• Title, Summary, Keyword: LQG/LTR(Linear Quadratic Gaussian/Loop Transfer Recovery)

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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.

LQG/LTR-PID based Controller Design of UAV Slung-Load Transportation System (LQG/LTR과 PID 기반의 무인항공기 슬렁-로드 수송 시스템의 제어기 설계)

  • Lee, Hae-In;Yoo, Dong-Wan;Lee, Byung-Yoon;Moon, Gun-Hee;Lee, Dong-Yeon;Tahk, Min-Jea
    • Journal of Institute of Control, Robotics and Systems
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    • v.20 no.12
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    • pp.1209-1216
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    • 2014
  • This paper copes with control design for unmanned aerial vehicle transportation system. Moving pendulum dynamics of slung-load system is derived using two methods: Udwadia-Kalaba equation and Newtonian approach. PID controller is applied to Udwadia-Kalaba equation model for structural consistency and linear quadratic Gaussian / Loop Transfer Recovery (LQG/LTR) technique is employed for Newtonian model with minimal state-space realization. Characteristics of PID and LQG/LTR controller are compared, and two controllers are combined to compensate the drawbacks of each other. Numerical simulation is set for two cases and conducted to evaluate performance of designed controllers. The result proves that combination of LQG/LTR and PID control performs stable and robust.

Transfer Function Derivation and LQG/LTR Speed Ratio Control for a Metal Belt CVT (금속벨트 CVT의 전달함수 도출과 변속비 LQG/LTR 제어)

  • 김종준;송한림;김현수
    • Transactions of the Korean Society of Automotive Engineers
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    • v.5 no.1
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    • pp.49-58
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    • 1997
  • In this paper, a transfer function was obtained for a PWM high speed solenoid valve controlled metal belt CVT system. The transfer function was defined as the ratio of speed ratio to PWM duty ratio and derived in time domain by linear regression analysis from the experimental results. The transfer function obtained showed different dynamic characteristics for the up and down shift. Also, LQG/LTR controller was designed for the CVT system using the transfer function. It is seen from the experimental results that LQG/LTR control showed good performance for the speed ratio tracking and disturbance rejection. The phase difference and relatively slow response are considered due to the inaccuracy os the transfer functions, which resulted from the inherent nonlinearities of the transmission characteristics of the metal belt CVT.

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Decomposed Linear Quadratic Gaussian with Loop Transfer Recovery Controller Design for an Undersea Vehicle (수중운동체를 위한 분할 LQG/LTR 제어기 구성)

  • Han, Hyung-Seok;Lee, Jang-Gyu
    • Proceedings of the KIEE Conference
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    • pp.121-124
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    • 1989
  • In this thesis, a decomposed LQG/LTR controller is designed for an undersea vehicle. The modellig error which results from decomposition of the original model is considered to the design specification for maintaining the robust stability. The LQG/LTR controller designed with new specification is simulated.

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LQG/LTR Control of Hydraulic Positioning System with Dead-zone (사역대가 포함된 유압 위치 시스템의 LQG/LTR 제어)

  • Kim, In-Soo;Kim, Yeung-Shik;Kim, Ki-Bum
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.8
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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.

LQG/LTR Control of Hydraulic Positioning System with Dead-zone (사역대가 포함된 유압 위치 시스템의 LQG/LTR 제어)

  • Kim, Ki-Bum;Kim, Yeung-Shik;Kim, In-Soo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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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.

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Robust Control of Two-axes Precise Stage Using LMI Optimization (LMI 최적화를 이용한 2축 정밀 스테이지의 강인제어)

  • Kim, Yeung-Shik;Park, Heung-Seok;Kim, In-Soo
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.22 no.5
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    • pp.845-851
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    • 2013
  • In this paper, a robust optimization approach is applied to the two-axes stage using a piezoelectric actuator for precise motion tracking. Robust control is based on LQG/LTR (linear quadratic Gaussian control with loop transfer recovery) control. Further, an LMI (linear matrix inequality) is used to find the optimal parameter in the loop transfer recovery step, instead of a trial and error method. A decoupler in the shape of FIR filter is added to reduce the coupling effect between the motions of the two axes, and hence, the feedback control loop is designed independently for each axis motion. The experimental result shows that the proposed control scheme can be applied effectively for motion control of the two-axes stage.

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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Robust Adaptive Control of Hydraulic Positioning System Considering Frequency Domain Performance (주파수역 성능을 고려한 유압 위치시스템의 강인 적응 제어)

  • Kim, Ki-Bum;Kim, In-Soo
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.23 no.2
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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.

End-Point Position Control of a Flexible Manipulator (유연한 조작기의 끝점 위치 제어)

  • 이재원;주해호
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.7
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    • pp.1307-1313
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    • 1992
  • The end-point position control of a flexible manipulator is a non-minimum phase system. The PD feedback of the end-point position is not stable in contrast with that of the hub jangle. However, the system can be stabilized conditionally by the feedback of both the hub rate angle and the end-point position. Even in the non-minimum system, the LQG/LTR control law is more systmatic controller design method than the classical control law which uses a root-locus technique.