• 한국산학기술학회논문지
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• 제13권6호
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• pp.2421-2427
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• 2012

본 논문은 쿼드로터 무인기의 비선형 적응 자세 제어기 설계에 대한 것이다. 쿼드로터 무인기는 4 개의 추력기를 갖는 불완전한 비선형시스템으로써 모델 파라미터가 변화하기 때문에 특별한 제어기가 필요하다. 본 연구에서는 산업 응용에 따른 페이로드의 변화에 따라서 무인기의 모델파라미터가 변화하더라도 페이로드에 따른 튜닝을 자동으로 할 수 있도록 적응제어기를 설계하였다. 특히, 무인기의 수학적 모델을 이용하여 비선형 적응제어기를 설계하였고 리야프노프 함수를 이용하여 이론적으로 안정성을 분석하였고 페이로드 변화에 따른 시뮬레이션을 통해서 제어기의 성능과 파라미터 추정법칙의 유효성을 입증하였다.

• International Journal of Control, Automation, and Systems
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• 제3권4호
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• pp.580-590
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• 2005

In this paper, we propose a new stability criterion and a controller design method for switched linear systems. The proposed stability criterion is applicable to each subsystem independently without the need to consider the overall system. The controller can be easily designed through geometric relations between eigenvalues of each subsystem matrix. The proposed methods provide a systematic and simple pole assignment approach for switched linear systems. Illustrative examples are given.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 추계학술대회 논문집 학회본부
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• pp.42-45
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• 1996

This paper presents a solution of the $H_{\infty}$ control problem for linear systems with input time delay. $H_{\infty}$ norm bounded condition is obtained as a sufficient condition for linear systems with input time delay. Based upon this sufficient condition, an $H_{\infty}$ controller design method which involves the solutions of linear matrix inequalities via convex optimization is developed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.555-558
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• 1991

The IESF(Integral Error and State Feedback) controller, which incorporates state feedback as a modern control scheme and integral action as a classical control scheme, has better performance than that of the conventional PID controller in linear time-invariant systems. The IESF controller requires the measurement of all the state variables. But, unfortunately, it may be difficult or impossible to measure all state variables in many applications. And the IESF controller is applicable only to pole-assignable linear time-invariant system without time delay. In this paper, new IESF controller structure was proposed which performs feedback with only measurable state variables. In order to estimate the unmeasurable state variables. It was adopted the filter mode by full-order obserber. The good performance and effectiveness of the proposed controller was confirmed by computer simulation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.956-959
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• 1996

In this study, we propose a neuro-genetic controller combined with a linear controller in parallel to improve the tracking performance of the Line of Sight(LOS) stabilization system and reject the effect of disturbances. A Genetic Algorithm(GA) is used to optimize weights of the neuro-genetic controller since this algorithm can search a global minimum without derivatives or other auxiliary knowledge. The LOS system is very complex and has limited measurable output data. Under these specific circumstances GA solves many problems that other training methods have. Computer simulation results show that the, proposed controller makes better tracking response and rejection of disturbance than a linear controller.

• 제어로봇시스템학회논문지
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• 제15권7호
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• pp.655-660
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• 2009

In many real applications, the discrepancy problem between controller outputs and plant inputs or the abrupt variation problem of controller outputs can occur. These problems have a negative effect on control performance and stability. It is well-known that two phenomena called 'windup' and 'bump' cause these problems. So far these problems have been studied separately in each side of the anti-windup and the bumpless transfer. This paper proposes a new unified method combines the anti-windup and the bumpless transfer method using the linear quadratic minimization and a proper state space model representation for the anti-windup controller. The proposed method has a feature that it takes account of both the anti-windup and the bumpless transfer in one formula. Finally, we exemplify the performance of the proposed method via numerical examples using the controller switching between the anti-windup PID controller and the anti-windup LQ controller.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 봄 학술발표회 논문집
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• pp.477-484
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• 2003

Recently, sliding mode control(SMC) method has been investigated for control of building structures under earthquake loadings. SMC keeps responses of a structure in sliding surface while the structure is stable. This control method uses both linear controller and nonlinear controller such as bang-bang controller. This paper presents vibration control of a structure using saturated sliding mode controller, whose maximum conrtol force is limited. The effectiveness of SMC method with controler saturation is investigated based on two performance evaluation criteria: root mean square(RMS) and maximum values of floor drifts and accelerations. Simulation results indicate that SMC method is effective in reduction of displacement and acceleration utilizing the saturated controller's capacity efficiently.

• 제어로봇시스템학회논문지
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• 제20권4호
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• pp.381-388
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• 2014

In this paper, the attitude of a quadrotor system is controlled by a time-delayed control method which uses the previous information to cancel out uncertainties in the system. Although the linear controller works for the attitude control, the robust performance against disturbance is relatively poor. Therefore, a time-delayed controller as a robust controller is used. Experimental studies are conducted to validate the performance by the time-delayed control method. The performances of both a linear controller and a time-delayed controller are compared.

• Journal of Power Electronics
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• 제9권2호
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• pp.267-274
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• 2009

This paper deals with a voltage and frequency (VF) controller for an isolated power generation system based on an asynchronous generator (AG) driven by a pico hydro turbine. The proposed controller is a combination of a static compensator (STATCOM) and an electronic load controller (ELC) for decoupled control of the reactive and active powers of the AG system to control the voltage and frequency respectively. The proposed generating system along with its VF controller is modeled in MATLAB using SIMULINK and PSB (Power System Block Sets) toolboxes. The performance of the controller is verified for the proposed system and feeding various types of consumer load such as linear/non-linear, balanced/unbalanced and dynamic loads.

• 유공압시스템학회논문집
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• 제5권1호
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• pp.1-5
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• 2008

Pneumatic driving systems have hard non-linear characteristic and large friction force compared with driving power. Hence, it cannot be robust against parameter uncertainties, modelling error, disturbance and noise. In this study, we apply a mixed $H_2/H_{\infty}$ control to the generalized plant for a pneumatic driving apparatus system including parameter uncertainty and disturbance. In order to design the $H_2/H_{\infty}$ controller, we use the LMI technique. To evaluate control performance and robust stability of the designed controller, we compare it with a conventional controller such as PVA(Position-Velocity-Acceleration state controller) using the simulation results. As a result, it can be known that designed controller shows better robust stability than the conventional controller.