• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1168-1172
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• 2004

This paper presents a speed controller based on an adaptive fuzzy algorithm for high performance permanent magnet synchronous motor (PMSM) drives under parameter and load variations. In many speed tracking control systems PI controller has been used due to its simple structure and easy of design. PI controller, however, suffers from the electrical machine parameter variations and disturbances. In order to improve the tracking control performance under load variations, the PI controller parameters are modified during operation by adaptive fuzzy method. This method based on optimal fuzzy logic system has simple structure and computational simplicity. It needs only sample data which is obtained by optimal controller off-line. As the sample data implemented in the adaptive fuzzy system can be modified or extended, a flexible control system can be obtained. Simulation results show the usefulness of the proposed controller.

• 대한기계학회논문집
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• 제16권7호
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• pp.1234-1243
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• 1992

본 연구에서는 국부적인 퍼지제어 셀(fuzzy control cell:cell)을 도입하여 계산량 감소를 달성하고, 추론과정을 선형근사화한 조직적인 설계를 통하여 선형제어 이론을 FLC의 실용적인 면에 접목하고자 한다. 이를 위하여, 확률밀도함수 형태의 멤버쉽함수(membership function)와 선형화된 제어공간이 얻어지도록 전반적인 제어방 책을 결정한 다음, 주어진 상태에 가장 지배적(dominant)인 규칙을 갖는 몇 개의 대표 점을 찾아서 그 점들로 구성된 퍼지제어 셀을 생성하고, 퍼지연산을 생성된 셀에서만 수행하여 알고리즘과 계산을 단순화시킨다. 평가기준을 공평함에 두어서 조건부연결 어 'AND'에 T-norm인 대수곱을 적용하여 적합도를 취하고, 규칙들의 작용이 병렬발화 라는 관점으로 규칙연결어 'ALSO'는 'AND'의 공액인 'OR'에 해당되는 대수합연산 대신 에 확률측도와 유사한 산술평균을 적용하여 퍼지추론을 한다. 그리고, 각각의 제어 규칙에 대하여 퍼지추론한 결과와 그것의 평균중심을 곱하여 통합한 후, 무게중심법으 로 역퍼지화하여 일반화된 제어값을 얻는다. 이 값을 PID제어기를 이용하여 구현한 디지틀 보상기를 통과시켜 시스템에 한 제어를 얻는 조직적인 방법을 제안한다.

• 한국지능시스템학회논문지
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• 제12권1호
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• pp.7-13
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• 2002

퍼지이론의 응용은 대부분 퍼지추론을 이용하는 것이다. 그러나 퍼지추론은 입력변수의 수가 많아지거나 각 입력변수에 많은 수의 퍼지라벨을 설정할 경우 그 추론에 필요한 계산시간이 많아지게 되며 이러한 것은 컴퓨터 연산의 대수곱(arithmetic product)의 수에 의해 결정된다. 더구나 퍼지추론의 응용이 가장 활발한 퍼지제어분야에서는 이러한 추론시간은 실제 시스템에 적용 시 가장 큰 제약조건이 된다. 특히, 마이크로프로세서를 이용하거나 PC-based 제어기를 설계할 때 이러한 추론시간은 매우 중요한 문제가 된다. 본 논문에서는 이러한 추론시간을 효율적으로 줄이기 위해, 즉 추론 시 필요로 하는 곱 연산의 수를 줄이기 위하여 삼각형 소속함수를 이용하는 퍼지시스템에 적용 가능하며 정보의 손실이 발생되지 않는 간단한 고속 퍼지추론 알고리즘을 제안한다. 이것은 퍼지추론 시 입력상태공간의 분할과 간단한 기하학적 해석을 통해 얻어지는 것이며 결과적으로 퍼지규칙의 수를 줄이는 것과 같다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.805-810
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• 1993

In this paper, we propose a compliance control scheme using a neurofuzzzy compliance model(NFCM). as a new control paradigm for telerobot systems. A NFCM, used as a compliance controller, is composed of a fuzzy compliance model(FCM), a neural network and a low pass filter. The NFCM is trained through a reinforcement learning algorithm, and then, can generate suitable compliant motion for a given task. A series of simulations have been performed to show applicability of the proposed algorithm send it is found that the NFCM can implement suitable compliant motion for a given task through the learning procedure.

