• Journal of Energy Engineering
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• v.25 no.1
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• pp.163-170
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• 2016

In the condition of electronic controlled acceleration system, APS Sensor is the only and the most important parts to reflect the will of driver. Especially, the non-reference type APS is the critical part of this system. It can't provide the cross-reference values and it will make the vehicle goes into the 'NMC(Non-moveable condition)' or 'Limp-home mode' on the malfunction situation easier. If the situation is happened, it's very dangerous condition for the drivers, soldiers and war material systems of battlefield. The electronic control is not a necessary system for the tactical vehicles. The tactical vehicles must be prepared the manual control system independently from the electronic control system to escape, save and rescue the soldier's life and war materials. Therefore it was studied the water-penetrated broken APS output. If the output value was changed without driver's will, even the cross-reference type APS, it will effect the uncontrollable engine RPM changing or the performance down on limp-home mode. It means the manual control system of tactical vehicle is needed for any kinds of APS.

• Journal of Ocean Engineering and Technology
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• v.28 no.5
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• pp.466-473
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• 2014

Underwater gliders do not have any external propulsion systems that can generate and control their motion. Generally, underwater gliders would obtain a propulsive force through the lift force generated on the body by a fluid. Underwater gliders should be equipped with mechanisms that can induce heave and pitch motions. In this study, an inner movable and rotatable mass mechanism was proposed to generate the pitch and roll motions of an underwater glider. In addition, a buoyancy control unit was presented to adjust the displacement of the underwater glider. The buoyancy control unit could generate the heave motion of the underwater glider. In order to analyze the underwater dynamic behavior of this system, nonlinear 6-DOF dynamic equations that included mathematical models of the inner movable mass and buoyancy control unit were derived. Only kinematic characteristics such as the location of the inner movable mass and the piston position of the buoyancy control unit were considered because the velocities of these systems are very slow. The effectiveness of the proposed dynamic modeling was verified through sawtooth and spiraling motion simulations.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.6
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• pp.619-627
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• 2014

An optimization method is proposed for the simultaneous design of structural and control systems using the equivalent static loads. In the past researches, the control parameters of such feedback gains are obtained to improve some performance in the steady-state. However, the actuators which have position and velocity feedback gains should be designed to exhibit a good performance in the time domain. In other words, the system analysis should be conducted for the transient-state in dynamic manner. In this research, a new equivalent static loads method is presented to treat the control variables as the design variables. The equivalent static loads (ESLs) set is defined as a static load set which generates the same displacement field as that from dynamic loads at a certain time. The calculated sets of ESLs are applied as multiple loading conditions in the optimization process. Several examples are solved to validate the proposed method.

• Nuclear Engineering and Technology
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• v.27 no.3
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• pp.336-343
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• 1995

The Self Tuning Regulator(STR) method which is an approach of adaptive control theory, is ap-plied to design the fully automatic power controller of the nonlinear reactor model. The adaptive control represent a proper approach to design the suboptimal controller for nonlinear, time-varying stochastic systems. The control system is based on a third­order linear model with unknown, time-varying parameters. The updating of the parameter estimates is achieved by the recursive extended least square method with a variable forgetting factor. Based on the estimated parameters, the output (average coolant temperature) is predicted one-step ahead. And then, a weighted one-step ahead controller is designed so that the difference between the output and the desired output is minimized and the variation of the control rod position is small. Also, an integral action is added in order to remove the steady­state error. A nonlinear M plant model was used to simulate the proposed controller of reactor power which covers a wide operating range. From the simulation result, the performances of this controller for ramp input (increase or decrease) are proved to be successful. However, for step input this controller leaves something to be desired.

• Journal of Navigation and Port Research
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• v.33 no.1
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• pp.35-41
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• 2009

A waypoint tracking algorithm(WTA) is designed for Unmanned Surface Vehicle(USV) in which water-jet system is installed for propulsion To control the heading of USV for waypoint tracking, the steering nozzle of water-jet need, to be controlled. Firstly, target heading is calculated by using the position information of waypoints input from the land control center. Secondly, the command for the steering nozzle of water-jet is calculated in real time by using the heading and the rate-of-turn( ROT) from magnetic compass, In this study, in order to consider the drift angle due to external disturbance such as wind and wave, the course of ground( COG) can be used instead of heading at higher speed than a certain value, To test the performance of newly-designed WTA, the tests were carried out in actual sea area near Gwang-an bridge of Busan. In this paper, the sea trial test results from WTA are analyzed and compared with those from manual control and those from commercial controller.

