• Title/Summary/Keyword: 루프 전달 회복

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Vibration-free Control of Double Integrator Typed Motor via Loop Transfer Recovery (루프 전달 회복을 통한 이중 적분 모터의 무진동 제어)

  • Suh, Sang-Min
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.10
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    • pp.900-906
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    • 2010
  • This note proposes vibration-free motor control through modified LQG/LTR methodology. A conventional LQG/LTR method is a design tool in the frequency domain. However, unlike the conventional one, the proposed one is a time response based design method. This feature is firstly designed by parameterized settling time control gain through the target loop design procedure and the feature is secondly realized by loop transfer recovery. In order to show convergence to the target loop transfer functions, asymptotic behaviors of the open and the closed loop transfer functions are shown. At the conclusion, it is verified that the proposed method is robustly stable to parametric uncertainties through ${\mu}$-plot.

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.

A Study on the Robust Control of Systems Dominantly Subkected to Modeling Errors and Uncertainties (모델링오차와 불확실성을 지배적으로 받는 시스템의 강인한 제어에 관한 연구)

  • 김종화
    • Journal of Advanced Marine Engineering and Technology
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    • v.19 no.2
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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.

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An Application of LTR Method in a DUOX System to Control a MDOF Structure Subjected to the Seismic Excitations (루프전달회복법(Loop Transfer Recovery: LTR)을 이용한 다자유도 DUOX 시스템의 지진동 제어)

  • Lee, Jin-Ho
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.12 no.5
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    • pp.65-73
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    • 2008
  • Retaining large stability margin is essential in designing a feedback control system to deal with the uncertainties inherently existing in the mathematical model and the control apparatus. The LQG controller in general loses the stability margin due to the embed Kalman filter. The performance of a control system called LTR with a DUOX structure(LTR/DOUX) to overcome the demerit of LQG controller is to be investigated from the responses in both the time and the frequency domain. The results indicated that the LTR/DOUX recovered the gain margin of 30dB approximately 20 times more than that of LQG/DOUX, resulting in a robust stable control system.

A Novel Approach on $H_{\infty}$-LTR Controller Design ($H_{\infty}$-LTR 제어기 설계의 새로운 접근방법)

  • Lhee, Chin-Gook;Park, Jae-Sam;Ahn, Hyun-Sik;Kim, Do-Hyun
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.36S no.2
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    • pp.38-45
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    • 1999
  • In this paper, A novel approach on $H_{\infty}-LTR$ design scheme is presented. The proposed scheme provides a design toll which can trade-off the recovery error against the control input. In the first stage, Kalman filter is designed to shape the loop to satisfy the required performance specifications. The designed Kalman filter, together with the plant transfer function, is used as a target transfer function. In the second stage, sensitivity function weighted $H_{\infty}-LTR$suboptimal LTR is designed to recover the target loop transfer function. Simulation results of LQG/LTR, $H_{\infty}-LTR$are compared to demonstrate the good property of the proposed scheme.

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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.

Motion Control of the Precise Stage using Piezoelectric Actuator (압전소자를 이용한 정밀 스테이지의 운동제어)

  • Kim, In-Soo;Kim, Yeung-Shik;Hwang, Yun-Sik
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.4
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    • pp.102-108
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    • 2011
  • LQG/LTR control scheme is applied to the two axes stage using piezoelectric actuator for tracking reference input and suppressing hysteresis effect in this paper. The plant is combined with an integrator to improve the tracking ability. LQG/LTR controller is designed by making desirable target filter loop remove all poles except for an integrator included in new design plant model and loop transfer recovery. Decoupler in the shape of FIR filter is added to remove the coupling effect between the two axes motion and so feedback control loop is designed independently for the each axis motion.

Robust Control of Vibration Using shape memory alloy actuator (형상기억합금 액추에이터를 이용한 강건한 진동제어)

  • ;Koval, L. R.
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.1
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    • pp.263-270
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    • 1995
  • The use of the shape memory alloy, Nitinol wire, is investigated as an actuator for enhancing the damping in structural vibration systems. The first-order mathematical model of the Nitinol wire is obtained from the experimental data for an actuator. Finite element method is utilized for the strain gage sensor model, which is installed at the root of cantilever beam. A simple system, cantilever beam, is built as a flexible structural system to implement a control law with the Nitinol wire actuator. The system model including sensor and actuator is derived, which agrees with the experimental results. The actuator dynamics is augmented with the system so as to design PI controller and the one of robust controllers, LQG/LTR controller, and the control laws are implemented experimentally. The experimental study shows the feasibility of utilizing the Nitinol wire as an actuator for the purpose of vibration control.

Aeromechanical stability analysis and control of helicopter rotor blades (헬리콥터 회전날개깃의 안정성 해석과 제어)

  • Kim, J.S.;Chattopadhyay, Aditi
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.9 no.1
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    • pp.59-69
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    • 2001
  • The rotor blade is modeled using a composite box beam with arbitrary wall. The active constrained damping layers are bonded to the upper and lower surfaces of the box beam to provide active and passive damping. A finite element model, based on a hybrid displacement theory, is used in the structural analysis. The theory is capable of accurately capturing the transverse shear effects in the composite primary structure, the viscoelastic and the piezoelectric layers within the ACLs. A reduced order model is derived based on the Hankel singular value. A linear quadratic Gaussian (LQG) controller is designed based on the reduced order model and the available measurement output. However, the LQG control system fails to stabilize the perturbed system although it shows good control performance at the nominal operating condition. To improve the robust stability of LQG controller, the loop transfer recovery (LTR) method is applied. Numerical results show that the proposed controller significantly improves rotor aeromechanical stability and suppresses rotor response over large variations in rotating speed by increasing lead-lag modal damping in the coupled rotor-body system.

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