implemented by the simulation and experiment focusing on the peg-in-hole task where friction exist significantly and is not constant. It also adopts and event control scheme for more efficient performance.
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In this paper, the double inverted pendulum having a single actuator is built and the controller for the system is proposed. The lower link is hinged on the plate to free for rotation in the x-z plane. The upper link is connected to the lower link through a DC motor. The double inverted pendulum built can be kept upright posture by controlling the position of the upper link even though the proposed inverted pendulum has no actuator in lower hinge. The algorithm to control the inverted pendulum is consisted of a state feedback controller within a linearizable range and a fuzzy logic controller coupled with a feedback linearization control for the rest of the range. Concept of the virtual work is employed to drive the linearlized model for the state feedback controller. The feedback linearization controller drives a DC motor with the modified reference joint angle from the fuzzy controller which adjusts a upright posture of a proposed pendulum system. Finally, the experiments are conducted to show the validity of the proposed controller.
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A contactless eddy current type braking system is developed to take advantages of the recent brake system which uses hydraulic force can show high efficiency in a certain velocity region, but not in a high velocity region, and has initial response delay time and pressure build-up time which make stopping distance longer. These are the limits of mechanical brake system of a contact type, which makes a concept brake system required. So, in this paper, the contactless brake system .of a inductive current type is chosen instead of hydraulic brake system. This brake system can be used almost forever for being no wear and contributed to lightening weight of a vehicle. Besides, the contactless brake system can be used as that of electric or solar car with anti-lock brake system. The analysis of induced electromotive force and braking torque obtained with theoretical approximate model, the design of a braking system and a nonlinear controller, and the results of simulation of the ABS, experiment are included.
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A bond graph modeling approach which is equivalent to a finite element method is formulated in the case of the piezoelectric thickness vibrator. This formulation suggests a new definition of the generalized displacements for a continuous system as well as the piezoelectric thickness vibrator. The newly defined coordinates are illustrated to be easily interpreted physically and easily used in analysis of the system performance. Compared to the Mason equivalent circuit model, the bond graph model offers the primary advantage of physical realizability. Compared to circuit models based on standard discrete electrical elements, the main advantage of the bond graph model is a greater physical accuracy because of the use of multiport energic elements. While results are presented here for the thickness vibrator, the modeling method presented is general in scope and can be applied to arbitrary physical systems.
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When a manipulator makes contact with an object having position uncertainty, performance measures vary considerably with the control law. To achieve the optimal solution for this problem, an unique objective function that weights time and impact force is suggested and is solved with the help of variational calculus. The resulting optimal velocity profile is then modified to define a sliding mode for the impact and force control. The sliding mode control technique is used to achieve the desired performance. Sets of experiments are performed, which show superior performance compared to any existing controller.
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When a magnetostrictive material is exposed to a magnetic field, its geometry changes due to a magnetostrictive effect. The magnetostriction is analogous to the piezoeletricity. The displacement of the magnetostrictive material is proportional to the applied current while that of the piezoelectric material is proportional to the voltage. A magnetostrictive material generates large displacement and higher compressive force compared with a piezoeletric material. These advantages provide a good performance of a vibration isolation of a platform. In this work, it is applied to a driving actuator for vibration isolation of a platform. The properties of a magnetostrictive material are investigated in terms of hysteresis and displacement vs. applied current for a various preload. Modeling of the displacement of the vibration isolating actuator is performed as it behaves as a flow source. A sliding mode controller is designed to demonstrate the ability of the magnetostrictive actuator to reduce the vibration at the platform. The effectiveness of the proposed scheme is demonstrated through experimental works. The experimental results of the vibration of the platform axe presented in terms of time response and frequency response.
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In this paper, Nonlinear VSS control based on bang-bang control concept is derived under the assumption that the control input is bounded. We try to derive control algorithm which has almost same performance as the time optimal control. We focus this control scheme on the real implementation of DC motor position controller of flexible link, i.e. we obtain the switching curves from the real data of DC motor system operating under the full maximum and minimum applied voltages. State space is separated into several regions and we set different switching surfaces in each region to reduce chattering problem. The efficiency of the proposed controller is compared with PID controller and it is shown that the controller converges fast than PID controller without chattering. The hybrid controller scheme is also proposed not only to control the position of hub but also to reduce the vibration of end tip of flexible link.
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In this paper, the dynamics of actuators for generating the input of plants is considered in a design of the variable structure systems. While the input for plants is usually implemented by means of a certain actuator, the actuator dynamics is not incorporated in most of the VSS researches until now. The control algorithm of a VSS incorporating actuator dynamics is presented, and the simulation is given to show the usefulness of the algorithms.
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In this paper, a continuous sliding mode controller for robot manipualator is proposed. The proposed scheme guarantees that the tracking error converges to zero maintaining the smoothness of the actual control signal. In order to estimate the acceleration data, a sliding mode observer is used, and the stability of the closed-loop system is shown.
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Robust stability conditions for discrete-time variable structure control is proposed. Conventionally the discrete-time variable structure control method with a variable structure uncertainty compensator approach requires a bounded changing rate of the uncertainties to ensure robust stability. However, when uncertainties vary as a function of state variables, which occur with parametric uncertainties, it is not reasonable to assume a bounded variation on the uncertainties. In this paper, uncertainties are assumed to consist of exogenous disturbances and parametric uncertainties. An uncertainty compensator is used to deal with the former, and a robust stability condition is derived using Small Gain Theorem for the latter.
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This paper uses genetic algorithm (GA) for optimal control. GA can find optimal control profile, but the profile may be oscillating feature. To make profile smooth, fuzzy genetic algorithm (FGA) is proposed. GA with fuzzy logic techniques for optimal control can make optimal control profile smooth. We describe the Fuzzy Genetic Algorithm that uses a fuzzy knowledge based system to control GA search. Result from the simulation example shows that GA can find optimal control profile and FGA makes a performance improvement over a simple GA.
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Two options arising during implementation of an advanced model-based control system on a process with low-level loops are discussed. Strengths and deficiencies of the options are examined and methods to overcome the deficiencies are proposed. Simulation results of a CSTR and distillation column are presented to demonstrate the performance improvements.
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The on-line calculation method is developed to obtain the temperature trajectory that brings the reactants to the desired state in batch styrene polymerization reactor. The temperature trajectory is obtained by applying the moments of the polymer concentration to the 2-step calculation method. The computer simulation is also carried out to verify the superiority of the on-line method to the off-line one. When a temperature disturbance of constant size is introduced, the off-line results shows considerable deviation from the target degree of polymerization. The on-line strategy set up a new trajectory to reach the desired state by using the current state of the reactor. Therefore, the on-line strategy deals with the changes of the system more adequately than the off-line strategy.
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The dynamic characteristics of a continuous MMA/MA free-radical solution copolymerization reactor were studied. A mathematical model was developed and kinetic parameters which had been estimated in the previous work were used. With this model, bifurcation diagrams were constructed with various parameters as the bifurcation parameter to predict the region of stable operating conditions and to enhance the controller performance. It was shown that the steady-state multiplicity existed over wide ranges of residence time and jacket inlet temperature. Periodic solution branches were found to emanated from Hopf bifurcation points. Under certain conditions isola was also observed, which would result in poor performance of feedback controllers.
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Two different issues, design of reduced-order robust model predictive control and input signal design for identification of a MIMO system, are addressed and design techniques based on singular value decomposition(SVD) of the pulse response circulant matrix(PRCM) are proposed. For this, we investigate the properties of the PRCM, which is a periodic approximation of a linear discrete-time system, and show its SVD represents the directional as well as the frequency decomposition of the system. Usefulness of the PRCM and effectiveness of the proposed design techniques are demonstrated through numerical examples.
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In the water purification plant, chemicals are injected for quick purification of raw water. It is clear that the amount of chemicals intrinsically depends on the water quality such as turbidity, temperature, pH and alkalinity etc. However, the process of chemical reaction to improve water quality by the chemicals is not yet fully clarified nor quantified. The feedback signal in the process of coagulant dosage, which should be measured (through the sensor of the plant) to compute the appropriate amount of chemicals, is also not available. Most traditional methods focus on judging the conditions of purifying reaction and determine the amounts of chemicals through manual operation of field experts or jar-test results. This paper presents the method of deriving the optimum dosing rate of coagulant, PAC(Polymerized Aluminium Chloride) for coagulant dosing process in water purification system. A neural network model is developed for coagulant dosing and purifying process. The optimum coagulant dosing rate can be derived the neural network model. Conventionally, four input variables (turbidity, temperature, pH, alkalinity of raw water) are known to be related to the process, while considering the relationships to the reaction of coagulation and flocculation. Also, the turbidity in flocculator is regarded as a new input variable. And the genetic algorithm is utilized to identify the neural network structure. The ability of the proposed scheme validated through the field test is proved to be of considerable practical value.
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In this paper, Active Noise Control(ANC) algorithm is proposed based on the estimated frequency estimator of the reference signal. The conventional feedforward ANC algorithms should measure the reference and use it to calculate the gradient of the squared error and filter coefficients. For ANC systems applied to aircrafts and passenger ships, engines from which reference signal is usually measured is so far from seats where main part of controller is placed that the scheme might be difficult to implement or very costly. Feedback ANC algorithm which doesn't need to measure the reference uses the error signal to update the filter and is sensitive to unexpected transient noise like a sneeze, clapping of hands and so on The proposed algorithm estimates frequencies of the desired signal in real time using adaptive notch filter. New frequency estimation algorithm is proposed with the improved convergence rate, threshold SNR and computational simplicity. Reference is not measured but created with the estimated frequencies. It has strong similarity to the conventional feedback control because reference is made from error signal. Enhanced error signal is used to update the controller for better performance under the measurement noise and impact noise. The proposed ANC algorithm is compared with the conventional feedback control.
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In this paper the modeling and control of a twin roll strip caster is investigated. Mathematical models for the strip casting process are obtained by analyzing five critical areas such that the molten steel level in the pool, solidification process, roll separating force and torque, roll dynamics including hydraulic actuators, and roll drive system. A two-level control strategy is proposed. At lower level, three local subsystems are independently feedback-controlled by suitable local controllers which perform well to the behaviors of each subsystem. They are a variable structure control of the molten steel level in the pool, an adaptive predictive control of the roll gap which is directly related to the strip thickness, and an
$H^{\infty}$ control of the roll drive system. At higher level, all reference signals to the lower level subsystems are generated by an optimal controller in the perspective of regulating the strip thickness and roll separating force. Simulations are provided.. -
This paper deals with the attitude control problem of nonlinear MIMO propeller setup. Multivariable GPC[Generalized Predictive Control] is adopted as the main controller, and it is implemented by TMS320C31 in the current paper. The main object of control is to move the propellers to wanted positions. System identification is performed to configure the system. Performance of the multivariable predictive controller implemented is shown via some experiments, which shows the controller meets the adequate control purpose.
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In this paper, we present a nonlinear dynamic controller for position tracking of brushless dc motors. In constructing the controller, a backstepping-type approach is used under the condition of full state information, while an adaptive controller is adopted for parameter uncertainty throughout the entire electromechanical system. The nonlinear dynamic controller using the adaptive learning technique approach is shown to drive the state variables of system to the desired ones asymptotically and whose effectiveness is also sown via computer simulation.
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In this paper we propose direct and indirect adaptive controllers for a nonlinear multivariable steam generating unit(200MW). In the direct adaptive scheme the estimation of the controller parameter are achieved from tracking error, while in the indirect approach the unknown parameter of the boiler system is estimated by the Hopfield network-based identifier. The performance of two proposed adaptive controllers is shown through simulations.
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This paper presents a dynamics failure detection algorithm developed for the two-motor-driven electric vehicle system. The algorithm is based on the application of the fault detection filter. The fault detection includes the identification of sudden pressure drops of the two rear tires in driving axis and dynamics faults of the two inverter-motor-paired actuators An E.V. dynamics simulator is developed, which includes the modeling of the E.V. dynamics as well as the driving dynamics. The simulator, which allows the generation of various fault situations, is utilized in the verification of the developed fault detection algorithm. The results of the simulations are also presented.
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In this paper, we propose a new longitudinal controller of automated vehicles. The controller is designed based on a sliding control method, which is known to be robust to disturbances and modelling errors. Contrary to currently available sliding controller, a switching controller gain method is suggested. It is shown throughout simulations that the proposed controller reduces the amount of overshoot, which may derive smoother velocity tracking in a platoon.
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Vehicle steering system determines the direction of a vehicle. A manual steering system consists of mechanical connections between the steering wheel and tires. Recent power steering system adds an actuator to help a driver to steer easily at low speed. However, at front collision, the driver can be injured by steering shaft and the power steering pump decreases the engine power. To solve these problems, electronic power steering system which connects the steering wheel and tires with electronic connection is proposed, that has advantages such as decrease of engine load and increase of driver safety reactive. Since the ratio between driver's steering torque and steering torque of tires can be controlled freely, the torque which is delivered from the road to the driver through tires and steering wheel can be reshaped to make the driver feel comfortable. In this paper, the ratio of delivering steering torque and the magnitude of force to be delivered from road to driver has been controlled using fuzzy controller, and it's effectiveness has been shown through simulation results.
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This paper presents a new anti-lock brake system(ABS) using electro-rheological(ER) valve actuators for the wheel slip control. The hydraulic dynamic model of the automotive brake system is formulated by incorporating electric field-dependent Bingham properties of ER fluid obtained experimentally. The brake system designed by this hydraulic model is able to control wheel slip by controlling the intensity of electric field which tunes the braking torque. The control fields of the ER valve to command desired wheel slip are determined by a sliding mode controller. A comparison between the proposed brake system and the conventional brake system is made by providing with computer simulations of vehicle motions under ABS performance requirement condition.
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There has been requested to automate the welding process in shipyard due to its dependence on skilled operators and the inferior working environments. According to these demands, multiple robot welding system for sub-assembly welding line has been developed, realized and installed at Keoje Shipyard. In order to realize automatic welding system, robots have to be equipped with the sensing system to recognize the position of the welding panels. In this research, a camera vision system is developed to detect the position of base panels for subassembly line in shipbuilding. Two camera vision systems are used in two different stages (Mounting and Welding) to automate the recognition and positioning of welding lines. For automatic recognition of panel position, various image processing algorithms are proposed in this paper.
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In this paper we suggest a development of surface defect inspection algorithms for cold mill strip using tree structure. The defects which exist in a surface of cold mill strip have a scattering or singular distribution. This paper consists of preprocessing, feature extraction and defect classification. By preprocessing, the binarized defect image is achieved. In this procedure, Top-hit transform, adaptive thresholding, thinning and noise rejection are used. Especially, Top-hit transform using local min/max operation diminishes the effect of bad lighting. In feature extraction, geometric, moment, co-occurrence matrix, histogram-ratio features are calculated. The histogram-ratio feature is taken from the gray-level image. For the defect classification, we suggest a tree structure of which nodes are multilayer neural network clasifiers. The proposed algorithm reduced error rate comparing to one stage structure.
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Recently, the development of computer achieves a system which is similar to the mechanics of human visual system. The 3-dimensional measurement using monocular vision system must be achieved a camera calibration. So far, the camera calibration technique required reference target in a scene. But, these methods are inefficient because they have many calculation procedures and difficulties in analysis. Therefore, this paper proposes a native method that without reference target in a scene. We use the grid type frame with different line widths. This method uses vanishing point concept that possess a rotation parameter of the camera and perspective ration that perspect each line widths into a image. We confirmed accuracy of calibration parameter estimation through experiment on the algorithm with a grid paper with different line widths.
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This research deals with a problem of reconstructing 3D surface structures from their 2D projections, which is an important research topic in computer vision. In order to provide robust reconstruction algorithm, that is reliable even in the presence of uncertainty in the range images, we first present a detailed model and analysis of several error sources and their effects on measuring three-dimensional surface properties using the space encoded range imaging technique. Our approach has two key elements. The first is the error modeling for the space encoding range sensor and its propagation to the 3D surface reconstruction problem. The second key element in our approach is the algorithm for removing outliers in the range image. Such analyses, to our knowledge, have never attempted before. Experimental results show that our approach is significantly reliable.
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This paper introduces a new vision technique for extracting roof edges of polyhedra having specularly reflecting surfaces. There have been many previous works on object recognition using edge information. But they can not be applied to specular objects since it is hard to acquire reliable camera images of specular objects. If there is a method which can extract the edges of specular objects, it is possible to apply edge-based recognition algorithms to specular objects. To acquire the reliable edge images of specular objects, scanned double pass retroreflection method is proposed, whose main physical characteristic is curvature-sensitive. This utility of the physical characteristic is motivated by the idea that roof edges can be characterized as local surfaces of high curvature. In this paper, the optical characteristics of double pass retroreflection are discussed and a series of simulation studies are performed to verify and analyze the sensor characteristics. The results from a series of simulations show the effectiveness of the proposed method.
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Electrostatic suspension is a method to levitate an object by using electrostatic forces. Its main advantage is to levitate objects without any mechanical contact which fulfills the requirement of an object handling in ultra clean environment. In this paper, the electrostatic suspension system for film-like thin plate such as aluminum sheet, is designed and controlled. In contrast with the conventional electrostatic suspension system which requires the costly and bulky high-voltage amplifiers, it is suggested to use the switching voltage control method in consideration of real industrial application for the handling of such flexible bodies. Some experimental results show that the developed electrostatic suspension system shows good performances to levitate flexible film-like thin plate.
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Grinding process takes a long time that grinding machine is setted properly. It is difficult for user to judge correctly the abnormal states generated in grinding process. Air grinding has to be reduced for the improvement of productivity. In addition, it is important to monitor the dressing and the grinding process so that the grinding working maintains optimal grinding conditions. In this study, the monitoring system using the acoustic emission is developed to monitor these processes continuously. This system was able to reduce the preparation as well as the machine setting time in grinding operation.
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A H
$_{\infty}$ control techniques with roll eccentricity filter is proposed to alleviate the effect of entry thickness variation and roll eccentricity occurred in rolling stand itself of tandem cold mills. A robust controller to the disturbances is designed using H$_{\infty}$ control techniques, which can reflect the input direction of disturbances and knowledge of disturbance spectrum in the frequency domain. And, non-standard H$_{\infty}$ control problem caused by selection of weight function having poles on j.omega. axis is discussed. The evaluation for the resultant controller composed by H$_{\infty}$ synthesis is done through computer simulations. The effectiveness of the proposed method is compared to those of the conventional LQ synthesis method and a feedforward controller against roll eccentricity, which was already studied.ied. -
In the modem manufacturing system, to achieve the unmanned automation, the stability of accuracy is required through a long working period. The thermal deformation of precision machine is predominant in this long time stability. While grinding slender and long workpiece at cylindrical grinding machine, we support workpiece using steadies to prevent the vibration of workpiece. The thermal deformation of the machine by grinding and internal heat source cause processing errors, so the steadies for compensating the thermal deformation in real time are strongly needed. In order to compensate these thermal deformation and grinding processing errors, the device to determine the precise positioning having the stroke of 10.mu.m is necessary. This paper suggests design and make the device to determine the precise positioning using thermoelectric device, to investigate the control characteristics and presents the heat actuator will be very useful in machine tool.
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The fieldbus is one of the communication networks in control and automation systems and allows the exchange of information between sensors/actuators and controlling elements. By means of the fieldbus, the various field devices can exchange their information among the nodes in the system. In this paper, we implemented the protocol of profibus, a kind of fieldbus for communication in FMS plant model. We applied this fieldbus to the FMS plant model which consists of three stations and eight slave stations.
