• 대한전기학회논문지
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• 제40권9호
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• pp.920-928
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• 1991

This paper proposes a design procedure based on the LQG/LTR (Linear Quadratic Gaussian/ Loop Transfer Recovery) method for a launch vehicle. Continuous-discrete type LQG/LTR compensators are designed using the e-transformation to overcome numerical problems occurring in the process of discretization. The e-LQG/LTR compensator using the e-transformation is compared width the z-LQG/LTR compensator using the z-transformation. The performance of the overall system controlled by the compensator is evaluated via simulations, which show that the discretization error problem is resolved and the control performances are satisfactory in the proposed compensator.

• 대한기계학회논문집
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• 제17권11호
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• pp.2730-2741
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• 1993

A mathematical model of the seeker scan-loop which is composed of a spin-stabilized gyroscope and its driving signal processors is derived. The derived model has a transmission zero pair on the imaginary axis near to the required bandwidth. The LQG/LTR design methodology is evolved for the derived scan-loop model. To implement the designed LQG/LTR compensator to the actual plant, the compensator order is reduced using the internally balanced realization method. The performances of the LQG/LTR compensator are tested and compared with those of the P-control. Especially, stability-robustnessexperiments for model uncertainties represented in the form of time-delays are performed. It is demonstrated that the LQG/STR compensator is actually very robust to model uncertainties.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 추계학술대회 논문집 학회본부
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• pp.413-416
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• 1990

This paper proposes a design procedure based on the LQG/LTR method for a launch vehicle autopilot. Continuous-discrete type LQG/LTR compensators are designed using the $\delta$-transformation [1] in order to overcome numerical problems occurring in the process of discretization. The $\delta$-LQG/LTR compensator using the $\delta$-transformation is compared with the $\delta$-LQG/LTR compensator using the $\delta$-transformation. The performance of the overall system controlled by the $\delta$-LQG/LTR compensator is evaluated via simulations, which show that the discretization error problem is resolved and the control performances are satisfied in the proposed compensator.

• 한국소음진동공학회논문집
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• 제22권8호
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• pp.729-735
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• 2012

A LQG/LTR(linear quadratic Gaussian/loop transfer recovery) controller with an integrator is designed to control the electro-hydraulic positioning system. Without considering the nonlinearity in the dead-zone, computer simulations are performed and show good performances and tracking abilities with the feedback controller based on the linear system model. However, the performance of the closed loop hydraulic positioning system shows big steady-state error in real system because of the dead-zone. In this paper, the feedback controller with a nonlinear compensator is introduced to overcome the dead-zone phenomenon in hydraulic systems. The inverse dead-zone as a nonlinear compensator is used to cancel out the dead-zone phenomenon. Experimental tests are performed to verify the performance of the controller.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.614-619
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• 2012

A LQG/LTR(Linear Quadratic Gaussian/Loop Transfer Recovery) controller with an integrator is designed to control the electro-hydraulic positioning system. Without considering the nonlinearity in the dead-zone, computer simulations are performed and show good performances and tracking abilities with the feedback controller based on the linear system model. However, the performance of the closed loop hydraulic positioning system shows big steady-state error in real system because of the dead-zone. In this paper, the feedback controller with a nonlinear compensator is introduced to overcome the dead-zone phenomenon in hydraulic systems. The inverse dead-zone as a nonlinear compensator is used to cancel out the dead-zone phenomenon. Experimental tests are performed to verify the performance of the controller.

• 대한기계학회논문집
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• 제16권7호
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• pp.1307-1313
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• 1992

본 연구에서는 유연한 조작기의 끝점 위치 제어를 위해 LQG/LTR 제어법을 적 용함으로서 기존의 고전적 제어방법과 비교하고자 한다.

• 한국통신학회논문지
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• 제16권10호
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• pp.981-991
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• 1991

LQG의 강인성 증진을 위하여 제안된 LGQ/LTR방법은 비 최소위상 플랜트에 대하여 적용할 수 없는 이론적 제한성을 갖는다. 본 논문에서는 비 최소위상 플랜트에 대해서도 적용될 수 있는 세 단계로 구성된 새로운 LQG/LTR방법을 제안한다. 첫번째 단계로 주어진 비 최소위상 플랜트를 최소위상 플랜트로 근사화 시키기 위한 부가적인 feed-forward 보상기를 설계하며 다음 단계에서 전개사양에 맞도록 근사화된 비 최소위상 플랜트에 대하여 목표 루우프를 설계한다. 마지막 단계로 개루우프의 전달함수가 목표 루우프로 회복시키는 LTR을 설계한다. 제안된 방법이 비 최소위상 플랜트에 대한 제약을 해결할 수 있음을 시뮬레이션 예제를 통하여 보인다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.327-332
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• 1990

Gunner primary sight stabilization system is a fully integrated sensor package designed to provide the stabilized Line-of-Sight. In this study, to improve disturbance rejection capabilities, two types of compensator (LQG/LTR, Lead-Lag) were designed and then stabilization performances were compared under severe off-road environment. Simulation results shows that the stabilization performances using LQG/LTR methodology is better than Lead-Lag methodology in spite of dynamic uncertainties.

• 한국생산제조학회지
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• 제23권2호
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• pp.157-163
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• 2014

In this paper, a robust MRAC (model reference adaptive control) scheme is applied to control an electrohydraulic positioning system under various loads. The inverse dead-zone compensator in the control system cancels out the dead-zone response, and an integrator added to the controller provides good position-tracking ability. LQG/LTR (linear quadratic Gaussian control with loop transfer recovery) closed-loop model is used as the reference model for learning the MRAC system. LQG/LTR provides a systematic technique to design the linear controller that optimizes the objective function using some compromise between the control effort and the system performance in the frequency domain. Different external load tests are performed to investigate the effectiveness of the designed MRAC system in real time. The experimental results show that the tracking performance of the proposed system is highly accurate, which offers considerable robustness even with a large change in the load.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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• pp.192-196
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• 1988

This paper presents a feasibility study related to the design of a linear multivariable compensator for a model of boiler-turbine system. The nonlinear dynamics are linearized at a operating condition. At the operating point an LQG/LTR compensator is designed. Simulations are included to illustrate the usefulness of this linear multivariable control law.