• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2270-2273
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• 2003

Fuzzy logic control has been widely implemented in air conditioning and ventilation systems which has uncertainty or high robust system. Since the dynamic behaviors of the systems contain complexity and uncertainty in its parameters , several fuzzy logic controllers had been implemented to control room temperature in the field of air conditioning system. In this paper, the fuzzy logic control has been developed to control room temperature and humidity in the precision air conditioning systems. The nonlinear mathematical model was formulated using energy and continuity equations. MATLAB was used to simulate the fuzzy logic control of the multi-variable air conditioning systems. The simulation results show that fuzzy logic controller can reduce the steady-state errors of the room temperature and relative humidity in multivariable air conditioning systems. The offset are less than 0.5 degree Celsius and 3 percent in relative humidity respectively under random step disturbance in heating load and moisture load respectively

• 한국지능시스템학회논문지
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• 제17권6호
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• pp.799-803
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• 2007

본 논문에서는 FSVM(Putty Support Vector Machine)의 퍼지소속함수를 새롭게 제안한다. SVM의 완화변수(slack-variable)에 퍼지소속함수를 결합하는 FSVM은 주어진 데이터베이스의 특성이 반영되어 안정적으로 분류성능을 향상시킬 수 있는 퍼지소속 함수를 필요로 한다. 시계열 자료의 패턴분류 성능을 비교하기 위하여 SVM, FSVM(1), 그리고 제안하는 FSVM(2) 등의 분류모델들을 비교 실험하였다. 사용한 데이터베이스는 한국금융시장의 시계열 경제지표 지수들이다.

• Journal of Electrical Engineering and Technology
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• 제12권6호
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• pp.2399-2410
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• 2017

In this paper, a linear matrix inequality-based sampled-data fuzzy observer design method is proposed based on the exact discretization approach. In the proposed design technique, a numerically relaxed observer design condition is obtained by using the discrete-time fuzzy Lyapunov function. Unlike the existing studies, the designed observer is robust to the uncertain premise variable because the fuzzy observer is designed under the imperfect premise matching condition, in which the membership functions of the system and observer are mismatched. In addition, we apply the proposed method to the state estimation problem of the attitude and heading reference system (AHRS). To do this, we derive a Takagi-Sugeno fuzzy model for the AHRS system, and validate the proposed method through the hardware experiment.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 춘계학술대회 논문집
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• pp.241-245
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• 1995

This paper shows that the proposed fuzzy-sliding mode for SCARA robot control could reduce chattering problemed in sliding mode control and is robust against parameter uncertainties. It was very small quantities of chattering in the fuzzy-sliding mode control conpared with that in sliding mode control with two dead-band. In here, the sliding mode control with two dead-band is the method to reduce some chattering by changing into a continuous variable lower control input gain when a state value in pahase palne converged sithin two dead-band. But, the fuzzy-sliding mode control for more reducing chattering is the method to change control input by slicing mode into that by fuzzy rule within two dead-band. Simulations show that the effect of reducing chattering by the fuzzy-sliding mode is superior to sliding mode control with two dead-band.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1993년도 Fifth International Fuzzy Systems Association World Congress 93
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• pp.822-825
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• 1993

A fuzzy logic controller derived from the variable structure control (VSC) theory is designed. Unlike the conventional design of the fuzzy controller, we do not fuzzify the error and the rate of error, but fuzzify the sliding surface. After the fuzzy sliding surface is introduced, the fuzzy rules are defined based on the sliding control theory. It will be shown this sliding mode fuzzy controller is a kind of VSC that introduces the boundary layer in the switching surface and that the control input is continuously approximated in the layer. As a result we can guarantee the stability and the robustness by the help of VSC, which were difficult to insure in the past fuzzy controllers. Simulation results for the inverted pendulum will show the validity.

• 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.

• 한국산업정보학회논문지
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• 제6권3호
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• pp.35-43
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• 2001

이 논문에서는 WBI(Web-Based Instruction) 시스템의 영역 독립적인 학습자 모듈을 구축하는데 있어 핵심이 되는 요소를 영역 전문가가 쉽게 입력할 수 있도록 하기 위하여 퍼지이론의 언어 변수 개념을 도입한 학습자 응답 진단 공식을 제안한다. 또한 학습자의 인지 상태를 추론하는 규칙을 영역 전문가가 언어변수를 입력하여 구축할 수 있도록 하고 이 규칙을 이용하여 학습자의 인지 상태를 추론할 수 있도록 학습자 모듈을 설계한다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.754-757
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• 1998

In this paper, the fuzzy control logic of Switched Reluctance Motor(SRM) is introduced to apply the variable speed drive system. Since the speed-torque property of SRM has high speed variation to the changes of torque like a DC motor, to apply SRM to the variable speed driving system, the optimal speed-torque control method is required. As the control method like this, the fuzzy logic and PI control are proposed, and characteristics of them are compared and verified through the experimental results

• 대한의용생체공학회:의공학회지
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• 제30권6호
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• pp.510-515
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• 2009

In this paper, variable characteristic ratio algorithm based on oscillometric method is proposed to enhance the accuracy of blood pressure measurement. We combined the slope-based approach and fuzzy inference technique to change the characteristic ratios of height-based method. The proposed algorithm was assessed on 255 measurements from 85 subjects and compared with the conventional height-based algorithm. The testing results showed that the developed algorithm achieved an overall grade A for both systolic and diastolic blood pressures according to the BHS protocol. And, mean standard deviation between the observers and the developed algorithm were 5.71mmHg and 6.29mmHg for systolic and diastolic pressures respectively, which also fulfilled the AAMI criteria. In conclusion, this algorithm was successfully developed and recommended for further clinical trials with the wider adult population.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.6-8
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• 1994

Switched reluctance motor drive system is well known as a variable speed drive system because it has a simple motor structure and a simple driving circuit. Widely slotted photo interrupter has been investigated as a position sensor for SRM speed control because it has advantages of low cost and simple structure. However it has low resolution and it produces dead-time signal. This paper studies variable speed SRM drive system with slotted photo-interrupter. Controller in this study is constructed by using fuzzy controller that covers system nonlinearities and small perturbations in sufficiency. The performance of this system is evaluated through computer simulation and experiment results.