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This paper presents a Petri net approach for the control and monitoring of discrete event system. The proposed model is fuzzy Petri nets based on the fuzzy logic with Petri nets and the hierarchy concept. Fuzzy Petri nets have been used to model the imprecise situations which can arise within automated manufacturing system, and also the hierarchy concept allow to handle the refinement of places and transition in Petri nets model. These will form the foundation of a simulator-tool with manipulation interface for application of fuzzy Petri nets.
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This paper analytically derives the variance of service time of a station in the symmetric IEEE 802.4 token bus network with single access class and finite buffer capacity. This performance measure is represented in terms of the total number of stations, the token hold time, the arrival rate of frames, the service rate, and other parameters. Using computer simulations, presented performance measure is validated.
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This paper presents the problem of fault-tolerant robust supervisory control of timed discrete event systems (DESs). First the concept of faults is quantitatively defined in timed DESs and fault tolerable event sequences are presented as a desired legal language. Given a timed DES with model uncertainty, the conditions for the existence of a supervisor which always guarantees fault tolerable event sequences embedded in the system are derived.
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Many small-sized real-time kernels do not provide memory management and device drivers, not to mention file management. In this paper, we propose a design and implementation of TCP/IP protocol stack for such small real-time kernels based on [6] where we studied issues to be considered for porting the functionalities of TCP/IP for such small real-time kernels.
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A design method of robust controller for the longitudinal autopilot of BTT missile is considered. The difficulties are a set of linearized dynamic models which corresponds to different operating points has a wide range of parameters and it has even Non-Minimum Phase(NMP) zeros. In this paper, such a family of models is expressed by an interval plant. Then a robust control design method using QFT is represented. A simulation result shows that the proposed controller satisfies the given specification well.
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We consider the robust control problem for nonminimum phase(NMP) systems with parametric uncertainty which appear often in aircraft and missile control. First, a new method that makes such an uncertain NMP system to be factored as a interval minimum phase(MP) transfer function and a time delay term in the Pade approximation form has been presented. The controller to be proposed consists of a compensator
$C_{Q}$ (s) with Smith predictor in the internal model control(IMC) structure, so that it can have good robustness and performance against the structured uncertainty and the time delay behaviour due to NMP plant the$C_{Q}$ (s) is designed on the MP model by using QFT. The stability and performance of overall system has been evaluated by the generalized Kharitonov theorem.rem. -
This paper proposes a robust H
$_{\infty}$ tracking filter to improve the unacceptable target tracking performance for systems with parameter uncertainties. Also, we use here the input estimation approach to account for the possibility of maneuver. Simulation results show that the robust H$_{\infty}$ tracking filter which is proposed here to solve the systems with all system parameter uncertainties, has a good tracking performance for a maneuvering target tracking problem.m. -
In this paper, an intervalwise receding horizon control (IRHC) is proposed which stabilizes linear continuous and discrete time-varying systems each other by means of a feedback control stemming from a receding horizon concept and a minimum quadratic cost. The results parallel those obtained for continuous [4],[9] and discrete time varying system [5],[15] each other.
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In this paper, we present an
$H^{\infty}$ controller design of RTP system satisfying robust stability and performance using weighted mixed sensitivity minimization. In industrial fields, RTP system is widely used for improving the oxidation and the annealing in semiconductor manufacturing process. The main control factors are temperature control of wafer and uniformity in the wafer. The control of temperature and uniformity has been solved by PI control method. We improve robust stability and performance of RTP system by the design of$H^{\infty}$ controller using the weighted mixed sensivity function. An example is proposed to show the validity of proposed method.d. -
This paper studies a semi-active suspension with ER damper controlled Fuzzy Net Controller designed GA(Genetic Algorithm). Apparent viscosity of ERF(Electro-Rheological Fluid) can be changed rapidly by applying electric field. Semi-active suspension for ground vehicles are expected to improve ride quality with less vibration. This paper deals with a two-degree -of-freedom suspension using the ER damper for a quarter vehicle system. In this paper, the GA is applied for generating Fuzzy Net Controllers. The GA designs the optimal structure and performance of Fuzzy Net Controller having hybrid structure. Computer simulation results show that the semi-active suspension with ER damper has good performances of ride quality.
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We present a hybrid self-tuning method of fuzzy inference systems with hyper elliptic Gaussian membership functions using genetic algorithm(GA) and back-propagation algorithm. The proposed self-tuning method has two phases : one is the coarse tuning process based on GA and the other is the fine tuning process based on back-propagation. But the parameters which is obtained by a GA are near optimal solutions. In order to solve the problem in GA applications, it uses a back-propagation algorithm, which is one of learning algorithms in neural networks, to finely tune the parameters obtained by a GA. We provide Box-Jenkins time series to evaluate the advantage and effectiveness of the proposed approach and compare with the conventional method.
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We propose a control law in discrete time domain of the bilateral feedback teleoperation system using neural network and the reference model type of adaptive control. Different from traditional teleoperation systems, the transmission time delay irregularly changes. The proposed control method controls master and slave systems through identification of master and slave models using neural networks.
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An active control for the swing of crane systems is very important for increasing the productivity. This article introduces the control for the position and the swing of a crane using the fuzzy learning method. Because the crane is a multi-variable system, learning is done to control both position and swing of the crane. Also the fuzzy control rules are separately acquired with the loading and unloading situation of the crane for more accurate control. The result of simulations shows that the crane is just controlled for a very large swing angle of 1 radian within nearly one cycle.
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As in most industrial processes, the dynamic characteristics of an electric power system are subject to changes. Amongst those effects which cause the system to be uncertain, faults on transmission lines are considered. For the stabilization of the power system, we present an indirect adaptive control method, which is capable of tracking a sudden change in the effective reactance of a transmission line. As the plant dynamics are nonlinear, an input-output feedback linearization method equipped with nonlinear damping terms is combined with an identification algorithm which estimates the effect of a fault. The stability of the resulting adaptive nonlinear system is investigated.
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In this paper, we propose a variable structure control approach for the system with matched and unmatched uncertainty. By using time-varying sliding mode, the reaching mode is removed, and the design methodology represents a realistic design approach with quadratic criterion for systems incorporating both matched and unmatched uncertainties. The criterion contains states and linear part of input for all time. The practical application of the control strategy is presented in the design of a stability augmentation system for an aircraft is presented.
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In this paper, a high precision track following control algorithm is proposed for micro electrostatic actuator considering of the application for hard disk drive. The micro electrostatic actuator proposed has nonlinear voltage-displacement characteristic in a working range of 0.8.mu.m and has uni-directional movement. Mid range reference and open-loop bias are proposed for the revision of negative position error, and inverse model for linearization.
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In this paper, we investigate the time-sampling effects on the digital implementation of singular perturbation based STT autopilot with excellent performance and propose a compensation method for the time-sampling effects. In digitization of analog STT autopilot, it is found that the stability margin of the fast dynamics is mostly affected to lead to rapid decrease. Under the this analysis, a composite digital controller with additional compensator for fast dynamics is proposed to improve the time-sampling effect and a simulation verifies the result.
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The principle objective of this paper is to explain and demonstrate the advantage of the output-feedback controller proposed by Ailon in [61 by using simulation and experimental results. Namely, the goal of this study is to design and implement a real-time controller for set-point regulation of a one-link rigid robot manipulator with unknown parameters using only position measurement. For implementation a direct drive one-link rigid robot manipulator is constructed and a TMS320C40 DSP systems board is used in implementing real-time control algorithm.
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The focus of this paper is to implement of virtual plant using module concept for the dynamic simulation of drum type boiler and to simulate the control trends of dynamic characteristics. MAtlab & Simulink is used for implement virtual plant & analyzation the dynamics & control trends. They are available for analyzing the dynamic characteristics of drum type Boiler by means of applying well measured data to virtual plant.
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A fossil power plant can be modeled by a lot of algebraic equations and differential equations. When we simulate a large, complicated fossil power plant by a computer such as workstation or PC, it takes much time until overall equations are completely calculated. Therefore, new processing systems which have high computing speed is ultimately needed to develope real-time simulators. Vital points of real-time simulators are accuracy, computing speed, and deadline observing. In this paper, we present a enhanced strategy in which we can provide powerful computing power by parallel processing of DSP processors with communication links. We designed general purpose DSP modules, and a VME interface module. Because the DSP module is designed for general purpose, we can easily expand the parallel system by just connecting new DSP modules to the system. Additionally we propose methods about downloading programs, initial data to each DSP module via VME bus, DPRAM and processing sequences about computing and updating values between DSP modules and CPU30 board when the simulator is working.
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In this paper a simulation program for the powertrain control of a gasoline engine with automatic transmission is presented, The object-oriented programming approach has been pursued, and MATLAB/ SIMULINK was adopted for its environment. The purpose of the paper is to demonstrate the programmability of a control system in the object-oriented fashion so that the transferability of the objects is guaranteed. The program developed in the paper was applied to a gasoline engine and the mathematical models used in the paper were just adopted from the literature. It is shown that the simulation results and real experimental results coincide well. Therefore, it is expected that the program or objects made in the paper are useful for the automotive engineers when they design a new engine/transmission system or modify a part of existing system.
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The PMGS(Plant Model Generating System) was developed based on modular modeling method and fluid network calculation concept. Fluid network calculation is used as a method of real-time computation of fluid network, and the module which has a topology with node and branch is defined to take advantages of modular modeling. Also, the database which have a shared memory as an instance is designed to manage simulation data in real-time. The applicability of the PMGS was examined implementing the HRSG(Heat Recovery Steam Generator) control logic on DCS.
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Integral type system is that a system is represented by a proper rational function. In this paper, novel control scheme based on model reference approach is proposed for integral type system. The proposed scheme compensates various undesirable effects of the system. In especially, the proposed scheme applied to DC servo control system, analyzed its control characteristic. Performances of the proposed system show excellent control characteristics; complete compensation of the undesirable nonlinear friction and load viscous, For proving realistic validities, LOS(Line Of Sight) stabilization system which has typically many nonlinear effects is experimented. After executing the computer simulation in "MATLAB", then the results are compared with the experiments. The results are very similar in theoretical study and the proposed control scheme is successfully verified. verified.
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This paper describes the operating software of a motion system developed for a driving simulator, consisting of a six degree of freedom Stewart platform driven hydraulically. The drive logic, consisting of an washout algorithm, inverse kinematic analysis, and a control algorithm, has been developed and applied for creating high fidelity motion cues. The basic environment of the operating software is based on LabVIEW 4.0 and DLL modules compiled by Fortran.
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In this paper, we investigate the control methodology of inverter Airconditioner, using the three dimensional vector scheme. The method of three dimensional vector aims at the determination of optimal switching patterns for PWM to reduce switching loss and to improve the performance supplied voltage. The induction motors are widely used for home Airconditioners. These motors can be classified into two types: on or off control of Airconditioner and the speed control of motor. For speed control of motors, generally PWM methods are used. The PWM method based upon the modulation of triangular wave can not afford to supply line voltage to the motor sufficiently because of the capacity of processing speed of micro processors. Therefore airconditioner can not be operated efficiently. This problem can be solved with the method of three dimensional vector since it can increase the supplied voltage and maximum operating frequency of motor to 173V and 96Hz, respectively. As the result, this method shows 10 - 15% increase of voltage and 10% increase of operating frequency over the modulation of triangular wave. According to a theoretical study, the number of switching in the method of three dimensional vector is smaller than that of the modulation of triangular wave. The power consumption can be reduced and the supplied voltage can be increased. In other words, the efficiency of Airconditioner can be improved. We show that the method of three dimensional vector can supply higher voltage than the modulation of triangular method through the experiments and verify the degree of improvement of efficiency theoretically.
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It is well known that Variable Structure Controller(VSC) is robust to parameters variation and disturbance but its performance depends on the design parameters such as switching gain and slope of sliding surface. This paper proposes a more robust VSC that is composed of local VSC's. Each local VSC considers the local system dynamics with narrow parameter variation and disturbance. First we optimize the local VSC's by use of Evolution Strategy, and next we use Artificial Neural Network to generalize the local VSC's and construct the overall VSC in order to cover the whole range of parameter variation and disturbance. Simulation on BLDC motor current control shows that the proposed VSC is superior to the conventional VSC.
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Recently the development of motor speed control systems with both good dynamic performance and simple implementation has been required. The vector control scheme considering flux harmonics for the permanent-magnet AC servo motor having low inertia, low weight, and high efficiency is proposed. To reduce the torque harmonics, current harmonics is employed. The vector control strategy is verified through digital simulation.
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In this paper the fuzzy-genetic controller for path-tracking of WMRs is proposed. Fuzzy controller is implemented to adaptive adjust the crossover rate and mutation rate, and genetic algorithm is implemented to adaptive adjust the control gain during the optimization. The computer simulation shows that the proposed fuzzy-genetic controller is effective.
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In this paper, the control of the temperature for the vehicle air conditioner is implemented with the fuzzy controller using a micro controller. The linguistic control rules of the fuzzy controller are separated into two out variables(multi input multi output ; MIMO) : one is those for the blower motor, and the other is those for air mix door. The error in fuzzy controller, the input variable is defined as difference between the reference temperature and the actual temperature in the cabin room. The fuzzy control rules are established from the human operator experience, and based engineering knowledge about the process. The method of the center of gravity is utilized for the defuzzification.
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This paper presents FPGA implementation of fuzzy controller using Product-Sum inference method. Product-Sum inference method has much better performance than other inference methods. This fuzzy controller is composed of several digital modules, e.g. fuzzifier, rule base, adder, multiplier, select center and divider, and is operated by error and error variation. We synthesized the fuzzy controller and performed wave simulation using Xilinx VHDL tool(ViewLogic, ViewSim).
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Conventional target tracking algorithms based on the linear estimation techniques perform quite efficiently when the target motion does not involve maneuvers. Target maneuvers involving short term accelerations, however, cause a bias in the measurement sequence. Accurate compensation for the bias requires processing more samples of which adds to the computational complexity. The primary motivation for employing a neural network for this task comes from the efficiency with which more features can be as inputs for bias compensation. A system architecture that efficiently integrates the fusion capabilities of a trained multilayer neural net with the tracking performance of a Kalman filter is described. The parallel processing capability of a properly trained neural network can permit fast processing of features to yield correct acceleration estimates and hence can take the burden off the primary Kalman filter which still provides the target position and velocity estimates.
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This paper deals with the kinematic and dynamic modeling of a 3 degree-of-freedom redundantly actuated mobile robot for the purpose of analysis and control. Each wheel is driven by two motors for steering and driving. Therefore, the system becomes force-redundant since the number of input variable is greater than the number of output variable. The kinematic and dynamic models in terms of three independent joint variables are derived. Also, a load distribution method to determine the input loads is introduced. Finally we demonstrate the feasibility of the proposed algorithms through simulation.
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This paper describes the design of a fuzzy-logic controller for a differential-drive mobile robots. This controller uses absolute position information to modify control parameters to compensate the orientation error. CC-Control method is compensated for the internal error by wheel encoders and the fuzzy-logic control provides compensation for external errors. The validities of the proposed scheme is evaluated using simulation.
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This paper presents a three dimensional modeling and a trajectory generation for minimized impact walking of the biped robot. Inverse dynamic analysis and forward dynamic analysis are performed considering impact force between the foot and ground for determining the actuator capacity and for simulating the proposed biped walking robot. Double support phase walking is considered for close to human's with adding the kinematic constraints on the one of the single support phase.
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In this paper, a precise trajectory tracking method for mobile robot using a vision system is presented. In solving the problem of precise trajectory tracking, a hierarchical control structure is used which is composed of the path planer, vision system, and dynamic controller. When designing the dynamic controller, non-ideal conditions such as parameter variation, frictional force, and external disturbance are considered. The proposed controller can learn bounded control input for repetitive or periodic dynamics compensation which provides robust and adaptive learning capability. Moreover, the usage of vision system makes mobile robot compensate the cumulative location error which exists when relative sensor like encoder is used to locate the position of mobile robot. The effectiveness of the proposed control scheme is shown through computer simulation.
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In this paper, we propose a dynamic localization method using a rotating sonar and a map. The proposed method is implemented by using extended Kalman filter. The state equation is based on the encoder propagation model and the encoder error model, and the measurement equation is a map-based measurement equation using a rotating sonar sensor. By utilizing sonar beam characteristics, map-based measurements are updated while AMR is moving continuously. By modeling and estimating systematic errors of a differential encoder, the position is successfully estimated even the interval of the map-based measurement. Monte-Carlo simulation shows that the proposed global position estimator has the performance of a few millimeter order in position error and of a few tenth degrees in heading error and of compensating systematic errors of the differential encoder well.
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Performance of force tracking impedance control of robot manipulators is degraded by the uncertainties in the robot and environment dynamic model. The purpose of this paper is to improve the controller robustness by applying neural network. Neural networks are designed to learn the uncertainties in robot and environment model for compensating the uncertainties. The proposed scheme is verified through the simulation of 20DOF robot manipulator.
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Recently, increasing attention has been paid to the application of learning control method to robot manipulator control. Because the learning control method does not require an exact dynamic model, it is flexible and easy to implement. In this paper, we implement a learning control scheme which consists of a unique feedforward learning controller and a linear feedback controller. The learning control method does not require acceleration terms that are sensitive to noise and has the capability of rejecting unknown disturbances and adapting itself to time-varying system parameters. The feasibility of the learning control scheme is soon by implementing the control scheme to a commercial robot manipulator and the performance of which is also compared with the conventional linear PID control method.
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In this paper, we propose a cooperative multi-robot control algorithm. Specifically, the cooperative task is that two mobile robots should transfer a long rigid object along a predefined path. To resolve the problem, we introduce the master-slave concept for two mobile robots, which have the same structure. According to the velocity of the master robot and the positions of two robots on the path, the velocity of the slave robot is determined. In case that the robots can't move further, the role of the robot is interchanged. The effectiveness of this decentralized algorithm is proved by computer simulations.
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The conventional impedance control has been known to have the following problems: it has lack of specifying force directly and unknown environment stiffness has to be known priori in order to specify the reference trajectory. In this paper, new impedance force control that can control a desired force directly under unknown stiffness is proposed. A new nonlinear impedance function is developed based on estimation of unknown stiffness from force and position measurements. The nonlinear characteristics of the proposed impedance function are analyzed based on unknown environment position. Simulation studies with robot manipulator are carried out to test analytical results.
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This paper deals with the problem of extraction of voice signal embedded in 1/f noise. We propose the extraction method using wavelet. This method is based on Wornell's modelling which can construct 1/f process in terms of uncorrelated variables and is well suited on treating 1/f process. Finally, we show further describe our method through simulation.
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Recently, the number of techniques for analyzing medical images has been increasing in computer vision, employing X-ray CT images, ultrasound images, MR images, moire topographic images, etc. Spinal deformity is a serious problem especially for teenagers and medical doctors inspect moire topographic images of their backs visually for the primary screening. If a subject is normal, the moire image is almost symmetric with respect to the middle line of the subject's back, otherwise it shows asymmetric shape. In this paper, an image analysis technique is described for discriminating suspicious cases from normal in human spinal deformity by recognizing asymmetric moire images of human backs. The principal axes which are sensitive to asymmetry of the moire image are extracted at two parts on a subject's back and their angles are evaluated with respect to the detected middle line of the back. The two angles compose a 2-D feature space and inspected cases are divided into two clusters in the space by a linear discriminant function based on the Mahalanobis distance. Given 120 cases, 60 normal and 60 abnormal, the leave-out method was applied for the recognition and 75% recognition rate was achieved.
