• Title/Summary/Keyword: LQG/LTR

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Control of a Helicopter in Hover Using the LQG and LQG/LTR Methods (LQG와 LQG/LTR방법을 이용한 헬리콥터의 비행위치 제어)

  • Kim, Jong-Shik;Ma, Sam-Sun;Song, Myong-Hun
    • Journal of the Korean Society for Precision Engineering
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    • v.7 no.1
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    • pp.74-85
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    • 1990
  • The LQG and LQG/LTR compensators have the same structrues in dynamics. The only difference is the values of the design parameters in the two compensators. The design parameters of the LQG and LQG/LTR compensators are selected in the sense of the least-squares error minimi- zation and loop shaping, respectively. In this paper, the LQG and LQG/ LTR design methods are applied to the helicopter in hover which is modeled as a SISO fourth order system. The dynamic characteristics and the perfor- mance of the two control systems are analyzed by the computer simulation. It is found that the LQG/LTR design method is systematic and has good performance in comparision with the LQG design method.

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Digital Autopilot Design Using $\delta$-LQG/LTR Compensators ($\delta$-LQG/LTR보상기에 의한 디지털 자동조종장치 설계)

  • 이명의;김승환;권오규
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.40 no.9
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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.

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Autopilot Design Using LQG/LTR Method for a Launch Vehicle (LQG/LTR 기법에 의한 발사체의 자동조종장치 설계)

  • Kim, Seung-Hwan;Kwon, Oh-Kyu
    • Proceedings of the KIEE Conference
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    • 1990.11a
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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.

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A Study on the LQG/LTR for Nonminimum Phase Plant (II) : Realization for the Optimal Approximation Method (비 최소위상 플랜트에 대한 LQG/LTR에 관한 연구(II) : 최적 근사 방법의 실현)

  • 강진식;서병설
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.16 no.10
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    • pp.981-991
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    • 1991
  • LQG/LTR method suggested to improve robustness of LQG have a theoritical constraint that it cannot apply to nonminimum phase plant(NMP). In this paper, we suggest a new LQG/LTR method for NMP which consist of three design steps. The first step is design a additional feed-foward compensator which approximate the given NMP plant to minimum phase(MP) plant and the next step is design a target loop transfer function for approximated MP plant satisfying the design specifications such as robust-performance and robust-stability. The last step is loop transfor recovery(LTR) that the open loop transfer function recovers the terget loop. It was shown by simulation example that the suggested method can solve the NMP constraint in designing LQG/LTR.

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Modelling and LQG/LTR Compensator Design of the Seeker Scan-Loop (탐색기의 주사루프 모델링과 LQG/LTR보상기 설계)

  • 황홍연;이호평
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.11
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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.

Motion Analysis and LQG/LTR Control of a Proportional Solenoid Valve (비례 솔레노이드 밸브의 운동해석 및 LQG/LTR 제어)

  • Kim, Ki-Bum;Kim, In-Soo;Kim, Yeung-Shik;Kim, Jun-Sik
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.12
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    • pp.1607-1612
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    • 2011
  • In this study, dynamic analysis of a proportional solenoid valve is performed, and an LQG/LTR controller with an integrator is designed to control the proportional solenoid valve. The dynamic characteristic of a valve is identified using experimental data by employing the frequency-domain modeling technique. The purpose of LQG/LTR control with an integrator is to enhance the system response and to improve the tracking accuracy for a complex input signal. Experimental tests are performed to verify the performance of the controller, and the results prove the high performance of the controller.

Implementation and performance analysis of digital servo controller using LQG/LTR method (LQG/LTR 방법을 이용한 견실한 디지탈 서어보 제어기 실현 및 성능분석)

  • 최중락;이장규
    • 제어로봇시스템학회:학술대회논문집
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    • 1987.10b
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    • pp.570-574
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    • 1987
  • The robust servo controller is designed by the procedure of LQG/LTR method in the continuous-time domain. This design results is equivalently converted to the discrete-time suboptimal LQG in order to implement by the microcomputer system. The LTP, condition of the discrete-time LQG is analyzed and approved by the experiments against the uncertainty of real plant, the discretized LQG /LTR control shows the good robustness.

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Design Procedure of Robust LQG/LTR Controller of TCSC for Damping Power System Oscillations (전력시스템 동요 억제를 위한 TCSC의 강인한 LQG/LTR 제어기 설계절차에 관한 연구)

  • Son, Kwang-Myoung;Lee, Tae-Gee;Jeon, In-Su
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.16 no.6
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    • pp.30-39
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    • 2002
  • This paper deals with the design of a robust LQC/LTR (Linear Quadratic Gaussian with Loop Transfer Recovery) controller of the TCSC for the power system oscillation damping enhancement. Designing LQG/LTR controller involves several design parameter adjustment processes for performance improvement. this paper proposes a systematic design parameter adjustment procedure which is suitable for robust multi-monde stabilization. The designed controller is verified by nonlinear power system simulation, which shows that the controller is effective for damping power system oscillations.

A design of controller for robust servomechanism using LQG/LTR method (LQG/LTR 방법을 이용한 강인한 서어보메커니즘의 제어기 설계)

  • 최중락;이장규
    • 제어로봇시스템학회:학술대회논문집
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    • 1986.10a
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    • pp.483-487
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    • 1986
  • The LQG/LTR method is applied to the real servomechanism with the unknown modeling error and system noise variance Q$_{2}$. The equivalent discretized LQG controller is implemented on the 16-bit microcomputer and the experimental results show the improved stability and the satisfactory performance when the noise variance Q$_{2}$ is increased infinitly.

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Dynamic Modeling and LQG/LTR Controller Design for the Flexible Structures (유연 구조물에 대한 동역학 모델링 및 LQG/LTR 제어기 설계)

  • 채장수;박태원
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.2
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    • pp.67-73
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    • 2004
  • Some of Spacecraft's structures are flexible so that a certain expected disturbance can easily excite a low frequency vibration on these structures, having very low natural damping. Such vibration will degrade the performance of the system, which should to be kept in a specific shape or attitude against the undesired vibration. In this paper, LQG/LTR controller is developed using an additional dynamic model to increase the performance of the frequency responses at low frequency area. This study presents that the LQG/LTR design was an effective controller for the flexible structure.