• 제어로봇시스템학회논문지
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• 제5권6호
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• pp.656-666
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• 1999

In this paper, we design the optimal PD control system which has the robust performance. This PD control system is designed by applying genetic algorithm (GA) to the determination of proportional gain KP and derivative gain KD that are given by PD servo controller, to make the output of plant follow the output of reference model optimally. These proportional and derivatibe gains are simultaneously optimized in the search domain guaranteeing the robust performance of system. And, this PD control system is compared with $\mu$ -synthesis control system for the robust performance. The PD control system designed by the proposed method has not only the robust performance but also the better command tracking performance than that of the $\mu$ -synthesis control system. The effectiveness of this control system is verified by computer simulation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.718-723
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• 1992

A hydraulic gun/turret servo system requires fast and robust controller performance because of severe operating condition and precise target tracking objective. Digital controllers are able to satisfy this requirement due to high speed electronic device. The purpose of this study is to compare with pre-EPU with new-designed optimal, adaptive controllers by simulating nonlinear hydraulic simulation program. The designed digital controller shows good tracking performance and robustness to disturbance.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.724-727
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• 1999

The previous LQ-servo PI design methods have some serious design problems happened from the frequency matching of the maximum and minimum singular values of loop transfer function at both low and high frequency regions on the Bode plot. To solve these problems, this paper proposes a new design technique based on the inverse-optimal control and convex optimization.

• Journal of Advanced Marine Engineering and Technology
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• 제15권2호
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• pp.53-63
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• 1991

This study suggests a new type shaft generator driven by hydraulic power suitable for small size vessels. Since the shaft generator system is very easy to be affected by disturbances such as speed variation of main engine and load variation of the generator, a robust servo control must be implemented to obtain stable electric power with constant frequency. Thus, in this study two types of controller design method-the reference following optimal control method and robust servo control method-are adopted to the controller design. In the experiment, static and dynamic characteristics of the shaft generator system according to the variation of input frequency setting, the speed variation of the pump and the load variation of the generator are investigated. From the considerations on the computer simulation results and experimental results, it is ascertained that the shaft generator system proposed in this study has good control performances.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.257-262
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• 1994

This paper describes an autotuning fuzzy PID controller for a position control of DC serve motor. Because ZNM(Ziegler-Nichols Method) with relay feedback has the difficulty in re-tuning the PID parameters and adaptive method has complex algorithm, a new method to overcome those problems is required. The proposed scheme determines the initial PID gains by using ZNM with relay feedback, and then re-tunes the optimal PID parameters by using fuzzy expert system whenever control conditions are changed. To show the validity of the proposed method, a position control of DC servo motor is illustrated by computer simulation and is experimented by a designed controller.

• 한국정밀공학회지
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• 제19권12호
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• pp.163-170
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• 2002

The quality of a precision product, in general, relies on the accuracy and precision of its manufacturing and inspection process. In many cases, the level of precision in the manufacturing and inspection system is also dependent on the positioning capability of tool with respect to the work piece in the process. Recently the positioning accuracy level has reached to the level of submicron and long range of motion is required. For example, for 1 GDARM lithography, 20nm accuracy and 300mm stroke needs. This paper refers to the lithography stage especially to fine stage. In this study, for long stroke and high accuracy, the dual servo system is proposed. For the coarse actuator, LDM (Linear DC Motor) is used and for fine one VCM is used. In this study, we propose the new structure of VCM for the fine actuator. It is 3 axis precision positioning stage for an aligner system. After we perform the optimal design of the stage to obtain the maximum force, which is related to the acceleration of the stage to accomplish throughput of product. And we controlled this fine stage with TDC. So we obtained 50nm resolution. So later more works will be done to obtain better accuracy.

• 대한기계학회논문집A
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• 제37권4호
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• pp.475-481
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• 2013

직접구동형 서보밸브의 제어시스템은 비선형적이며 밸브스풀에 미치는 유체력의 영향은 매우 크고 부하압력의 크기에 좌우된다. 제어시스템의 설계요구조건을 만족시키기 위해, 제약직접탐색방법인 유전자 알고리즘과 콤플렉스법을 적절히 활용하여 진상-지상제어기 및 미분피드백제어기의 최적 상수값을 탐색하였다. 최적 제어기 상수값을 대입하여 제어시스템을 시뮬레이션한 결과 설계요구조건을 만족하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.485-485
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• 2000

A design method of model following control system using neural networks is proposed. An unknown nonlinear single-input single-output plant is identified using a multilayer neural networks. A linear controller is designed fer the linear approximation model obtained by linearinzing the identification model. The identification model is also used as a plant emulator to obtain the prediction error. Deficient servo performance due to controlling nonlinear plant with only linear controller is mended by adjusting the linear controller output using the prediction output and the parameters of the identification model. An optimal preview controller is adopted as the linear controller by reason of having good servo performance lowering the peak of control input. Validity of proposed method is illustrated through a numerical simulation.

• 제어로봇시스템학회논문지
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• 제5권7호
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• pp.862-867
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• 1999

In general, the realization of high performance brushless permanent magnet motors which are widely used in servo drive is focused on the linear control for ripple-free torque. This is also the main problem that should be solved in all AC motors including induction motor to achieve high performance control, and recent papers deal with this problem. In this paper, the novel optimal excitation scheme of brushless permanent magnet motor producing loss-minimized ripple-free torque based on the d-q-0 reference frame is presented including 3 phase unbalanced condition. The optimized phase current waveforms that are obtained by the proposed method can be a reference values and the motor winding currents are forced to track it by delta modulation technique. As a results, it can be shown that the proposed work can minimize the torque ripple by the optimal excitation current for brushless permanent magnet motor with any arbitrary phase back EMF waveform. Simulation and experimental results prove the validity and practical applications of the proposed control scheme.

• 조명전기설비학회논문지
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• 제20권7호
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• pp.81-91
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• 2006

유전자 알고리즘은 지금까지의 방법으로써는 해결이 곤란한 문제에 대해서 실용상의 최적해를 랜덤하고 빠르게 찾는 방법으로서 사용되어 왔으며, 종래의 검색 알고리즘과 달리 검색 공간 중 하나의 점뿐만 아니라 많은 점을 동시에 고려하기 때문에 국부 최소점(local minima)점에 수렴되는 현상을 극복할 수 있다. 따라서 본 논문에서는 목적 함수에 연속미분조건이 없으며 다수의 변수들을 하나의 문자열로 부호화(coding)함으로써 병렬연산 및 동시최적화가 가능한 유전자 알고리즘을 이용한 PI제어기를 교류서보전동기에 적용하여 작업환경변화에 능동적으로 대응하는 제어방법을 제안하였으며 산업현장에서의 로보트 액추에이터 등의 응용과 정밀제어를 실현하기 위한 교류서보전동기의 드라이버에 적용할 수 있는 제어기를 구현하고자 한다.