• Journal of IKEEE
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• v.13 no.1
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• pp.30-35
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• 2009

A new controller which can achieve the asymptotic tracking is proposed for the nonlinear system having a uncertainty in the input coefficient. A high gain observer is used to estimate the state variables when the nonlinear system has a modeling uncertainty. A variable structure control is used to achieve an asymptotic tracking, while ultimate boundness was achieved in the previous work. A Lyapunov analysis is used to justify the our proposal. The performance of proposed method is demonstrated via simulation.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.109-112
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• 1997

In this note, we investigate a noniterative design method of an observer-based robust H$\_$2/ controller in the presence of structured real parameter uncertainty by applying Riccati approach based on the guaranteed cost function. Motivated by the numerical difficulty of the problem, we try to develop a simple design method named as block-diagonal approach, which can be solved by the LMIs method. By assuming the block-diagonal structure of Riccati solution, the original problem can be derived into two sequentially decoupled optimization problems as LQG control problem. The proposed method seems to be numerically efficient in obtaining a feasible compensator.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1656_1657
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• 2009

This paper presents a new method for estimating rotor resistance of induction motor. The rotor resistance changes dramatically with temperature and frequency. Speed is controlled by PID as it is simplest and most intuitive control method. The change in rotor resistance has a great influence on the performance of IM. In this paper rotor resistance is estimated using Non Linear Disturbance Observer. The model uncertainty and system non linearity are treated as disturbance in this method. Using NDO it does not require an accurate dynamic model to achieve high precision motor control. Controller with NDO has more superior tracking performance. Simulation results are presented to show the validity of the proposed controller.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.1
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• pp.11-18
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• 2003

We consider a single-input-single-output nonlinear system which is represented in a normal form. The model contains the uncertainty. A high-gain observer is used to estimate the states variables to reject a modeling uncertainty We design the globally bounded output feedback controller using sliding mode control to stabilize the closed-loop system. The globally bounded output feedback controller reduce the peaking in the states variables. The proposed method give a more design freedom in the design of the globally bounded controller than that of the previous work.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.233-236
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• 2002

We consider a single-input-single-output nonlinear system which can be represented in a normal form. The nonlinear system has a modeling uncertainties including the input coefficient uncertainties. A high-gain observer is used to estimate the states variables to reject a modeling uncertainty. A globally bounded output feedback integral sliding mode control is proposed to stabilize the closed loop system. The proposed integral sliding mode control can asymptotically stabilize the closed loop system in the it presence of input coefficient uncertainty.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1211-1214
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• 1999

Power system operating conditions vary with system configuration and loading conditions. Coefficients in nominal system model change in a complex manner with different operating point and so does system dynamic behavior. With the aid of unstructured and structured uncertainty descriptions the worst system variations can be estimated and formulated into two different uncertainty models multiplicative unstructured uncertainty in the form of transfer function and structured uncertainty with the parametric uncertainty description. in frequency domain

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1843-1846
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• 2004

This paper considers a robust observer-based $H_{\infty}$ controller design method for descriptor systems with parameter uncertainties using just one LMI condition. The sufficient condition for the existence of controller and the controller design method are presented by a perfect LMI condition in terms of all variables using singular value decomposition, Schur complement, and change of variables. Therefore, one of the main advantages is that a robust observer-based $H_{\infty}$ controller is found by solving one LMI condition compared with existing results. Numerical example is given to illustrate the effectiveness of the proposed controller design method.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.1
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• pp.11-16
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• 2005

This paper considers a robust observer-based H/sub ∞/ controller design method for singular systems with parameter uncertainties using an LMI condition. The sufficient condition for the existence of controller and the controller design method are presented by a perfect LMI condition in terms of all variables using singular value decomposition, Schur complement, and change of variables. Therefore, one of the main advantages is that a robust observer-based H/sub ∞/ controller can be established by solving one LMI condition compared with existing results. Numerical example is given to illustrate the effectiveness of the proposed controller design method.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.170-173
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• 2005

This paper presents an Fuzzy-Neuro Observer system for an ac servo motor dirve to track periodic commands using a neuro-fuzzy observer. AC servo motor drive system is rather similar to a linear system. However, the uncertainties, such as machanical parametric variation, external disturbance, uncertainty due to nonideal in transient state. therefore an intelligent control system that isan on-line trained neural network controller with adaptive learning rates.

• Journal of Power Electronics
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• v.16 no.6
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• pp.2150-2161
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• 2016

Mechanical and electrical parameter uncertainties cause dynamic and static estimation errors of the rotor speed and position, resulting in performance deterioration of sensorless control systems. This paper applies an extended nonlinear observer to interior permanent magnet synchronous motors (IPMSM) for the simultaneous estimation of the rotor speed and position. Two compensation methods are proposed to improve the observer performance against parameter uncertainties: an on-line rotational inertia adjustment approach that employs the gradient descent algorithm to suppress dynamic estimation errors, and an equivalent flux error compensation approach to eliminate static estimation errors caused by inaccurate electrical parameters. The effectiveness of the proposed control strategy is demonstrated by experimental tests.