• 전자공학회논문지B
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• 제32B권6호
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• pp.828-839
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• 1995

Although the fuzzy logic controller(FLC) has been adopted in many engineering applications, its performance is not guaranteed since there is no definite theoretic analysis. It may be the main factor that one hesitates to adopt the FLC in critical applications. In this paper, observing the similarity in the pattern of control input between the FLC and a conventional robust controller, i.e., the variable structure controller, we present theoretic analysis for robustness of a fuzzy control system based on the Lyapunov theory.

• 전자공학회논문지B
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• 제33B권2호
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• pp.1-9
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• 1996

Although the fuzzy logic controller (FLC) has been adopted in many engineering applications, one hesitates to adopt the FLC in critical applications, since there was no definite control theoretic analysis. In this paper, based on the stability/robustness analysis of an FLC by S.Y.Yi$^{[3]}$, we apply the FLC to robot manipulator with the structured and unstructured uncertainties e.g., load variation and firction, etc. And we verify the performance of the FLC by computer simulation on a simple two-link robot manipulator.

• 전자공학회논문지CI
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• 제40권2호
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• pp.9-16
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• 2003

본 논문에서는 개선된 SOFM(Self Organizing Feature Map)방식을 이용한 근전도 패턴인식으로 가상 로봇 팔을 제어하는 방식을 제안한다. 개선된 SOFM 방식은 근전도 신호의 전처리기를 사용하는 대신에 근전도 신호 자체를 SOFM에 입력으로 사용하고, 퍼지논리시스템을 이용하여 SOFM의 이웃반경과 학습율을 자동 조절하는 간단한 방식으로 입력 패턴을 더욱 빠르고 신뢰성있게 분류한다. 개선된 방식의 성능을 확인하기 위하여 어깨, 손목, 팔꿈치의 여섯 가지 동작의 근전도 패턴인식을 실험한 결과 기존의 일반적인 SOFM방식보다 제안한 SOFM방식의 인식율이 21.7% 향상되고, 평균학습 수도 절반이하로 감소되었으며, 인식한 근전도 신호를 이용하여 컴퓨터 상의 가상 로봇 팔을 정확하게 제어하였다.

• 전력전자학회논문지
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• 제4권6호
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• pp.531-538
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• 1999

본 논문에서는 퍼지 논리에 기초를 둔 DC-DC converter를 위한 범용 FLC는 기존의 제어기와 비교할 때, 오버슈트 문제와 파라메터 변화에 대한 민감도 면에서 향상된 성능을 나타내었다. 이러한 성능 향상은 FLC 규칙들이 다양한 동작 영역에서 각각 적합하게 설정됨으로써 소신호 응답과 대산호 응답 모두 효과적으로 동작하도록 설계되었기 때문이다. 그 적용 예로 부스터(booster)에 대한 시뮬레이션 결과는 제안된 제어 기법의 타당성을 보여주고 있다.

• 한국지능시스템학회논문지
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• 제23권1호
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• pp.65-71
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• 2013

본 논문은 센서 고장을 갖는 타카기-수게노 (Takagi-Sugeno: T-S) 퍼지 시스템의 샘플치 고장검출 관측기 설계 문제를 다룬다. 고장검출을 위해 T-S 퍼지 모델 기반의 관측기가 사용된다. $\mathfrak{H}$_ 성능 지수를 도입하여 고장에 가능한 한 민감한 관측기를 설계한다. 고장 판단 논리에 의해 고장 발생 여부를 확인할 수 있다. 관측기의 설계조건을 선형행렬부등식으로 제안한다. 모의실험에서 수치 예제를 통해 제안한 고장검출 기법의 효용성을 입증한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.356-361
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• 1990

This paper presents a new self organizing fuzzy linguistic control (SOFLC) strategy for application to an arc welding process control. The proposed SOFLC is based on on-line modification of the control rules according to the extent of deviation of the one step ahead predictive output of the process from the desired output. The Predictive output of the process is estimated by a fuzzy predictor which is updated from the input and output data of the process. The rule base of the fuzzy subsets describing the control rules is modified by the improving mechanism based on the hill climbing approach. Simulation results show that this proposed SOFLC improves the response of the process in presence of the variation of the process dynamic characteristics.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.708-712
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• 1991

This paper presents a new adaptive structure with fuzzy logic applied to adaptive controller. In the conventional adaptive control, good performance cannot be expected due to the adaptation gain of gradient algorithm fined as a constant. To change adaptation gain property, fuzzy rules, which are based on the output error and its rate of change, have been established. The proposed fuzzy adaptive law shows fast parameter convergence and improved performance. The fuzzy logic base is added to the conventional adaptive structure and little additional computation time is required.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.548-551
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• 1991

The Sliding Mode Control of Variable Structure System is applied to robot manipulators or servo system for its merits of robustness to variable system parameters and disturbances. But Switching frequency of control input is excessively high during sliding mode operation. In this paper, a new control algorithm usings fuzzy logic is proposed to solve this problem. With the proposed algorithm, a dc motor speed control system has been simulated and the result shows expected performances.

• 전기학회논문지
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• 제56권4호
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• pp.777-783
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• 2007

In this paper, we present a novel control approach for linear motor-based transfer systems in which friction reduction and enhancement of control performance are considered. In general, in such systems friction effects from rails and wheels, and internal bearings complicate control scheme since in particularly its dynamics are arbitrarily changed due to mass variation, detent force of motor systems, and gaps among stators. Our control approach is achieved to reduce this undesired friction dynamics using fuzzy system. We construct hybrid control approach for this control system which Is composed of a nominal control and a vertical control against friction. Fuzzy parameter vector is optimally determined from iterative simulation experiments. We demonstrate its superiority via numerical simulations comparing with a traditional control method.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권12호
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• pp.713-715
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• 2005

The work in this paper presents development of fuzzy logic-based energy management strategy for a fuel cell hybrid electric vehicle. In order for the fuel cell system to overcome the inherent limitation such as slow response time and low fuel economy especially at the low power region, the battery system has come to compensate for the fuel cell system. This type of hybrid configuration has many advantages, however, the energy management strategy between power sources is essentially required. For the optimal power distribution between the fuel cell system and the battery system, a fuzzy logic-based energy management strategy is proposed. In order to show the validity and the robustness of suggested strategy, some simulations are performed for the standard drive cycles.