• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.154-157
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• 2002

본 연구는 관성의 변화, 비선형 마찰 등에 견실한 피드포워드 적응 위치제어기를 제안한다. 제안된 적응 위치제어기의 특징은 제어기 적응파라미터가 위치오차에 기준모델의 속도 정보를 받아들여 셀프 튜닝된다. 이것은 과도응답 특성을 향상시키고, 정상상태의 수렴 시간을 줄여 시스템의 성능을 개선시킨다. 시뮬레이션을 통하여 제안된 피드포워드 적응 위치제어기의 동작과 설계 방법의 타당성을 보였다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.6
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• pp.64-72
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• 2010

In general, due to the interactions among subsystems, it is difficult to design an decentralized controller for nonlinear interconnected systems. In this study, the model of nonlinear interconnected systems is studied via decentralized fuzzy control method with time delay and polytopic uncertainty. First, the nonlinear interconnected system is represented by an equivalent Takagi-Sugeno type fuzzy model. And the represented model can be rewritten as Parameterized Linear Matrix Inequalities(PLMIs), that is, LMIs whose coefficients are functions of a parameter confined to a compact set. We show that the resulting fuzzy controller guarantees the asymptotic stability and disturbance attenuation of the closed-loop system in spite of controller gain variations within a resulted polytopic region by example and simulations.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.1
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• pp.52-58
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• 2005

Among various modern control theories, PID control has been well used for several decades. PID algorithms need some tuning methods which are used for selecting PID parameters. But in some cases various kinds of performance indices are used instead of well-known tuning rules, and so variable type of performance index must be tested so that controllers, output characteristics and disturbance rejection property meet some specifications. In this paper, linear conbinational type of performance index using error signal, time, control input and robustness is used to the PID control of air conditioning system. By use of the 2 DOF PID parmeters minimizing perfromacne index controllers, output characteristics and robustness properties are analyzed. Simulations are done by use of MATLAB with Simulink.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.3
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• pp.40-47
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• 2011

This paper addresses the problem of fault detection and tolerance for asynchronous sequential machines using state feedback control. The considered asynchronous machine is affected by intermittent faults. When intermittent faults occur, the machine undergoes unauthorized state transitions and, for a finite duration, remains at the fault state, not responding to the change of the external input. In this paper, we postulate the scheme of detecting intermittent faults and present the existence condition and design algorithm for a robust state feedback controller that overcomes the adversarial effect of intermittent faults. We also undertake a comparative study between the previous control scheme for transient faults and the present strategy for intermittent faults. The design procedure for the proposed controller is described in a case study.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.173-179
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• 2002

This paper presents a new approach to the design of adaptive control system using DSPs(TMS320C50) fur robotic manipulators to achieve trajectory tracking angles. Digital signal processors are used in implementing real time adaptive control algorithms to provide motion for robotic manipulators. In the proposed scheme, adaptation laws are derived from the improved second stability analysis based on the indirect adaptive control theory. The proposed control scheme is simple in structure, fast in computation, an suitable fur implementation of real-time control. Moreover, this scheme does not require an accurate dynamic modeling, nor values of manipulator parameters and payload. Performance of the adaptive controller is illustrated by experimental results for a SCARA robot.

• ICROS
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• v.1 no.2
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• pp.21-29
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• 1995

이 글에서는 H/sub .inf./ 설계법의 장단점에 대해서 알아보았다. H/sub .inf./ 제어기법은 이론적인 연구와 함께 산업응용에 관한 연구도 활발하여, 자동차 제어, 항공우주 제어(고성능 헬리콥터의 비행제어, 비행체의 핏치축 제어, 우주구조물체의 제어), 공정제어(발전소에서의 핵반응로 제어), 및 기계제어 등에 광범위하게 응용되고 있다. H/sub .inf./ 제어기법은 여타의 다른 제어기 설계기법에 비해 많은 수학적 지식을 필요로 하고 제어이론 및 설계과정이 복잡한 것으로 인식돼 우리나라에서는 그다지 많은 관심을 끌지 못하고 있는 것 같다. 그러나, 응용사례에서 알 수 있는 것처럼 그 응용대상이 광범위하고, 또한 고성능의 제어목적을 달성하기 위해 필요한 제어기법으로 자리잡아가고 있으므로 보다 더한 관심을 기울일 필요가 있을 것으로 사료된다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.4
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• pp.251-263
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• 2003

This paper presents matrix inequality conditions for Η$_2$control and Η$_2$controller design method of linear time-invariant descriptor systems with parameter uncertainties in continuous and discrete time cases, respectively. First, the necessary and sufficient condition for Η$_2$control and Η$_2$ controller design method are expressed in terms of LMI(linear matrix inequality) with no equality constraints in continuous time case. Next, the sufficient condition for Hi control and Η$_2$controller design method are proposed by matrix inequality approach in discrete time case. Based on these conditions, we develop the robust Η$_2$controller design method for parameter uncertain descriptor systems and give a numerical example in each case.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.3
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• pp.9-16
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• 2004

This paper provides an observer-based Η$\infty$ output feedback controller design method for descriptor systems with time-varying delay by just one LMI(linear matrix inequality) condition. The sufficient condition for the existence of controller and the controller design method are presented by perfect LMI approach which can be solved efficiently by convex optimization. The design procedure involves solving an LMI. Since the obtained condition can be expressed as an LMI form all variables including feedback gain and observer gain can be calculated simultaneously by Schur complement changes of variables, and singular value decomposition. Moreover, The proposed controller design algorithm can be extended to the observer-based robust Η$\infty$ output feedback controller design method for descriptor systems with parameter uncertainty and time delay. An example is given to illustrate the results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.255-256
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• 2009

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.4
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• pp.39-48
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• 2009

Asynchronous sequential machines, or clockless logic circuits, have several advantages over synchronous machines such as fast operation speed, low power consumption, etc. In this paper, we propose a novel robust controller for input/output asynchronous sequential machines with uncertain state transitions. Due to model uncertainties or inner failures, the state transition function of the considered asynchronous machine is not completely known. In this study, we present a formulation to model this kind of asynchronous machines ana using generalized reachability matrices, we address the condition for the existence of an appropriate controller such that the closed-loop behavior matches that of a prescribed model. Based on the previous research results, we sketch design procedure of the proposed controller and analyze the stable-state operation of the closed-loop system.