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X-ray laminography and DT(digital tomosynthesis) that can form a cross-sectional image of 3-D objects promise to be good solutions for inspecting interior defects of industrial products. The major factors of the digital tomosynthesis that influence on the quality of x-ray cross-sectional images are also discussed. The quality of images acquired from the DT system varies according to image synthesizing methods, the number of images used in image synthesizing, and X-ray projection angles. In this paper, a new image synthesizing method named 'log-root method' is proposed to get clear and accurate cross-sectional images, which can reduce both artifact and blurring generated by materials out of focal plane. To evaluate the quality of cross-sectional images, two evaluating criteria: (1) shape accuracy and (2) clearness in the cross-sectional image are defined. Based on this criteria, a series of simulations were performed, and the results show the superiority of the new synthesizing method over the existing ones such as averaging and minimum method.
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Discussed is stroke identification technique for automatic recognition of kanji characters without using the order of drawing strokes of a character.
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This paper presents a construction method of logic-based switching control system which operates in widely changing environments. The logic-based switching controller is composed of a family of candidate controllers together with a supervisor. The system does not require any identification schemes of environments. Switching from one candidate controller to another is carried out based on monitoring the output of the system. The basic ideas of adaptation are as follows: (1)each candidate controller is prepared for each environment in advance; (2)the supervisor applies a sequence of speculative controls to a plant with candidate controllers just after the control has started and just after the change of the environment has been detected. It is important that each candidate controller can keep the system stable during a sequence of speculative controls, and the most appropriate candidate controller for the environment to which the system is exposed can be selected before the last speculative control is ended. An application to an antiskid braking system clarifies the effectiveness of the proposed method.
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In this paper, we propose a simple algorithm to calculate the number of passing cars at night by using an image processing sensor for digital black and white images with 256 tone levels. To recognize cars, we capture their head lamps. The reflection of the head lamps is one of the most troublesome factors in recognizing cars. The main problem in this paper is how to recognize cars under the influence of the reflection of the head lamps especially in rainy days. In general, the image of a head lamp is nearly circular and the reflection is long and narrow. On the difference of these forms, we can exclude the reflection in our proposed algorithms For real-time operation and simple calculation, we recognize the existence of cars using fifteen lines with 256 tone levels. In the experimental application on a road, the recognition rate of a real-time operation is more than 90%. Moreover, we will also explain briefly how to recognize passing cars for 24 hours.
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This paper is concerned with the properties of zeros of discrete-time systems which are composed of a hold, a continuous-time plant and a sampler in cascade. Here the signal reconstruction is based on the fractional order hold. In order to overcome the implementing problem of the fractional order hold, the piecewise constant reconstruction method by use of the zero order hold is introduced. The properties of the zeros are explored in the limiting cases when the sampling period tends to zero. The stability conditions of the zeros for sufficiently small sampling periods are also presented.
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In this paper, the authors propose a new method for linearizing a nonlinear dynamical system by use of polynomial compensation. In this method, an M-sequence is applied to the nonlinear system and the crosscorrelation function between the input and the output gives us every crosssections of Volterra kernels of the nonlinear system up to 3rd order. We construct a polynomial compensation function from comparison between lst order Volterra kernel and high order kernels. The polynomial compensation function is, in this case, of third order whose coefficients are variable depending on the amplitude of the input signal. Once we can get compensation function of nonlinear system, we can construct a linearization scheme of the nonlinear system. That is. the effect of second and third order Volterra kernels are subtracted from the output, thus we obtain a sort of linearized output. The authors applied this method to a saturation-type nonlinear system by simulation, and the results show good agreement with the theoretical considerations.
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In this paper, a pole assignment problem in the unit disk for a linear discrete system is discussed. The analysis is based on the Luenberger's canonical form and Gershgorin's disk. The proposed method for pole assignment is convenient for a linear time invariant discrete system.
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According to the way of the robot control, the robot systems of all the teams which participate in the MIROSOT can be divided into three categories : the remote brainless system, the vision-based system and the robot-based system. The MIRAGE I robot control system uses the last one, the robot-based system. In the robot-based system the host computer with the vision system transmits the data on only the location of the ball and the robots. Based on this robot control method, we took part in the MIROSOT '96 and the MIROSOT '97.
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The soccer robot system consists of multi agents, with highly coordinated operation and movements so as to fulfill specific objectives, even under adverse situation. The coordination of the multi-agents is associated with a lot of supplementary work in advance. The associated issues are the position correction, prevention of communication congestion, local information sensing in addition to the need for imitating the human-like decision making. A control structure for soccer robot is designed and several behaviors and actions for a soccer robot are proposed. Variable zone defense as a basic strategy and several special strategies for fouls are applied to SOTY2 team.
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In this paper, two kinds of controller are proposed for a soccer robot system.. One for Supervisor and defense mode, and the other for attack mode. Robot soccer game has very dynamic characteristics. Furthermore, there exist competitions between agents. The soccer-playing robot should take an appropriate action according to its surroundings. Initially, an attack mode controller using a vector field concept is designed, then a supervisor and a defense mode controller are designed with a Petri-net. The efficiency and applicability of the proposed controllers are demonstrated through a real robot soccer game(MiroSot 97).
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We have built a robot soccer system to participate in MIROSOT97. This paper represents hardware specification of our system and our strategy. We select a centralized on-line system for a soccer game. The paper explains hardware specifications of our system for later development. Also, the paper explains our strategy from two viewpoints. From the viewpoint of cooperation, some heuristic ideas are implemented. From the viewpoint of path plan, Cubic spline is used with cost function which minimized time, radius of curvature for smoothness, and obstacle potential field. Direct comparison will be realized in MIROSOT97.
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This paper presents the design procedure for soccer-playing rovots based on the centralized approach. Using a fast vision system, we obtain the configuration of each robot and then the host computer computes the desired motion and commands each robot directly via RF communication. The robot soccer game has a lot of problems such as obstacle avoidance, coordination between robots, dribbling the ball, and so on. To implement such motions, we think that the centralized approach seems to be more powerful than the distributed approach. We describe the technical tips for developing the robots in detail here and explain our strategy for getting the scores.
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In this paper the new neural network and sliding mode suspension controller is proposed. That neural network is error self-recurrent neural network. For fast on-line learning, this paper use recursive least squares method. A new neural networks converges considerably faster than the backpropagation algorithm and has advantages of being less affected by the poor initial weights and learning rate. The controller for suspension systems is designed according to sliding mode technique based on new proposed neural network.
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This paper presents the design method of controller which is combined Genetic Algorithms with the Generalized minimum variance self tuning controller. It is shown that the controllers adapts to changes in the system parameters with time delays and noises. The self tuning effect is achieved through the recursive least square algorithm at the parameter estimation stage and also through the Robbins-Monro algorithm at the stage of optimizing a polynomial parameters. The computer simulation results are presented to illustrate the procedure and to show the performance of the control system.
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In this paper we present a scheme of adaptive backstepping controller for nonlinear system. Backstepping approach has recently been adopted as a design tool for nonlinear control and especially backstepping with modular design used to seperately design controller and identifier. In the modular design the nonlinear damping term is contained in controller for input-to-state stability (ISS). We compare the ISS controller, which used in general case, with the weak-ISS controller that attenuates the effect of nonlinear damping term and prove their advantages and disadvantages by simulation.
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In this paper, a dynamic control scheme is proposed which not only compensates for the lateral dynamics and longitudinal dynamics but also deal with the yaw motion dynamics. Using the dynamic control technique, adaptive and learning algorithm together, the proposed controller is not only robust to disturbance and parameter uncertainties but also can learn the inverse dynamics model in steady state. Based on the proposed dynamic control scheme, a dynamic vehicle simulator is contructed to design and test various control techniques for 4-wheel steering vehicles.
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This paper describes speed controller of a induction motor for electric vehicles using PLL and Fuzzy logic. The proposed system is combined precise speed control of PLL and robust, fast speed control of Fuzzy logic. The motor speed is adaptively incremented or decremented toward the PLL locking range by the Fuzzy logic using information of sampled speed errors and then is maintained accurately by PLL. The results of experiment show excellence of proposed system and that the proposed system is appropriates to control the speed of induction motor for electric vehicles.
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Asymmetric cylinders are usually used as an actuator of active suspensions. The conventional optimal controller design does not include actuator dynamics as a state and force controller is needed to track the desired force. But the actuator is not ideal, so performance of an active suspension system is degraded. In this paper, we take account nonlinear actuator dynamics and obtain a linear model using a feedback linearization technique then apply optimal control method. Effectiveness of proposed method is demonstrated by numerical simulation of 1/4 car model.
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This paper proposes methods for the cooperative control of multiple mobile robots and constructs a robotic soccer system in which the cooperation will be implemented as a pass play of two robots. To play a soccer game, elementary actions such as shooting and moving have been designed, and Q-learning, which is one of the popular methods for reinforcement learning, is used to determine what actions to take. Through simulation, learning is successful in case of deliberate initial arrangements of ball and robots, thereby cooperative work can be accomplished.
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An exploration for an intelligence paradigm has been delineated. Artificial intelligence and artificial life paradigms seem to fail to show the whole picture of human intelligence. We may understand the human intelligence better by adding the emotional part of human intelligence to the intellectual part of human intelligence. Emotional intelligence is investigated in terms of composing machine as a modern abstract art. Various algorithmic composition and performance concepts are currently being investigated and implemented. Intelligent mapping algorithms restructure the traditional predetermined composition algorithms. Music based on fractals and neural networks is being composed. Also, emotional intelligence and aesthetic aspects of Korean traditional music are investigated in terms of fractal relationship. As a result, this exploration will greatly broaden the potentials of the intelligence research. The exploration of art in the view of intelligence, information and structure will restore the balanced sense, of art and science which seeks happiness in life. The investigations of emotional intelligence will establish the foundations of intelligence, information and control technologies.
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In order to improve vehicle safety, collision warning systems have been proposed by many researchers. This paper presents several algorithms to determine the degree of real end collision by using fuzzy logic and neural networks. In order to provide realistic data for the algorithm design, a data collection system has been installed on a passenger car.
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In recent manufacturing process, the increase of productivity is required by reducing machining time with the increase of cutting force. However, the excessive increase of cutting force can cause tool breakage, and have a bad effect on both the manufacturing machine and the workpiece. Thus, it is necessary to estimate and control cutting force in real time during the process. In this study, use of disturbance observer is proposed for the indirect cutting force estimation. The estimated cutting force is used for the real time control of feedrate, making the actual cutting force follow the reference force command. Since the suggested method does not need an expensive sensor like a dynamometer, the method is expected to be used practically. By reducing the machining time resulting from making the actual cutting force follow the reference force, the increase of productivity are also expected, and the quality of cutting surface has been improved due to the adjusted feedrate. Besides, an actual constant cutting force guarantees the prevention of tool breakage. To show the effectiveness of the suggested cutting force control method, an experimental setup has been made without the force sensor, applied to several workpieces. Experiments show that the suggested method is superior to the conventional method operated by constant feedrate.
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For higher component density per chip, it is necessary to identify and control the semiconductor manufacturing process more stringently. Recently, neural networks have been identified as one of the most promising techniques for modeling and control of complicated processes such as plasma etching process. Since wafer states after each run using identical recipe may differ from each other, conventional neural network models utilizing input factors only cannot represent the actual state of process and equipment. In this paper, in addition to the input factors of the recipe, real-time tool data are utilized for modeling of 64M DRAM s-poly plasma etching process to reflect the actual state of process and equipment. For real-time tool data, we collect optical emission spectroscopy (OES) data. Through principal component analysis (PCA), we extract principal components from entire OES data. And then these principal components are included to input parameters of neural network model. Finally neural network model is trained using feed forward error back propagation (FFEBP) algorithm. As a results, simulation results exhibit good wafer state prediction capability after plasma etching process.
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This paper describes a new process-plan selection method using a modified Fuzzy Quantification Theory(FQT). The problem for process-plan selection can be characterized by multiple attributes and used subjective, uncertain information. Fuzzy Quantification Theory is used for handling such informations because it is a useful tool when human judgment or evaluation is quantified via linguistic variables and the proposed method is concerned with the selection of a process plan by derivation of the values of categories for each attribute. In this paper, a modified Fuzzy Quantification Theory(FQT) is described and the procedure of this approach is explained and examples are illustrated.
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This paper proposes a structure of the control system for the step & scan exposure tool. The step & scan exposure tool is used for the manufacturing process of the semiconductor DRAM memory of giga bit. The control system employs the VME bus instead of the conventional ISA bus so that all control signals and data can be managed separately by the 4 VME-PCs for fast and fault-free flow of signals for multi-tasking. A high speed I/O card is equipped for the real-time monitoring and control of the sub module equipment. Then all the subsystems are integrated and aligned for the operation of the step & scan exposure tool with the VME bus and, I/O card.
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Networking for manufacturing is gaining importance as a nerve system of computer-integrated manufacturing(CIM). Among the various network types, the most inexpensive type called fieldbus is specifically aimed to interconnect simple devices such as sensors and actuators. For this purpose, there are several choices of the protocol such as Profibus, FIP, Foundation Fieldbus, and IEC/ISA fieldbus. This paper presents the simulation results of Profibus and FIP. Both protocols has been simulated in order to evaluate the performance such as transmission delay and throughput under different protocol parameter setting and traffic conditions.
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Fieldbus system should be designed by considering the number of sensors/actors(actuators+ controllers) and their sampling times. But the number of sensors/actors and which are connected to the network bus can be varied by addition and/or fault of the field devices. That variation decreases the efficiency of system which is off-line designed optimally. This paper proposes an algorithm that ensures transmission of cyclic data even though there is the number change in the field devices. We assign the different weight values to cyclic data and acyclic data. By simulation and experiment, the cyclic and acyclic data are processed via the proposed network, and the results are compared with those of the Profibus system. It is shown that the proposed algorithm is more robust with the uncertainties of the field devices of the control system.
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In order to access to the Business Computer (B/C), the Process Computer(P/C), and the Database Server in one terminal, the Open Man Machine Interface (MMI) System has been developed. The testbed to develop the interface functions for B/C, P/C, DB server, and CCD camera were constructed, which consisted of Workstations and Personal Computers (PC). Graphic display programs Monitoring the process states of Tandem Cold Mill plant were developed using four Graphic User Interface tools: InTouch, FIX32, Open Interface Environment, and ILOG Views. With regard to the CPU utilization and response delay required to open new display, the performance tests have been carried out on each MMI platform.
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This paper presents an
$H^{\infty}$ controller design method for linear time-invariant systems with delayed state and control. Using the second method of Lyapunov, the stability for delayed systems is discussed. For delayed systems, we derive a sufficient condition of the bounded real lemma(BRL) which is similar to BRL for nondelayed systems. And the sufficient conditions for the existence of an output feedback$H^{\infty}$ controller of any order are given in terms of three linear matrix inequalities(LMls). Futhermore, we briefly explain how to construct such controllers from the positive definite solutions of their LMIs and give a simple example to illustrate the validity of the proposed design procedure.e. -
Nonlinear robust attitude controller for 3-axis stabilized spacecraft is designed. Robust stability analysis for nonlinear spacecraft system with disturbance is conducted. External disturbances and parametric uncertainties decrease Spacecraft's attitude pointing accuracy. Sliding Mode Control(SMC) provides stability of system in the face of these disturbances and uncertainties. The concept of quadratic boundedness and quadratic stability are applied to the robust analysis for the nonlinear spacecraft system subject to bounded disturbance torques. Numerical simulation is conducted to compare the analysis result and actual nonlinear simulation. The simulation show that analysis result is valid.
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In this paper, we presents that for discrete system with matched perturbation of uncertain parameters in the state coefficient matrix A(i.e., with perturbation of A in the range of the input matrix B), the poles of the perturbed closed loop system can be placed into the preassigned circle by the static-state feedback. We discuss the robust stabilization of the system satisfying the matching condition and application to the controller design problem.
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A robust controller for a 6 DOF magnetically levitated fine manipulator is presented. The proposed controller consists of following two parts : a model reference controller (MRC) and a H
$_{\infty}$ controller (HIC). First, the MRC stabilizes the motion of the manipulator. Then, the motion of the manipulator follows that of the reference model. Second, the HIC minimizes errors generated from the MRC due to noise and disturbance since the HIC is a kind of robust controller. The experiments of position control and tracking control are carried out by use of the proposed controller under the conditions of free disturbances and forced disturbances. Also, the experiments using PID controller are carried out under the same conditions. The results from above two controllers are compared to investigate the control performances. As the results, it is observed that the proposed controller has similar position accuracy but better tracking performances comparing to the PID controller as well as good disturbance rejection effect due to the robust characteristics of the controller. In conclusion, it is verified that the proposed controller has the simple control structure, the good tracking performances and good disturbance rejection effect due to the robust characteristics of the controller.. -
In this paper, we present a fuzzy logic based tuner for continuous on-line tuning of PID controllers. The essential idea of the scheme is to parameterize a Ziegler-Nichols-like tuning formula by a singler parameter .alpha., then to use an on line fuzzy logic to self-tune the parameter. The adaptive scaling makes the controller robust against large variations in parametric and dynamics uncertainties in the plant model. New self-tuning controller has the ability to decide when to use PI or PID control by extracting process dynamics from relay experiments. These scheme lead to improved performance of the transient and steady state behavior of the closed loop system, including processes with nonminimum phase processes.
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This paper proposes the hybrid algorithm for the optimization of the structure and parameters of the fuzzy neural networks by genetic algorithms (GA) to improve the behaviour and the design of fuzzy neural networks. Fuzzy neural networks have a distinguishing feature in that they can possess the advantage of both neural networks and fuzzy systems. In this way, we can bring the low-level learning and computational power of neural networks into fuzzy systems and also high-level, human like IF-THEN rule thinking and reasoning of fuzzy systems into neural networks. As a result, there are many research works concerning the optimization of the structure and parameters of fuzzy neural networks. In this paper, we propose the hybrid algorithm that can optimize both the structure and parameters of fuzzy neural networks. Numerical example is provided to show the advantages of the proposed method.
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In image jacobian based visual servoing, generally, inverse jacobian should be calculated by complicated coordinate transformations. These are required excessive computation and the singularity of the image jacobian should be considered. This paper presents a visual servoing to control the pose of the robotic manipulator for tracking and grasping 3-D moving object whose pose and motion parameters are unknown. Because the object is in motion tracking and grasping must be done on-line and the controller must have continuous learning ability. In order to estimate parameters of a moving object we use the kalman filter. And for tracking and grasping a moving object we use a fuzzy inference based reinforcement learning algorithm of dynamic recurrent neural networks. Computer simulation results are presented to demonstrate the performance of this visual servoing
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An integrated program of driving simulator has been developed for excavators using the Motif, OpenGL, and C compiler. The developed program not only offers a GUI but also covers graphic algorithms, therefore, the user can easily run the driving simulator whose components include a simplified visual graphics system. Several graphics technique are combined and applied to the simulator program in order to increase the speed of graphical representation, which access computer memories, mix 2D models with 3D ones, and use the basic position detection method. A text format environment file has been utilized for organizing more flexible driving circumstances.
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This paper presents a cooperative control method for multiple robots. This method is based on local sensors. The proposed method integrates all information obtained by local perception through a set of sensors and generates commands without logical conflicts in designing control logic. To control multiple robots effectively, a global control strategy is proposed. These methods are constructed by using AND/OR logic and transition firing sequences in Petri nets. To evaluate these methods, the object-searching task is introduced. This task is to search an object like a box by two robots and consists of two sub-tasks, i.e., a wall tracking task and a robot tracking task. Simulation results for the object-searching task and the wall tracking task are presented to show the effectiveness of the method.
