• Title/Summary/Keyword: LQG design

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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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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.

Design of a Robust Turret-Gun Servo Controller Using LQG/LTR Method (LQG/LTR 방법을 이용한 강인한 터렛서보 제어기 설계)

  • Kim, In-Hwan;Kim, Jong-Hwa;Lee, Man-Hyung
    • Proceedings of the KIEE Conference
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    • 1989.07a
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    • pp.66-69
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    • 1989
  • In this paper, the LQG/LTR design method is applied of the third order linear time invariant plant model which is the SISO turret-gun servo-mechanism. The dynamic characteristics and the performance of the LQG/LTR controller are analyzed by the computer simulation, and compared with those of PID controller which has been already applied to the turret servomechanism under the sane design specifications.

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Frequency Tracking Error Analysis of LQG Based Vector Tracking Loop for Robust Signal Tracking

  • Park, Minhuck;Kee, Changdon
    • Journal of Positioning, Navigation, and Timing
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    • v.9 no.3
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    • pp.207-214
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    • 2020
  • In this paper, we implement linear-quadratic-Gaussian based vector tracking loop (LQG-VTL) instead of conventional extended Kalman filter based vector tracking loop (EKF-VTL). The LQG-VTL can improve the performance compared to the EKF-VTL by generating optimal control input at a specific performance index. Performance analysis is conducted through two factors, frequency thermal noise and frequency dynamic stress error, which determine total frequency tracking error. We derive the thermal noise and the dynamic stress error formula in the LQG-VTL. From frequency tracking error analysis, we can determine control gain matrix in the LQG controller and show that the frequency tracking error of the LQG-VTL is lower than that of the EKF-VTL in all C/N0 ranges. The simulation results show that the LQG-VTL improves performance by 30% in Doppler tracking, so the LQG-VTL can extend pre-integration time longer and track weaker signals than the EKF-VTL. Therefore, the LQG-VTL algorithm is more robust than the EKF-VTL in weak signal environments.

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.

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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Power System Stabilizer Design of a Turbo-Generator using LQG/LTR Control Synthesis (LQG/LTR에 의한 터-빈 발전기의 PSS 說計)

  • Chung, Dae-Won;Kim, Kern-Joong
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.8
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    • pp.965-971
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    • 1999
  • This paper presented to design the power system stabilizer(PSS) for a turbo-generator system using LQG/LTR control synthesis for improving small-signal stability. Application study of LGG/LTR control synthesis is more appropriate in this system since a turbo-generator system is usually operated under circumstance of unmeasurable uncertainties and external disturbance. The LQG/LTR control theory was briefly reviewed for good understanding and the reasonable design approach. The design results are simulated for a case study and to check the system performance in comparison with currently operating lead-lag filtered PSS performance.

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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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