• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.58-62
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• 1998

In the industrial motor drive systems, a torsional vibration is often generated because of the elastic elements in torque transmission. One of general methods for the system is H$\infty$ controller to suppress the torsional vibration and reject the torque disturbance. vibration and reject the torque disturbance. Moreover, the two-degrees-of-freedom controller, which includes the H$\infty$ controller, is designed in order to improve the command following property. In this paper, we propose a new H$\infty$ controller with partial state feedback. This method having simple structure satisfies with the fast command following property and the attenuation of disturbances and vibrations simultaneously, just like the complicated TDOF H$\infty$ controller

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.521-521
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• 2000

This paper investigates the problem of robust H$_{\infty}$ filter with FIR(Finite Impulse Response) structure for linear continuous time-varying systems with sampled-data measurements. It is assumed that the system is subject to real time-varying uncertainty which is represented by the state-space model having parameter uncertainty. The robust H$_{\infty}$ FIR filter is proposed for the continuous-time linear parameter uncertain systems. It is also derived from the equivalence relationship between the robust linear H$_{\infty}$ FIR filter and the robust linear H$_{\infty}$ filter with sampled-data measurements.

• Journal of KSNVE
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• v.7 no.5
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• pp.803-810
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• 1997

This paper is concerned with the vibration control of multi-layer structure for ultra-tall buildings and main tower of large bridge etc. We have modeled the multi-layer structure with the distributed mass system as the lumped mass system of two-degree-of-freedom structure and made experimental equipment. The $H_\infty$control theory was applied to the design of the control system. The designed control system was simulated by computer. As a result, the designed $H_\infty$controller showed the good vibration control performance to impulse response and frequency response.

• Proceedings of the KIEE Conference
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• 1997.07c
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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.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.3
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• pp.85-94
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• 2000

In this paper, a robust H$\infty$ optimal tuning problem of a structure-specified PSS is investigated for power systems with parameter variation and disturbance uncertainties. Genetic algorithm is employed for optimization method of PSS parameters. The objective function of the optimization problem is the H$\infty$-norm of a closed loop system. The constraint of the optimization problem are based on the stability of the controller, limits on the values of the parameters and the desired damping of the dominant oscillation mode. It is shown that the proposed H$\infty$ PSS tuned using genetic algorithm is more robust than conventional PSS.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.9
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• pp.1796-1801
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• 2009

This paper is concerned with the problem of delay-dependent robust $H_{\infty}$ filtering for uncertain descriptor systems with time-varying delay. The considering uncertainty is convex compact set of polytoic type. The purpose is the design of a linear filter such that the resulting filtering error descriptor system is regular, impulse-free, and asymptotically stable with $H_{\infty}$ norm bound. By establishing a finite sum inequality based on quadratic terms, a new delay-dependent bounded real lemma (BRL) for delayed descriptor systems is derived. Based on the derived BRL, a robust $H_{\infty}$ filter is designed in terms of linear matrix inequaltity (LMI). Numerical examples are given to illustrate the effectiveness of the proposed method.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.328-330
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• 1993

In this paper, we present a robust $H^{\infty}$ controller for a state delayed system with uncertainties. The unstructured and norm bounded uncertainties enter into both the state and the input matrix, where the matching condition of the uncertainties is not assumed. A robust stabilization condition and also a robust $H^{\infty}$ stabilization condition are suggested. The robust $H^{\infty}$ controller is obtained by solving a Riccati equation which is derived from the suggested robust $H^{\infty}$ stabilization condition.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.331-334
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• 1993

It is a standard problem that designs a controller to minimize the $H_{\infty}$-norm of a given plant. By reducing a standard problem to a model-matching problem, we can obtain all the parameters which consist of a controller. After presenting a practical model and applying it to a tracking model, we design an $H_{\infty}$ controller and an LQ controller to concrete that $H_{\infty}$ control theory is far more robust than LQ control theory. And we show the advantage of an $H_{\infty}$ controller by obtaining a desired Bode diagram and comparing it with that of an LQ controller.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.556-559
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• 1996

In this paper, we suggest a H center .inf. generalized predictive control(H center GPC) which guarantees $H_{\infty}$-norm bounds. THe suggested control is obtained by solving the min-max problem in nonrecursive forms. The stability conditions of the suggested control are derived in a somewhat simple form and it is not required for the derived solution to be a saddle point solution. It is also shown that the suggested control guarantees the $H_{\infty}$-norm bounds under the same conditions of stability.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.6
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• pp.12-22
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• 1996

A numerous designs of PI controllers have been suggested to solve out trade-off between tracing and regulating problems. We constructed the PI controller system with two-degree-of-freedom that is more analytic and a better approach to a practical one. In the conventional H$_{2}$ design of optimal PI controllers, the cost function includes only the plant output terms due to the divergent problems. Since the platn input temr is not considered in PI controller design, occasionally, the plant input thends to be either very large or saturated. To solve the prior mentioned problems, we employed a mixed $H_2/H_{\infty}$ method that combines the H$_{2}$ design method to decide optimal parameters of PI controller and the $H_2/H_{\infty}$ design method to minimize the maximum amplitude of plant input. The calculation time of the H$_{infty}$ norm was considerably reduced by the simple scalar function obtained by the wiener-hopf factorization of non-scalar functions.