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In this paper, we developed a Windows 95 version Off-Line Programming System which can simulate a Robot model in 3D Graphic space. 4 axes SCARA Robot (especially FARA SM5)was adopted as an objective model. Forward kinematics, inverse kinematics and robot dynamics modeling were included in the developed program. The interface between users and the OLP system in the Windows 95's GUI environment was also studied. The developing language is Microsoft Visual C++. Graphic libraries, OpenGL, by Silicon Graphics, Inc. were utilized for 3D Graphics.
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This paper discusses approximation modelling of discrete-time linear time-varying system(LTVS). The wavelet transform is considered as a tool for representing and approximating a LTVS. The joint time-frequency properties of wave analysis are appropriate for describing the LTVS. Simulation results is included to illustrate the potential application of the technique.
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Variable Structure Controller(VSC) is usually known to have robustness to bounded exogenous disturbances. The robustness is attributed to the discontinuous term in the control input. However, this discontinuous term also causes an undesirable effect called chattering. To alleviate chattering, a hybrid controller consisting of VSC and Fuzzy Logic Controller(FLC) is proposed, which belongs to the category of Fuzzy Sliding Mode Controller(FSMC). The role of FLC in FSMC is to replace a fixed gain of a discontinuous term with a time-varying one based on a specified rule base. The characteristics of proposed controller are shown to be similar to those of VSC with a saturation function instead of sign function. The only remarkable difference is the nonlinearity whose form can be adjusted by free parameters, normalize gain, denormalize gain, and membership functions. Applied to AC servo motor, the proposed controller is compared with VSC in a regulation problem as well as a speed tracking problem. The simulation results show a substantial chatter reduction.
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In recent years, there has been a renewed interest in the BLDC motor as a research subject. In this paper we inspect sources of the torque ripple, which is one of the elements causing performance depreciation of BLDC motors. Based on the inspected sources of the torque ripple, feedforward compensation methods are proposed to reduce the size of torque ripple. The effectiveness of the proposed methods is verified with experiments.
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Reference models are used in many control algorithms for improvement of transient response characteristics. They provide desired trajectories that the plant should follow. Most control systems have bounded control inputs to avoid saturation of the plant. If we design reference models that do not account for limits of control inputs, control performance of the system may be deteriorated. In this paper, therefore, the way of determining variable reference models for TDC(time delay control) technique is proposed. The variable reference model is determined based on the information of bounded control inputs and reference inputs. This proposed method is also verified by application to the position control experiment using the BLDC motor.
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High performance digital computer technology enables the digital computer-based controllers to replace traditional analog controllers used for factory automations. This replacement, however, brings up the side effects caused by discrete quantization and non-real-time execution of control softwares. This paper describes the structure of real-time simulator and controller that can be used for design and verification of real-time digital controllers. The virtual machine concept adopted by real-time simulator make the proposed simulator be independent from the specific hardware platforms. The proposed system can also be used in the loosely coupled distributed environments connected through local area network using real-time message passing algorithm and virtual data table based on the shared memory mechanism.
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The White Beamline of the Pohang Accelerator Laboratory(PAL) consists of main and second slits, a microprobe system, two ion chambers, a video-microscope, and a Si(Li) detector. These machine components must be controlled remotely through computer system to make user experiments precise and speedy. A real-time computer control system was developed to control and monitor these machine components. A VNIEbus computer with OS-9 real-time operating system was used for low-level data acquisition and control. VME I/O modules were used for step motor control and scaler control. The software has modular structure for maximum performance and easy maintenance. We developed database, I/O driver, and control software. We used PC/Window95 for data logging and operator interface. Visual C++ was used graphical user interface programming. RS232C was used for communication between VME and PC.
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In this paper, a scheduling algorithm is proposed for a programmable logic controller(PLC) with remote I/Os, assuming the multi-tasking facilities. Since sequence programs are executed on the application processor and I/O data are transmitted by the network processor concurrently, the proposed algorithm schedules the data transmission as well as the sequence program execution. The suggested algorithm guarantees the bounded WCRT(worst case response time), which is the one third of the WCRT in the absence of scheduling. Computer simulation shows that the algorithm can be easily applied to a real PLC without critical constraints on utilization of resources and inter-relation among tasks.
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Multi-arm cooperation robot system is required for more specific and dextrous jobs such as transferring very large or heavy objects, or grasping work piece while processing on it. There is little research on 3-dimensional multi-arm robot. Here we propose two performance indices presenting isotropy of end-effector's acceleration and velocity capabilities with constraints of joint torques, that is Isotropic Acceleration Radius [IAR] and Isotropic Velocity Radius [IVRI. Also the procedure to find 3-dimensional IAR, IVR is proposed, where available acceleration set concept is used. The case of 3-dimensional two 3 joint robot system was simulated and the distributions of IAR, IVR was studied.
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Using telesensor programming method, we control the space robot which has two 2-DOF manipulators. To make this control system, we devide total works by elemental operation. And we make a simulation system that can simulate sensors and robot. In the simulation system, we make a sensor data and robot paths by "Teaching by showing" method. And using these data, we control the real space robot. This off-line method can solve long time delay problem in teleoperation.operation.
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This paper presents the modulation of the dexterity of a parallel manipulator using joint freezing/releasing and joint unactuation/actuation. In this paper, individual limbs have redundant number of joints, and each joint can be frozen/released and unactuated/actuated, as needed. First, given a task, the restrictions on joint freezing and joint unactuation of a parallel manipulator are derived. Next, with/without joint freezing and/or joint unactuation, the kinematics of a parallel manipulator is formulated, based on which the manipulability ellipsoid is defined. The effects of joint freezing and joint unactuation on the manipulability are analyzed and compared. Finally, simulation results for a planar parallel manipulator are given. Joint mechanisms, such as joint freezing and joint unactuation, are rather simple to adopt into a parallel manipulator, but is quite effective to improve the task adaptability of the system.
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Geometric probing addresses the problem of determining geometric aspects of a structure from the mathematics and results of a physical measuring device such as a probe. This paper presents a new algorithm to recognize the shape of an unknown object by using a robot hand with a force and torque sensor. The new algorithm is called S.E.P.(Shape Exploration Procedure) which finds the global shape of an unknown object. The proposed method is composed of three major parts, finding contact informations such as contact point, calculation of shape information such as curvature, and expression of global shape from these informations. Comparing with the conventional approaches, the advantages of the proposed method are explained and verified by conducting experiments with a 3-dof SCARA robot.
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A high speed tracking control for 6-6 Stewart platform manipulator is performed by employing the joint-axis sliding mode control based on dynamics. Because of the complex dynamics and kinematics of Stewart platform manipulator, two computer systems, consisting of a PC and a DSP, are adopted, so that real time tasks are run in synchronous and asynchronous modes. It is experimentally proven that the proposed control system leads to an easy to implement and effective control task, and it can achieve the high performance tracking control under the high speed and severe payload condition.
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We propose a remote controller for a SCARA typed direct drive manipulator with two degrees-of-freedom(DOF). A remote controller system for SCARA robot of DDA is designed using a 2 DSP (TMS320c31) board and Winsock(Internet program class library supplied by Microsoft). The design objective of the system is to implement real time dynamic control algorithms which have been tested only by simulations so far and remote control regardless of the distance between user and robot. Because this system runs on Win95, we developed a VxD program to communicate with DSP controller.
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In this paper, accurate position control of a stenciling robot manipulator is designed. The stenciling robot is requried to draw lines and characters on the pavement. Since the robot is huge and heavy, the inertia is expected to play a major role in the tracking performance as desired. Here we are proposing neural network control scheme for a computed-torque like controller for the stenciling robot. On-line compensation is achieved by neural network. Simulation studies with stenciling robot are carried out to test the performance of the proposed control scheme.
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Automatic realization of on-off human decision making was derived based on a conditional probability. Following the proposed procedure, problems of insulator washing timing in power substations and spike detection on EEG(electroencephalogram) records were appropriately solved.
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This paper proposes a method which selects essential elements in a human evaluation model using the Choquet integral based on fuzzy measures, and applies the model to the evaluation of human interface. Three kinds of concepts are defined to select essential elements. Increment Degree implies the increment degree from fuzzy measures of composed elements to the fuzzy measure of a combined element. Average of Increment Degree of an element means the relative possibility of superadditivity of the fuzzy measure of each combined element. Necessity Degree means the selection degree of each combined element as a result of the human evaluation. A task experiment, which consists of a static work and two dynamic works, is performed by the use of some human interfaces. In the experiment, (1) a warning sound which gives an attention to subjects, (2) a color vision which can be distinguished easily or not, (3) the size of working area and (4) a response of confirmation that is given from an interface, are considered as human interface elements. Subjects answer the questionnaire after the experiment. From the data of the questionnaire, fuzzy measures are identified and are applied to the proposed model. Effectiveness of the proposed model is confirmed by the comparison of human interface elements extracted from the proposed model and those from the questionnaire.
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Based on a systematic ide developed for experience-based expertise acquisition systems, a human-oriented methodology for plant operation is described.
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This paper deals with a new method to derive the Generalized Jacobian Matrix of a space robot. In a conventional method to derive the Generalized Jacobian Matrix, generalized coordinates select Joint angles and a space robot body's position and attitude angle. But, in this paper, we select position and attitude angle of the end-effector or the handled floating object as generalized coordinates. Then, we can derive the Generalized Jacobian Matrix of the system which consists of several space robots and a handled floating object. Moreover control methods operated by only one space robot can be easily extended to the cases of cooperation task by several space robots. Computer simulations show that the Generalized Jacobian Matrix derived here is effective.
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In this paper, a force estimation method is proposed for the sensorless force control. For this, a disturbance observer is applied to each joint of an n degrees of freedom manipulator to obtain a simple equivalent robot dynamics(SERD) being represented as an n independent double integrator system. To estimate the output of disturbance observer in the absence of external force, the observer estimator is designed, where the uncertain parameters of the robot manipulator are adjusted by gradient method to minimize the output between the disturbance observer and the observer estimator. When the external force is exerted, the external force is estimated using the difference between the output of disturbance observer which include the external torque signal and that of observer estimator. And then, a force controller is designed for force feedback control employing the estimated force signal. To verify the effectiveness of the proposed force estimation method, several numerical examples are illustrated for the 2-axis planar type robot manipulator.
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Digital control of robot manipulator employs discrete-time robot models. It is important to explore effective discrete-time robot models and to analyze their properties in control system designs. This paper presents a new type discrete-time robot model. The model is derived by using trapezoid rule to approximate the convolution integral term, then eliminating nonlinear force terms from robot dynamical equations. The new model obtained has very simple structure, and owns the properties of independence to the nonlinear force terms. According to evaluation criteria, three aspects of the model properties: model accuracy, model validity range and model simplicity are examined and compared with commonly used discrete-time robot models. The validity of the proposed model and its advantages to control system designs are verified by simulation results.
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In this paper, the torque optimization of a kinematically redundant manipulator for minimizing the torque demands is discussed. The minimum torque solution based on a local optimization has been known to encounter the instability problem and then the global torque optimization was suggested as one of the alternatives. Herein, by adopting the infinity-norm rather than the 2-norm for the magnitude of torques, we are to propose a new cost function more advantageous to the avoidance of torque limits. By the way, a solution to the global torque optimization formulated with the new cost function can not be obtained by the previous methods due to their difficulties such as inability to treat discontinuous cost functions and various constraints on the joint variables. Thus, to overcome those deficiencies, we are developing a new approach using the dynamic programming. The effectiveness of the proposed method is shown through simulation examples for a 3-link planar redundant manipulator.
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In this paper, an intelligent control strategy for a mobile vehicle, based on the technology of the artificial neural network in a Neurocomputer, is presented. The mobile vehicle learned recognizing and driving knowledge by a neurocomputer. Moment Invariants computation was used to extract the shape of objects. The technologies of both neurocomputer and Neumann-type computer are applied into the control system, and make the mobile vehicle be capable of tracking designated objects and avoiding obstacles.
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This paper presents a cell-based motion control strategy for soccer playing mobile robots. In the central robot motion planner, the planar ground is divided into rectangular cells with variable sizes and motion indices to which direction the mobile robot should move. At every time the multiple objects-the goal gate, ball, and robots-detected, integer values of motion indices are assigned to the cells occupied by mobile robots. Once the indices being calculated, the most desirable state-action pair is chosen from the state and action sets to achieve successful soccer game strategy. The proposed strategy is computationally simple enough to be used for fast robotic soccer system.
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This paper presents a robot which is steered by vision system. The proposed robot system has an AM188ES CPU(5.3 MIPS) and 2DC motors with encoder and turns accurately at any speed and shows a movement like a human controlled car using a steering wheel. To the robot only steering angle value is sent without considering the speed. We present how to control this robot using our real time vision system.
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One of the most important design factor for the image tracker is the speed of the data processing which allows real-time operation of the system and provides reasonably accurate performance at the same time. Use of powerful DSP alone does not guarantee to meet such requirement. In this paper, a simple efficient algorithm for real-time multi-target image tracking is suggested. The suggested method is based on a recursive centroiding technique and color table look-up. This method has been successfully implemented in a image processing system for Micro-Robot Soccer Tournament(MIROSOT). This tracker can track positions of a ball, 3 enemies, and 3 agents at the same time. The experimental results show that the processing time for each frame of image is less than 7ms, which is well within the 60Hz sampling interval for real-time operation.
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In this paper, we first analyze the structural limitation of the conventional PID controller in controlling unstable processes through mathematical proof. To overcome this structural limitation, we add an internal feedback loop to the PID controller. Secondly, we obtain conditions when unstable processes can be stabilized by a controller through an analytical analysis. Finally, we propose a simple on-line process identification and autotuning method for unstable processes. Many simulation results show that, in spite of its simplicity, the proposed on-line process identification method provides good accuracy in modeling the unstable process and acceptable robustness to measurement noises and disturbances. Also, the proposed autotuner shows good control performances for both servo and regulatory problems.
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In recent years, much progress has been made in the automation of welding coped with a variety of highly flexible sensors. Among these sensors, only the eddy current sensor can detect the center location of the butt joint whose gap distance is zero. Thus, in this study the eddy current sensor is used to develop a robust and useful joint tracking system. The developed system is tested to qualify the performance of the system and seam tracking algorithm is proposed and two simulation are executed to show the performance of the proposed tracking algorithm.
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김은기;변승현;이찬주 840
We applied a DCS which was developed in Korea to test furnace. Test furnace is a pilot-scale plant made for finding combustion in firing coal. In this paper, we describe control system which was implemented in test furnace in detail. Finally, we describe the fire box temperature control loop, and show fire box temperature control result during commissioning stage using implemented control system. -
In this paper, scheduling problem is dealt for the minimization of due date penalty for the customer order. Multiproduct batch processes have been dealt with for their suitability for high value added low volume products. Their scheduling problems take minimization of process operation for objective function, which is not enough to meet the customer satisfaction and the process efficiency simultaneously because of increasing requirement of fast adaptation for rapid changing market condition. So new target function has been suggested by other researches to meet two goals. Penalty function minimization is one of them. To present more precisely production scheduling, we develop new scheduling model with penalty function of earliness and tardiness We can find many real cases that penalty parameters are divergent by the difference between the completion time of operation and due date. That is to say, the penalty parameter values for the product change by the customer demand condition. If the order charges different value for due date, we can solve it with the due date period. The period means the time scope where penalty parameter value is 0. If we make use of the due date period, the optimal sequence of our model is not always same with that of fixed due date point. And if every product have due date period, due date of them are overlapped which needs optimization for the maximum profit and minimum penalty. Due date period extension can be enlarged to makespan minimization if every product has the same abundant due date period and same penalty parameter. We solve this new scheduling model by simulated annealing method. We also develop the program, which can calculate the optimal sequence and display the Gantt chart showing the unit progress and time allocation only with processing data.
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A graphic simulation program is developed to assimilate the remote dismantling process of research nuclear reactors. This program makes extensive use of a commercial robot graphic instruction program. Firstly, a realistic graphic model of research reactors are built along with various dismantling equipments. Using the graphic instruction languages provided by IGRIP, then, a graphic process simulation program is developed that operates interactively with the user. Consequently, it is made possible for a process designer to visualize an arbitrary dismantling sequence and interactively modify the process. It is expected that the developed system will be utilized as an effective operator aid in both design and execution phases of remote dismantling of research reactor.
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In this paper, the vibration diagnosis system of a rotating machinery is introduced, in which the vibration signals of multiple accelerometers and displacement sensors are used combinedly as input parameters and their characteristics of the vibration response and mutual relationships between each sensor signal are considered to improve the reliability of the diagnosis system. The fuzzy logic is utilized for inferencing the fault from the vibration signal patterns.
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In this paper we treat the application of fault detection method in DC motor having both model mismatch and noise problems. A fault detection method presented by Kwon et al. (1994) for SISO systems has been here experimented. The model mismatch includes here linearization error as well as undermodelling. Comparisons are made with the real plant, DC motor. The experimental result of robust fault detection method is shown to have good performance via with the alternative fault detection method which do not account noise.
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FCM(Fuzzy Cognitive Map) is a fuzzy signed directed graph for representing causal reasoning which has fuzziness between causal concepts. Authors have already proposed FCM-based fault diagnostic scheme. However, the previously proposed scheme has the problem of lower diagnostic resolution. In order to improve the diagnostic resolution, a new diagnostic scheme based on extended FCM which incorporates the concept of fuzzy number into FCM is developed in this paper. Furthermore, an enhanced TAM(Temporal Associative Memory) recall procedure and pattern matching scheme are also proposed.
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In a fault-tolerant modern manufacturing systms characterized by the configuration, in which automated redundant machines prone to unexpected failures are interconnected with other complex subsystems such as AGV's, robots, computer control systems to produce complete parts, faulures together with repairs and reconfigurations should be considered as the three basic events to be modeled for computing the performance of manufacturing systems. In this papre, transient analysis is applied to modular cell manufacturing systems form a performability viewpoint whose modeling adantage is that various performanc e measures can be evaluated compositely in the context of application. The hypothertical modular cells are modeled firstly with hybrid decomposition method and availability measures as special cases of performability are computed and comments on performabililty modeling analysis are mentioned.
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An assembly sequence is considered to be optimal when it minimizes assembly cost while satisfying assembly constraints. to generate such sequences for robotic assembly, this paper proposes a method using a genetic algorithm (GA). This method denotes an assembly sequence as an individual, which is assigned a fitness related to the assembly cost. Then, a population consisting of a number of individuals evolves to the next generation through genetic operations of crossover and mutation based upon the fitness of the individuals. The population continues to repetitively evolve, and finally the fittest individual and its corresponding assembly sequence is found. Through case study for an electrical relay, the effectiveness of the proposed method is demonstrated. Also, the performance is evaluated by-comparing with those of previously presented approaches such as a neural-netowork-based method and a simulated annealing method.
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The industrial automation market encompasses all aspects of the discrete process in the manufactring industries. Nowadays many manufacturers are increasingly moving to increase plant capacity, and are trying to produce better quality at the lower costs. We have studied a modern projection-automation system to achieve the communication network which makes connection among all of the projection machines and connect them to a central computer. This communication system have to be very flexible and fast. Also we have studied the communication interface for the automatic production system including the hardware elements and the communication software.
