• 한국지능시스템학회논문지
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• 제26권2호
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• pp.135-140
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• 2016

비동기 순차 회로를 위한 교정 제어기는 회로를 재설계하지 않고도 회로 내에 존재하는 여러 고장을 탐지하고 극복하는 능력을 보인다. 이번 논문에서는 교정 제어기의 크기를 줄이기 위한 방법으로서 정적 교정 제어기(static corrective controller)를 제안한다. 동적 제어기에 비해 정적 제어기는 제어기 상태가 필요 없으므로 조합 회로(combinational circuit)만으로 구현 가능하다. 본 논문에서는 상태 천이 고장에 대한 정적 내고장성 교정 제어기가 존재할 조건과 설계 과정을 규명한다. 또한 제안된 제어 기법을 FPGA로 구현된 SEU 오류 카운터에 적용하여 그 효용성을 실험적으로 검증한다.

• 한국자동차공학회논문집
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• 제22권1호
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• pp.20-28
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• 2014

This paper presents static output feedback LQ and $H_{\infty}$ controllers for rollover prevention. Linear quadratic static output feedback controllers have been proposed for rollover prevention in such a way to minimize the lateral acceleration and the roll angle. Rollover prevention capability can be enhanced if $H_{\infty}$ controller is designed. To avoid full-state measurement for feedback requirement or sensitiveness of an observer to nonlinear model error, static output feedback is adopted. To design static output feedback controllers, Kosut's method is adopted because it is simple to calculate. Differential braking and active anti-roll bar are adopted as actuators that generate yaw and roll moments, respectively. The proposed method is shown to be effective in preventing rollover through the simulations on nonlinear multi-body dynamic simulation software, CarSim.

• International Journal of Control, Automation, and Systems
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• 제6권4호
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• pp.495-505
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• 2008

This paper describes modeling Voltage Sourced Inverter (VSI) type Flexible AC Transmission System (FACTS) controllers and control methods for power system dynamic stability studies. The considered FACTS controllers are the Static Compensator (STATCOM), the Static Synchronous Series Compensator (SSSC), and the Unified Power Flow Controller (UPFC). In this paper, these FACTS controllers are derived in the current injection model, and it is applied to the linear and nonlinear analysis algorithm for power system dynamics studies. The parameters of the FACTS controllers are set to damp the inter-area oscillations, and the supplementary damping controllers and its control schemes are proposed to increase damping abilities of the FACTS controllers. For these works, the linear analysis for each FACTS controller with or without damping controller is executed, and the dynamic characteristics of each FACTS controller are analyzed. The results are verified by the nonlinear analysis using the time-domain simulation.

• International Journal of Control, Automation, and Systems
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• 제5권3호
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• pp.349-354
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• 2007

This paper considers the problem of designing static output feedback controllers for nonlinear systems represented by Takagi-Sugeno (T-S) fuzzy models. Based on linear matrix inequality technique, a new method is developed for designing fuzzy stabilizing controllers via static output feedback. Furthermore, the result is also extended to $H_{\infty}$ control. Examples are given to illustrate the effectiveness of the proposed methods.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 추계학술대회 논문집
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• pp.192-197
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• 1992

The position error in multi-axis machine tools are due to many elements, such as the static friction, servo lag, a nonlinear disturbance, the gain mismatch between multi-axis controllers. In the work, modeling for the plant was carried out through the velocity response by the step input signal. Digital PI controllers, LQ optimal controllers and feedforward controllers are designed for a high tracking performance based on the model. The results of experimentation showed that the controllers worked properly.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.398-402
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• 1996

This paper addresses the design and the gait control of quadruped walking robot. First, we concern the mechanical and electronical(control system) hardware of walking robot, and the second is the results of experiments. The walking robot is the most suitable form to substitute fot human being. So walking robot is worthy of research. The quadruped walking robot and control system is the simplest type of walking robot, therefore we designed a small seale robot for realization of static gait. The robot is designed commpactly and its legs are constructed parallel link type and able to move freely in space. Control system consists of one upper level controller and four lower level controllers. The upper level controller plans the walking path and commands the low level controllers to follow the planned path. The main function of low level cotrollers is control of motors. Total number of motors is twealve and they operate four legs. And robot is ordered to walk and realize static wave gait.