• Wind and Structures
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• v.36 no.2
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• pp.91-103
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• 2023

Tuned liquid dampers (TLDs) are increasingly being used as efficient dynamic vibration absorbers to mitigate wind-induced vibration in super high-rise buildings. However, the damping characteristics of screens and the control effectiveness of actual structures must be investigated to improve the reliability of TLDs in engineering applications. In this study, a numerical TLD model is developed using computational fluid dynamics (CFD) and a simulation method for achieving the coupled vibration of the structure and TLD is proposed. The numerical results are verified using shaking table tests, and the effects of the solidity ratio and screen position on the TLD damping ratios are investigated. The TLD control effectiveness is obtained by simulating the wind-induced vibration response of a full-scale structure-TLD system to determine the optimal screen solidity ratio. The effects of the structural frequency, damping ratio, and wind load amplitude on the TLD performance are further analyzed. The TLD damping ratio increases nonlinearly with the solidity ratio, and it increases with the screens towards the tank center and then decreases slightly owing to the hydrodynamic interaction between screens. Full-scale coupled simulations demonstrated that the optimal TLD control effectiveness was achieved when the solidity ratio was 0.46. In addition, structural frequency shifts can significantly weaken the TLD performance. The control effectiveness decreases with an increase in the structural damping ratio, and is insensitive to the wind load amplitude within a certain range, implying that the TLD has a stable damping performance over a range of wind speed variations.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.147-151
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• 2005

CAN(Controller Area Network) is a simple and efficient network system for real time control and measurement. As it is not only good at error detection but also strong in electromagnetic interference, CAN has been widely used all over the industries. Basically, CAN needs a master node in charge of sensor data collection, node scheduling for data transmission to a monitoring system and error detection. According to the number of mater nodes, the CAN system is classified into two type of master system. One is a single master system that has only one master node and the other is a multi-master system where any sensor node can become a master node depending on the system's conditions. While it has the advantage of its fault tolerance, the multi-master system will suffer form the overall performance degradation when a defect is found in the master node. It is because all sensor nodes pertaining to a defective master node lose their position. Moreover, it is difficult and expensive to implement. For a single master system, the whole system will be broken down when a problem happens to a single master. In this paper, a dynamic master system is presented that there are several sub-master nodes of which basic functions are those of other sensor nodes at ordinary times but dynamically changed to replace the failing master node. An effective scheduling algorithm is also proposed to choose an appropriate node among sub-master nodes, where each sub-master node has its precedence value. The performance of the dynamic master system is experimented and analyzed.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1679-1684
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• 2004

This paper introduces a novel approach that can provide the three dimensional information on the movement of a spreader by using two CCD cameras and a laser distance sensor, which enables an ALS (Automatic Landing System) to be used for yard cranes at a harbor. So far a kind of 2D Laser scanner sensor or laser distance measuring units are used as corner detectors for the geometrical matching between the spreader and a container, which provides only 2D information which is not enough for an accurate and fast ALS system required presently. In addition to this deficiency in performance, the price for the system is too high to be adopted widely for the ALS. Therefore, to overcome these defects, a novel method to acquire the three dimensional information for the movement of a spreader including skew and sway angles is proposed using two CCD cameras and a laser distance sensor. To show the efficiency of proposed algorithm, real experiments are performed to show the accuracy improvement in distance measurement by fusing the sensory information of CCD camera and laser distance sensor.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1102-1105
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• 2004

In this paper, the problem of a viewer's head tracking in a desktop-based interactive stereoscopic display system is considered. A fast and low-cost approach to the problem is important for such a computing environment. The system under consideration utilizes a shuttle glass for stereoscopic display. The proposed method makes use of an image taken from a single low-cost video camera. By using a simple feature extraction algorithm, the obtained points corresponding to the image of the user-worn shuttle glass are used to estimate the glass center, its local 'yaw' angle, as measured with respect to the glass center, and its global 'yaw' angle as measured with respect to the camera location. With these estimations, the stereoscopic image synthetic program utilizes those values to interactively adjust the two-view stereoscopic image pair as displayed on a computer screen. The adjustment is carried out such that the so-obtained stereoscopic picture, when viewed from a current user position, provides a close-to-real perspective and depth perception. However, because the algorithm and device used are designed for fast computation, the estimation is typically not precise enough to provide a flicker-free interactive viewing. An error concealment method is thus proposed to alleviate the problem. This concealment method should be sufficient for applications that do not require a high degree of visual realism and interaction.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.277-281
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• 2004

The following paper proposes the new design of digital sine wave generator which allows users to define the phase shift of the out put sinewave according to user's demands. This new sinewave generator will have 2 outputs, cos(${\omega}_0n$) and cos(${\omega}_0n$+${\phi}$) The design of the new system starts from the construction of discrete time system with impulse response as cos(${\omega}_0n$) in a pair of conjugate complex poles and a pair of zeros at the origin and the real axis. If users want to make a phase shift of sign wave, users can change the position of zero at the real axis. The results of the experiment have shown that the new design of sign wave generator has generated sine wave with the correct phase shift according to the theory.