• Journal of Advanced Marine Engineering and Technology
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• 제23권6호
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• pp.731-737
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• 1999

This paper describes the path tracking control for a mobile robot which has two casters at the front and rear to keep balance and two driving wheels on the left and right sides of its body. Power wheeled steering method is adapted to control heading of the robot. It is very difficult to find appropriate feedback gains when linear regulator control scheme is adapted to path tracking con-trol of this type of robot. Therefore in this paper we propose the path tracking control algorithm using the fuzzy logic control scheme for this type of root. Simulation to prove the validity of the proposed two algorithms is performed. The results are reported as last part in this paper.

• 전기학회논문지P
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• 제51권4호
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• pp.163-168
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• 2002

This paper presents the comparison results of control algorithm for the simultaneous control of a multi output converter system that controls, simultaneously and independently, the separate Buck converter and Boost converter with the different specification by one DSP digital controller. As two separate converters are regulated by only one DSP, it is possible to achieve the simple digital control circuit for regulating the multi output DC-DC converter. By setting the software switch state, PI and Fuzzy controller can be applied as a controller for each converter without any change of hardware. Also, it is included the control characteristics comparison between PI and Fuzzy controller. The control characteristics of each PWM DC-DC converter is validated by experimental results.

• 대한전기학회논문지
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• 제41권9호
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• pp.1071-1084
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• 1992

In this paper, the method for navigation and obstacle avoidance of the autonomous mobile robot is proposed. The proposed algorithms are based on the fuzzy inference system which is able to deal with imprecise and uncertain information. The self-tuning algorithm, which adopts the simplex method, modifies the parameters of membership functions of the input-output linguistic variables by changing the support of these fuzzy sets according to the integral of absolute error(IAE) of the system response. The wall-follwing navigation and obstacle avoidance of the mobile robot are based on range data measured from the internal sensors(encoder) and the outer sensors(sonar sensor). In addition, the algorithm for the obstacle detection proposed in this paper is based on the expert's experience. Finally, the effectiveness of navigation and obstacle avoidance algorithm is demonstrated through simulation and experiment.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2003년도 ISIS 2003
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• pp.676-678
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• 2003

Microtunneling techniques play a crucial role in the construction of pipelines. This paper shows the automatic tunneling algorithm of microtunneling system using fuzzy logic technology to assist operators to assure the quality of microtunneling construction. To have effective output value of fuzzy controller, we slightly modified the conventional defuzzification methods. The proposed automatic tunneling algorithm shows good tunneling results comparable with those of experts.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 B
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• pp.621-623
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• 1999

In this paper, Model following PID control system, which is combined PID controller with Model Reference Adaptive Controller, is proposed. To decrease complex and much calculation which is produced in tuning process, the tuning method of parameter with fuzzy algorithm is introduced. Fuzzy algorithm isn't used in the form of controller generally much used, but tuner. Experimental results show that proposed controller has the PID parameter be tuned by fuzzy algorithm. Therefore, We expect model following PID to be operated in the real-time control.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 정기총회 및 추계학술대회 논문집 학회본부
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• pp.299-303
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• 1993

There can be two methods in control systems: one is to use a linear controller, the other is to use a nonlinear controller. The PID controller and the fuzzy controller can be said to belong the linear and the nonlinear controller respectively. In this paper, a new hybrid controller which is consist of the linear PID controller of which the gain is tuned and the nonlinear self tuning fuzzy controller is proposed. In the PID controller, an algorithm which parameterizes the proportional, the intergral, and the derivative gain as a single parameter is used to improve the performance of the PID controller. In the self tuning fuzzy controller, an algorithm which changes the shape of the triangle membership function and changes the scaling factor which is multiplied to the error and the error change. The evaluation of the performance of the suggested algorithm is carried on by the simulation for the Rhino XH-2 robot manipulator with 5 links revolute joints.