• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.8
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• pp.1269-1275
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• 2002

This paper presents a new method for removing reaching phase in variable structure control systems using Bell type switching function. By proposed method, during the entire control process reaching phase is removed. For effective speed control of trapezoidal type brushless DC motor, a time varying switching function based speed controller is developed as illustration.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.2
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• pp.213-220
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• 1989

This paper describes the application of the variable structure control(VSC) concept for the position control of an electro-hydraulic servomotor system. The basic philosopy of VSC is that the structure of the feedback control is altered as the state crosses discontinuity surfaces in the state space with the result that certain desirable properties are achieved. The switching of the control function yields total(or selective) invariance to system parameter variations and disturbances, and closed loop eigen value placement in time-varing and uncertain systems. The control scheme is derived, implemented and tested in the laboratory where analog controller have been used to control the representive servosystem. The control system schematics are given and simple results are shown for illustration. And the results of variable structure system for the electro-hydraulic servomotor were compared to that of the fixed structure system when load disturbance and system parameter variation exists.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.546-548
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• 1998

초음파는 초음파 가공기나 초음파 세척기 등에 많이 이용되고 최근 액추에트로서 초음파 전동기가 주목을 받고 있다. 압전 혹은 자기비틀림 효과를 이용하여 얻는 초음파 진동기는 전기-기계 변환효율이 다른 수단에 비하여 매우 높으므로 이것을 이용하여 얻는 초음파 진동은 왕복운동에서 직선 혹은 회전운동으로 변환시키는 연구가 행해지고 있다. 본 연구에서는 진행파 방식의 초음파 전동기를 중심으로 그 회전 원리를 이해하고 모델링 하였다. 외란에 대하여 강인한 제어방식으로 알려져 있는 가변구조제어의 이론을 이해고 회전형 진행파 방식의 초음파 전동기를 이용한 가변구조, 제어에 의한 서보계를 설계한다. 이때 제어방법은 속도패턴을 미리 정하여 두고 그 패턴에 따라 슬라이딩 모드를 사용하여 속도를 제어하여 위치를 제어하는 것이다. 초음파 전동기의 가변구조제어에 의한 위치제어를 컴퓨터 시뮬레이션으로 검토하고 제어 파라미터를 결정하였다. 그리고 인터페이스 보드를 제작하고 컴퓨터와 전동기를 접속하여 실제 제어 알고리즘을 이용하여 초음파 전동기의 제어 실험을 행하였다.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.8 no.3
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• pp.88-95
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• 1994

A scheme of IESFVSC(Integral Error State Feedback Variable Structure Controller) is proposed for a DC servo position control system with the disturbances which do not satisfy the matching condition. The proposed control system is composed of servo compensator and state feedback VSC. The servo compensator enhances the robustness of the control system against various types of disturbance, and makes effective tracking possible without using error dynamics. The IESFVSC is applied to the practical design of a robust DC servo control system and the control performances are verified through theoretical analyses and simulations.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.508-512
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• 1989

A new control law of a VSCS is illustrated and put into an analytical form. Using the presented control law, a VSCS shows smooth response, low control input and high accuracy in comparison with those by typical control law.

• Nuclear Engineering and Technology
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• v.17 no.4
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• pp.247-255
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• 1985

This paper describes a new method for the design of variable structure model-following control systems(VSMFC). This design concept is developed using the theory of variable structure systems (VSS) and slide mode. The new results are presented on the sliding control methodology to achieve accurate tracking for a class of nonlinear, multi-input multi-output(MIMO), time varying systems in the presence of parameter variations. The design requires little computational effort. The dynamic response is insensitive to parameter variations. The feasibility and the advantages of the method are illustrated by applying it to a 1000 MWe boiling water reactor(BWR). The control is studied in the range of 85%∼90% of rated power for load-following control. A set of 12 nonlinear differential equations is used to simulate the total plant. A 6-th order linear model has been developed from these equations at 85% of rated power. The obtained controller is shown by simulations to be able to compensate for a plant parameter variation over a wide power range.

• Journal of the Korean Society for Precision Engineering
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• v.6 no.2
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• pp.30-39
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• 1989

Variable structure control (VSC) systems control the state vectors using sliding regime (SR) constructed switching logic, switching plane and control law. Saturation function switching logic is used to improve the drawback which occurs in traditional sign function switching logic. Switching plane with time-varying parameter is proposed to improve the drawback which occurs in switching plane with constant parameter and it is suggested the control law which has time-varying parameter. The stability of VSC system controlled by proposed time-varying SR is discussed, and the good control behavior was shown through computer simulation using proposed SR.

• 제어로봇시스템학회:학술대회논문집
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• 1988.10a
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• pp.261-263
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• 1988

In this study, the several control laws and switching planes are considered to eliminate the steady state error and to obtain the rapid response for variable structure control systems. An elimination algorithm is achieved by combination with each other control law, and the type of control law having the most rapid response is shown through some simulations.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.945-950
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• 1991

A method to design a robust servomechanism by continuously variable structure control is proposed. The state and control signal of this servomechanism do notchatter since a continuous control scheme is used. The input-output relation of this servomechanism is determined by prescribing a hyperplane in a state space of which the neighborhood is asymptotically attractive everywhere. This control mechanism was applied to a single rod cylinder servomechanism which has the nonlinerities due to their nonsymmetrical structure and its excellency was verified.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.266-271
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• 1989

In eliminating the nonliner charateristics such as piston displacement drift and difference in speeds of the reciprocating motion due to their nonsymetrical structure of single rod cylinder, modelling was carried out by additional outside disturbance, suggest the position control of single rod cylinder servosystem using VSS and compared with PD control of fixed structure system.