• Smart Structures and Systems
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• 제20권1호
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• pp.85-97
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• 2017

The aim of this research is to develop a new method to use magnetorheological (MR) damper for vibration control. It is a new way to achieve the MR damper response without the need to have detailed constant parameters estimations. The methodology adopted in designing the control structure in this work is based on the experimental results. In order to investigate and understand the behaviour of an MR damper, an experiment is first conducted. Force-displacement and force-velocity responses with varying current have been established to model the MR damper. The force for upward and downward motions of the damper piston is found to be increasing with current and velocity. In cyclic motion, which is the combination of upward and downward motions of the piston, the force with hysteresis behaviour is seen to be increasing with current. In addition, the energy dissipated is also found to be linear with current. A proportional-integral-derivative (PID) controller, based on the established characteristics for a quarter car suspension model, has been adapted in this study. A fuzzy rule based PID controller (F-PID) is opted to achieve better response for a varying frequency input. The outcome of this study can be used in the modelling of MR damper and applied to control engineering. Moreover, the identified behaviour can help in further development of the MR damper technology.

• 융합신호처리학회 학술대회논문집
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• 한국신호처리시스템학회 2001년도 하계 학술대회 논문집(KISPS SUMMER CONFERENCE 2001
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• pp.137-140
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• 2001

In this paper, Fuzzzy Digital PI+D Controller plans for load, noise, plant change, Fuzzy Controller makes use of simple four rule and membership function, and plant used three phase Induction Motor. Characteristic of system compared from experimentation respectively the proposed Control System, Digital PID Control and Digital PI+D Control System.

• Journal of Advanced Marine Engineering and Technology
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• 제39권3호
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• pp.298-305
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• 2015

본 논문에서는 선박용 동기발전기 여자제어시스템의 성능을 확인하기 위해 선급기술규칙에 따라서 시행한 실험 결과를 제공한다. 실험에서는 발전기의 각 부하 변화에 대해 PID 제어기와 퍼지제어기를 적용하고 두 제어기법이 선급의 기술규칙을 만족하는 지 관찰하고 성능을 비교 검토 한다. 이를 위해 PID 제어기법과 퍼지제어기법을 랩뷰 프로그램으로 작성한 후, PID 제어기의 경우는 한계 감도법과 약간의 조정을 통해 이득값을 결정한다. 퍼지제어기는 맘다니(Mamdani)의 방법으로 전압오차값과 전압오차변화율값, 출력전압값에 대해 멤버쉽함수를 구성한다. 이상의 PID 제어기법과 퍼지제어기법을 실제 소형 발전기에 적용하고 선급기술규칙에 따른 실험을 통해 안정성과 성능개선 특성을 비교 검토한다.

• 전자공학회논문지S
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• 제34S권11호
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• pp.80-92
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• 1997

This research focuses onan efficient control method of temperature for multiple points using only one processor. For a yarn production system, the surface temperature control of heaters are very important for quality control. Therefore, we designed a temperature controller for a draw and twist machine and applied Fuzzy-PWM algorithm to the controller. If we use a processor for the temperature control of multiple points with the conventional ON/OFF control, the control performance of the system becomes poor. To overcome these problems, we developed a new Fuzzy-PWM algorithm for the adjustment of power rate to the heaters in the conventional ON/OFF control. It is shown that this algorithm has the same effects as the PID algorithm for the temperature control of each point. The proposed algorithm is robust against the production condition and environment such as the reference temperature and the thickness of yarn, since the power rate to the heater is adjusted by Fuzzy Rules derived from the values of the reference termperatureand the thickness of yarn. To obtain optimal Fuzzy rulees, the control simulations are perfodrmed through the modelling of the heater and simulation of Fuzzy rules. This algorithm is applied for the multiple pont temperature controller and showed satisfactory performance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.370-372
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• 1994

