• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.1371-1376
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• 1990

The paper presents a method of constructing simple fuzzy control rules for the determination of stabilizing signals of automatic voltage regulator and governor, which are controllers of electric power systems. Fuzzy control rules are simplified by considering a coordinate transformation with the rotation angle .theta. on the phase plane, and by expanding the range of membership functions. Also, two rotation angles .theta. $_{1}$ and .theta. $_{2}$ are selected for the linearizable region and the nonlinear one of the system, respectively. Here, .theta. $_{1}$ is chosen by the pole assignment method, and .theta. $_{2}$ by a performance index. Fuzzy inference is applied to the connection of two rotation angles .theta. $_{1}$ and .theta. $_{1}$ by regarding the distance from the desired equilibrium point as a variable of condition parts. The control effect is demonstrated by an application of the proposed method to one-machine infinite-bus power system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.105-108
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• 1988

In this paper, a control system design method is proposed for DC motor drive. A state space model is used to control sysytem and for closed loop system the technique of pole assignment is applied. The control system is designed with state feedback theory and to improve the response further more feedforward theory is applied to control system. The microprocessor as a controller and the interfaces in the system are proposed. Digital simulation results for step changes in reference velocity and load torque are shown.

• Journal of Advanced Marine Engineering and Technology
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• 제34권1호
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• pp.92-101
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• 2010

본 연구에서는 회전체를 지지하는 자기 베어링에 관하여, 2장에서는 적분형 서보계를 이용하여 횡축형 자기베어링 시스템(Horizontal-shaft Magnetic Bearing System: HMBS)에 대한 불확실성을 고려하면서 과도상태 응답개선에 대한 이론적인 고찰과 제어기설계 수식을 유도한다. 그리고 HMBS에 대해 물리 퍼래미터 변동에 대한 강인성과 외란의 영향을 저감하고 기준위치 변경에 따른 추종성을 갖도록 상태 피드백 제어기를 LMI 기법을 이용하여 설계한다. 3장에서는 설계한 제어칙을 가지고 시스템 불확실성의 변동에 대해 시간영역의 설계사양을 고려한 경우와 고려하지 않은 경우에 대하여 시뮬레이션을 행하고 실제 적용 가능성을 검토한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국제학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.144-149
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• 1993

This paper discusses a design of a nonlinear control for a class of single-input double-output nonlinear mechanical systems. When conventional linearization methods are applied to the mechanical systems, some problems of oscillation and unstable phenomena arise. The proposed nonlinear control system resolves these problems. In this design the eigenvalues of the closed-loop nonlinear system are assigned to desired locations and local asymptotic stability of the closed-loop system. is guaranteed. The design method is applied to an inverted pendulum system with a moving weight mechanism. Experimental results show that the proposed nonlinear controller is more effective for stability than the usual linear controller.

• 대한전기학회논문지
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• 제41권2호
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• pp.199-208
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• 1992

MIESF(Modified Integral Error and State Feedback) controller suggested in order to control the processes with time delay is the control scheme that combines Smith predictor and IESF(Integral Error and State Feedback). This control scheme has better performance than the conventional PID controller incorporating Smith predictor with respect to the robustness and control performance for the modelling error. MIESF controller can be simply designed by pole assignment algorithm. BUT in such a case, it is difficult to find proper poles which gurantee robustness with respect to process parameter uncertainties. In order to solve the aforementioned difficulties, we suggest a new design method for MIESF controller and show the validity of the proposed design method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1986년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 17-18 Oct. 1986
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• pp.238-243
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• 1986

Distillation columns are widely used in almost every chemical plant. The use of multivariable control for such units is attractive because of the strong interactions exhibited between outputs and inputs and the desire to control simultaneously both top and bottom products. In this research design of a robust multivariable controller for distillation column was considered; output feedback controller with proportional and integral modes was designed using pole assignment. The transfer function matrix was obtained by fitting the step response realtions between single input double output pairs of variables. This matrix was then converted to linear time invariant state space model by multivariable realization technique. With the proposed multivariable proportional and integral controller applied to the process, the result of the digital computer simulation showed a good performance of asymtotic tracking. The limited experimental performance of this multivariable control was compared with the result from simulation. It was found that the proposed controller performed satisfactorily for the distillation column which separated binary mixture of methanol and water.

• Journal of Power Electronics
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• 제4권4호
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• pp.228-236
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• 2004

This paper describes the optimal current-control of a permanent magnet synchronous motor by the use of robust and simple current controllers, based upon the analytical procedure known as the inverse LQ (ILQ) design method. The ILQ design method is a strategy for finding the optimal gains based on pole assignment without solving the Riccati equation. It is very important to keep the motor in robust servo-lock. By experiments and simulations, we will show that the ILQ optimal servo-system with servo-lock is more insensitive at low speeds to variations in armature inductance than the standard PI servo-system. Variations in armature inductance have the greatest influence on the responses of a servo-system.

• 대한전기학회논문지
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• 제39권3호
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• pp.301-311
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• 1990

A multiple controller structure consisting of a typical feedback controller and an additive redundant controller is proposed for enhancing the reliability of the control system. For the case where the main controller is chosen as a pole assignment controller with input/output measurements and the redundant controller as the Model Reference Adaptive Controller (MRAC) whose reference model is the closed-loop combination of the plant and the main controller, it is proven that the tracking error between the command input and plant output converges to zero under failure in one of the controllers or parameter perturbations of the plant, and further that the reliability measured by Mean Time To Failure (MTTF) is greater than that of the system with only a single main controller. A simulation Example is provided to illustrate reliable operation of the proposed control system against the controller failure.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.1045-1049
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• 1996

For the precision positioning and tracking control, the proper friction compensation is essential. The friction causes steady state error. The friction compensation based on the velocity and the controlling input or the desired velocity provides limited performance if the compensation value is fixed. In this paper, a friction compensation scheme using a fuzzy logic is proposed. The friction compensation amount is adjusted depending on the velocity and controlling input. The proposed fuzzy friction compensator with a pole-assignment controller is implemented in a linear positioning system. To illustrate the effectiveness of this scheme, computer simulations and experiments are carried out for the cases of no friction compensation, the proposed fuzzy friction compensation, and another friction compensation scheme based on velocity and control input, and the results are compared with each other.

• 대한기계학회논문집
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• 제15권1호
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• pp.78-89
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• 1991

본 연구에서는 ARSC를 엔드밀링 공정에 적용하여, 절삭력을 추종제어하는 실 예를 제시하고자 한다.제2장에서는 ARSC를 절삭공정에 일반적으로 적용하기 위한 구체적인 이론전개를 설명하여, 제3장에 실시간 시뮬레이션의 방법과 결과를 예시하 고,마지막으로, 제4장에 엔드밀링 절삭시험을 위한 장치의 구성 및 그 결과를 설명하 였다.