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Cutting process has been automated by progress of CNC and CAD/CAM, but polishing process has been depended on only experiential knowledge of expert. To automate the polishing pricess polishing robot with 2 degrees of freedom which is attached to a machining center with 3 degrees of freedom has been developed. this automatic polishing robot is able to keep the polishing tool normal on the curved surface of die to improve a performance of polishing. Polishing task for a curved surface die demands repetitive operation and high precision, but conventional control algorithm can not cope with the problem of disturbance such as a change of load. In this research, we develop robust controller using real time sliding mode algorithm. To obtain gain parameters of sliding model control input, the signal compression method is used to identify polishing robot system. To obtain an effect of 5 degrees of freedom motion, 5 axes NC data for polishing are divided into data of two types for 3 axis machining center and 2 axis polishing are divided into data of two types for 3 axis machining center and 2 axis polishing robot. To find an efficient polishing condition to obtain high quality, various experiments are carried out.
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The proportion of the aged people is rapidly increasing toward the 21st century. This change will cause serious problems in the area of daily activities, preservation of health, medical care and physical rehabilitatiion for the aged. for the solution of these problems this paper suggest a new type of robot for the aged man, called a silver robot. This paper presents a concept of silver robot and it's feasibility study.
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In this article, the configuration of weight lifer is analyzed using manipulibility polytope. After modeling body as 7-link redundant robot, optimal joint angles during first stage are searched by dynamic programmi technique and compared with standard reference data.
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The basic technology of virtual reality can be described as the cognition of the condition change in virtual world by stimulating the visual, auditory, kinesthetic and tactile sensation. Among these, the kinesthetic and tactile sensation is one of the most important things to recognize the interaction. In this paper, it is addressed the haptic device which help the human feel the sense of the operator, and is designed in modular type to expand for five fingers later. the haptic device is driven by tendon and ultrasonic motors located in the wrist part. Each joint is actuated by coupled tendons and adopts more actrator by one than the number of the joints, called 'N+1 type'. The haptic device adopts metamorphic 4-bar linkage structure and the length of linkages, shape and the location of joint displacement sensor are optimized through the analysis.
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Typical biomechanical system such as human body and mammals possess abundant muscles which are more than required for motion generation of such systems. We have shown that the excess number of muscles play important roles in spring-like impedance modulation. redundant kinematic structure, which is another feature of biomechanical systems, allows modulations of inertia and damping properties of such systems. In this work, we propose a frequency modulation algorithm which combines the spring-like impedance with inertia impedance. also, a load distribution method for frequency modulation is also introduced. The frequency modulation represents a simulataneous control of force and kinematic redundancies, which has not been addressed in the literature.
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We investigate a design methodology for master arm which is employed in remote-site control. Though counter-balancing has been employed for the purpose of lessening the actuator loads, it results in the increase of dynamic load at the task position. Therefore, there exist a trade-off between counter-balacing and dynamic performance. The concept of a composite index is introduced to simulataneously consider those two effects in the design of master arms. Several alternative designs of master arms are suggested.
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Generally, singularity analysis of 6-DOF parallerl manipulators is very difficult and, as result, velocity relation has many uncertainties. In this paper, an alternative method using the local structurizatioin method(LSM) for the analysis of singular configuraions is presented. With LSM, the velocity relation can be represented in a simple form, and the result is totally equivalent to the conventional velocity relation. The velocity relation suggested in this paper gives a closed-form solution of singularities.
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A new approach to the three-dimensional measurement of the object surface and moving particles is introduced. A single TV camera with an apparatus to add the circular bias to the image enables us to record the three-dimensional information of measuring points as streaks on a single image. Every shaped of the streak on the image plane is related to the position of the measuring point. the information is extracted form the image using an image processign technique.
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Fabric hand feeling is an important property used in apparel industry. This paper shows a sensing method to output a fiber whisker's stick slip vibration by scanning it on the fabric. Then the vibration waveforms are transformed to the Symmetrized Dot Pattern images. Experimental results show that SDP images of fiber whisker's stik slip is potentially useful to the detection of fabric hand feeling values.
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Application of eddy current sensing principle for the non-contact estimation of very low concentration of electrolytic solution is presented in this paper. for this application, a new, simple, low-cost, low-power structure for the eddy current sensor is proposed. By measuring the eddy current produced in the conducting electrolytic solution, the concentration is estimated. Therefore, the unknown concentration can be estimated comparing with the database which is prepared as the relation between the change in inductance and various concentrations of electrolytic solution. The concentration, as low as l ppm of the solutioin can be detected by this sensor. It was tested on various low concentration solutions of NaCl. It shows distinct response for various concentrations.
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For realizing artificial skin sensing as a final goal, a mono-material pressure-conductive rubber sensor which is also sensitive for temperature is described. Firstly, discimination of the hardness and the thermal property of material using a proposed sensor is presented. Furthermore, a tactile sensor constints of four pressure-conductive rubber sensor to discriminate surface model which imitaties the surface roughness of material is proposed.
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A method for two-dimensional position measurement using an enclosing field has been studied and reported. The feature of this mehtod is zooming functional measurement by operating both the initial phase shift and the brightness ratio of the lighting function. An experimental system was developed and the experimental results on zooming effects are shown in this paper. This system is also an example of a "progressive learning measurement system".tem".uot;.
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A new feedback control law design techniqed usign of-off thrusters for the rotational maneuver of a flexible arm is discussed in this study. a two state on-off thruster actuator is taken as a primary actuation device for theis study. The on-off thruster operation is emulated in conjunction with the conventioal minimum-time trackig control law. The actuator input region is divided into two separate parts ; one is constant input and the other is time varying tegion. the new control law has potential applicatioin for the relatively low frequency structure such as large flexible space structure being currently used in various space echnology areas.
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In designing the controller by changing the weighting matrix for the pirpose of satisfying constraints, the physical meaning of weighting matrix may disapperar and the system may not yield best performance because operation condition such as periodic disturbance was not considered. In this paper, the weighting matrix is fixed and controller is designed to minimize the new performance index to reduce the effects of periodic-type disturbances. This method is applied to design the satellite controller to verify the effetiveness.
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In this paper, the optimal torque shaping is obtained for 3-axis rotation of a spacecraft. The true optimal 3-axis rotation of rigid spaeraft is first investigated via parameter optimization method with prescribed switching times. Input torque shape of the troque generating device mounted on the central hub is optimized using fourier Series expansion so that the spacecraft may slew while minimizing the vibration energy of flexible modes. Numerical results show that proposed method suggests a reference trahectory for open-loop control, and also verify that it can minimize the vibratory modes of the spacecraft during/after the rest-to-rest maneuver.
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A spacecraft attitude control ground hardware simulator development is discussed in the paper. The simulator is called KT/KARI HILSSAT(Hardware-In-the Loop Simulator Single Axis Testbed), and the main structure consists of a single axis bearing and a satellite main body model on the bearing. The single axis tabel as ans experimental hardware simulator that evaluates performance and applicability of a satellite before evolving and/or confirming a mew or and old control logic used in the KOREASAT is developed. Attitude control of spaceraft by using reaction wheel is performed.
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In this paper, we propose angular rate computation algorithm using GPS carrier phase. A direct angylar rate masurement has not previously been available form GRS, although its availability is highly desirable for use in state feedback control. So we propose angular rate computationalgorithm which derive angular rate from the velocity of differentiated carrier phase og GPS. The proposed algorithm contains attitude determination using double-differentiated carrier phase and 2 baseline configuration whcih provide more practical applications than 3 baseline.
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In this paper, we performed simulations of aircraft automatic landing using GPS, DGPS and CDGPS. Our purpose is examining the possibility of aircraft landing using GPS through the simulation results. The aircraft landing is composed of two stages, glide-slope and flare. Therefore, LQG controllers are designed separately. In simulations, measurement noise depends not only on UERE and UERRE(which have different values in GPS, DGPS, and CDGPS) but also on DOPs. DOPs are determined only by the geometry of GPS satellite constellation. For DOP calculation, we also made program for GPS satellites orbit simulatiion. Accordin to the simulation results, ICAO CAT III can be achieved of CDGPS is used.
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The federated Kaman filter(FKF) is being widely used in many multisensor navigatiion systems. It is know that the FKF has advantages of simplicity and fault-tolerance over other decentralized filter techniques. In this paper, optimal and suboptimal FKF configuratiions are mentioned and a covariance analysis technique for the suboptimal FKF is newly presented. The suboptimal FKF configuration, known as No-reset(NR) mode, has better fault tolerance capability than the optimal FKF coniguratioin. In the suggested technique, a suboptimal fusion process of FKF is considered a swell as suboptimal gains of local filters. An upper boun of error covariance for suboptimal FKF is derived. Also, it is mathematically shown that this bound is smaller thanexisting bound in the literatrue. A vehicle-navigaion system is designed using the FKF. In thissystem, a map constraing equation is introduced and used as a measurement equatioin of Kalman filter. Performance analysis is done by the suggested covariance analysis techniques.
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This paper presents the algorithm for estimating the attitude of an underwater vehicle using EFK. The system model is designed by linerizing the nonlinear Euler angle differential equation and the measurements is a speed logger output. The simulation result shows that the estimation lagorithm is adequate for decreasing attitude errors that grow abruptly during the motion with acceleration and rotation. It also shows that we can adapt the algorithm for compensating initial attitude errors generated after initial leveling.
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There are various methods to detect the faulty electric facilities(esp, insulator) indirectly on power distribution lines at a certain distance apart. This paper describes the proto type equipment to detect a faulty insulator by receiving a electric discharge noises, which are generated with a periodicity of 120Hz.
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Development and realizatioin of adaptive Active Noise Cntrol used for quieting transformer nosie are planed to provide workers with comfortable working environment and to attenuate the noise for residents in many noisy areas(power plant, power transformer, GIS transformer etc.).
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To operate electric power systems economically and stably, and to supply the electric power of good quality, it is necessary that the measured information (current, voltage, and so on) be detected and transmutted with high reliability and high effieincy. For the reason, the optical magnetic field sensor is possible to rapidly detect to over current and recover when electric power line have fault. In addition, the optical sensor have no electro magnetic distortion and no electric insulation. In this study, we designed OCR(Over Current Relay) using optical sensor. The designed OCR using optical sensor was measured characteristic and compared contentional OCR. This system have highest optical advantages and reliability.
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This paper presents a vision algorithm for finding the centers of steam generator tubes using the generalized symmetry transform, which is used for ECT(Eddy Current Test) of steam generator tubes in nuclear power plants. The geometrical properties of the image representing steam generator tubes shows that they have amost circular or somewhat elliptic appearances and each tube has strong symmetry about its center. So we apply the generalized symmetry transform to finding centers of steam geneator tubes. But applying the generalized symmetry transform itself without any modification gives difficulties in obtaining the exact centers of steam generator tubes. But applying the generalized symmetry transform itself without any modification gives difficulties in obtaining the exact centers of tubes due to the shadow effect generated by the local light installed inside steam generator. Therefore we make the generalized symmetry transform modified, which uses a modified phase weight function in getting the symmetry magnitude in order to overcome the misleading effect by the local light. The experimental results indicate that the proposed vision algorithm efficiently recongnizes centers of steam generator tubes.
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We had developed the on-line environmental monitoring system which has installed around Kori Nuclear Power Plants and will be taken the place of the existing system. The system consists of a main computer and 11 sets of radiation monitoring post equipments. Nal(Tl) scintillation detectro was adopted in addition to ion-chamber detector and implemented with DCU(Dose Conversion Unit) and SCA(Single Channel Analyzer). Compared with the existing system, it has revised feature in the radiation measurements which are detection of artificial radioactivity and 2-ways of the radiatiion detectors. The field test trsults show that the developed radiation detecting equipments can measure environmental radiation withn 5.0% of the theoretical value.
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In this paper, we presents the algorithm which is to recognize the traffic sign on the road the traffic signal in a video image for autonomous navigation. First, the rocognition of traffic sign on the road can be detected using boundary point estimation form some scan-lines within the lane deducted. For this algorithm, index matrix method is used to detemine what sign is. Then, the traffic signal recognition is performed by usign the window minified by several scan-lines which position may be expected. For this algoritm, line profile concept is adopted.
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We introduce a fast implementation of the adaptive transversal filter which uses least-mean-square(LMS) algorithm. The fast Hadamard transform(FHT) is used for the implementation of the filter. By using the proposed filter we can get the significant time reduction in computatioin over the conventional time domain LMS filter at the cost of a little performance. By computer simulation, we show the comparison of the propsed Hadamard-domain filter and the time domain filter in the view of multiplication time, mean-square error and robustness for noise.
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Discrete cosine transform(DCT) is the most popular block transform coding in lossy mode. DCT is close to statistically optimal transform-the Karhunen Loeve transform. In this paper, a module for DCT encoder is made with TMS320C80 based on JPEG and MPEG, which are intermational standards for image compression. the DCT encoder consists of three parts-a transformer, a vector quantizer and an entropy encoder.
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In this paper we propose a novel way to restore degraded image using wavelet transform & filterbank. First, we devide a degraded image into 4-suband images using UDWT(Undecimated Wavelet Transform), and then use a proper CLS (Constrained Least Square) filter in each subband. Using a proper CLS filter ineach subband, we can save high grequency components of original image. We reconstruct a restored image from the downsampled subband images using wavelet tansform. Even though there is a trade-off between ISNR and calculation loads, we reduce the calculation loads by using wavelet transform in reconstruction with a negligible degradatiion in ISNR.
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This paper proposes a new image processing algorithm to recognize korean documents. It take out the region of text area form input image, then it makes esgmentation of lines, words and characters in the text. A precision segmentation is very important to recognize the input document. The input image has 8-bit gray scaled resolution. Not only the histogram but also brightness dispersion graph are used for segmentation. The result shows a higher accuracy of document recognition.
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Flexible parts comparing with rigid parts can be deformed by contact force during assembly. for successful assembly, information about their deformation as well as possible misalignment between mating parts is essential. Howecer, because of the complex relationship between parts deformation and reaction forces, it is difficult to acquire all required information from the reaction forces alone. In this paper, we measure parts deformation and misalignments by using the visual sensing system presented for flexible parts assembly. Experimental results show that the system can be effectively used for detecting parts deformation and misalignments between mating parts.
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Design methodology of Interactuve Measuring Part Program Generating Tools(IMPPGT) realized on the FANUC 15MA using touch trigger probes and interactive macro functions of the CNC was described in this paper. Measuring G codes have been designed according to probe ste up, basic and applied inspection items by using measuring arguments. Menu driven measuring and inspection functions of the IMPPGT were studied and implemented on the CNC through the macro executor and ROM writer. Using the developed measuring G code system on the machine tool, untended measurement and inspection operation was able to be realized in precision FMS lines.
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Generally, G.P.S(Global Positioning System) is using for the car navigation system but it has some restrictions such as the discontinuity of earth satellites and SA (Selective Availability). Recently, the hybrid navigation system combining with G.P.S and Dead-reckoning are much attractuve for improving the accuracy of a vehicle positioning. G.P.S called satellite navigation system, can measure its position by using satellites. Dead-Reckoning is the self-contained navigatioin system using a wheel sensor for the vehicle velocity and a gyro sensor for the vehicle angular velocity. Some algorithm could be generated for finding the vehicle position and orientation. In this paper, we developed a hybrid algotithm wiht G.P.S DR and Map-Matching.
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Advanced sensor design and filtering technology have been studied to obtain information for condition monitoring and diagnostics inmachining processes. To develope and economic monitoring system in end milling processes, indirect and reliable type of cutting force estimators were required. In this paper, an estimation method of cutting forces during end milling processes was studied through the measurement of current signals obtained from spindle and feeddrive motors. Cutting force and torque models were derived from the cutting geometry in down milling processes. Relationships between motor currents and cutting forces were also developed in the form of AC and DC components from the developed force models. The validity of the cutting force estimator was confirmed by the experiments under various cutting conditions.
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It is essential to obtain a distane informaion in order to completely execute assembly tasks such as a grasping and an insertion. In this paper, we propose a method estimating a measurement distance from a sensor to an object through using the omni-directional image sensing system for assembly(OISSA) and show its features and feasibility by a computer simulation. The method, utilizing a forwarded motion stereo technique, is simple to search the corresponding points and possible to immediatiely obtain a three-dimensional 2.pi.-shape information.
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An accurate length measuring system has been develope by a modified Michelson interferometer. A frequency stabilized laser source and a 20 fold frequency interpolation and digitizing circuit were applied to the system. Resolutioin of .lambda./40, 16 nm, was achieved from the discrete length measuring system. In order to obtain a resoltuion of 1.mu.m a decimalizing module was designed for the 0.016.mu.m resolution system. The refractive index of the ambient air was calibrated on the decimalizing module through the Edlen's formula. Performance of the system was evaluated on the machining center in short and long length measruements.
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This paper deals with the Appliation of robust fault detection problem in uncertain linear systems, having both model mismatch and noise. A robust fault detection method presented by Kwon et al.(1994) for SISO uncertain systems. Here we experimented this method to the diesel engine systems described by difference ARMA models. The model mismatch includes here linearization error as well as undermodeling. Comparisons are made with alternative fault detection method which do not account noise. The new method is shown to have good performance.
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This paper deals with an algebraic approach to FDI observer design procedure. In general, FDI observer can be designed a sLuenbrger-type and equations for unknown input and actuator fault estimation include derivation of system outputs which is not available from the measurement directly. At this point, this paper presents STWS approach which can convert the derivation procedure to the recursive algebraic form by using its orthogonality and disjointess to alleviate such problems.
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This paper presents an efficient fault diagnosis methodology for lare chemical processes. The methodology is based on a two-tier strategy, When a falt occurs in a process, a top tier identifies the sector (process part or unit) that may contain the fault(s). Afterwards, a bottom tier or lower level evaluates the suspicious sector. The process modeling methodology based on functionality-behavior relations of process units, is proposed and utilized in the top-tier. This methodology models a target process as sequences of functions and variables and their relations. In the bottom tier, each sector has a dedicated diagostic module, which is tailored to the available information or models of the sector. For the sectors selected in the top-tier diagnosis, each diagnostic module is executed to identify the actual faults within the sector. Teh utility of the methodology is illustrated in the diagnosis of the CSTR with heat exchanger.
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This paper proposes a fault detection and isolation metho by combining the parameter estimation method[4] with the observer method[2] to use merits of both methods. To verify the performance of the method proposed some simulations applied to remotely piloted vehicle are performed.
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The objective of this paper is to present an efficient and practical approach to the automatic classification of power quality(PQ) disturbances, where and orthogonal polynomial approximation method is emloyed for the detection and localization of PQ disturbances, and a feature vector, newly extracted form the bispectra of the detected signal, is utilized for the automatic rectgnition of the various types of PQ disturbances. To demonstrae the performance and applicabiliyt of the proposed approach, some simulation results are provided.
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The optimal residual generator based on parity relation approach for the fault detection and isolation of a arge diesel engine actuator position servo system is presented. The closed-loop residual generator is designed to have robustness against modeling errors and noise. Main purpose of the fault detection and isolation system in the process is to detect and isolate two important faults, i.e., actuatro fault and fault of speed sensor, that, if not detected and compensated, degrade the overall control system performance. Simulation results are give to show the practical applicability of the fault detecrtion and isloation scherme.
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In this paper, the problen of dseigning a H.inf. controller is considered, where the controller is realized through digital equipment. We show that the existing discrete-time controller design method can be improved by usign the inveres bilinear transformation. The usefulness of the given method is confirmed by simulation.
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In this paper, a speed control of nin-servo induction motor is considered. In this case, it is difficult to satisfy precise control performance. SO H.inf. robust controller is designed for this problem by usign polynomial approach and Youla parameterization.
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This paper studies the problem of approximating commensurate input delay sustems by finite dimensional systems based on the Hankel singular values. I is shown that the Gankel singular values are solutions a trancendental equation and the Hankel singular vectors are obtained form the kernel of the matrix. The computaioin is carried out in state spae framework. Once singular values and vectors are calcualted, finite dimensional approximated systems are constructed using stadnard linear system computational tools. An example is included.
