• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.383-386
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• 1996

In this paper, we propose a design method and control law for plannar type two-link flexible manipulator. In designing flexible links, we use Rayleigh's principle. To control flexible manipulator, input distribution controller is used, which is primarily on the basis of nonlinear variable structure control(VSC). The simulation results are also shown.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.1066-1071
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• 1992

A new scheme of OFVSC(Output Feedvack Variable Structure Controller) is proposed for the servo control system. The main structure of proposed control scheme is composed of servo compensator and dynamic switiching function. By the use of dynamic switiching function the assumption of full state availability can be removed and the disturbances which does not satisfy the matching condition cna be rejected. And the servo compensator which is designed for each output variable the robustness for the all type of disturbances. And the performances of proposed control system are evaluated through simulation studies for a numerical example.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.404-409
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• 1998

In this paper, the discrete variable structure controller (DVSC) is proposed for vector controlled induction motor position control. The variable structure control (VSC) which guarantees accuracy and robustness in nonlinear control system is developed in discrete time domain for applying to real servo system. Furthermore, the load torque observer is introduced to reduce chattering problem. The computer simulation results are presented to verify the proposed control scheme.

• 전자공학회논문지T
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• 제35T권2호
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• pp.39-47
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• 1998

가변구조 제어기는 이론적으로 빠른 응답특성을 가지며 오버슈트가 없고 외란이나 파라미터 변동에 강인한 제어기로 알려져왔다. 그러나 가변구조 제어기는 모델링과정에서 무시된 플랜트의 고주파 동특성을 여기할 수 있고, 또 시스템을 구성하는 소자들에 손상을 줄 수 있는 채터링현상이 발생하기 때문에 산업현장에서 널리 적용되지 못하고 있다. 본 논문에서는 채터링을 저감시키기 위한 개선된 가변구조 제어기를 제안하고 유도전동기의 위치제어에 적용한다. 기존의 가변구조 제어기는 한 개의 스위칭면을 중심으로 고주파 스위칭을 행하여 시스템의 구조를 절환한 반면에, 개선된 가변구조 제어기는 한 개의 면 대신 슬라이딩 영역을 이루기 위해 두 개의 스위칭면을 가지며 이 영역 내에서 저주파 스위칭으로써 시스템 구조를 절환하게 된다. 그러므로 제안된 알고리즘은 기존의 가변구조 제어기가 가지는 빠른 응답성이나 강인성을 유지하면서 고주파 채터링을 저감시키는 특징을 가지며 전동기정수 변동에도 양호하게 동작하고 있다. 제안하는 제어기의 타탕성을 확인하기 위해 실험을 행하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.156-161
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• 1991

It is difficult to realize precise control by a fuzzy control scheme alone because control signals are derived from fuzzy inferences. On the other hand, pole-placement control can offer a precise control to a known system. In this paper, a VSC(variable structure control)scheme is proposed, which is an attempt to take merits of pole-placement control and fuzzy control. On the vicinity of the reference point the pole-placement control scheme takes over the role of the fuzzy controller to improve the set point response.

• 제어로봇시스템학회논문지
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• 제3권3호
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• pp.265-271
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• 1997

A fuzzy logic controller (FLC) has been widely used for many applications in recent years. But the relationship between control performance and design parameters has not been handled explicity in the conventional theory of fuzzy logic control. In this paper, based on the similarity between an FLC and a variable structure control (VSC) theory, a performance evaluation of an FLC, which gives quantitative accounts on the relationship is presented. The validity of the analysis is verified through extensive computer simulations.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.936-941
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• 2004

An Optimal Feedforward Integral Variable Structure or FIVSC approach for an electrohydraulic position servo control system is presented in this paper. The FIVSC algorithm combines feedforward strategy and integral in the conventional Variable Structure Control (VSC) and calculating the control function to guarantee the existence of a sliding mode. Furthermore, the chattering in the control signal is suppressed by replacing the sign function in the control function with a smoothing function. The simulation results illustrate that the purposed approach gives a significant improvement on the tracking performances when compared with some existing control methods, like the IVSC and MIVSC strategies. Simulation results illustrate that the purposed approach can achieve a zero steady state error for ramp input and has an optimal motion with respect to a quadratic performance index. Moreover, Its can achieve accurate servo tracking in the presence of plant parameter variation and external load disturbances.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1218-1220
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• 1992

This paper presents the three section sliding mode control algorithm based on variable structure current controller design in a synchronous frame and indirect field oriented control method, and applies it to the position control of induction motor. This control scheme solves the problem of robustness loss during the reaching phase that occurs in a conventional VSC strategy, and ensures the stable sliding mode and robustness enhancement throughout an entire response. As the performance of a VSI fed induction motor drives depends on the characteristics of inner loop current controller, it is desired that the current controller have the fast tracking and robust nature. Therefore, we introduced the voltage mapping table based on the concept of voltage space vector for variable structure current control, and implemented fully digital control system using 16-bit microcontroller with on-chip peripherals without additional processing circuits. Simulation and experimental results confirm the validity of this control scheme for robust AC servo drive system of VSI fed induction motor.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.389-394
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• 2004

A Fuzzy Logic Sliding Mode Control or FLSMC for the uninterruptible power system (UPS) is presented, which is tracking a sinusoidal ac voltage with specified frequency and amplitude. The FLSMC algorithm combines feedforward strategy with the Variable Structure Control (VSC) or Sliding Mode Control (SMC) and fuzzy logic control. The control function is derived to guarantee the existence of a sliding mode. FLSMC has an advantage that the stability of FLSMC can be proved easily in terms of VSC. Furthermore, the rules of the proposed FLSMC are independent of the number of system state variables because the input of the suggested controller is fuzzy quantity sliding surface value. Hence the rules of the proposed FLSMC can be reduced. The simulation results illustrate that the purposed approach gives a significant improvement on the tracking performances. It has the small overshoot in the transient and the smaller chattering in the steady state than the conventional VSC. Moreover, its can achieve the requirements of robustness and can supply a high-quality voltage power source in the presence of plant parameter variations, external load disturbances and nonlinear dynamic interactions.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.395-398
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• 2000

The method of Variable Structure Control (VSC) design of windmill power systems is proposed. In the design of sliding mode control, we use Riccati equations arising in linear H$\^$$\infty$/ control to decide a stable sliding surface. Then the reachability to the sliding surface is realized by designing a nonlinear controller for the windmill power system. The capability of the proposed controller to damp out the oscillations of power and the robustness with respect to the system parameter variations and model errors are evaluated in the simulation study.