• 대한전기학회논문지:시스템및제어부문D
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• 제51권12호
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• pp.542-548
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• 2002

We consider an unknown linear time invariant plan with static load disturbance. A saturation function nonlinear element is sued to find th one point information in the frequency domain. We analyze an asymmetric self-oscillation caused by static load disturbance with relay feedback and saturation function feedback. We propose a new method to tune a PID controller using a saturation nonlinear feedback element in the presence of asymmetric oscillation. The proposed method does not require the knowledge of plant d.c. gain with an asymmetric oscillation in the plat output.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1115-1119
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• 2007

Five control methods (Speed Control, PID Gain Scheduling, Loop Time Control, Simple PID, Switching Control) have been applied to the control of an Inline Co-axial valve by the simulation of AMESim. The simulation results have shown that the speed control method is the most stable and the fastest way to reach to the set point in the simulation of the flow control. Moreover, It has been found that the five control methods have the almost same characteristics in the power consumption, the counter electromotive force, and the motor angular velocity. According to the analysis results, the fast and stable control characteristics of the speed control method is the most suitable for the flow control using a inline co-axial valve with a DC(BLCD) motor.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.184-187
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• 2007

본 논문은 DSP Controller를 적용한 연료전지시스템의 유량제어에 관한 논문이다. 그리고 이 연구에서 사용된 시스템은 1kW급 계통연계 연료전지 시스템이다. 이 연료전지 시스템이 안정적으로 전원을 공급할 수 있도록 시스템에서 요구하는 공기 유량을 정확히 공급하도록 제어하는 것이 본 연구의 목적이다. 이 목적을 이루기 위해 공기 공급 장치에 PID 제어기를 설계하여 적용하였다. PID 제어기의 Gain값은 지글러 니콜스 Tuning 방식으로 정하였다. 이 제어기를 적용하여 실험한 결과, 적용 전 상태와 비교하면 맥동이 30% 저감하였고, 정상상태 오차가 제거되어 온도 변화와 같은 외란과 상관없이 정확한 요구 공기 유량을 공급함을 확인할 수 있었다. 그리고 부하가 변동함에 따라 해당 요구 공기 유량이 바뀔 때 1초 내에 그 요구 공기 유량을 추종하여 스택이 안정적으로 운전될 수 있도록 하였다.

• Earthquakes and Structures
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• 제6권2호
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• pp.217-235
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• 2014

In this paper, different feedback control strategies are presented for active seismic control using proportional-integral-derivative (PID) type controllers. The parameters of PID controller are found by using an numerical algorithm considering time delay, maximum allowed control force and time domain analyses of shear buildings under different earthquake excitations. The numerical algorithm scans combinations of different controller parameters such as proportional gain ($K_p$), integral time ($T_i$) and derivative time ($T_d$) in order to minimize a defined response of the structure. The controllers for displacement, velocity and acceleration feedback control strategies are tuned for structures with active control at the first story and all stories. The performance and robustness of different feedback controls on time and frequency responses of structures are evaluated. All feedback controls are generally robust for the changing properties of the structure, but acceleration feedback control is the best one for efficiency and stability of control system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 B
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• pp.609-611
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• 1999

The purpose of this research is on figuring out the optimal PID parameter using critical gain and critical frequency that are obtained by relay feedback. The operating has been done under the condition that the least information about the object plant is given and also the operating is processed within the limit which dose not give rise to bad influence on the object plant. For simulation auto-tuning PID controller using relay feedback which also works on on-line at the same time is developed by the upper procedure. This algorithm is tried to apply to level-temperature control plant on a real time with PC Interface Card.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 B
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• pp.859-861
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• 1999

This paper describes the development of a fuzzy gain scheduling scheme of PID controller for inverted pendulum system. Fuzzy rules and reasoning are utilized on-line to determine the controller parameters based on the error signal and its difference. Simulation results demonstrate that better control performance can be achieved in comparison with PID controller using pole placement to control of a Inverted pendulum.

• 한국정밀공학회지
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• 제13권5호
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• pp.74-83
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• 1996

An iterative tuning technique is derived for PID controllers which are widely used in industries. The tuning algorithm is based upon a fuzzy indirect reasoning method and an iterative technique. The PID gains for the first tuning action are determined by a method which is modified from the Ziegler-Nichols step response method. The first PID gains are determined to obtain a control performance so close to a design performance that the following tuning process can be made effectively. The design paramaters are given as time-domain variables which human is familiar with. The results of simulation studies show that the proposed tuning method can produce an effective tuning for arbitrary design performances.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 A
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• pp.389-391
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• 1999

Recently, the application of the linear machine for industrial field is remarkable increased, especially for the gantry machine. machine tool system and CNC. In these application fields. high precise position control performance is essentially required in both the steady and transient state. And linear machine is necessary for high-precision processing and manipulation when relatively high forces are involved. This paper presents the new unified PID position control algorithm which have rare sensitivity to disturbance, which the gain adjusting process is simple. Also this paper investigates the use of the New Unified PID control to design for high stiffness. Through the experimental results, it is shown that the proposed algorithm has high dynamic characteristic for the linear machine application field nevertheless of its simple structure.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2006년도 춘계학술발표논문집
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• pp.348-351
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• 2006

This paper proposes a modified IMC-PID controller that introduces controlling factor of the system identification to the standard IMC-PID controller in order to meet the design specifications such as gain, phase margin and maximum magnitude of sensitivity function in the frequency domain as well as the design specifications in time domain, settling, rising time and overshoot, and so on.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2333-2335
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• 2000

The main motivation of this research is to develop an intelligent control strategy for Activated Sludge Process(ASP). ASP is a complex and nonlinear dynamic system because of the characteristic of a wastewater, the change of an influent flow rate, weather conditions, and etc. The mathematical model of ASP also includes uncertainties which are ignored or not considered by process engineer or controller designer. The ASP is generally controlled by a PID controller that consists of fixed proportional, integral, and derivative gain values. The PID gains can be adjusted by the expert in the ASP. The ASP model based on Matlab$^{(R)}$5.3/Simulink$^{(R)}$3.0 is developed in this paper. Various control methods are applied to the ASP model and the control results are disscussed. Three control methods are designed and tested: conventional PID controller, fuzzy logic control approach to modify setpoints, and fuzzy-PID control method.