• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.5
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• pp.22-28
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• 2011

This paper presents an active roll motion control of a passenger vehicle. The roll controller is designed in the framework of $H_{\infty}$ control scheme based on the 3 DOF vehicle model taking into consideration parameter variations, which affect the roll dynamics, and unmodeled high frequency dynamics for robustness and performance. In order to investigate the feasibility of the active roll control system in a car, its performance is evaluated by simulation in a full vehicle model with nonlinear tire characteristics under various operating conditions. Finally, in order to enhance the performance in a transient region taking into account the limited bandwidth of the actuating module, a hybrid control strategy is presented.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.323-326
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• 2003

본 논문에서는 PID 제어기를 이용해 외란제거를 함은 물론 최적 제어가 될 수 있는 파라메터를 유전자 알고리즘을 통해 구하는 방법을 제안하였다. 외란제거를 위해 $H_\infty$-norm을 응용하여 제어시스템의 외란 제거 조건들을 제시하고 이 조건들을 만족하는 PID 제어기를 설계하였다. 설계된 PID제어기의 최적 파라메터를 구하기 위해 유전자 알고리즘을 이용하였고 최적 파라메터를 평가하기 위하여 ITSE(Integral of time weighted squared error)성능지수를 이용하였다. 위의 설계 기법들을 서보모터의 제어에 적용하여 만족할 만한 결과를 얻었다.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2134-2136
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• 2003

ATM 네트워크 중에서 ABR 서비스만이 피드백(feedback) 메커니즘이 가능하며, 이를 이용한 체증제어(congestion control)연구가 다양한 방법으로 진행되고 있다. 본 연구에서는 현대 제어기법을 이용한 ABR 서비스의 체증제어 문제에 관심을 가지고, ABR 서비스 트래픽의 체증을 억제하고 체증 발생시 제어함으로써 최대의 QoS(Quality of Service)를 보장하도록 한다. 문제해결을 위해 제어 이론을 기반으로 한 ABR Explicit Rate 알고리즘을 이용하며, 불확실한 외란에 대해서도 강인하고 안정된 성능을 보이는 시스템 모델을 연구한다. 그리고 이 시스템에 대한 $H_{\infty}$ 제어기를 설계하고 시뮬레이션을 통하여 설계한 제어기의 타당성을 보인다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.11a
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• pp.279-282
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• 2006

본 논문은 시간지연을 갖는 이산 비선형 시스템에 대한 점근적 안정화 및 $H_{\infty}$ 성능을 갖는 퍼지 제어기 설계 방법을 제안한다. 시간지연을 갖는 이산 Takagi-Sugeno 퍼지 모델에 대한 점근적 안정화 및 $H_{\infty}$ 성능을 만족하는 제어기 존재조건을 선형행렬부등식으로 나타낸다. 리아프노프 함수에 조정파라미터를 도입함으로써 제어기 존재조건을 조정파라미터를 포함하는 선형행렬 부등식으로 나타낸다. 선형행렬부등식에 있는 조정 파라미터를 조정함으로써 시스템의 응답속도 및 오버슈트 등의 동적 성능을 개선시킬 수 있다.

• Journal of Mechanical Science and Technology
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• v.18 no.7
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• pp.1074-1085
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• 2004

There are many intermediate web guides in cold rolling mills process such as CRM (cold rolling mill), CGL (continuous galvanizing line), EGL (electrical galvanizing line) and so on. The main functions of the web guides are to adjust the center line of the web (strip) to the center line of the steel process. So they are called CPC (center position control). Rapid process speed cause large deviation between the center position of the strip and the process line. Too much deviation is not desirable. So the difference between the center position of the strip and the process line should be compensated. In general, the center position control of the web is obtained by the hydraulic driver and electrical controller. In this paper, we propose modelling and several controller designs for web-guide systems. We model the web and guide by using geometrical relations of the guide ignored the mass and stiffness of the web. To control the systems, we propose PID controllers with their gains tuned by the Ziegler-Nichols method, the H$\_$$\infty$/ controller model-matching method, and the coefficient diagram method (CDM). CDM is modified for high order systems. The results are verified by computer simulations.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.351-354
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• 1993

In this paper, reheat-fan engine is described as class of models constructed from nominal and uncertainty model for robust control. In this class of models, uncertainty model consists of structured and unstructured uncertainty, and each model is identified from nonlinear simulation using FFT and ML technique. Then, control requirements and augmented plant are specified. H$_{\infty}$ controller satisfying the control requirements is designed by using constant scaling matrix. Finally, efficacy of the H$_{\infty}$ controller is showed by computer simulation.n.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.9
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• pp.1524-1530
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• 2016

This paper deals with a robust $H_{\infty}$ sampled-data controller design problem for nonlinear systems in Takagi-Sugeno fuzzy form with singular perturbation. The employed controller takes a state-feedback form. The design condition is represented in terms of linear matrix inequalities. A numerical examples is included to show the effectiveness of the theoretical development.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2723-2725
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• 2005

In this paper, a robust $H{\infty}$ stabilization problem to a uncertain discrete-time nonlinear systems with time-delay via fuzzy static output feedback is investigated. The Takagi-Sugeno (T-S) fuzzy model is employed to represent an uncertain nonlinear systems with time-delayed state. Then parallel distributed compensation technique is used for designing of the robust fuzzy controller. Using a single Lyapunov function, the globally asymptotic stability and disturbance attenuation of the closed-loop fuzzy control system are discussed. Sufficient conditions for the existence of robust $H{\infty}$ controllers are given in terms of linear matrix inequalities via similarity transform and congruence transform technique.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.356-359
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• 1995

This paper uses a new method to improve the performance criterion of an active suspension car. The used control strategy is based on robust H$_{\infty}$ control theory taking into consideration the chasis flexibility. It will be shown that the modeling errors can be lumped into an unstructured uncertainty and the robust controller designed in the presence of these perturbations could maintain the stability and performance even for the controlled true system..

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.1141-1144
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• 1999

This note addresses the problem of reliable (equation omitted) output-feedback control design for linear systems with actuator and/or sensor failures. An output feedback control design is proposed which stabilizes the plant and guarantees an (equation omitted)-norm bound on at-tenuation of augmented disturbances including all admissible actuator/sensor failures. Based on the linear matrix inequality (LMI) approach, the output- feedback controller design method is constructed by formulating to LMIs that cover all failure cases. Ef-fectiveness of this controller is validated via a numerical example.