• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.927-929
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• 1999

In this research a real-time control system was developed without program codings during control system designing procedures. On the Simulink window control system is designed in the form of block diagrams, program codes are produced automatically with the real time workshop package, then C-compiler compiles the program codes. With this automatic real-time program producing mechanism rapid prototyping is realized. To show effectiveness of the proposed system designing scheme a DSP-based DC motor speed control system was constructed and PI and Fuzzy control methods were implemented.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.95-97
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• 1997

This paper deals with design and implementation of the controller for optically guided AGV. When AGV has only three photo sensors in front of body, AGV doesn't know how much the entry angle to guide line is. In this case, it is difficult to compensate the tracking error. To make sure that the AGV does not secede the guide line in tracking, PI controller and fuzzy logic controller is proposed. The proposed controller was verified and experienced through real AGV system.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.85-89
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• 1998

A switching power stage is a very nonlinear system because it has two or more operation modes in one switching cycle. To model a switching power stage, the state space averaging method has been developed. Though it allows a unified treatment of a large variety of switching power stages, the model it yields is always very nonlinear. So, it is required to linearize the averaged model. But it is well known that a controller for a nonlinear plant designed by the linearization frequently fails in showing satisfactory control performance. Hence it is very natural to try to design a nonlinear controller for a switching power stage. In design of a switching power system, nonlinear control approaches such as adaptive control and fuzzy control have been widely studied so far. In this research, a recently developed control method, time delay control is briefly studied and a design example for a ZVS PWM half bridge converter is given. The performance of the time delay controller is compared to its conventional counterpart, PI controller by computer simulations.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.372-374
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• 2001

An automatic operation of train is executed by an automatic train operation(ATO) system. The main function of ATO system is to control train speed as well as train brake system. So that train can stop at its programed position on platform and run with passenger comfort. In this paper, the gain scheduled control is designed for speed control considering the disturbances. The simulation is executed to verify the speed control performance and to compare its performance with the conventional PI and general Fuzzy control.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.149-151
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• 2001

This paper proposes the design of STATCOM(static synchronous compensator) stabilizer for improving power system stability using fuzzy logic controller(FLC). The STATCOM DC voltage regulator contributes negative damping to the power system as the installation of STATCOM DC voltage regulator. STATCOM stabiliser is superimposed on the AC voltage regulator to compensate the negative damping effect. To evaluate usefulness of the proposed method, we perform the nonlinear simulation on a single-machine infinite bus system. As results of the simulations, the proposed method shows better control performance than PI controller in terms of damping effects.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.3 no.1
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• pp.78-86
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• 2003

Multivariable control system exist widely in many types of systems such as chemical processes, biomedical processes, and the main steam temperature control system of the thermal power plant. Up to the present time, Pill Controllers have been used to operate these systems. However, it is very difficult to achieve an optimal PID gain with no experience, because of the interaction between loops and gain of the Pill controller has to be manually tuned by trial and error. This paper suggests a tuning method of the Pill Controller for the multivariable power plant using an immune algorithm, through computer simulation. Tuning results by immune algorithms based neural network are compared with the results of genetic algorithm.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.9
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• pp.26-35
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• 2010

The maximum output torque developed by the machine is dependent on the allowable current rating and maximum voltage that the inverter can supply to the machine. Therefore, to use the inverter capacity fully, it is desirable to use the control scheme considering the voltage and current limit condition, which can yield the maximum torque per ampere over the entire speed range. This controller is controlled speed and current using hybrid PI(HBPI) controller and estimation of speed using ANN. Also, this paper is proposed maximum torque control of induction motor using slip angular speed and current condition at widely speed range. The performance of the proposed induction motor drive with maximum torque control using HBPI controller is verified by analysis results at dynamic operation conditions.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.491-492
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• 2013

본 연구는 STATCOM을 이용하여 고속철도 급전 계통의 전압 변화를 보상하는 기법에 관한 것이다. 기존의 PI 제어기를 이용한 제어기법를 대신하여 본 연구에서는 퍼지제어기(FLC) 적용을 제안하며, 퍼지제어기와 PI제어기의 제어결과를 비교한다. 퍼지제어기를 통해 내부 파라미터 변동이나 외부의 환경 변화 등 계통의 변화시에 정상상태 편차, 정상상태 도달 시간 등을 최소화 시킬 수 있음을 보인다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.4 no.3
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• pp.311-315
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• 2004

Because of the characteristics of the cyber world, such as usefulness, anonymousness, patency, economic performance, rapidness, etc., cyber counseling has great possibility. Because he or she may not meet a consultant directly, a client can expose his/her inside problems or secret personal problems, keeping anonymousness. However, existing cyber counseling has the limit in durability of counseling because target counseling appropriate to a client is impossible and a counseling activity is done by one time counseling. In this paper, we attempt to develop a target cyber counseling system in which target cyber counseling is possible. The system will use a counseling assistance agent who can play the role of a counseling supporter as well as a counselor in the cyber space. If target counseling becomes possible, it can heighten efficiency of cyber counseling because a client is satisfied with the result of counseling and thus counseling activities can be continued.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.6 no.4
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• pp.277-281
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• 2006

Cyber counseling, one of the most compatible type of consultation for the information society, enables people to reveal their mental agonies and private problems anonymously, since it does not require face-to-face interview between a counsellor and a client. However, there are few cyber counseling centers which provide high quality and trustworthy service, although the number of cyber counseling center has highly increased. Therefore, this paper is intended to enable an appropriate consultation for each client by analyzing client propensity using Bayesian variable selection. Bayesian variable selection is superior to stepwise regression analysis method in finding out a regression model. Stepwise regression analysis method, which has been generally used to analyze individual propensity in linear regression model, is not efficient since it is hard to select a proper model for its own defects. In this paper, based on the case database of current cyber counseling centers in the web, we will analyze clients' propensities using Bayesian variable selection to enable individually target counseling and to activate cyber counseling programs.