• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.284-284
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• 2000

In adaptive fuzzy control systems. fuzzy systems are used to approximate the unknown plant nonlinearities. Until now. most of the papers in the field of controller design for nonlinear system using fuzzy systems considers the affine system with fixed grid-rule structure based on system state availability. This paper considers observer-based nonlinear controller and dynamic fuzzy rule structure. Adaptive laws for fuzzy parameters for state observer and fuzzy rule structure are established so that the whole system is stable in the sense of Lyapunov.

• 제어로봇시스템학회논문지
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• 제12권11호
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• pp.1057-1060
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• 2006

This paper presents an LMI-based method to design a reduced order observer based sliding mode controller for a class of uncertain systems. Using LMIs we derive an existence condition of a reduced order observer and a sliding mode control law. And we give explicit formulas of the gain matrices. Finally, we give a numerical design example, together with a design algorithm.

• Journal of Power Electronics
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• 제14권1호
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• pp.125-134
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• 2014

This paper presents a robust and speed-sensorless stator flux estimation for induction motor direct torque control. The proposed observer is based on sliding mode approach. Stator electrical equations are used in the rotor orientation reference frame to eliminate the observer dependence on rotor speed. Lyapunov's concept for systems stability is adopted to confine the observer gain. Furthermore, the sensitivity of the observer to parameter mismatch is recovered with an adaptation technique. The nonlinearities of the pulse width modulation voltage source inverter are estimated and compensated to enhance stability at low speeds. Therefore, a new method based on the model reference adaptive system is proposed. Simulation and experimental results are shown to verify the feasibility and effectiveness of the proposed algorithms.

• Nuclear Engineering and Technology
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• 제52권3호
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• pp.552-559
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• 2020

This paper presents an observer-based chattering free robust optimal control scheme to regulate the total power of a nuclear reactor. The non-linear model of nuclear reactor is linearized around a steady state operating point to obtain a linear model for which an optimal second order integral sliding mode controller is designed. A second order integral sliding mode observer is also designed to estimate the unmeasurable states. In order to avoid the chattering effect, the discontinuous input of both observer and controller are designed using the super-twisting algorithm. The proposed controller is realized by combining an optimal linear tracking controller with a second order integral sliding mode controller to ensure minimum control effort and robustness of the closed-loop system in the presence of uncertainties. The condition for the selection of gains of discontinuous control based on the super-twisting algorithm is derived using a strict Lyapunov function. Performance of the proposed observer based control scheme is demonstrated through non-linear simulation studies.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.139-144
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• 1987

The problem of process(Sensor) fault management in Observer Based Control System are considered and structures of Fault Tolerant Observer based Control Systems (FMCS) that function well in the face of the faults are proposed. The FTOCSs include detection logic unit and an additional observer driven by residuals of primary observer and estimate estimation errors of primary observer and fault variables. Since the FTOCSs have the ability to detect and accomodate the faults the original control objectives can be accomplished without considerable control performance deterioration even in the faulty environments. Therefore, the Proposed FMCSs can effectively be used for enhancing the functional reliability of the Observer Based Control Systems.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.925-934
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• 2015

This paper considers the robust controller design problem for a boost DC-DC converter. Based on the Takagi-Sugeno fuzzy model-based approach, a fuzzy controller as well as a fuzzy load conductance observer are designed. Sufficient conditions for the existence of the controller and the observer are derived using Linear Matrix Inequalities (LMIs). LMI parameterizations of the gain matrices are obtained. Additionally, LMI conditions for the existence of the fuzzy controller and the fuzzy load observer guaranteeing α-stability, quadratic performance are derived. The exponential stability of the augmented fuzzy observer-controller system is shown. It is also shown that the fuzzy load observer and the fuzzy controller can be designed independently. Finally, the effectiveness of the proposed method is verified via experimental and simulation results under various conditions.

• Journal of Power Electronics
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• 제12권2호
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• pp.294-304
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• 2012

This paper proposes a fuzzy speed tracking controller and a fuzzy rotor angular acceleration observer for a surface-mounted permanent magnet synchronous motor (SPMSM) based on the Takagi-Sugeno (T-S) fuzzy model. The proposed observer-based controller is robust to load torque variations since it utilizes rotor angular acceleration information instead of the load torque value. Linear matrix inequality (LMI) sufficient conditions are given to compute the gain matrices of the speed tracking controller and the observer. In addition, it is mathematically verified that the proposed observer-based control system is asymptotically stable. Simulation and experimental results are presented to confirm that the proposed control algorithm assures a better transient behavior and less sensitivity under model parameter variations than the conventional PI control method.

• 전기학회논문지
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• 제60권2호
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• pp.330-337
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• 2011

This paper presents a new fuzzy speed controller based on a fuzzy angular acceleration observer to realize a robust speed control of permanent magnet synchronous motors(PMSM). The proposed speed controller needs the information of the angular acceleration, thus the first-order fuzzy acceleration observer is designed. The LMI existence condition is given for the proposed fuzzy speed controller, and the gain matrices of the controller are calculated. It is verified that the augmented control system consisting of the fuzzy speed controller and the fuzzy acceleration observer is mathematically stable. To validate the effectiveness of the proposed acceleration observer-based fuzzy speed controller, the simulation and experimental results are shown under motor parameter variations. It is definitely proven that the proposed control scheme can precisely track the speed of a permanent magnet synchronous motor.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1652_1653
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• 2009

본 논문에서는 passivity based controller에 high gain observer를 접목시킨 유압 모터의 위치 제어기를 제시 한다. 본 논문에서는 5차 비선형 동역학 모델을 사용 하였다. Passivity based controller는 유압 모터의 높은 위치 추정능력을 구현하지만 그것을 위해서는 유압 모터의 상태 및 부하의 정보를 알아야 한다. 상태 및 부하의 정보를 추정 하기 위하여 high gain observer를 제안하였다. High gain observer을 사용함으로서 유압 모터와 부하의 동역학의 비선형성을 줄여 상태 및 부하를 효과적으로 추정 하였다. 유압 모터의 위치 제어 성능 및 부하의 관측 능력 평가를 위하여 Matlab/Simulink를 이용하여 모의 실험을 구현 하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.1159-1161
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• 1997

This paper presents a power system stabilizer(PSS) using the $H_{\infty}$ observer-based sliding mode controller($H_{\infty}$ observer-based SMC) for unmeasurable state variables. The effectiveness of the proposed $H_{\infty}$ observer-based SMPSS for unmeasurable state variables is shown by the simulation result.