In this paper, a stable adaptive composite control system consisting of a PID and a fuzzy controllers is designed to control nonlinear systems. In the fuzzy controller, parameters of membership functions characterizing the linguistic terms change according to some adaptive law. Also, parameters of PID controller change according to some adaptive law. These adaptive laws are based on the Lyapunov synthesis approach. Then, it is proved that the closed-loop system using such an adaptive composite control system is globally stable in the sense that all signals involved are bounded and the tracking error converges to zero. We apply this adaptive composite control system to control a nonlinear system.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.1127-1128
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• 2008

In this paper, we propose a control method to improve control performance for a Quad-rotor Unmanned Aerial Vehicle's stabilization. The proposed method is the Fuzzy+I control that contains a fuzzy controller which processes signals from the error and the change of error, and generates the control signal by summing up fuzzy output signal and integral signal. We simulated and experimented on the fuzzy+I control method by implementing Quad-rotor UAV that is able to hovering, for the purpose of verifying the effectiveness of the proposed fuzzy+I control method in comparison with general PID control, and we found out that fuzzy+I controller improved control performance of the system.

• Journal of Advanced Marine Engineering and Technology
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• 제39권5호
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• pp.563-569
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• 2015

A chemical reaction occurring in CSTR (Continuous Stirred Tank Reactor) is significantly affected by the concentration, temperature, pressure, and reacting time of materials, and thus it has strong nonlinear and time-varying characteristics. Also, when an existing linear PID controller with fixed gain is used, the performance could deteriorate or could be unstable if the system parameters change due to the change in the operating point of CSTR. In this study, a technique for the design of a fuzzy PD plus I controller was proposed for the temperature control of a CSTR process. In the fuzzy PD plus I controller, a linear integral controller was added to a fuzzy PD controller in parallel, and the steady-state performance could be improved based on this. For the fuzzy membership function, a Gaussian type was used; for the fuzzy inference, the Max-Min method of Mamdani was used; and for the defuzzification, the center of gravity method was used. In addition, the saturation state of the actuator was also considered during controller design. The validity of the proposed method was examined by comparing the set-point tracking performance and the robustness to the parameter change with those of an adaptive controller and a nonlinear proportional-integral-differential controller.

• Journal of Mechanical Science and Technology
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• 제16권8호
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• pp.1039-1052
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• 2002

This paper presents an application where a Fuzzy-Logic Controller (FLC) is used at a supervisory level to implement mutual coordination of the steering of the two front wheels of a motorcar. The two front wheels are steered by two independent discrete time state feedback controllers with a view to optimize the steering slip angles. The functions of the two controllers are tied together by way of a FLC. Because of the presence of unmodelled dynamics and disturbances acting on the two sides, it is difficult to achieve the desired performance using conventional control systems. This is the primary reason that FLC is emploged to solve the problem. The results show that the implemented system achieved desired coupling between the two independent systems and thereby reduces the difference between the two steered angles.

• Journal of Advanced Marine Engineering and Technology
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• 제22권3호
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• pp.311-319
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• 1998

DC Motors have been widely used in industry as driving power motors for electrical vehicles cranes and winches due to their strong starting torques and as servo-motors for position and speed control systems due to their convenience of speed control etc. Generally in the speed control systems of motors speed sensors are required and this fact results in he increased price and operating cost and in the limitted applications. This paper presents a new speed control method for sensorless DC motors. In this scheme the speed signal is estimatd by the measurement values of the armature voltage and current. A Fuzzy feedback controller instead of the conventional PID controller. Through simulations the effectiveness and usefullness of the proposed method are illustrated.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.108.4-108
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• 2001

The integrated environment for the fuzzy logic controller with the acceleration converter to improve the dynamic characteristic of a one-axis moving table is proposed in the paper. The two inputs of the fuzzy logic controller are position error and velocity. The two inputs of the acceleration converter used to produce the acceleration input for the one-axis moving table are actual and setting rotational speeds. The proposed controller is implemented on a personal computer by using MATLAB and Visual Basic for a real time control via a motion control board. The position control results when the stair input is applied to control the position of the one-axis moving table, are shown. The experimental results of the proposed position control system are compared to the conventional PID ...