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In this paper, a control system using robust H.inf. controller based on convex parametrization is presented for nonlinear system with uncertainty. accounting for the time delay, noise and linearization error by frequency analysis, the suboptmal controller is designed to meet robust stability and performance for uncertainty. The desinged control system is applied to a nonlimear boiler moderl to test its performances.
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The aim of this paper is to suggest a design method of the model following optimal boiler-turbine H.inf. control system using genetic algorithm. This boiler-turbine H.inf. control system is designed by applying genetic algortihm with reference model to the optimal determination of weighting functions and design parameter .gamma. that are given by Glover-Doyle algornithm whch can design H.inf. contrlaaer in the sate. space. The first method to do this is ghat the gains of weightinf functions and .gamma. are optimized simultaneously by genetic algroithm. And the second method is that not only the gains and .gamma. but also the dynamics of weighting functions are optimized at the same time by genetic algonithm. The effectiveness of this boiler-turbine H.inf. control system is verified and compared with LQG/LTR control system by computer simulation.
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We propose a decentralized state estimation method in the multisensor state estimation problem. The proposed method bounds teh maximum energy gain from uknown external disturbances to the estimation errors in the suboptimal case. And we formulate aternative H/sip .inf./ filter gain equatiions with teh idea that the suboptimal H.
$^{\infty}$ filter is the special form of Kalman filter filter whose state equations are defined in indefinite inner product spaces. Using alternative filter gain equations we design the decentralized$H^{\infty}$ state estimator which is composed of local filters and central fusion filter that are suboptimal in the$H^{\infty}$ sense. In addition, the proposed update equations between global and local data can reduce unnecessary calculation burden efficently.y. -
For system state estimation, existing LMS type esimators widely used. For example Kalman filter is one of them. In this paper, a state estimator is derived for the H
$_{\infty}$ norm of the estimation error spectrum matrix to be minimized. For the solution of this problem classical NP interpolation problem is used. Also, by deriving the duality between the filter problem and the well-known H$_{\infty}$ control problem, another solution is obtained. The computer simuation results show that H$_{\infty}$ estimator has less estimation error and so this is better than the existing Kalman filter estimator.or. -
This paper presents a scheme for continuous-time fuzzy modelling of nonlinear systems, based on the adjustment technique and the genetic algorithm technque. The fuzzy model is characterized by fuzzy "If-then" rules whcih represent locally linear input-output relations whose consequence part is defined as subsystem of a nonlinear system. To compute the final output and deal with the initialization and unmeasurable signal problems in on-line estimatio of the fuzzy model, a discrete-time model is obtaned. Then the parameters of both the premis and consequence of the fuzzy model are adjusted on-line by a genetic algorithm. A simulation work is carried out to demonstrate the effectiveness of the proposed method.ed method.
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This paper is concerned with the design of a suboptimal robust Kalman filter using LMI approach for system models in the state space, which are subjected to parameter uncertainties in both the state and measurement atrices. Under the assumption that augmented system composed of the uncertain system and the state estimation error dynamics should be stable, a Lyapunov inequality is obtained. And from this inequaltiy, the filter design problem can be transformed to the gneric LMI problems i.e., linear objective minimization problem and generalized eigenvalue minimization problem. When applied to uncertain linear system modles, the proposed filter can provide the minimum upper bound of the estimation error variance for all admissible parameter uncertainties.
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The vehicle driving simulator expects vehicle motion with real-time simulation arise from driver's steering, accelerating, stopping and simulates motion of vehicl with visula, audio and washout algorithm. And it gives a vivid feeling to driver in reality. Vehicle driving simulator with vehicle integration control system is used for analysis of analysis of vehicle controllaility, steering capacity and safety in various pseudo environment alike. basides, it analyzeds vehicle safety factor dirver's reaction and promotes traffic safety without driver's own risks. The main proceduress of development of the vehicle driving simulator are classified by 3 parts. first the motion base system which can be generated by the motion queues, should be developed. Secondly, real-time vehicle software which can afford the vehicle dynamics, might be constructed. The third procedure is the integration of vehicle driing simulator which can be interconnected between visual systems with motion base. In this study, we are to study of the motion base for a vehicle driving simulator design and that of its real time control and using an extra gyro sensor and accelerometers to find a position and an orientatiion of the moving platform except for calculating forward kinematics. To drive the motion base, we use National Instruments corp's Labview software. Furthemore, we use analysis module for the vehicle motionand the washout algorithm module to consummate driving simulator, which can be driven by human in reality, so we are doing experimentally process about various vehicle motion conditon.
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The capacity of memory chip has increased vert quickly and 64MDRAM becomes main product in semiconductor manufacturing lines consists of many sequential processes, including etching process. although it needs direct sensing of wafer state for the accurae detching, it depends on indirect esnsing and sample test because of the complexity of the plasma etching. This equipment receives the inner light of etch chamber through the viewport and convets it to the voltage inetnsity. In this paper, EDP voltage signal has a new role to detect etching failure. First, we gathered data(EPD sigal, etching time and etchrate) and then analyzed the relationships between the signal variatin and the etch rate using two neural network modeling. These methods enable to predict whether ething state is good or not per wafer. For experiments, it is used High Density Inductive coupled Plasma(HDICP) ethcing equipment. Experiments and results proved to be abled to determine the etching state of wafer on-line and analyze the causes by modeling and EPD signal data.
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To increase reliability and performance of an IMS(Intelligent Manufacturing System), fault tolerant control based on an accurate fault diagnosis is needed. In this paper, robot FDI(fault detection and identification) is proposed for IMS where the robot is controlled with state estimates of a nonlinear filter using a mathematical robot model. The Chi-square distribution is applied fault detection and fault size is estimated by a proposed bias filter. Performance of the proposed algorithm is tested by simulation for studies.
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Cropping of head and tail ends of rod in wire Rolling Process is required to aviod roll damage, and prevent cobbles. In order to reduce the crop loss, the new crop control system for rotary shear of Wire rolling Process has been developed. Performance shows the developed system cut precisely within setting length. As a result, it is expected to increase the yield ratio of products about 0.2 percent and stabilize the operantional condition.
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Recently the major requirements have emerged in industrial substation system field. One is the simple arrangement of main power supply equipment and the other is the introduction of highly computer-controlled system for operation, maintenance and protection. This paper deals with the systems including motor-type relay systems, supervisory and control systems, digital type relay protectiion systems.
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In this paper a multiple channel EPD controller is developed which enables us to detect endpoints simultaneously in the plasma etching process operated in multiple etching chambers and its performance characteristic are investigated. for the accurate detectiion of endpoint the developed EDP controller was able to implement endpoint detectiions by integrating the existing EPD controllers with the techiques of artificial intellignet, to enhance its performance. The performance of the developed EPD controller was carried out by repeated experiments of endpoint detection in the acrual production line of semiconductor manufacturing. It's utility for endpoint detectiion was accurately evaluated in various etching process. The control capability of multiple etching chambers enhances its application compared with the existing one, and also increases the user utility os that the efficiency of operation was improved.
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In this paper, we investigate a traffic flow modeled by stochastic Petri nets. The model consists of two parts : the traffic flow model and signal controller model. These models are used for analyzing the flow of the traffic intersection. The results of the evaluation are derived from a Petri Net-based simulation package, Greatspn. Through simulation we compare the performances of the pretimed signal controller with those of the trafic-adaptive signal controller.
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In this paper, design parameters of Rapid Thermal Processing(RrW) to minimize the wafer tempera ture uniformity errors are proposed. 1,anip ling positions and the wafer height are important parameters for waf er temperature uniformity in R'I'P. We propose the method to seek lamp ling positions and the wafer height for optimal temperature uniformity. l'he ~~roposed method is applied to seek optimal lamp ling positions and the waf er height of 8 inch wafer. 'I'o seek the optimal lamp ling positions and the wafer height, we var\ulcorner. lamp ling 110s itions and the wafer height and then formulate the wafer temperature uniformity problem to the linear programmi ng problem. Finally, it is shown that the wafer temperature uniformity in RI'I' designed by optimal prarneters is improved to comparing with Ii'l'P designed by the other method.
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One of the advantages of master-slave teleoperation is scaling concept such as position scaling, force scaling Meanuhile, lots of quantization effects are generated from position and force sensors in the master and slave manipulator. In this paper, to show the output error caused by the quantizaion effects from the position sensor and position scaling factor, simulation is done for free motion without contact in slave side. Transfer functiion model in which the quantization effect is assumed to be a disturbance input to the system is derived. Model shows that Jacobian, scaling factors, and controller affect the output by quantization effects form esnsors. One dof master and slave are used for simulation. In our study, the higher sensor resolution decreases the output error form quantization. Scaling factors can amplify the quantizatiion effects form the sensors in master and slave manipulators.
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With disseminationof Distributed Control Systems(DCS), the huge amounts of process operation data could have been available and led to figure out process behaviors better on the statistical basis. Until now, the statistical modeling technology has been susally applied to process monitoring and fault diagnosis. however, it has been also thought that these process information, extracted from statistical analysis, might serve a great opportunity for process operation improvements and process improvements. This paper proposed a general methodolgy for process operation improvements including data analysis, backing up the result of analysis based on the methodology, and the mapping physical physical phenomena to the Principal Components(PC) which is the most distinguished feature in the methodology form traditional statistical analyses. The application of the proposed methodology to the Balst Furnace(BF) process has been presented for details. The BF process is one of the complicated processes, due to the highly nonlinear and correlated behaviors, and so the analysis for the process based on the mathematical modeling has been very difficult. So the statisitical analysis has come forward as a alternative way for the useful analysis. Using the proposed methodology, we could interpret the complicated process, the BF, better than any other mathematical methods and find the direction for process operation improvement. The direction of process operationimprovement, in the BF case, is to increase the fludization and the permeability, while decreasing the effect of tapping operation. These guide directions, with those physical meanings, could save fuel cost and process operator's pressure for proper actions, the better set point changes, in addition to the assistance with the better knowledge of the process. Open to set point change, the BF has a variety of steady state modes. In usual almost chemical processes are under the same situation with the BF in the point of multimode steady states. The proposed methodology focused on the application to the multimode steady state process such as the BF, consequently can be applied to any chemical processes set point changing whether operator intervened or not.
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A rigorous dynamic simulation was performed in binary gas mixture H
$_{2}$ /CO (70:30 vol.%) to determinate start-up operating conditions of PSA(Pressure Swing Adsorption) processes. The rigorous dynamic model for the PSA process contains an Ergun equation for expressing the pressure drop in a bed, and valve equations to compute the boundary pressure change of the bed. As the result of the continuous dynamic simulation of 100 operating cyles in various initial conditions, the unsteady-state appeared in the early period and the cyclic steady-state came out about 20th cycle in feed condition and vaccum condition, and 30th cycle in pure H$_{2}$ condition. As time goes by valve equations made change the pressure at each end of the bed in ressurization, countercurrunt-depressurization and pressure equalization steps. The H$_{2}$ purity and the recovery is 99.99% and 86.73% respectively, which is slightly higher than the experimental data. Main contributiion of this study includes supplying fundamental technologies of handling combined variables PSA processes by developing rigorous models. -
로봇기술의 발달로 인하여 로봇의 활용 분야는 점차 확대되고 있으며 의료 및 재활분야에도 이용되는 추세이다. 의료분야에 이용되는 메디칼 로봇은 최소 절개 수술에 적용하는 경우 많은 이점을 얻을 수 있다는 점과 전문의사가 현장에 있기 힘든 오지나 낙도 또는 전쟁터 같은 곳에서도 원격 수술이 가능하다는 장점으로 많은 관심을 받고 있다. 원격 수술은 수술 계획, 로봇에게 환자 등록, 원격 수술 시행의 세가지 과정을 거치게 된다. 본 논문에서는 원격 수술을 위한 위 과정의 연구 동향을 기술하고 현재 본 실험실에서 수행하고 있는 연구 내용을 다룬다. 원격 수술을 위한 의료시스템을 구축하기 위해 팬-틸터 구동부를 가지 스테레어 시각 시스템을 제작하고 여기서 얻어지는 정보를 HMD에 투시하여 현장감을 느끼게 만드는 것과 수술대에서 환자를 수술하는 듯한 느낌을 제공할 수 있는 기술인 매스터 조작기와 슬레이브 조작기 사이의 힘 피드백 구현에 대해 다룬다.
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Many radiological modalities has been applied to medicine as a basic fundamental diagnosis and therapy recently. The prevalence of computer systems affect most images to be digitized. However conventional X-ray film images are not digital images eventhough they covers 70% of all radiologica images. This is the hinderacne of building PACS. In this paper all radiological digital imaging parts such as DSA. CR. MRI. SPECT. PET and ultrasonography were briefly introduced and the applications were described. In brief digital radiography contribute to enhance the medical service quality. And the digital substituition of conventional X-ray film image is inevitable.
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Recently, many advanced technologies in electronics, mechanics, material and computer science have been applied to medictine and they have changed the method of diagnosis and treatment to more quantitative way than before. Now day, with the aid of this technology, the device for the minimal invasive diagnosis and treatment is being developed for the convenience and safety of patients. this paper introduces application of senso and MEMS(Micro Electro Mechnical System) in medicine and biotechnology, which are essential factor for the realization of minimal invasive diagnosis and treatment.
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The rehailitation robot, one of the service robot, is the important area in the service automation. In the paper, we describe the overall configuration of KARES(KAIST Rehabilitation Engineering System), which is an intellingent rehabilitaion robotic system designed to assist the independent livelihood of the handicapped and the eldrly. KARES consists of the 6 degree of freedom robot arm mounted on a wheelchair, the controller ofr the arm, sensors to perceive environment, and user interface. Basic desired hobs in KARES are gripping the target object and moving it to the user's face for eating, drinking, or cooperation work wiht the mouth. Currently, the manual operation of the arm is available for gripping to target objects. The autonomous functionality will be ginven for the facilities of the human operator.
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A Force-refecting hand controller can provide the kinesthetic information obtained from a slave manipulator to the operator of a teleoperation system. This thesis presents the desgn and the analysis of a 6-degree-of-freedom force-reflecting hand controller using fivebar parallel mechanism. The goal of this thesis is to construct a superior hand controller that can provide large workspace and good force-reflecting ability. The forward kinematics of the fivebar paprallel mechanism has been calculated in real-time using three pin-joint sensors in addition to six actuator position sensors. A force decomposition approach is used to comput the Jacobin. To analyze the characteristics of the fivebar parallel mechanism, it has been compared with the other three parallel mechanisms in terms with workspace and manipulability measure. The force-reflecting hand controller using the fivebar parallel mechanism has been constructed and tested to verify the feasibility of the design concept.
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In this paper, a optimal algorithm that can produce the FOV is proposed in terms of using the Kohonen's Self-Organizing Map(KSOM). A FOV, that stands for "Field Of View", means maximum area where a camera could be wholly seen and influences the total time of inspection of vision system. Therefore, we draw algorithm with a KSOM which aims to map an input space of N-dimensions into a one-or two-dimensional lattice of output layer neurons in order to optimize the number and location of FOV, instead of former sequentila method. Then, we show demonstratin through computer simulation using the real PCB data. PCB data.
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In the paper, we porpose a new mehtod of extending PLS(Partial Least Squares) regressiion method to nonlinear framework and apply it to the estimation of product compositions in high-purity distillation column. There have veen similar efforets to overcome drawbacks of PLS by using nonlinear-mapping ability of meural networks, however, they failed to show great improvement over PLS since they focused only in capturing nonlinear functional relationship between input data, not on nonlinear correlation inthe data set. By incorporating the structure of Robust Auto Associative Networks(RAAN) into that of previous nonlinear PLS, we can handle nonlinear correlation as well as nonlinear functional relationship. The application result shows that the proposed method performs better than previous ones even for nonlinearities caused by changing operating conditions, limited observations, and existence of meas-unrement noises.
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In this paper, we have built an experimental magnetic levitation system for a possible use of control education. We have give a mathermatical model of the nonlinear system and have shown the stability region of the linearized system when it is controlled by a PD controller. We also proposed a neural network control system which uses a neural network as a feedforward controller thgether with a conventional feedback PF controller. We have generated a desired output trajectory, which was designed for the benefit of the generalization of the neural network controller, and trained the desired output trajectory, which was desigend for the benefit of the generalization of the neural netowrk controller, and trained a neural network controller with the data of the actual input and the output of the system obtained by applying the desired output trajectroy. A good tracking performance was observed for both the desired trajectiories used and not used for the neural network training.
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In the study, simulation result was studied by connecting PID controller in series to the established Neural Networks Controller. Neural Network model is composed of two layers to evaluate tracking performance improvement. The reqular dynamic characteristics was also studied for the expected error to be minimized by using Widrow-Hoff delta rule. As a result of the study, We identified that tracking performance inprovement was developed more in case of connecting PID than Neural Network Contoller and that tracking plant parameter in 251 sample was approached rapidly case of time variable.
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In this paper, a fuzzy based machine-cell formation algorithm for cellular manufacturing is presented. The fuzzy lovic is employed to express the degree of appropriateness when alternative machnies are specified to process a part shape. For machine grouping, the similarity coefficient based approach is used. The algorithm produces efficient machine cells and part families which maximize the similarity values.
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In this paper, we present an associative memory network (AMN) controller for dynamic robot control. The purpose of using AMN is to reduce the size of required memory in storing and recalling large of daa representing input relationship of nonlinear functions. With the capability AMN can be used to dynamic robot control, which has nonlinear properties inherently. The proposed AMN control scheme has advantages for the inverse dynamics learning no limitatiion of inpur range, and insensitive of payload change. Computer simulations show the effectiveness and feasibility of proposed scheme.
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In this paper we present an associative menory network(AMN) controller for learning of robot trajectories. We use AMN controller in order to improve the performance of conventional learning control, e.g. RCL, which had studied by Sadegh et al. Computer simulations show the feasibility and effectiveness of the proposed AMN controller.
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A hybrid control method based on using the relative motion between a manipulator and a workpiece is described for a two-dimensional manipulator, in which it is assumed that there are no collisions between the robot manipulator and the workpiece, and that we use a computed force law which is similar to the computed torque law in the trajectory tracking problem of a robot manipulator. The effectiveness of the proposed hybrid control emthod is illustratec by some simulations.
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This paper poropsed an efficient optimization technuque to resolve redundancy and a trajectory planning for a high precision control using proposed optimization technique. The proposed techniqus is the joint disturbance torque optimizatioin considering redundancy in the joing servo control. Joint disturbance torque is not unknown it is described dynamic equation ignored friction and viscosity. The proposed technique is used the dynamic equatiion included the joint disturbance torque characteristics. Numerical example of 3 joint planar redundant robot manipulator is simulated. In the 2-norm minimization of joint disturbance torque we compared pseudoinverse local optimization with proposed technique, and the results showed better the proposed technique. So the proposed technique can be highly precision controlled redundant robot manipulators in the joint servo control.
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In this paper, divide total workspace of robot manipulator into several subspaces and construct PID controller ineach subspace. Using EvolutionSTrategy we optimize the gains of PID controller in each subspace. But the gains may have a large difference on the boundary of subspaces, which can cause bad oscillatory performance. So we use Aritificial Neural Network to have continuous gain curves htrough the entire subspaces. Simualtion results show that the proposed method is quite useful.
