• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 춘계학술대회 논문집
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• pp.133-142
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• 1992

A kineamatic nonlinear multivariable laundher is modeled of which the azimoth and elevation axes are drived simultaneously and SISO and MIMO LQG/LTR controllers are designed and evaluated for this system. Also, the suitable command input function is suggested for the desired command following performance and the LQG/LTR control system with disturbances and load variation is evaluated for the entire operating range by computer simulation. It is found that the linear SISO LQG/LTR controller can be used for the kinematic nonlinear multivariable launder in the entire operating range and is effective for disturbance rejection and load variation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.60.3-60
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• 2002

1. Introduction 2. The Localized Aerosol Hyperthermia 3. Hardware Development of a Heated Vapor Inhalator 4. Modeling of the Control System 5. The Design of LQG/LTR Controller 6. Conclusion

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국제학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.749-752
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• 1988

In this paper, the delay margins of the LQ and the LQG regulators are obtained in the time domain. These margins are represented in terms of the singular values of system matrices and the solutions of a Riccati equation and a Lyapunov one. And their asymptotical properties when gains tend to infinity are investigated.

• Journal of Advanced Marine Engineering and Technology
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• 제19권2호
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• pp.67-80
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• 1995

In order to control systems which are dominantly subjected to modeling errors and uncertainties, control strategies must deal with the effect of modeling errors and uncertainties. Since most of control methods based on system mathematical model, such as LQG/LTR method, have been developed mainly focused on stability robustness, they can not smartly improve the transient response disturbed by modeling errors and/or uncertainties. In this research, a fuzzy PID control method is suggested, which can stably improve the transient responses of systems disturbed by modeling errors as well as systems not entirely using mathematical models. So as to assure the effectiveness of suggested control method, computer simulations are accomplished for some example systems, through the comparison of transient responses.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.646-653
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• 2001

LQG/LTR Control Methology is recently used for the analysis of multi-variable control in frequency domain. Target filter loop is designed by the demanding requirements such as cross-over frequency, disturbance rejection in low frequency domain, zero steady-state error, identification of maximum and minimum singular values and sensor noise rejection in high frequency domain. Loop transfer recovery is accomplished by solving the cheap control and then simulation close to the target filter loop. In this study, LQG/LTR Control Methodology is applied to the seat suspension system. It is found that this technique is very effective to control the system and improve the ride quality of human body.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.193-196
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• 1992

When there exist parameter uncertainty, modelling errors and nonminimum phase zeros in control object system. the stability robustness of conventional LQG and LOG/LTR methods are not satisfactory[2, 8]. Since these methods are performed on the infinite horizon, it is very hard to establish exact design parameters and thus they have lots of problems to be applied to real systems, So in this paper we propose RHLQG/FIRF optimal controller which has robust stability against parameter uncertainty, nonminimum phase zeros and modelling errors. This method uses only the information around at present and therefore shows good performance even when we do not know exact design parameters. We here compare LQG and LQG/LTR method with RHLQG/FIRF controller and exemplify that RHLQG/FIRF controller has better robust stability performance via simulations.

• 한국산업융합학회 논문집
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• 제25권2_2호
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• pp.193-198
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• 2022

In this paper, we introduce the improved control method are communicated between a master and a slave robot in the teleoperation systems. When the master and slave robots are located in different places, time delay is unavoidable under the network environment and it is well known that the system can become unstable when even a small time delay exists in the communication channel. The time delay may cause instability in teleoperation systems especially if those systems include haptic feedback. This paper presents a control scheme based on the estimator with virtual master model in teleoperation systems over the network. As the behavior of virtual model is tracking the one of master model, the operator can control real master robot by manipulating the virtual robot. And LQG/LTR scheme was adopted for the compensation of un-modeled dynamics. The approach is based on virtual master model, which has been implemented on a robot over the network. Its performance is verified by the computer simulation and the experiment.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.77-80
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• 1997

In this paper presented is a temperature controller for a semiconductor test handler. Using ARMAX model and least square method, the chamber model for the design of a controller is identified through experiment. With the identified model an LQG/LTR controller is designed. Experiment with a real test handler demonstrated good performance in that its overshoot is small and response time is fast.

• 한국항공운항학회지
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• 제9권1호
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• pp.59-69
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• 2001

복합재로 된 회전날개깃을 상자보로 모델링하고 수동/능동 감쇠를 주기 위해 ACL(Active Constrained Damping Layer)을 상하양면에 부착하고 복합변위이론에 기초한 유한요소방법을 이용하여 구조해석을 수행하였다. 이 이론은 ACL내의 복합재와 점탄성층 그리고 압전층의 전단변형효과를 정확하게 모델링하는데 효과적이다. Hankel 의 특이값을 이용해 축차모델을 유도하였으며 축차모델과 측정된 출력에 기초한 LQG 제어기를 설계하였다. 그러나 LQG 제어기는 공칭 운전속도에서는 좋은 성능을 보여주었으나 운전속도가 변하는 상황에 대해서는 강인안정성을 보여주지 못했다. 이 LQG제어기의 강인안정성을 개선하기 위하여 루프전달회복을 통한 강인한 제어기를 설계하였다. 수치 예를 통해 제시된 제어기가 회전날개깃의 공기역학적인 안정성을 개선하는데 효과적이며 동체모드와 연계된 리드-래그 모드감쇠를 증가시켜 회전날개깃의 진동을 효과적으로 억제하는 것을 보였다.

• 한국지진공학회논문집
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• 제9권5호
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• pp.41-52
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• 2005

지진응답제어를 위한 효율적 방법으로 제시된 퍼지관리제어기법은 퍼지에 기반한 의사결정과정을 통하여 가변 제어이득행렬을 구현함으로써 하나의 제어이득만으로 표현되는 선형제어기법보다 개선된 제어성능을 발휘할 수 있다. 이 논문에서는 퍼지관리제어기법의 효율성을 하중 및 교량모델의 불확실성에 대한 제어성능의 강인성 측면에서 평가하였다. 강인성 평가에 있어서는 Dyke등이 제시한 벤치마크 교량에 대하여, 최적설계된 LQG기법과 제어성능을 비교하는 방법을 사용하였다. 불확실성을 주는 요인으로는 주파수 특성이 다른 여러 지진가속도의 규모 및 교량의 강성변화를 가정하였다. 최적설계된 LQG 제어기와 제어효과를 비교한 결과, FSC시스템이 지진의 종류와 규모에 따라 보다 작은 전력을 사용하면서도 개선된 제어성능을 발휘하였다. 특히, LQG 제어시스템이 강성변화에 대하여 불안정한 제어성능을 보인 반면, FSC 시스템은 매우 안정적인 응답제어효과를 보이면서도 제어시스템에 소요되는 전력량과 제어장치의 스트로크에 있어서도 큰 변화를 보이지 않음으로써 매우 탁월한 강인성을 보장할 수 있는 것으로 나타났다.