• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.504-506
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• 1996

In the industrial motor drive systems, a shaft torsional vibration is often generated when a motor and a load are connected with a flexible shaft. This paper treats the vibration suppression control of this system. The resonance ratio control is proposed for suppressing the torsional vibration. In this paper, first, the optimal resonance ratio is sellected and the controller to the resonance ratio controlled outward plant is designed based on $H_{\infty}$ control theory. Secondly, the two-degree-of-freedom controller, which includes the above $H_{\infty}$ controller, is designed in order to improve the tracking characteristics for the commanded speed. The control performances are examined by the computer simulations and it is clarified that the proposed speed control system is useful for two-mass system.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.3
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• pp.190-194
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• 2013

This paper presents experimental results of the attitude control for a two-rotor system with 3-DOF(degree-of-freedom). Two DC motors are equipped at the two ends of a rectangular beam to generate lift force and the relation between motor voltage and lift force is found experimentally. And inertial sensors are mounted at the center of the beam to measure the roll angle and a complementary filter is designed to get the angle during DC motors driving. A controller with nonlinear compensation, integrator and state feedback to achieve asymptotic tracking for a step input and reject input disturbance is designed and experimented.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.1
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• pp.66-72
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• 2004

PID control has been well used for several decades. For PID algorithms, some tuning methods are used for selecting PID parameters and with these selected parameters, PID control system is designed. But in some cases various kinds of performance indices are used instead of well-known tuning rules, and so variable type of performance index must be tested so that the designed control system meets the some specifications. For 2 DOF PID controller design this paper presents a linear combinational type of performance indices constituting of index for robust performance, which is obtained by h infinity norm of a weighted complementary sensitivity function, including other time domain indices such as error, energy and changing rate of control input. By numerical methods, the optimal 2 DOF PID parameters are obtained. Therefore various types of 2 degree of freedom PID controllers such as I-PD controller are used so that this two degree of freedom PID controllers may give more desirable output characteristics. Simulations are done with MATLAB m file and mdl files.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2003.06a
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• pp.177-182
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• 2003

The robust output tracking control problem of general nonlinear MIMO systems is discussed. The robustness against parameter uncertainties is considered. In this paper, we proposed the robust output tracking control scheme for a class of MIMO nonlinear dynamical systems using output feedback linearization method. The presented control scheme is based on the VSS. We assume that the nonlinear dynamical system is minimum phase, the relative degree of the system is r$_{1}$＋r$_{2}$＋…r$_{m}$$\leq$ n and zero dynamics is stable. It is shown that the outputs of the closed-loop system asymptotically track given output trajectories despite the uncertainties while maintaining the boundedness of all signals inside the loop. And we verified that the proposed control scheme is then applied to the control of a two degree of freedom (DOF) robotic manipulator with payload.d.

• Earthquakes and Structures
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• v.13 no.1
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• pp.51-58
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• 2017

Passive dynamic vibration absorbers (DVAs) are often used to suppress the excessive vibration of a large structure due to their simple construction and low maintenance cost compared to other vibration control techniques. A new type of passive DVA consists of two pendulums connected with spring and dashpot element is investigated. This research evaluated the performance of the DVA in reducing the vibration response of a two degree of freedom shear structure. A model for the two DOF vibration system with the absorber is developed. The nominal absorber parameters are calculated using a Genetic Algorithm(GA) procedure. A parametric study is performed to evaluate the effect of each absorber parameter on performance. The simulation results show that the optimum condition for the absorber frequencies and damping ratios is mainly affected by pendulum length, mass, and the damping coefficient of the pendulum's hinge joint. An experimental model validates the theoretical results. The simulation and experimental results show that the proposed technique is able be used as an effective alternative solution for reducing the vibration response of a multi degree of freedom vibration system.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.217-217
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• 2000

A decentralized robust EA(eigensoucture assignment) controller is designed for an active suspension system of a vehicle based on a full car model with 7-degree of freedom. Using overlapping decomposition, the full car model is decentralized by two half car models. For each half car model, a robust eigenstructure assignment controller can be obtained by using optimization approach. The performance of the decentralized robust EA controller is compared with that of a conventional centralized EA controller through computer simulations.

• Journal of Power System Engineering
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• v.8 no.4
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• pp.17-23
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• 2004

A delivery ship is used to handle the cargo with the crane to/from the ships. The ship is inclined in the direction of a cargo which is hung on a crane. In this case, a arc shaped rail should be in the equilibrium state to get good anti rolling performance. In this study, a device and control algorithm are developed to take accurate and quick equilibrium of the rail. The device is composed of a hinged immovable support and two screw jacks. And the control algorithm demands two controllers. One controller is designed such that the screw jack 1 and 2 follow the position reference signal generated by a tilt sensor. The other controller of two degree of freedom is designed to remove the synchronous error occurred between jack 1 and jack 2. The simulation results show that the desirable control performance is achieved.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.1
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• pp.18-25
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• 2000

In the two-mass servo system driving a load through a flexible shaft, a shaft torsional vibration is often generated. PI controller has been generally used is speed control of such system because of the simplicity of structure and related theory. This paper presents the inertia ratio of the PI servo control system which can be designed by using optimal pole assignment method is fixed. Therefore, it's difficult to obtain the desired control characteristics for different systems only by PI control algorithm. To solve this problems the two-mass speed control system with PID controller is designed by using pole assignment method and an optimum PID parameters are derived by evaluating ITAE(Integral of time multiplied by the absolute error) performance index. But this design method has some problems due to a trade-off between the fast command following property and the attenuation of disturbances and vibrations. In this paper, 2-DOF PID control method which satisfies the command following property, the reduction of overshoot and the property of disturbance rejection at the same time is proposed. This is a practical speed controller using the desired value filter and the feedforward gain. From several simulations, it's clarified that the proposed 2-DOF PID controller is useful for the two-mass system, in comparison with the conventional PID controller.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.8
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• pp.1119-1126
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• 1995

The construction of rule-base for a nonlinear time-varying system, becomes much more complicated because of model uncertainty and parameter variations. Furthemore, FLC does not have an ability of adjusting rule- base in responding to some sudden changes of control environments. To cope with these problems, an auto-tuning method of the fuzzy rule-base is required. In this paper, the GA-based Fuzzy-Neural control system combining Fuzzy-Neural control theory with the genetic algorithm(GA), which is known to be very effective in the optimization problem, will be proposed. The tuning of the proposed system is performed by two tuning processes(the course tuning process and the fine tuning/adaptive learning process). The effectiveness of the proposed control system will be demonstrated by computer simulations using a two degree of freedom robot manipulator.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.397-400
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• 1992

Many dynamic control have been proposed; however, most of them are limited within stage of simulation study. The main reason is that the computations required for inverse dynamics are far beyond the ability of the present commercially available microprocessors. In this paper, In order to achieve real-time processing in robot dynamic control, a parallel processing computer for robot dynamic control is implemented using two transputer. Two transputer compute two degree of freedom robot. The transputer is a special purpose MPU for parallel processing. Transputers are used in networks to build a high performance concurrent system. A network of transputers and peripheral controllers is constructed using point-to-point communication. To gain most benifit from the transputer architecture, the whole system is programmed in OCCAM which is a high level language for concurrent applications. This control algorithm is applied to the RHINO SCARA type manipulator. We could taked about 438.6 microseconds to compute robot dynamic with two-processors.