• 제어로봇시스템학회논문지
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• 제3권2호
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• pp.162-168
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• 1997

Digital variable structure controller(DVSC) is implemented to control the temperature for the hot water heating circulating pump control system. For the DVSC, a control algorithm is suggested, which using a nonlinear sliding surface and a PID sliding surface outside and inside of steady state error boundary layer, respectively. Smith predictor algorithm is used for the compensation of long dead time. The DVSC of the suggested algorithm yields improved control performance compared with the one of existing algorithm. The system responses with the suggested DVSC shows good responses without overshoot and steady state error inspite of heating load change. By decreasing sampling time, dead time and rise time are increasing, and system output noise by flow dynamics is amplified.

• 제어로봇시스템학회논문지
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• 제2권2호
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• pp.115-120
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• 1996

In this paper, a sliding mode controller which is characterized by high accuracy, fast response and robustness is applied to speed control of AC-SERVO motor. The control input is changed to the continuous one in the boundary layer to reduce the chattering phenomenon, and the boundary layer converges to zero when the state variables of system reach to steady state values. The integral compensator is added to reduce steady state error and to provide the continuous torque reference. The acceleration which is necessary for the sliding plane is estimated by an obsever. Sliding surface is included in control input to enhance the robustness and transient response without increasing sliding mode controller gain. The proposed controller is implemented by DSP(digital signal processor). The effectiveness of the proposed scheme is demonstrated through experimental works.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.215-218
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• 1995

In this paper, a sliding mode controller (SMC) which can be characterized by high accuracy, fast response and robustness is applied to speed control of AC-SERVO motor. The control input is changed to continuous one in the boundary layer to reduce the chattering phenomenon, and the boundary layer converges to zero when the state variables of system reach to steady state values. The integral compensator is added to reduce steady state error and to provide the continuous torque reference. The acceleration which is necessary to get the sliding plane is estimated by an observer. Sliding surface is included in control input to enhance the robustness and transient response without increasing sliding mode controller gain. The proposed controller is implemented by DSP(digital signal processor). The effectiveness of the proposed control scheme for speed controller is shown by the real-time experimental results in the paper.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.232-237
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• 1991

Digital Variable Structure Controller(DVSC) is proposed to control variable speed recirculating pump for hot-water heating control system. In this study, nonlinear sliding line is used beyond output error boundary layer and PID sliding line is used within the layer. For long dead time compensation, constraint is added to Smith predictor algorithm. Steady state error is eliminated by using the proposed sliding line in spite of heating load change. By decreasing sampling time, good sliding motion is yielded but system output noise bv flow dynamics is amplified.

• 한국지능시스템학회논문지
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• 제6권2호
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• pp.3-12
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• 1996

탁월한 비선형 제어 특성을 가지고 있는 슬라이딩 모우드 제어기는 제어 대상 플랜트의 모델링 과정에서 발생하는 부정확성과 각종 외란등으로 인하여 제어 입력 신호가 매우 높은 주파수의 비연속적인 특성을 가진다. 이를 방지하기 위하여 슬라이딩 평면에 얇은 경계층을 도입하는 방법을 많이 사용하고 있지만 이 경우에는 원하지 않는 정상 상태 오류가 유발될 수도 있다. 이때의 정상 상태 오차는 경계층의 폭에 비례해서 증가하는 특성이 있다. 본 논문에서는 정상 상태 오차와 제어 입력 신호의 불연속성 사이에는 구해지는 경계층의 폭을 정상 상태에 접근할수록 퍼지 규칙베이스에 의해 자동으로 감소시키는 자기동조형 경계층을 가지는 슬라이딩 모우드 제어기를 제안하였다. 그리고 제안된 알고리즘의 성능을 역진자 계통의 추적 제어 시뮬레이션을 통하여 입증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 전력전자학술대회 논문집
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• pp.249-254
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• 1998

A control approach for the robust position control of induction motors based on the improved binary disturbance observer is described. The conventional binary disturbance observer is used to remove the chattering problem of a sliding mode disturbance observer. However, the steady state error may be existed in the conventional binary disturbance observer because it estimates external disturbance with a constant boundary layer. In order to overcome this problem, a new binary disturbance observer with an integral augmented switching hyperplane is improved. The robustness is achieved, and the continuous control is realised by employing the improved observer without the chattering problem and the steady state error. The effectiveness of the improved observer is confirmed by the comparative experimental results.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권4호
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• pp.203-211
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• 1999

A control approach for the robust position control of induction motors based on the binary disturbance observer is described. The conventional binary disturbance observer is used to remove the chattering problem of a sliding mode disturbance observer. However, the steady state error may exist in the conventional binary disturbance observer because it estimates external disturbance with a constant boundary layer. In order to overcome this problem, new binary disturbance observer with an integral augmented switching hyperplane is proposed. The robustness is achieved, and the continuous control is realized by employing the proposed observer without the chattering problem and the steady state error. The effectiveness of the proposed observer is confirmed by the comparative experimental results.

• 제어로봇시스템학회논문지
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• 제6권3호
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• pp.256-262
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• 2000

This paper proposes a new sliding mode controller combined with a multi-layer neural network using the error back propagation learning algorithm,, The network acts as a compensator of the conventional sliding mode controller to improve the control performance when initial assumptions of uncertainty bounds of system parameters are violated. The proposed controller can reduce th steady state error of conventional sliding mode controller with the boundary layer technique Computer simulation results show that the proposed method is effective to control dynamic systems with unexpectably large uncertainties.

• 한국지능시스템학회논문지
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• 제12권2호
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• pp.164-170
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• 2002

슬라이딩 모드 제어방식은 가변구조 제어이론의 하나로서 불확실성을 가진 비선형 시스템에 대한 강인한 특성을 가지고 있지만 제어입력에 채터링 현상을 발생시키기 때문에 그 적용에 한계를 가지고 있다. 채터링을 제거하는 방식에는 여러 가지 방식이 있으나 본 논문에서는 특수한 비선형 함수와 퍼지시스템 이용하여 기존의 고정 경계층 이용방식에 비하여 정상상태 오타를 줄일 수 있는 개선된 채터링 제거전략을 제안한다. 제안된 제어방식에서는 퍼지시스템의 출력변수 상에 설정된 퍼지집합의 구간 범위를 조절함으로써 trade-off관계에 있는 정상상태 오타와 채터링의 크기를 적절히 조절할 수 있다. 제안된 전략의 타당성을 보이기 위해 기존의 고정 경계층 방식을 간단히 분석하고 컴퓨터 시뮬레이션을 통하여 이를 비 교 분석 한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 B
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• pp.438-441
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• 1998

In this paper, we proposes an adaptive flux observer to estimate initial values of rotor fluxes and unknown rotor resistance. The error system between the model of induction motor and a proposed observer is devided as a fast subsystem and a slow one by a singular perturbation system. The fast subsystem is exponentially convergent on a boundary-layer. And the overall error system is reduced to a quasi-steady-state system. The adaptive law for an unknown rotor resistance is designed to stabilize the approximate error system. As computer simulation results show, the proposed adaptive flux observer estimates fast initial values of rotor fluxes and unknown rotor resistance.