• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.1081-1082
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• 2010

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.328-330
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• 2005

Most of the water level controllers of the actual plant are PID controllers. But they have limitations in appling for tracking the set point and getting rid of disturbances, so there are some defects to apply in the actual ground even though many research works represented the resolution to solve it. In this paper, we design a fuzzy logic system (FLS) for controlling the steam generator water level in nuclear power plants. Some computer simulations reveal similar performance with the conventional PID controller.

• 한국지능시스템학회논문지
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• 제8권2호
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• pp.106-116
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• 1998

유연 로봇 매니퓰레이터의 위치 제어 알고리즘에 대한 연구를 하였다. 제안하는 알고리즘은 신경회로망의 학습 알고리즘에 근거한 자동 구축 퍼지 적응 제어기(ACFAC : Automaitc Constructed Fuzzy Adaptive controller)에 기본으로 한다. 제안하는 시스템은 비지도 경쟁 학습 알고리즘을 사용하여 입력 변수의 멤버십 함수와 지도 Outstar 학습 알고리즘을 사용하여 출력 정보를 학습시킨다. ACFAC는 유연 로봇 매니퓰레이터의 동력한 모델을 필요로 하지 않는다. ACFAC는 유연 로봇 매니퓰레이터의 끝점이 원하는 궤적을 따라가도록 설계되었다. 이 제어기의 입력은 위치 오차, 위치 오차의 미분 값과 오차의 variation에 의해 결정된다. ACFAC의 우수서을 보여주기 우해서 PID 제어나 신경회로망 알고리즘을 사용한 결과와 비교를 하였다.

• 한국해양공학회지
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• 제25권6호
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• pp.1-8
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• 2011

This paper describes a new method for a digital gas metal arc welding (GMAW) system. The GMAW system is an arc welding process that incorporates the GMAW power source (PS-GMAW) with a wire feed unit (WFU). The PS-GMAW requires an electric power of constant voltage. A constant magnitude is maintained for the arc current by controlling the wire-feed speed of the WFU. A mathematical model is derived, and a self-tuning fuzzy proportional-integral-derivative (PID) controller is designed and applied to control the welding current. The electrode wire feeding mechanism with this controller is driven by a DC motor, which can compensate for both the molten part of the electrode and undesirable fluctuations in the arc length during the welding process. By accurately maintaining the output welding current and welding voltage at constant values during the welding process, excellent welding results can be obtained. Simulation and experimental results are shown to prove the effectiveness of the proposed controller.

• 한국항공우주학회지
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• 제42권3호
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• pp.237-242
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• 2014

항공기용 터보팬 엔진의 성능이 이륙과 같이 급격하게 변하는 상황일 때 압축기에서 서지현상이 발생할 수 있는데, 본 논문에서는 이를 방지하는 것을 목적으로 한다. 제안된 시스템은 연료유량을 개루프 명령으로 생성하고, 가변 안내익을 폐루프로 설계하여 터보팬 엔진에 대한 제어시스템을 고전적인 PID제어기와 퍼지 추론 기법을 적용하여 설계하였다. 시뮬레이션은 SIMULINK를 이용하였는데, 제어로직 구성을 위한 동역학적 모델링은 NPSS(엔진해석프로그램)와 SIMULINK를 연동시켜주는 SIMUNLINK BLOCK인 NPSS S-function을 설계하여 이용하였다. 그리고 시뮬레이션 결과로 PID와 Fuzzy 모든 방법에 있어 VIGV의 제어결과로 서지현상을 방지할 수 있음을 증명하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.992-994
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• 1995

FLC has a good performance for complication system or unknown model by using human linguistic method but many part control design are based on expert knowledge or trial-error method and it is difficult to prove stability and robustness of controller. In this paper we improve this problem by setting fuzzy rules by dividing phase plane of error and rate of error change by switching surface. We can guarantee the stability in nonlinear system, and also in fuzzy PID type controller the complexity of controller design is increased by increasing the number of input variables and defining more range of operation if we want performance of more specific rules, thus we need to fine the method to decrease the number of control rules used in FLC design. In this paper the algorithm is validated by simulation using conventional FLC and proposed method.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1995년도 추계학술대회 학술발표 논문집
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• pp.145-152
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• 1995

This paper presents a novel SOFLIC(self organizing fuzzy logic intelligent controller) for reactor rod control system in nuclear power plant. The output of fuzzy controller is gener ated by using two signal : the error between reference and average temperature, and the error between reference and neutron flux-converted temperatures. Flexibility of the controller is enhanced by using self-organizing feature and the controller respond to variation of system parameter with more precision. performances of the SOFLIC and PID are simulated with the model developed for a nuclear power plant. The SOFLIC is superior to PID : SOFLIC provides more rapid load following capability. more robustiness for variation in process dynamics and minimization of engineer's mistakes in controller design.

• 한국지능시스템학회논문지
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• 제9권5호
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• pp.480-489
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• 1999

Design and experimental results of yaw rate controller is described for electricallydriven four wheel vehicle without steering mechanism. Yaw rate controller has been known to be necessary to cope with nonlinear char-acteristics of the wheel/road conditions with respect to different road condition and steering angle. For an effective yaw rate control, a fuzzy PID gain scheduler is considered with changing control parameters. In order to apply proposed algorithm to the system a downsized four wheel drive electrically driven vehicle without steering mechanism was manufactured. With these techniques the proposed yaw rate controller is shown by experiment results to be obtained suficient performance in the whole steering regions.

• 산업기술연구
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• 제16권
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• pp.231-237
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• 1996

In this paper, the nonlinear I/O characteristic of fuzzy logic controller is analyzed by using cell concept. Sources of the nonlinearity in a fuzzy logic controller include the fuzzification, the fuzzy reasoning and the defuzzification. A closed form expression for the defuzzified output is derived in case of a fuzzy logic controller with two inputs, triangular memberships, MacVicar-Whelan type linguistic rules, and direct fuzzy reasoning. As a result, it is shown that fuzzy logic controller is a nonlinear controller. Also its nonlinearity is analyzed with respect to the conventional PID control and the sliding mode control.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 ISIS 2003
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• pp.350-353
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• 2003

In this paper, we proposed the method to design fuzzy controller using the experience of the operating expert and experimental numeric data for the robust control about the noise and disturbance instead of the traditional PID controller for the main steam temperature control of the thermal power plant. The temperature of main steam temperature process has to be controlled uniformly for the stable electric power output. The process has the problem of the hunting for the cases of various disturbances. In that case, the manual action of the operator happened to be introduced in some cases. We adopted the TSK (Takagi-Sugeno-Kang) model as the fuzzy controller and designed the fuzzy rules using the informations extracted directly from the real plant and various operating condition to solve the above problems and to apply practically. We implemented the real fuzzy controller as the Function Block module in the DCS(Distributed Control System) and evaluated the feasibility through the experiment81 results of the simulation.