• 에너지공학
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• 제5권1호
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• pp.72-79
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• 1996

본 논문은 전력계통의 안정도에 미치는 제어장치들의 영향과 안정도 개선에 대해 연구하였다. 제어장치로는 여자기와 전력계통안정기(PSS) 그리고 무효전력보상기(SVC)를 일기무한모선계통에 설치하고, 이때의 상태행렬의 구조를 제시하였다. 상태행렬의 구조식과 고유치, 고유벡터로부터 제동이 불량한 고유치에 대한 감도계수를 구하여 각 제어기별로 중요진동모드에 대한 영향을 수치적으로 나타내었다. 또한 계통의 운용조건을 달리하여 계통변화에 따라 제어장치들이 안정도에 미치는 영향을 관찰하였다. 계통의 안정도를 개선시키기 위해서 제어기정수의 일차고유치감도계수를 선형계획법인 심플렉스법에 적용하여 제어기정수의 최적화를 수행하였다 이때 일차고유치감도계수만으로 최적화를 하는데 따른 문제점을 해결하기 위해 각 제어기정수의 변화폭을 좁게 설정하고, 각 반복계산마다 전단계에서 구한 최적 정수값을 제어기정수의 변화범위를 달리하여 다시 최적화하는 방법을 사용하였다.

• 제어로봇시스템학회논문지
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• 제11권9호
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• pp.750-754
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• 2005

This paper deals with the design problem of multivariable PID controllers guaranteeing the closed-loop system stability and a prescribed $H_\infty$ norm bound constraint. We reduce the problem to the static output feedback stabilization problem. We derive a necessary and sufficient condition f3r the existence of PID controllers and we give an explicit formula of PID controllers. We also give an existence condition of PID controllers guaranteeing a prescribed decay rate. Finally, we give an LMI-based design algorithm, together with a numerical design example.

• 제어로봇시스템학회논문지
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• 제20권7호
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• pp.701-705
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• 2014

This article presents a comparison among several yaw and roll motion controllers for vehicle rollover prevention. In the previous research, yaw and roll motion controllers can be independently designed for rollover prevention. Following this idea, several yaw and roll motion controllers are designed and compared in terms of rollover prevention. For the yaw motion control, PID, LQR, SMC (Sliding Mode Control) and TDC (Time-Delay Control) are adopted. For the roll motion control, LQR, LQ SOF (Static Output Feedback) control, PID, and SMC are adopted. To compare the performance of each controller, simulation is performed on a vehicle simulation package, CarSim$^{(R)}$. From simulation, TDC and LQ SOF are the best for yaw and roll motion control, respectively.

• International Journal of Control, Automation, and Systems
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• 제6권1호
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• pp.24-34
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• 2008

A novel neural network model, termed the standard neural network model (SNNM), similar to the nominal model in linear robust control theory, is suggested to facilitate the synthesis of controllers for delayed (or non-delayed) nonlinear systems composed of neural networks. The model is composed of a linear dynamic system and a bounded static delayed (or non-delayed) nonlinear operator. Based on the global asymptotic stability analysis of SNNMs, Static state-feedback controller and dynamic output feedback controller are designed for the SNNMs to stabilize the closed-loop systems, respectively. The control design equations are shown to be a set of linear matrix inequalities (LMIs) which can be easily solved by various convex optimization algorithms to determine the control signals. Most neural-network-based nonlinear systems with time delays or without time delays can be transformed into the SNNMs for controller synthesis in a unified way. Two application examples are given where the SNNMs are employed to synthesize the feedback stabilizing controllers for an SISO nonlinear system modeled by the neural network, and for a chaotic neural network, respectively. Through these examples, it is demonstrated that the SNNM not only makes controller synthesis of neural-network-based systems much easier, but also provides a new approach to the synthesis of the controllers for the other type of nonlinear systems.