• 제어로봇시스템학회논문지
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• 제3권6호
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• pp.569-575
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• 1997

모델 불확실성이 있고 n축 자유도(degree of freedom)를 갖고 있는 로봇 동작부(manipulator)에 대해서 위치 정보만을 이용하여 가변 구조 제어기(variable structure controller)를 설계하였다. 모델의 불확실성이 존재하는 경우에도 제어기에 사용되는 속도를 잘예측하기 위해 고이득 관찰기를 사용 하였으며 고이득 관찰기를 사용할때 발생할 수 있는 상태변수의 피킹현상(peak phenomenon)를 적게 하게 하기위하여 제어기의 값을 제한 (globally bounded)하여 제어기를 설계하였다. 부하(payload)의 범위만 알고 있는 2축 자유도를 갖는 로봇 동작부에 대해서 제안된 제어 방법에 따라 제어기를 설계하여 그 성능를 확인 하였다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권12호
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• pp.569-575
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• 2005

This paper proposes a gain scheduled control technique using time-delay for the nonlinear system with plant uncertainties and unexpected disturbances. The time delay-based gain scheduled control depends on a direct estimation of a function representing the effect of uncertainties. The information from the estimation is used to cancel the unknown dynamics and the unexpected disturbances simultaneously. The proposed estimation scheme with a finite convergence time is formulated in order to estimate the unknown scheduling variable variation. In other words, the time delay-based gain scheduled control uses the past observation of the system's response and the control input to directly modify the control actions rather than to adjust the controller gains or to identify system parameters. It has a simple structure so as to minimize the computational burden. The benefits of this proposed scheme are demonstrated in the simulation of an electromagnetic suspension system with plant uncertainties and external disturbances, and the proposed controller is compared with the conventional state feedback controller.

• 한국통신학회논문지
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• 제29권10A호
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• pp.1223-1229
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• 2004

본 논문에서 ETRI 0.5$\mu\textrm{m}$ MESFET 라이브러리 공정을 이용하여 동작 주파수 5GHz대 저전압구동 가변이득 저잡음 증폭기 MMIC를 설계 및 제작하였다. 이 저잡음 증폭기는 HIPERLAN/2의 Adaptive Antenna Arrays와 함께 사용할 수 있도록 이득조절이 가능하도록 설계하였다. 가변이득 저잡음 증폭기는 2단 캐스케이드 구조이며, 게이트전압에 따라 채널저항이 제어되는 증가형 MESFET과 저항으로 구성된 부귀환 회로를 제안하였다. 제작된 가변이득 저잡음 증폭기의 측정값은 $V_{DD}$ =1.5V, $V_{GG1}$=0.4V, $V_{GG2}$=0.5V일때 5.5GHz의 중심 주파수, 14.7dB의 소신호 이득, 10.6dB의 입력 반사손실, 10.7dB의 출력 반사손실, 14.4dB의 가변이득, 그리고 잡음지수 2.98dB이다. 또한, 가변이득 저잡음 증폭기는 -19.7dBm의 입력 PldB, -10dBm의 IIP3, 52.6dB의 SFBR, 그리고 9.5mW의 전력을 소비한다.다.다.

• 한국자동차공학회논문집
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• 제23권1호
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• pp.56-64
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• 2015

This study presents a model-based gain scheduling strategy for PI-based EGR controllers. The air-to-fuel ratio is used as an indirect measurement of the EGR rate. In order to cope with the nonlinearity and parameter varying characteristics of the EGR system, we proposed a static gain model of the EGR system using a new scheduling parameter. With the 810 steady-state measurements, the static gain model achieved 0.94 of R-squared value. Based on the static gain of the EGR system, the PI gains were robustly designed using quantitative feedback theory. Consequently, the gains of the PI controller are scheduled according to the static gain parameter of the EGR path in runtime. The proposed model-based gain scheduling strategy was validated through various operating conditions of engine experiments such as setpoint step responses and disturbance rejections.

• 전기학회논문지
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• 제58권8호
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• pp.1592-1594
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• 2009

This paper presents an LMI-based method to design a reduced order output feedback sliding mode controller for a class of uncertain systems. Using LMIs we derive an existence condition of a reduced order sliding mode control law. And we give explicit formulas of the gain matrices. Finally, we give a numerical design example, together with a design algorithm.

