• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.947-949
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• 1995

In this paper, model reference adaptive fuzzy controller (MRAFC) was proposed in order to overcome the difficulty of extracting rules and defects of the adaptation performance in the FLC. MRAFC comprised inner feedback loop consisting of the FLC and plant, and outer loop consisting of an adaptation mechanism which is designed for tuning a control rule of the FLC. A reference-model was used for design criteria of a fuzzy controller which characterizes and quantizes the control performance required in the overall control system. Tuning control rules of FLC is performed by the adaptation mechanism. For this, the fuzzy model for tuning the contorl rules is designed in accordance with the feature of error information. And DC servo motor was selected for case study of actual industrial plant and tested on various loads.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.795-797
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• 1995

In this paper, we present a simple auto-tuning PID controller using genetic algorithms. The basic idea of the scheme is to parameterize a Ziegler-Nichols-like tuning formula by a single parameter ${\alpha}$, then to use GA to select optimal tuning parameter. Also, simple rule mechanisms make the controller adapt against large variations in parametric and dynamics uncertainties in the plant. These scheme lead to improved performance of the transient and steady state behavior of the closed loop system, including processes with long delay-time and nonminimum phase systems.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.311-316
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• 1991

This paper deals with designing the PID autotuner. The system parameters are identified using the relay control, where the unidirectional relay with hysteresis is adopted. The digital PID tuning rule on Nyquist plot is derived, and the statistical wordlength is adopted for the coefficient wordlength. The experimental results of temperature control exhibit the satisfactory performance and the validity of the derived statistical wordlength.

• 대한기계학회논문집A
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• 제20권10호
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• pp.3038-3047
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• 1996

In telerobot systems, visual servoing of a task object for a slave arm with an eye-in-hand has drawn an interesting attention. As such a task ingenerally conducted in an unstructured environment, it is very difficult to define the inverse feature Jacobian matrix. To overcome this difficulty, this paper proposes an auto-tuning fuzzy rule-based visual servo algorithm. In this algorithm, a visual servo controller composed of fuzzy rules, receives feature errors as inputs and generates the change of have position as outputs. The fuzzy rules are tuned by using steepest gradient method of the cost function, which is defined as a quadratic function of feature errors. Since the fuzzy rules are tuned automatically, this method can be applied to the visual servoing of a slave arm in real time. The effctiveness of the proposed algorithm is verified through a series of simulations and experiments. The results show that through the learning procedure, the slave arm and track object in real time with reasonable accuracy.

• 한국조명전기설비학회지:조명전기설비
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• 제11권2호
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• pp.89-93
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• 1997

산업의 자동화에 따라 PI 제어기에 의해 제어되는 직류 서보 전동기는 정밀한 제어가 요구된다. 하지만 시스템의 특성이 변화하면 정밀한 제어는 어렵게 된다. 이를 해결하기 위한 한 방법으로 본 논문에서는 전동기 속도제어 시스템을 위한 규칙기반 자동동조 PI 제어기를 제안하였다. 규칙은 Ziegler-Nichols의 계단응답과 전문가 지식을 기초로 하였다. 제어 매개변수는 오차, 기울기, 가장 큰 기울기의 점, 허용 오버슈트에 의해서 결정된다. 제어의 정밀성은 시뮬레이션에 의해 확인하였다.

• 한국지능시스템학회논문지
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• 제8권6호
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• pp.106-118
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• 1998

The study concerns a design procedure of rule-based systems. The proposed rule-based fuzzy modeling implements system structure and parameter identification in the efficient from of "IF..., THEN..." statements, and exploits the theory of system optimization and fuzzy implication rules. The method for rule-based fuzzy modeling concerns the from of the conclusion part of the the rules that can be constant. Both triangular and Gaussian-like membership function are studied. The optimization hinges on an autotuning algorithm that covers as a modified constrained optimization method known as a complex method. The study introduces a weighted performance index (objective function) that helps achieve a sound balance between the quality of results produced for the training and testing set. This methodology sheds light on the role and impact of different parameters of the model on its performance. The study is illustrated with the aid of two representative numerical examples.

• 한국지능시스템학회논문지
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• 제6권2호
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• pp.3-12
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• 1996

탁월한 비선형 제어 특성을 가지고 있는 슬라이딩 모우드 제어기는 제어 대상 플랜트의 모델링 과정에서 발생하는 부정확성과 각종 외란등으로 인하여 제어 입력 신호가 매우 높은 주파수의 비연속적인 특성을 가진다. 이를 방지하기 위하여 슬라이딩 평면에 얇은 경계층을 도입하는 방법을 많이 사용하고 있지만 이 경우에는 원하지 않는 정상 상태 오류가 유발될 수도 있다. 이때의 정상 상태 오차는 경계층의 폭에 비례해서 증가하는 특성이 있다. 본 논문에서는 정상 상태 오차와 제어 입력 신호의 불연속성 사이에는 구해지는 경계층의 폭을 정상 상태에 접근할수록 퍼지 규칙베이스에 의해 자동으로 감소시키는 자기동조형 경계층을 가지는 슬라이딩 모우드 제어기를 제안하였다. 그리고 제안된 알고리즘의 성능을 역진자 계통의 추적 제어 시뮬레이션을 통하여 입증하였다.

• Journal of Power Electronics
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• 제14권5호
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• pp.980-988
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• 2014

This paper proposes an online gain tuning algorithm for a robust sliding mode speed controller of surface-mounted permanent magnet synchronous motor (SPMSM) drives. The proposed controller is constructed by a fuzzy neural network control (FNNC) term and a sliding mode control (SMC) term. Based on a fuzzy neural network, the first term is designed to approximate the nonlinear factors while the second term is used to stabilize the system dynamics by employing an online tuning rule. Therefore, unlike conventional speed controllers, the proposed control scheme does not require any knowledge of the system parameters. As a result, it is very robust to system parameter variations. The stability evaluation of the proposed control system is fully described based on the Lyapunov theory and related lemmas. For comparison purposes, a conventional sliding mode control (SMC) scheme is also tested under the same conditions as the proposed control method. It can be seen from the experimental results that the proposed SMC scheme exhibits better control performance (i.e., faster and more robust dynamic behavior, and a smaller steady-state error) than the conventional SMC method.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.72-77
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• 2017

This paper proposes the explicit tuning rule of multi-loop PID controller for brushless direct current motors to predict the system behaviors in time and frequency domains, using properties of the convex combination method. The convex set of the proposed controllers formulates the envelope to satisfy the performances in time and frequency domains. The final control parameters are determined by solving the convex optimization problem subject to the constraints which are represented as convex set of time domain performances. The effectiveness of the proposed control method is shown in the numerical simulation, in which controller tuning algorithm and dynamics of brushless DC motor are well taken into account.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.523-525
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• 2004

Over the last few years, the control of bipedal robot has been considered a promising research field in the community of robotics. But the problems we encounter make the control of a bipedal robot a hard task. The complicated link connection of the bipedal robot makes it impossible to achieve its exact model. In addition, the joint velocity is needed to accomplish good control performance. In this paper a control method using ANFIS as an system approximator is purposed. First a model biped robot of a biped robot with switching leg influence is presented. Unlike classical method, ANFIS approximation error estimator is inserted in the system for tuning the ANFIS. In the entire system, only ANFIS is used to approximate the uncertain system. ANFIS tuning rule is given combining the observation error, control error and ANFIS approximation error. But this needs velocity information which is not available. So a practical method is newly presented. Finally, computer simulation results is presented to show this control method has good position tracking performance and robustness without need for leg switching acknowledgement.