• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.3
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• pp.70-78
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• 1989

In the control of the robot system using the variable structure control(VSC) method, up to these days the advantage of the VSC method has not been applied effectively because the parameters are selected arbitrarily by the existence condition of sliding mode without a precise analysis about the VSC parameters. This paper reveals the relation between dynamic constraints and the VSC parameters of robot system, and analyzes the effect on the trajectory of the joint angle and the hand when the analytical result of the relation is applied to the robot system control. The result of the analysis in this paper is applied effectively to the path tracking control and the trajectory planning using the VSC method.

• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.1
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• pp.63-69
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• 2003

The main property of VSC is that the system response is robust and insensitive to parameter variations and external disturbances in the sliding mode if their bounds are known to the designer of the system control. But sometimes these bounds may not be easily obtained. However, fuzzy control provides an effective way to design the controller of the system with the disturbances and parameter variations. Therefore, combination of the best feature of fuzzy control and sliding mode control is considered. When using the conventional VSC, generally the reaching phase problem occurs, which cause the system response to be sensitive to parameter variations and external disturbances. In order to overcome these problems, a robust position control method of the BLDC motor using an adaptive fuzzy VSC without leaching phase is presented.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.5
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• pp.1178-1183
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• 2008

The variable structure control(VSC) with sliding mode is an important and interesting topic in modern control of nonlinear systems. However, the discontinuous control law in VSC leads to undesirable chattering in practice. As a method solving this problem, in this paper, we propose a scheme of the VSC with neural network sliding surface. A neural network sliding surface with boundary layer is employed to solve discontinuous control law. The proposed controller can eliminate the chattering problem of the conventional VSC. The effectiveness of the proposed control scheme is verified by simulation results.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.2
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• pp.39-47
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• 1998

It has been known that variable structure control(VSC) has theoretically powerful control technique of providing fast response, no overshoot, and very robust control with respect to system parameter variations and disturbances. However, the technique has not become more widely extended in the industrial circles because chattering phenomenon which may excite high-frequency unmodelled plant dynamics and damage to system components exists. In this paper, a modified variable structure control(MVSC) is developed to alleviate these problems which are applied to the position control of induction motor. While the conventional VSC makes the structure of the system change with high-frequency switching on the center of the one switching surface, in the MVSC two switching surface are used to establish a sliding sector. The structure of the system will be changed with low-frequency switching. Therefore, the proposed algorithm has the properties of reducing chattering, retaining the benefits achieved in the conventional VSC, and working even under the influences of parameter variations. Experimental results show the effectiveness of the control strategy proposed here for the position control of induction motor.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.37 no.3
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• pp.19-32
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• 2000

This paper suggests the variable structure controller with a new variable boundary layer for the accurate tracking control of the variable structure systems. Up to now, variable structure controller (VSC) applying the variable boundary layer did not remove chattering from an arbitrary initial state of the system trajectory because VSC has the limited initial state according to the fixed sliding surface. But, by using the linear time-varying sliding surfaces, the scheme has the robustness against chattering from all states. The suggested method can be applied to the second-order nonlinear systems with parameter uncertainty and extraneous disturbances, and has better tracking performance than the conventional method. To demonstrate the advantages of the proposed algorithm, it is applied to a two-link manipulator.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.12a
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• pp.145-148
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• 2001

일반적으로 가변구조제어는 외란과 변수 변화에 대해 강인한 특성을 가지지만 제어기 설계자는 이러한 값들에 대한 상한 값과 하한 값을 알아야한다. 그러나 때로는 이러한 상한 값과 하한 값을 얻는다는 것은 쉽지가 않다. 이에 반해 퍼지제어기는 외란과 변수 변화에 대한 제어기 설계에 있어서 효과적인 방법을 제공한다. 따라서 퍼지제어기와 가변구조제어기가 가지는 장점들을 결합하는 연구가 진행되어져 왔다. 본 논문에서는 기존의 선형 슬라이딩 면을 가지는 퍼지제어기를 이용하는 방법 대신 비선형 슬라이딩 면을 가지는 퍼지제어기를 이용한 적응 퍼지 가변구조제어기를 이용하였다. 따라서 시스템의 결과는 선형 슬라이딩 면을 가지는 제어기 설계에서 나타나는 동적 특성과 정적 특성의 대립을 해결할 수 있다. 또한, 가변구조제어의 동적 특성을 결정하는 제어입력을 도입하여 적응 퍼지 가변구조제어기의 안정도를 판명하였다. 제안된 제어 알고리듬의 유용성을 입증하기 위해 비선형성이 큰 가변 길이를 갖는 진자 시스템을 이용하였다.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.1
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• pp.132-139
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• 2005

This paper describes the application of sliding mode control based on the variable structure control(VSC) concept for high-performance position control of an induction servo motor A design method based on external load parameters has been developed for the robust control of AC induction servo drive. Also, a slip frequency vector control with software current control technique has been adopted to achieve fast response of an induction motor drive The position control scheme is comprised of a variable structure controller and slip frequency vector control for inverter fed induction servo motor. Simulated results are given to verify the proposed design method by adoption of sliding mode and show robust control for a change of shaft inertia, viscous friction and torque disturbance.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.504-507
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• 1997

It is well known that Variable Structure Controller(VSC) is robust to parameters variation and disturbance but its performance depends on the design parameters such as switching gain and slope of sliding surface. This paper proposes a more robust VSC that is composed of local VSC's. Each local VSC considers the local system dynamics with narrow parameter variation and disturbance. First we optimize the local VSC's by use of Evolution Strategy, and next we use Artificial Neural Network to generalize the local VSC's and construct the overall VSC in order to cover the whole range of parameter variation and disturbance. Simulation on BLDC motor current control shows that the proposed VSC is superior to the conventional VSC.

• Journal of Korea Society of Industrial Information Systems
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• v.7 no.4
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• pp.66-73
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• 2002

Although the general sliding mode control has the robust property, bounds on the disturbances and parameter variations are known to the designer of the system control. But sometimes these bounds may not be easily obtained. However, fuzzy control provides an effective way to design the controller of the system with the disturbances and parameter variations. Therefore, combination of the best feature of fuzzy control and sliding mode control is considered. When using the conventional VSC, generally the reaching phase problem occurs, which cause the system response to be sensitive to parameter variations and external disturbances. In order to overcome these problems, an adaptive fuzzy VSC with sliding surface eliminating reaching phase is proposed. The validity of the proposed scheme is shown by results of experiments for the BLDC motor.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2634-2638
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• 2009

The variable structure control(VSC) with sliding mode is the discontinuous control law in leads to undesirable chattering in practice. As a method solving this problem, in this paper, we propose a scheme of the VSC with neural network sliding surface. A neural network sliding surface with boundary layer is employed to solve discontinuous control law. The proposed controller can eliminate the chattering problem of the conventional VSC. The effectiveness of the proposed control scheme is verified by simulation results.