• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 추계학술대회 논문집
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• pp.134-138
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• 2001

Basic governing equations for the Active Magnetic Bearing system are derived. Characteristic difference between PD and PID controllers are studied. It is shown that I-control action is able to minimize the steady state error and increase the stiffness in low frequency range.

• Journal of Advanced Marine Engineering and Technology
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• 제31권6호
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• pp.791-796
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• 2007

When 2 sets of PID controllers are coupled directly each other to configure a closed control loop on behalf of coupling a controller and a plant. the behaviors or this exclusive loop system are expected to be unique in inherent system responses. If its properties be disclosed and generalized well in advance, it is possible for us to use the results for the purpose of fault detection and performance monitoring between control stations from the stage of system design. particularly in such cases as cascade control systems. In this paper. general properties of the proposed system are analyzed firstly to check whether it is controllable and how its steady responses would be. To simplify calculation, the analysis has been performed based on the transfer equation derived from a modelled case which consists of 2 PI controllers and signal converters between them. including time delay element and first-lag element to consider the situation of signal transmission. The results acquired from simulation are suggested to show how it works actually.

• International Journal of Control, Automation, and Systems
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• 제4권6호
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• pp.756-762
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• 2006

Shape Memory Alloy(SMA) actuators, which have the ability to return to a predetermined shape when heated, have many potential applications such as aeronautics, surgical tools, robotics and so on. Although the conventional PID controller can be used with slow response systems, there has been limited success in precise motion control of SMA actuators, since the systems are disturbed by unknown factors beside their inherent nonlinear hysteresis and changes in the surrounding environment of the systems. This paper presents a new development of a SMA position control system by using a self-tuning fuzzy PID controller. This control algorithm is used by tuning the parameters of the PID controller thereby integrating fuzzy inference and producing a fuzzy adaptive PID controller, which can then be used to improve the control performance of nonlinear systems. The experimental results of position control of SMA actuators using conventional and self-tuning fuzzy PID controllers are both included in this paper.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.1371-1376
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• 2003

In the thermal power plant, the main steam temperature is typically regulated by the fuel flow rate and the spray flow rate, and the reheater steam temperature is regulated by the gas recirculation flow rate. However, Strictly maintaining the steam temperature can be difficult due to heating value variation to the fuel source, time delay changes in the main steam temperature, the change of the dynamic characteristics in the reheater. Up to the present time, PID Controller has been used to operate this system. However, it is very difficult to achieve an optimal PID gain with no experience, since the gain of the PID controller has to be manually tuned by trial and error. This paper focuses on tuning of the 2-DOF PID Controller on the DCS for steam temperature control using immune based multiobjective approach. The stable range of a 2-DOF parameter for only this system could be found for the start-up procedure and this parameter could be used for the tuning problem. Therefore tuning technique of multiobjective based on immune network algorithms in this paper can be used effectively in tuning 2-DOF PID controllers.

• Journal of Advanced Marine Engineering and Technology
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• 제29권1호
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• pp.116-123
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• 2005

The PID controllers have been widely accepted in many industrial systems due to their robust performance in a wide range of operating conditions and their functional simplicity To implement a PID controller, its three parameters must be determined for the given plant. Conventional tuning methods are mainly based on experience and experiment and are lack of systematic procedure Recently. to overcome drawbacks of conventional tuning methods, genetic algorithms have been used, In this paper a real-coded genetic algorithm is employed to search for the optimal parameters of the PID controller for speed control of marine gas turbine engines. Simulation results show the effectiveness of the proposed scheme.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.45.1-45
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• 2001

This paper proposes a Mamdani fuzzy PID controller for controlling a process with small dead time. The controller composes of a parallel structure of fuzzy PI controller and fuzzy PD controller. Each controller has two inputs, error and change of error. Hence, the control signal of the proposed controller is the average value of the output of the fuzzy PI and PD controllers. The Mamdani fuzzy PID controller is easily to be adjusted to meet the desired control system performances both in transient state and steady state. The simulation results of the proposed Mamdani fuzzy PID controller by using the same parameters (proportional gain, integral time and derivative time) as the conventional PID controller are shown. The response of the Mamdani fuzzy PID control system is faster than the conventional PID control system. Both system responses have ...

• 대한전기학회논문지:시스템및제어부문D
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• 제52권3호
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• pp.134-141
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• 2003

PID controllers with constant gains have been widely used in various control systems due to its powerful performance and easy implementation. But it is difficult to have uniformly good control performance in all operating conditions. In this paper, we propose a nonlinear variable PR controller with immune feedback mechanism. An immune feedback mechanism is based on the functioning of biological T-cells, they include both an active term, which controls response speed. and an inhibitive term, which controls stabilization effect. Therefore, the proposed nonlinear PID controller is based on immune responses of biological. immune feedback mechanism which is the cell mediated immunity and In order to choose the optimal nonlinear PID controller games, we also propose the tuning algorithm of nonlinear function parameter in immune feedback mechanism. To verify performance of the proposed algorithm, the speed control of nonlinear DC motor are performed. Front the simulation results, we have found that the proposed algorithm is more superior to the conventional constant fain PID controller.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 B
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• pp.617-619
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• 1998

A PID-controller is proposed as a controller to the IFAC93 benchmark process. It is compared with a Textbook PID-controller and a Derivative of output PID-controller. Especially, the Derivative of output PID controller works within the critical bounds of ${\pm}1.5$ except for 1 out of 15 periods at stress level 1,2. The objective of this paper, then, is to report on an alternative benchmark (IFAC93) and reveal more efficient PID controller between Textbook PID-control and Derivative of output PID-controller.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 B
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• pp.803-805
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• 1999

Robust fuzzy logic control, PID control, and sliding mode controllers are designed to control the speed of a third order linear time-invariant model of a motor. The step response performance of each controller, applied to the motor plant, is Presented. We conclude fuzzy logic control can be a useful tool for the control engineering.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1749-1750
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• 2008

This paper presents a Matlab toolbox for proportional-integral-derivative (PID) controller design. By means of the tool, the complete set of controllers simultaneously satisfying multiple design specifications such as stability and robust stability margins can be obtained directly from the only frequency response data on the plant.