• Nuclear Engineering and Technology
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• 제25권1호
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• pp.110-124
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• 1993

적응 비례-적분-추정 (PIF) gain 및 가변구조 제어기를 사용하는 비선형 모델에 의한 하이브리드 제어방법 (NHC)이 개발되었다. 이 제어기는 모델의 불확실성에 대해 robust한 성질을 가지며 단일 입-출력 비선형 시스템의 추적제어 (tracking control)에 응용된다. 이 방법의 특징은 제어기가 각각 특정 역할을 수행하는 4개 부분으로 구성되는 것이다. 즉, 적응 P-I-F 및 가변구조 제어기로 구성된다. Lyapunov의 제 2방법으로 결정된 적응 PIF gain에 의한 제어성능 확보 및 모델의 불확실도를 평가하여 피이드백 함으로써 모델의 불확실성에 대해 robust한 제어기를 구성하였다. 가변구조 제어기는 PIF gain이 적절히 결정되지 않은 상태인 초기의 오차증가를 제어하기 위해 도입되었다. 새로 개발된 NHC방법을 원자로의 출력변동 제어에 응용한 결과 기존의 모델을 이용한 제어방법 (model-based controller)들에 비해 제어성능이 크게 개선되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.465-467
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• 1994

A VSC with Inertial COFB(Coordinate-Operator Feedback) is presented for chattering alleviation. Athought the conventional sliding mode controller has good properties of robustness for disturbances or parameter variations, fast response, and easy implementation, there exists an inevitable chattering problem which deteriorates the control performance of system. VSC using Inertial COFB has properties of bounded feedback gain, reduced chattering, and robustness for disturbances or parameter variations. The validity of the proposed method is demonstrated through computer simulation for a position control of BLDCM.

• 대한전기학회논문지:전력기술부문A
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• 제48권10호
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• pp.1327-1334
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• 1999

The stabilization control of ball-beam system is difficult because of its nonlinearity and structural unstability. Futhermore, a series of classical methods such as the PID and the full state feedback controller(FSFC) based on the local linearizations have narrow stabilizable regions. At the same time, the fine tunings of their gain parameters are also troublesome. Therefore, in this paper, three improved design techniques of stabilization controller for a ball-beam system were proposed. These parameter tuning methods in the double PID controller(DPIDC), the FSFC and the a sliding mode controller(SMC) were dependent upon the Real Value Elitist Genetic Algorithm (RVEGA). Finally, by applying the DPIDC, the FSFC and the Real Variable Elitist Genetic Algorithm based Sliding Mode Control(RVEGA SMC) to the stabilizations of a ball-beam system, the performances of the RVEGA SMC technique were showed to be superior to those of two other type controllers.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.719-720
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• 2006

In the mechanical system, optimization of motion control is very essential in the aspect of automation technique progress. In the servo system, the function of controller is very important but most of the controllers have played only the role of pulse generator because the controller with main function is very expensive. In this thesis, the system was composed of PC, commonly used driver AC servo motor and a produced control board. The PC transmit a gain, a locus data to a driver and controller. At the same time, it converts imformation from the controller and convert them into data and offer an output with graph. The role of a controller is to trasmit a locus data to a driver and counting the pulse on the phase of an encoder to the PC. We have performed the experiment in order to confirm with variable PID parameter capable of the optimization of gain tuning with the counting of feedback control sensor signal with regard to the external interface into the system, such as torque. Based on the experiment result, we have confirmed as follows: First, it was confirmed that we could easily input control factors P.I Gain, constant $K_P,\;K_I$ into PC. Second, not only pulse generator function was possible, but with this pulse it was also possible to count using software with PIC chip. And third, using the multi-purpose PIC micro chip, simple operation and the formation of small size AC Servo Controller was possible.

• Journal of Power Electronics
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• 제13권6호
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• pp.1024-1031
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• 2013

This paper addresses linear quadratic regulation (LQR) for variable speed variable pitch wind turbines. Because of the inherent nonlinearity of wind turbines, a set of operating conditions is identified and then a LQR controller is designed for each of the operating points. The feedback controller gains are then interpolated linearly to get a control law for the entire operating region. In addition, the aerodynamic torque and effective wind speed are estimated online to get the gain-scheduling variable for implementing the controller. The potential of this method is verified through simulation with the help of MATLAB/Simulink and GH Bladed. The performance and mechanical load when using LQR are also compared with those obtained when using a PI controller.