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Among the prerequisite abilities (perception of environment, path planning and position estimation) of an autonomous mobile robot, position estimation has been seldom studied by mobile robot researchers. In most cases, conventional positioin estimation has been performed by placing landmarks or giving the entrire environmental information in advance. Unlikely to the conventional ones, the study addresses a new method that the robot itself can select distinctive features in the environment and save them as landmarks without any a priori knowledge, which can maximize the autonomous behavior of the robot. First, an orjentaion probaility model is applied to construct a lcoal map of robot's surrounding. The feature of the object in the map is then extracted and the map is saved as landmark. Also, presented is the position estimation method that utilizes the correspondence between landmarks and current local map. In dong this, the uncertainty of the robot's current positioin is estimated in order to select the corresponding landmark stored in the previous steps. The usefulness of all these approaches are illustrated with the results porduced by a real robot equipped with ultrasonic sensors.
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Because the leg mechanism of walking roblt affect on the mobility and energy efficiency, we focus on the design of new leg mechanism based on the previous leg mechanisms. We mention the deficiency of the previous leg mechanisms and propose a new leg mechanism that consists of a 2-d.o.f pantograph mechanism and a vertical linear actuator. The pantograph mechanism is attached to the horizontal plane of the body and the verical linear actuator is vertical to that plane. In order to design a quadruped walking robot, we consider the kinematics of the 2-d.o.f pantograph mechanism and the arrangement of twol linear motion guides that drive the pantograph mechanism.
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Most autonomous mobile robots view things only in front of them. As a result they may collide against objects moving from the side or behind. To overcome the problem we have built an Active Omni-directional Range Sensor that can obtain omni-directional depth data by a laser conic plane and a conic mirror. Also we proposed a self-localization algorithm of mobile robot in unknown environment by fusion of Odometer and Active Omn-directional Range Sensor.
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The most important topic in research of mobile robot is path planning in order to avoid with obstacle. In this study the path planning algorithm using a neural network model is proposed. The inputs of neural network are range data which are acquired form laser range finderm and weights are based on difference with goal direction. The thresholds are made by consdiering the marginal distance between mobile robot and obstacle. Consequently the outputs are obtained by multiplying input and weight. The obtained heading directiion enables the mobile robot to approach the goal, without any collision with obstacles around. The effectiveness of the this method of real-time navigation of a mobile robot is estimated by computer simulation in complex environment.
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In this paper, a new onmidirectional robot with one spherical wheel is porposed. The peculiar structure of the proposed mobile robot makes it possible not only to move sideways but to be easy to implement. The wheel is derived by two stepping motors and equipped with 8-infrared sensors. To prove the validity of the proposed robot, the experiment of going through a way is performed.
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Kinematically redundantant manipulators have a nimber of potential advantages over nonredundant ones. Questions associated with manipulability measures for (non)redundant manipulators derived by minimum 2-norm solution and minimum infinity-norm solution in unit joint velocity are examined in detail.
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In order to develop a human hand mechanism, a 5-bar finger with redundant actuation is designed and implemented. an optimal set of acutator locations and link lengths for the case of one redundant actuator is obtained by employing a composite design index which simulataneously consider several performance indices such as workspace, isotropic index, and force transmission ratio. Each joing is driven by an compact actuator mechanism having ultrasonic motor and a gear set with poeneiometer an controlled by VME Bus-based control system.
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This paper describes the camera caliberation based-neural network with a camera modeling that accounts for major sources of camera distortion, namely, radial, decentering, and thin prism distortion. Radial distoriton causes an inward or outward displacement of a given image point from its ideal location. Actual optical systems are subject to various degrees of decentering, that is the optical centers of lens elements are not strictly collinear. Thin prism distortion arises from imperfection in lens design and manufacturing as well as camera assembly. It is our purpose to develop the vision system for the pattern recognition and the automatic test of parts and to apply the line of manufacturing. The performance of proposed camera aclibration is illustrated by simulation and experiment.
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Use of teaching pendant is the most widespread and economical way to teach desired motion to robots. It is also very primitive,time consuming and ineffective way of teaching which has not changed since the early days of robot. In order to reduce the teaching effor, a new efficient form of teaching is needed. Also, the recent robotics research trend into service robots such as home robot, nurse robot and medical robot calls for a new teaching method which is both easy and inexpensive. In this paper, the design and operation principle of a low cost force/moment sensor is presented. The proposed sensor architecture is so simple and inexpensive that it opens the prospect for a new paradigm of robot teaching which is easy and efficinet. Other prospective areas of application are tele-manipulation of robots wher it can be used in master arm, and virtual environment where it can be used as an user input device.
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The 6-DOF parallel manipulator is a closed-kindmatic chain robot manipulator that is capable of providing high structural rigidity and positional accuracy. Because of its advantage, the parallel manipulator have been widely used in many engineering applications such as vehicle/flight driving simulators, rogot maniplators, attachment tool of machining centers, etc. However, the kinematic analysis for the implementation of a real-time controller has some problem because of the lack of an efficient lagorithm for solving its highly nonliner forward kinematic equation, which provides the translational and orientational attitudes of the moveable upper platform from the lenght of manipulator linkages. Generally, Newton-Raphson method has been widely sued to solve the forward kinematic problem but the effectiveness of this methodology depend on how to set initial values. This paper proposes a hybrid method using genetic algorithm(GA) and Newton-Raphson method to solve forward kinematics. That is, the initial values of forward kinematics solution are determined by adopting genetic algorithm which can search grobally optimal solutions. Since determining this values, the determined values are used in Newton-Raphson method for real time calcuation.
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The purpose of this study is to see the method of the analysis of EEG(Electroencephalography) whcih is a nonlinear system, to quantize human emotion under color stimulation using the analysis of EEG. The result of this study would be used clinical study and development fo image instruments with color. In this study, the method of the analysis of EEG is power spectrum using FFT(Fast Fourier Transform) and the modelling of EEG under color stimulation base on back propagation Neural Networks ond of AI(Artfical Intellignece) skills. First, input layer make a match to relative power which get analyzing s in 4 channels, and output layer make a match to color stimulation which is measured human emotion. Finally, weights of each neurons determine by learing back porpagation Neural Networks.
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Since surgery is usually a difficult task because of physiological tremor, eye strain, and tremor, contagious and radioactive hazard, it is necessary to develop micro-surgery telerobotic system using improved tools suitable for their specific tasks. Nowadays the growth of interest on microsurgery and medical applications of robotics has been so rapid. But the medical robots are only practical applications of the industrial robots. This paper identifies five general areas of advanced microsurgery based on the current technological background and expertise, and analyzes the motion, tool and accuracy with respect to microsurgery task, and proposed the criteria to evaluate micro-surgical manipulator. The analysis of microusrgery can be heplful to clarify some basic concept and design of micro-surgical manipulators. With these data we will alos propose an efficient in-parallel-platform manipulator having special kinematic structrue structure suitable for microsurgery.
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A measurement of conduction veloctiy of the action potentials along the muscle fibres has been applied to various diagnosis. When we measure muscle fiber conduction velocity, it occurs that not only change of conduction velocity but alos inclusion of mipulse component by physiological and experimental reason. So, robuster time delay estimation algorithm than general methods[1] is needed to find correct time delay form these signals. In this paper we, propose new time delay estimation algorithms, robust in impulsive noise, by using characteristic of .alpha.-stable distribution whcih defines impulsive noise well. Then we apply proposed algorthms to measure muscle fiber conduction velocity and compare them with other studies.
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In this paper, the autonomic function analysis system was designed to noninvasively assess the autonomic function of cardiovascular system. Orthostatic stress protocol was designed to stimulate the autonomic nervous system. designed protocol and analysis algorithm were evaluated by experiments for 25 normal subjects and 22 hemiplegia patients. Data were processed by usign the power spectral analysis. Nwe indexes of autonomic function, LF
$_{N}$ and HF$_{N}$ , were proposed and were compared with LF/HF ratio. New indexes of the sympathetic and parasympathetic activity, respectively. The IST and the DPT are balanced and have positive value for normal subjects during orthostatic stress but not for hempilegia patients. This result suggest that the IST and the DPT are used as new criteria of normal autonomic function during orthostatic stress.ess. -
In this study, the method is proposed, which enable us to noninvasively assess baroreflex sensitivity through the closed-loop feedback modle between RR flucturarion and arterial blood pressure fluctuation. The proposed indexes of baroreflex sensitivity, BRS
$_{LF}$ 와 BRS$_{HF}$ are calculated by the modulus (or gain) of the transfer function between fluctuatuons in blood pressure and RR interval in the LF band HF band, where the coherence is more than 0.5 to evaluate the performance of the proposed method, it is applied to various cardiovascular variability signals obtained form subjects under the submaximal ecericse on bicycle ergometner. In result it is concluded that the proposed method can noninvasively assess the baroreflex sensitivity.ty. -
This paper presents the control law of Automatic Rudder Trim System(ARTS) for the KTX-1. The proposed ARTS is designed mainly t reduce the pilot's work load for trimming in the various conditiions of engine torque. airspeed, and aircraft configuration. The ARTS partially compensates the transient yawing motion due to change of engine power in turboprop aircraft because of the limitation of the actuation speed of the trim motor. In this paper flight test data are analyzed to understand the phenomena and the dynamics of the reversible rudder flight control system is derived. Finally, the control concept and conrtol law of ARTS are described and the characteristics of the ARTS are analyzed through simulation study.
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Restiction of vertical and lateral accelerations is one of the very important requierments which has to be satisfied on the practice of automatically controlled flights of the civil aviation passenger planes. This goal could be achived on the basis of the optimization procedure using specilly constructed quadratic performance index. In the report the application of this procedure to the parameteric optimization of the control laws with known structure for autopilot of midium-size aircraft in the level flight model is demonstrated. Performance index is calculted on the basis of the controllability grammian. Results of simulation of control processes in the lateral and longitudinal channels sre represented.
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To obtain aircraft dynamic parameters, various estimation methods such as Maximum Likelihood, Linear Regression are applied. In this paper we adopt the extended Kalman filter(EKF) to estimate the stability and control derivatives in aircraft dynamic models from flight test data. The extended Kalman filter is applied to nonlinear augmented system assuming that unknown parameters are additional states. In this work, the results of the extended Kalman filter are compared with the results of the wind tunnel test using Chang Gong-91 aircraft flight test data.
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The objective of this paper is to estimate the aerodynamic derivatives of a single turbo-prop aircraft at a specified flight condition for the best deduction of the dynamic characteristics using modified maximum likelihood estimation method whcih is known to be unbiased, efficient, and consistent. The flight test data necessary to the estimation of aerodynamic derivatives is obtained by implementing the six degree of freedom nonlinear flight simulation to consider the effects of several control input types, control deflection amplitudes, and intensity of turbulence. The simulated data is added with the measurement noise, which is regarded as the actual flight test data.
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The purpose of this paper is to find how to determine the controllability and stability derivatives form flight test and to display the stability of the Twinbee aircraft. There are various methods developed to find the derivatives : wind tunnel testing, predicted result from empirical data, flight test and so on. Among those methods, the estimation form flight test of real aricraft is the most reliable. We performed the flight test of Twinbee and recorded the states of aorcraft. Using those states and parameter setimation algorithem based on the Maximum Likdlihood(MMLE) criterion, we can estimate the controllability and stability derivatives. In this paper, wel will show the process form designing the proper flight test input to estimation of derivatives.
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We consider the probelem of identifying and underwater vehicle. It is assumed that a priori information about the parameteric model structure and values of the hydrodynamic coefficients is available from some other schemes. The concept of relative esnsitivity is introduced to plan and efficinet identification procedure. An analysis of the sensitivity of the overall system to a particular hydrodynamic coefficinet provides a tool to evaluate the relative importance of the same coefficient in a particular maneuver. Then it can be made possible to reduce the filter size by selecting some dominatn hydrodynamic coefficients as parameters to be estimated for a given maneuver, and this fact may be used for establishing a gradual identification scheme. The main merit of a gradual identification is substantially reduced computer burden with increased nimerical stability. An illustrative simualtion result is given.
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In tihs paper, an acceleratiion transformation algorithm which compensates the sculling error is proposed for strapdown inertial navigation system. The algorithm utilize the corss-product of the acceleromenter outputs and gyro outputs to keep the accuracy of the vehicle velocity under high frequency dynamic motion. From the error analysis of the algorithm, it is shown that the magnitude of estimation error is reduced by four orders.
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In this paper, an attitude determination system(ADS) for KOMPSAT using GPS LI carrier phase measurements is considered. The baseline vector is estimated by the Exetnded Kalman Filter (EKF) which used the double differenced carrier phased measuremenmts made by three GPS receivers mounted on the spaceraft. The attitude angles of three axes of spacecrat are computed by the estimated baseline vectors, directly. The proposed ADS is verified by the simulation results.
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In this paper a linear Kalman filter for calibration of gimballed inertial navigation system(GINS) is designed and its performace is analyzed through the simulation with a real navigation data. Simulation results show that the proposed Kalman filter gives a good performance to calibrate the sensor errors.
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A dynamic load simulator which can reproduce on-ground the hinge moment of aircraft control surface is and essential rig for the loaded performance test of aircraft test of aircraft acutation system. The hinge moment varies wide in the aricraft flight enveloped depending on specific flight condition and maneuvering status. To replicate the wide spectrum of this hinge moment variation within some accuracy bounds, a force controller is designed based on the Quantiative Feedback Theory (AFT). Through the analysis on hinge moment dynamics, a design specification for the force controller is suggested. The efficacy of QFT force controller is verivied by simulation, in which combined aricraft dynamics/flight control law and hydraulic actuation system dynamics of aircraft control surface are considered.
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In the time-invarient system, the adaptive controller was designed for the non-tracking error in the 1980's. In this study, the Model Reference Adaptive Control using on-line processing method is used to identify the coefficients of the model, and the Robust Controller (H.inf.) is designed to stabilize the rigid body and the flexible body of satellite, which can be perturbed due to disturbance, etc. The result obtained by H.inf. controller is compared with that of the PI(Proportional and Intergation) controller which is commonly used for stabilizing satellite.
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In this paper, a new control scheme for master-slave control of telerobot is proposed. The porposed method can be classified into unilater master-slave control methods in the aspect of the data flow. But the master arm in the proposed control scheme can deliver operator the similar kinesthetic sense as other bilateral force reflecting master arms do. The principle concept is that the sensed operator's force/torque is used as the reference input for a damping controller type of telerobot controller which track the operators efforts. Master arm and master controller can be implemented in a simple form, and it needs not be driven by actuators, but force sensing capability.
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The robot mainpulator for inspection of pressurizer in the nuclear power plant has been developed, which consists of four parts : 2 arms, movable gripper, base frame, contorl console. To extract the damaged electric heating rod inside pressurizer, the gripper has been developed using wire lope and self-locking mechanism. for the examination of the structural stability of the robot manipulator, stress analysis is performed by using the ANSYS code.
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The flexibility of the manipulator inevitably inducess the vibration at the end effector. For the increase in speed and accuracy at the end tip, in this work, position and vibration control of a flexible manipuator with a separate voice coil type actrator for vibration suppression, is studied. The flexible manipulator with a tip mass is modeled an Euler-Bernoulli beam. An H.inf. controller is designed in order to make the controlled system robust against unmodeled higher-order mode vibration of the manipulator, output sensor noise, and etc. Simulations and experiments show that the modeling of the system is valid and that robust vibration control of the flexible manipulator is efficiently achieved.
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In this work, position and vibratiion control of a two-link manipulator with one flexible link, which an unkoun but bounded payload mass and two pair of artificial muscle-type penumatic actuators, are investgated. A flexible link robot has advantages over a figid link robot in the sense that it is much safer when it cones into contact with its environment, including humans. Furthermore, for the sake of safety, it would be more desirabel if an actuator could deliver required force while maintaining proper compliance. An artificial muscle-type penumatic actuator is adequate for such cases. In this study, a controller based on singular perturbation method, adaptive and sliding mode contro, and .mu.-synthesis is developed. The effectiveness of the proposed control scheme is confirmed through simulations and experiments.
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In teleoperation of a manipulator, kinesthetic feedback can take an essential role in the sense that it provides an operator with more realistic information. In this paper, in order to implement the concept of kinesthetic feedback, force mapping algorithms based on screw theory have been presented. In the development of such algorithms, the virtual environment has been modeled usign a spring and dampers, and the forces caused by hitting the joint limits of a conrtolled manipulator were considered. Finally, some experimental results of force mapping algorithm have been presented.
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A human operator is able to perform some tasks smoothly with force feedvack for the teleoperation or a virtual device in a the virtual environments. This paper describes a virtual force generation method with which operator can feel the interactive force between virtula robot and artificial environments. A virtual force generation algortihm is applied to generate the contact force at the arbitrary point of virtual robot, and the virtual force is displayed to the human operator via a tendon master arm consisted with 3 motors. Some experiments has beencarried out to verify the effectiveness of the force generation algorithm and usefulness of the developed backdrivable master arm.
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An image processing algorithm is developed in order to recognize the type of cars, the position of a number plate and the characters on the plate. to recognize the type of cars, comparison of two images is used. One has a car image, the other is just a background image without car. After that recognition, a vertical line filter is used to find the location of the plate. Finally the simularity mehod is used to recognize the numbers on plates.
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This paper presents image analysis method using a Markov random field(MRF) model. Particulary, image esgmentation is to partition the given image into regions. This scheme is first segmented into regions, and the obtained domain knowledge is used to obtain the improved segmented image by a Markov random field model. The method is a maximum a posteriori(MAP) estimation with the MRF model and its associated Gibbs distribution. MAP estimation method is applied to capture the natural image by TMS320C80(MVP) and to realize the segmented image by a MRF model.
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In general, the solvability of linear robust output regulation problem are not preserved under time-sampling. Thus, it is found that the digital regulator implemented by itme-sampling of anlog output regulator designed based on the continuous-time linear system model is nothing but a 1st order approximation with respect to time-sampling. By the way, one can design an improved sampled-data regulator with respect to sampling time by utilizing the intrinsic structure of the system. In this paper, we study the system structures which it is possible to design an improved sampled-data regulator with respect to sampling time.
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In this paper, a realization of a subband coding with TMS320C80 is studied. TMS320C80 is a multi-media processor specially designed for an image process. A main topic of this paper, as mentioned above, is an application of TMS320C80 to subband coding. Subband coding is the coding that devides full image to several subbands and encodes each subband with different coding methods. As using that methods, good image compression can be obtained. First above all, goal of this paper deals with TMS320C80 in coding still image and useds it in expending it's application to 3-D video coding.
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The conventional fire detection devices are operated after a processed fire phase, which are sensing only a high density of somke level or high temperature heat. They are not so precision to detect a fire in the early phase to protect the facility form the fire. We need to develope a new high precision smoke detection system to keep expensive industrial facilities most reliably form fire. A new optical precision smoke detection system was developed. It monitors very low level density of smoke particles in the air. It is operated continously through many years without a stop or any malfunction. The developed precision smoke detection system will be installed in important industrial facilities, such as power plants, underground common tunnel, main control rooms, computer rooms etc.
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This paper addresses the issue fo target classification and localization with a SONAR for mobiler robot indoor navigation. In particular, multiple refetions of SONAR sound are used actively and interntionally. As for the SONAR sensor, the multiple reflection has been generally considered as one of the noisy phenomena, which is inevitable in the indoor environments. However, these multiple reflections can be a clue for classifying and localizing targets in the indoor environment if those can be controlled and used well. This paper develops a new SONAR sensor module with a reflection plane which can actively create the multiple refection. This paper also intends to suggest a new target classification emthod which uses the multiple refectiions. We approximate the world as being two dimensional and assume that the targets consisting of the indoor environment are pland, corner, and edge. Multiple reflection paths of an acoustic bean by a SONAR are analyzed, by simulations and the patterns of the TOPs (Time Of Flight) and angles of multiple reflections from each target are also analyzed. In addition, a new algorithm for target classification and localization is proposed.
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We have developed a highly responsible probing system for inspection of electrical properties of assemble PCB
$_{s}$ (printed circuit boards). However, as the duration of the impact occurring between a probe and a solder joint on PCB is very short, it is very difficult to control the harmful peak impact force and the slip motion of the probe to sufficient level only by its vorce feedback control with high gains. To overcome these disadvantages of the prototype, it needs ot obtain some information of the solder joint in advance before the contact. In addition, to guarantee the reliability of the probing task, the probing system is required to measure several points around the probale target point at high speed. There fore, to meet such requirements, we propose a new noncontaet sensor capable of detecting simultaneously position and normal vectors of the multiple points around the probable target point in real time. By using this information, we can prepare a control strategy for stable contact motion on impact. In this paper, we described measuring priniciple, design, and development of the sensor. The effectiveness of the proposed sensor is verified through a series of experiments.s. -
A distributed optical fiber temperature sensor can continually monitor the measurand at every point along of its fiber length. It is based on OTDR technics which used extreamlly weak backward scattered light called Raman scattering. When the Pulsed high intensity laser light injected into the optical fiber there are several kind of backscattered light such as Rayleigh, Stokes, and anti-Stokes, etc. caused by impurities molecular vibrations. The temperature distribution is derived form the intensity ratio Raman scatted light-Stokes versus anti-Stokes-and the time function between light injection and signal detection. It is shown that the priniciple of distributed sensing, the system desing, and the result of experiments.
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This paper describes how the directivity pattern of the back-scattered sound pressure is distributed when a plane acoustic wave is incident on a righid spherical shell underwater. A coupled Finite Element-Boundary Element mehtod is developed as numerical technique. The result of the coupled FE-BE method is agreed with theoretical solution for algorithmic confirmation.
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Three-dimensional optimum design of coat-hanger die is performed using power-law and Carreau models. It is found that the three-dimensional optimum design algorithm shows good convergence with the non-Newtonian fludis. the nore realistic optimum design is accomplished by employing Carreau model with the three-dimensional design method. The effect of vixcosity modles is investigated by comparing the optimum manifold profiles and flow rate distributions of power-law and Carreau modles. Through the accurated viscosity representation of Carreau model, the effect of total flow rate on the optimum manifold profile is investigated.
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The problem of long range capacity expansion planing for chemical processing network under uncertain demand forecast secnarios is addressed. This optimization problem involves capactiy expansion timing and sizing of each chemical processing unit to maximize the expected net present value considering the deviation of net present values and the excess capacity over a given time horizon. A multiperiod mixed integer nonlinear programming optimization model that is both solution and modle robust for any realization of demand scenarios is developed using the two-stage stochastic programming algorithm. Two example problems are considered to illustrate the effectiveness of the model.
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Some ill-conditioned processes are very sensitive to small element-wise uncertainties arising in classical element-by-element model identifications. For such processes, accurate identification of simgular values and right singular vectors are more important than theose of the elements themselves. Singular values and right singular vectors can be found by iteraive identification methods which implement the input and output transformations iteratively. Methods based on SVD decomposition, QR decomposition and LU decomposition are proposed and compared with the Kuong and Mac Gregor's method. Convergence proofs are given. These SVD and QR mehtods use normal matrices for the transformations which cannot be calculated analytically in general and so they are hoard to apply to dynamic processes, whereas the LU method used simple analyitc transformations and can be directly applied to dynamic processes.
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Fast and accurate distillation design requires a model that significantly reduces the problem size withour loss of accruacy is especially suitable for rela-time applicatoins. the reduced order model is obtained by use of Principal Component Anlysis(PCA). Then the extended Kalman filter and the Recursie Predictiuon Error(RPE) mehtod are appliced to identify the model parameters and the feed compostion form the measuremenets of the coumn. as a consequence it is found that the model reduction thechique can account for the dynamics of the rigorous distillation model and not only the model parameters, bu also the feed compostion can be identified efficiently. this technique is applied to industrial operation data verify the performance of reduced order model.
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In this paper, a linear discrete time system subject to the input saturatioin is shown to be exponentially stabilizable on any compact subset of the constrained asymptotically stabilizable set by a linear periodic variable structure controller. We also establish tat any neutrally stable system subject to the input saturation can be globally asymptotically stabilizable via linear feedback.
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As factory automation is required, using the vision system is also essential. Especially, the pateh planning of parts with J-lead on PCB plays a import role of whole automation. Path planning is required because J-lead is scatteed compaed to L-lead on PCB. Therefore, in this paper, we propose path planning of part inspection with J-lead to use Hopfield Model(TSP : Traveling Salesman Problem). Then optical system suited to J-lead inspection is designed and the algorithm of J-lead solder joint and part inspection is proposed.
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The coke oven plant on a steel works has not, in the past, been regarded as a prime user of modern instrument technology. The reason for this perception may be due to the fact that the basic design of the coke battery has been changed little over the years. The recording and analysis of oven pushing force on a routine basis is seen as a means of monitoring plant operation. A torque sensor is set up at the shaft of the rotor for measuring pushing force. Pushing force data which is communicated form torque sensor to staor by telemetry method are shown on MMI(Man-Machine Interface) screen and stored in the database automatically. Perhaps the most important feature is that is allows a problem oven to be identified at an early stage and for corrective action to be taken before it develops into a refusal to push. In this way the mechanical loads imposed on the battery structlure can be held to a necessary minimum, so helping to prolong its service life.
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A combined algorithm called APEXS(Alarm Processing and Diagnosis Expert System) for power plants has been developed on the time-based alarm processing with a proper alarm prioritization and a diagnosis with a qualitative model(QM), qualitative interpreter(QI), and a state-transition trees(STT).
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In this paper constant-level luffing and time optimal control of a JIB crane is investigated. The crane is assumed to have only the derricking motion. the analysis of plance kinematics provides the relationship between the boom angle and the main hosit motor angle for constant-level luffing. The dynamic equations for the crane are very nonlimear, and therefore they are linearized for the application of the linear control theory. The time optimal control in the perspective of no-sway at the end of boom stroke is investigated.
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It is difficulte to control in the flow system because there are many disturbance. So it is impossible to control delicately sometimes by PI or PID. In this paper, we study on the application of intellignet control algorithms such as 2DOF PID control, neural network, Fuzzy contro, Relay feedback to the flow control system. the resultings are 2DOF-PID control is more good response.
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This thersis presents precise position control emthods of a 3-PRPS in-parallel manipulator for industrial applications such as assembly of highly integrated semiconductors and microsurgery. Since real-time ontrol is one of the most important issues required for industrial application, the experimental hardware is set up with a VME based DSP controller. In the 3-PRPS parallel mainpulator, structurally existing frictiion at three horizontal links considerably degrades the precise position control. In order to compensate the friction of the horizontal links in the joint space, a disturbance compensation usign disturbance and velocity observers has been proposed and investigated. We analyzed the decision method of eigenvalues of the disturbance observer and the effects of the control resulted form tehsystem model errors. Through a series of simulations and experiments, we see that the methods is capable of compensating variations of the robot parameters such as inertia and damping as well as the joint friction. Experiments show that the disturbance compensation method usign disturbance and velocity observer is very effective to compensate the friction. Compared with conventional PID position control, it decreased position errors ina circular motion by approximately 70%.
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This paper presents new feedback actuators to achieve an accurate position control of a flexible gnatry robot arm. the translational motion in the plane is generated by two d.c.motors and controlled by emplying elecor-rheological(ER) clutch acutators. The generated motion can be continuously controlled by controlling the intensity of lectric field imposed to the ER fluid domain which tunes the transmitted torque of the ER clutch. n the other hand, during control action of the translational motion a flexible arm attached to the moving mass produces undesirable oscillatins due to its inherent flexibility. The oscillations are actively suppressed by applying feedback voltages to piezoceramic acutators bonded on the surface of the flexible arm. The control electric fields to be applied to the ER clutch and the control voltage for the piezoceramic actuator are determined via the loop shaping esign procedures(LSDP) in the H.inf. control technique. Comsequently, an accuate positiion control at the end-point of the flexible am is achieved during planar motion.
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This paper presents a new approach to the design of cruise control system of a mobile robot with two drive wheel. The proposed control scheme uses a Gaussian function as a unit function in the fuzzy-neural network, and back propagation algorithm to train the fuzzy-neural network controller in the framework of the specialized learnign architecture. It is proposed a learning controller consisting of two neural networks-fuzzy based on independent reasoning and a connecton net with fixed weights to simply the neural networks-fuzzy. The performance of the proposed controller is shown by performing the computer simulation for trajectory tracking of the speed and azimuth of a mobile robot driven by two independent wheels.
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A position control algorithm for a flexible manipulato is stuudied. The proposed algorithm is based on a fuzzy theroy with a Steady State Genetic Algorithm(SSGA). The conventional fuzzy methods need expert's knowledges or human experiences. The SSGA, which is one of the optimization algorithms, tunes automatically the input-output membership parameters and fuzzy rules. The computer simulation is presented ot illustrate the approaches. Finally we applied a fuzzy theory with a SSGA to aposition control of a flexible manipulator.
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This paper treats the estimation of human impedance and their application to collaboration work robot. Initially, we performa an experiment at whcich teh human becomes a slave and the robot behaves like a master having F/T sensor on its end. the human impedance expressed interms of mass, damping, and stiffness properties are estimated based on the force data measured by F/T sensor and the positiion data of the robot. To show the effectiveness of the estimated human impedance, we perform the second experiment at which the roles of the human and the robot are reversed. It is shown that the robot using the estimated human impedance follows the trajectory commanded by human very smoothly.
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Using the vision system, robotic tasks in unstructured environments can be accompished, which reduces greatly the cost and steup time for the robotic system to fit to he well-defined and structured working environments. This paper proposes a dynamic control scheme for robot manipulator with eye-in-hand camera configuration. To perfom the tasks defined in the image plane, the camera motion Jacobian (image Jacobian) matrix is used to transform the camera motion to the objection position change. In addition, the dynamic learning controller is designed to improve the tracking performance of robotic system. the proposed control scheme is implemented for tasks of tracking moving objects and shown to outperform the conventional visual servo system in convergence and robustness to parameter uncertainty, disturbances, low sampling rate, etc.
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For the Cartesian space position controlled robot, it is required to have the accurate mapping from the Cartesian space to the joint space in order to command the desired joint trajectories correctly. since the actual mapping from Cartesian space to joint space is obtained at the joint coordinate not at the actuator coordinate, uncertainty in Jacobian can be present. In this paper, two feasible neural network schemes are proposed to compensate for the kinematic Jacobian uncertainties. Uncertainties in Jacobian can be compensated by identifying either actuator Jacobian off-line or the inverse of that in on-line fashion. the case study of the stenciling robot is examined.
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Majority of industrial robots are controlled by a simple joint servo control of joint actuators. In this type of control, the performance of control is influenced greatly by the joint interaction torques including Coriolis and centrifugal forces, which act as disturbance torques to the control system. As the speed of the robot increases, the effect of this disturbance torque increases, and makes the high speed-high precision control more difficult to achieve. In this paper, the joint disturbance torque of robots is analyzed. The joint disturbance torque is defined using the coefficients of dynamic equation of motion, and for the case of a 2DOF planar robot, the conditions for the maximum joint disturbance torques are identified, and the effect of link parameters and joint variables on the joint disturbance torque are examined. Then, a solutioin to the optimal path placement problem is proposed that minimizes the joint disturbance torque are examined. then, a solution to the optimal path placement problem is proposed that minimizes the joint disturbance torque during a straight line motion. the proposed method is illustrated using computer simulation. the proposed solution method cna be applied to the class of robots that are controlled by independent joint sevo control, which includes the vast majority of industrial robots. By minimizing the joint disturbacne torque during the motion, the simple joint servo controlled robot can move with improved path tracking accuracy at high speed.
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this paper, to represent the robot motion approximately in space, delas with algorithm for position recognition of space robot, target and obstacle with vision system in 2-D. And also there are algorithms for precise distance-measuring and calibration usign laser displacement system, and for trajectory selection for optimizing moving to object, and for robot locomtion with air-thrust valve. And the software synthesizing of these algorithms hleps operator to realize the situation certainly and perform the job without any difficulty.
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Off-line programming systems are widely spread in assembly lines of minute electronic products to huge offshore structures. Any OLP system has to be calibrated before the on-line robot tasks are performed because there are inherent differences between the CAD model on OLP and the real robot workspace. This paper uses simple geometric expressions to propose a calibration method applicable to an OLP for SCARA robots. A positioning task on the two-dimensional horizontal surface was used in the error analysis of a SCARA robot and the anaysis shows that the inaccuracy results from the two error sources non-zero offset angles of two rotational joints at the zero return and differences in link lengths. Pen marks on a sheet of plotting paper are used to determine the accurate data on the joint centers and link dimensions. The calculated offset angles and link lengths are fed back to the OLP for the calibration of the CAD model of the robot and task environments.
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This paper presents machine vision technique with a camera modeling that accounts for major sources of camera distortion, namely, radial, decentering, and thin prism distortion. Radial distortion causes an inward or outward displacement of a given image point from its ideal location. Actual optical systems are subject to various degrees of decentering, that is, the optical centers of lens elements are not strictly collinear. It is our purpose to develop the vision system for the pattern recognition and the automatic test of parts and to apply the line of manufacturing.
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The task environment of a robot is changing rapidly and task itself becomes complicated due to current industrial trends of multi-product and small lot size production. A convenient user-interfaced off-line programming(OLP) system is being developed in order to overcome the difficulty in teaching a robot task. Using the OLP system, operators can easily teach robot tasks off-line and verify feasibility of the task through simulation of a robot prior to the on-line execution. However, some task errors are inevitable by kinematic differences between the robot model in OLP and the actual robot. Three calibration methods using image information are proposed to compensate the kinematic differences. These methods compose of a relative position vector method, three point compensation method, and base line compensation method. To compensate a kinematic differences the vision system with one monochrome camera is used in the calibration experiment.
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Assuming that EEG(electroencephalogram), which is generated by a nonlinear electrical of billions of neurons in the brain, has chaotic characteristics, it is confirmend by frequency spectrum analysis, log frequency spectrum analysis, correlation dimension analysis and Lyapunov exponents analysis. Some chaotic characteristics are related to the degree of brain activity. The slope of log frequency spectrum increases and the correlation dimension decreasess with respect to the activities, while the largest Lyapunov exponent has only a rough correlation.
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This paper presents the development of depth detection algorithm for the 3D Endoscopic Data using a stereo matchod and depth calcuation.
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A three-dimensional biomechanical modle is proposed in order to simulate human pharyngeal function based on the FEM(Finite Element Method) utilizing optimization procedure.
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This paper describes the arousal measurement and the control system using fuzzy logic to prevent drowsy driving. Sugeno's method was used for fuzzy inference in this study. Membership function and rule base were determined form the modfied arousal level criteria. The output of fuzzy inference tracked well the change of subject's arousal level. When IRI(Inter-SIR interval) was under the 60sec, maximum output of three step warning method was medium sound, but that of fuzzy logic system was changed from medium to big. Furthermore, the output of the fuzzy inference was highly correlated with
$N_{z}$ (r=0.99). Therefore, the fuzzy inference method for evaluation and the control of arousal will be more effective at real driving sityation than three step warning method.ning method. -
Transfer alignement is the process of initializing attitude of slave INS using the data of master INS. This paper presents the performance analysis of transfer alignment at sea using convariance analysis method. Velocity & angle matching and angular rate & acceleration matching are used for analysis, and the performance of two matching methods are compared. We propose a new method for angular rate & acceleration matching. Under the assumption of accurate modeling of ship flexure, the performance of transfer alignment time and accuray is improved very much for the new method.
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Uncertainties in the aerodynamic coefficients or time delay effects in implementing an autopilot algorithm can make a Flight Control System(FCS) unstable. When a FCS enters unstable state, the actuator or sensor limiters in FCS make the unstable system not diverge but be in the state of stable limit cycle. If an autopilot recognize the FCS to be in the stable limit cycle phenomenon, it woudl be better to adjust autopilot gains to stabilize the FCS. A novel method to stabilize a FCS using parameter estimation and maintenance of given phase margin is proposed. The method is applied to roll control loop and verified its performance.
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Waypoint guidance is a technique used to steer an autonomous vehicle along a desired trajectory. In this paper, a waypoint guidance algorithm for horizontal plane is derived by combining a line following guidance law and a turning guidance law. The line following guidance is derived based on LQR while the turning guidance is designed using rendzvous problem. Through simulation, the proposed method shows a good performance.
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Crane operation is manually accomplished by skilled operators. Recently, the concept of automation is widely introduced in shipping and unloading operation using the overhead crane for the enhanced productivity. In this regards, we designed an angle detector and 3D position detectro which are key evices for this operation. As well as an intellignet control algorithm is developed for the implementation of swing free crane. The performance of the presented algorithm is tested for the swing angle and the position of the overheas crand. The control scheme adopts a feedback control of an angular velocity of swing in initial phase and then the fuzzy controller whose rule base is optimized by a genetic algorithm.
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Development of an efficient algorithm for the minimum distance calculation between general polyhedraThis paper developes an efficient algorithm for the minimum distance calculation between general polyhedra(convex and/or concave). The polyhedron approximates and object using flat polygons which composed of more than three veritices. The algorithm developed in this paper basically computes minimun distance betwen two convex polygons and finds a set of polygons whcih makes a global minimum distance. The advantage of the algorithm is that the global minimum distance can be computed in any cases. But the big disadvantage is that minimum distance computing time is repidly increased with the number of polygons which used to approximate an object. This paper developes a method to eliminate unnecessary sets of polygons, and an efficinet algorithm to compute a minimum distance between two polygons in order to compensate the inherent disadvantage of the algorithm. It takes only a few times iteration to find minimum distance for msot polygons. The correctness of the algortihm are visually tested with a line which connects two points making a global minimum distance of simple convex object(box) and concave object(pipe). The algorithm can find minimum distance between two convex objects made of about 200 polygons respectively less than a second computing time.
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An Parallax-Barrier type autostereoscopic display system is implemented to overcome the handicap of current glass-typed stereo imaging system which gives operators unnatural feeling and reluctance. This system is composed of image mixing part of two input images, A/D transformation part, scan conversion part to eliminate the rainbow interference phenomenon, and pin-hole type barrier lens. For the fine display the accurate slit width of barrier is calculated in consideration of retina size, and the samsung 10.4" TFT-LCO was used as flat display monitor.itor.
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The increasing concern over radiation exposure in the nuclear industry has fostered agrressive efforts to reduce the levels of radiation exposure. One area of the effot to reduce the radiation exposure is the development of a remote radiation monitoring system. Remote radiation monitoring can serve many benificaial functions reduce exposure to radiation by plant personnel, impruve the quality of the data that is collected and recognize the radiation environment easily. Radiation mapping system gives a good information that represents radiation level distribution. The system we have developed consists of a data acquistion parts, mobile robot and remote control parts. Data acquisition parts consist of radiation detection module and vision acquistion module which collect radiation data, visiion data and distance information. In remote control parts, the acquision data are processed and displayed. We have constructed radiation mapping image by overlaying the vision and radiation data. The radiation mapping techniques for displaying the results of the survey in an easily comprehendable form will facilitate a better understanding of the radiation environment in the facility. This system can reduce workers radiation exposure and aid to help work plan, so it has significant benifits in cost and safety.