• Title/Summary/Keyword: Sinusoidal Disturbance

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Design of a Model-Based Low-Order Disturbance Observer to Estimate a Sinusoidal Disturbance with Unknown Constant Offset (미지의 상수 오프셋을 갖는 삼각함수 외란 추정을 위한 모델기반 저차 외란 관측기 설계)

  • Lee, Cho-Won;Son, Young Ik
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.4
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    • pp.652-658
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    • 2016
  • In practical control systems differences between nominal and real systems arise from internal uncertainties and/or external disturbances. This paper presents a model-based low-order disturbance observer for a sinusoidal disturbance with unknown constant offset. By using the disturbance model of a biased harmonic signal, the proposed method can successfully estimate the biased sinusoidal disturbance with unknown amplitude and phase but known frequency. At the first stage of the observer design, a model-based disturbance observer is designed when all the system states are measurable. Next, a sufficient condition is presented for the proposed observer to estimate the sinusoidal disturbance with a minimal-order additional dynamics using only output measurement. Comparative computer simulations are performed to test the performance of the proposed method. The simulation results show the enhanced performance of the proposed disturbance observer.

Compensation of Unknown Time-Varying Sinusoidal Disturbances in Nonlinear Systems using Disturbance Accommodation Technique (외란 보상 기법을 이용한 비선형시스템에서의 미지의 시변 사인파형 외란 보상)

  • Chwa, Dong-Kyoung
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.10
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    • pp.1844-1851
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    • 2007
  • This paper presents methods for the compensation of sinusoidal disturbances with unknown amplitude, phase, and time-varying frequency in nonlinear systems. In the previous disturbance accommodation methods, the sinusoidal disturbance with unknown time-invariant frequency was considered. In the proposed method, the disturbance with unknown time-varying frequency is compensated. As for the control structure, two control inputs are designed separately in such a way that one of them is designed for the nonlinear system control without considering the disturbance, and the other one uses the disturbance estimate obtained from the disturbance accommodating observer. The stability analysis is done considering the disturbance estimation error and the numerical simulation demonstrates the proposed approach.

Robust Control for the Rewritable Optical Disk Drives with Sinusoidal Disturbance of Uncertain Frequencies (불확실한 주파수의 정현파 외란이 있는 기록형 광 디스크 드라이브의 강인 제어)

  • Lee, Moon-Noh;Jin, Kyoung-Bog;Moon, Jung-Ho
    • Journal of Institute of Control, Robotics and Systems
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    • v.8 no.8
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    • pp.682-690
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    • 2002
  • This paper presents an output feedback controller design method for uncertain linear systems with sinusoidal disturbance of uncertain frequencies. The controller needs to compensate for the performance deterioration due to the uncertain frequencies of sinusoidal disturbance. To this end, we introduce a virtual system including the dynamics corresponding to the uncertain frequencies and design a controller which minimizes the output difference between the virtual system and the closed-loop system. In other words, the controller is designed so that the closed-loop system approximates the virtual system. The feedback controller is achieved by solving an LMI optimization problem involving a robust $H_{\infty}$ constraint. The advantages of the proposed design method are examined by comparing it with a design method that only minimizes the $H_{\infty}$ norm of the transfer function between the sinusoidal disturbance and the output. The proposed design method is applied to the track-following system of rewritable optical disk drives and is evaluated through an experiment.

Adaptive Observer for a System with Sinusoidal Disturbance in Measurement Output (측정 출력에 삼각함수 외란이 포함된 시스템의 적응 관측기)

  • Son, Young-Ik;Kim, In-Hyuk
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.5
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    • pp.966-971
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    • 2010
  • An adaptive state observer is presented for a class of LTI systems that have a sinusoidal disturbance in the measurement output. Adaptation rules are developed for identifying the unknown sinusoidal disturbance signal from the system output. For the application of the identification result to the state estimation problem, the sinusoidal signal with arbitrary initial phase has been considered in this paper. In order to test the performance of proposed algorithm, comparative computer simulations have been carried out with an existing robust observer. The simulation results show the effectiveness of the proposed method.

Robust Disturbance Compensation for Servo Drives Fed by a Matrix Converter

  • Park, Ki-Woo;Chwa, Dong-Kyoung;Lee, Kyo-Beum
    • Journal of Power Electronics
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    • v.9 no.5
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    • pp.791-799
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    • 2009
  • This paper presents a time-varying sinusoidal disturbance compensation method (based on an adaptive estimation scheme) for induction motor drives fed by a matrix converter. In previous disturbance accommodation methods, sinusoidal disturbances with unknown time-invariant frequencies have been considered. However, in the new method proposed here, disturbances with unknown time-varying frequencies are considered. The disturbances can be estimated by using a disturbance accommodating observer, and an additional control input is added to the induction machine drive. The stability analysis is carried out considering the disturbance estimation error and simulation results are shown to illustrate the performance of the proposed solution.

A study on the Flux Feedback Approach for the Rejection of Dynamic Disturbance Forces in a Magnetically Suspended System (자기력 부상 시스템에서 외란 제거를 위한 자속 궤환 방식에 관한 연구)

  • Lee, Jun-Ho;Shin, Kyeong-Ho;Lee, Kang-Mi;Kim, Bak-Hyun;Kim, Jong-Ki;Kim, Yong-Kyu
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.1212-1217
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    • 2006
  • This study is concerned with static and sinusoidal disturbance rejection for a single periodic input disturbance with known period. In the area of active elimination of a disturbance force, the control input should have two different kinds of gains: one is to deliver a stable control and the other is a force component to cancel the external disturbance force. In this paper we employ a simple state feedback control law to make the balance beam stable and employ a linear observer to estimate the states which represent the external disturbance force components. Simulation results verify our proposed control method to reject a static and sinusoidal disturbance force.

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Design of a Speed Controller for Vertical One-Link Manipulator Using Internal Model-based Disturbance Observer (내부 모델 기반 외란 관측기를 이용한 수직 1축 머니퓰레이터의 속도 제어기 설계)

  • Lee, Cho-Won;Kim, In Hyuk;Son, Young Ik
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.5
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    • pp.751-754
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    • 2015
  • This paper deals with a robust speed control problem of a vertical one-link manipulator in the presence of parameter uncertainties and unknown input disturbance. Uncertain load weight causes an additional sinusoidal disturbance in the rotation of the link. In order to improve the robustness against parameter uncertainties and external input disturbances, this paper employs an internal model-based disturbance observer approach. Comparative computer simulations are performed to test the performance of the proposed controller. The simulation results show the enhanced performance of the proposed method.

A Study on the Rejection of Dynamic Disturbance Forces in a Magnetically Suspended System Using Flux Feedback (자기력 부상 시스템에서 자속궤한을 이용한 동적 외란력의 제거에 관한 연구)

  • Kim, Jong-Ki;Lee, Key-Seo;Lee, Jun-Ho
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.3 s.108
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    • pp.283-290
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    • 2006
  • This study is concerned with static and sinusoidal disturbance rejection for a single periodic input disturbance with known period. In the area of active elimination of a disturbance force, the control input should have two different kinds of gains: one is to deliver a stable control and the other is a force component to cancel the external disturbance force. In this paper we employ a simple state feedback control law to make the balance beam stable and employ a linear observer to estimate the states which represent the external disturbance force components. Simulation results verify our proposed control method to reject a static and sinusoidal disturbance force.

Design of Output Regulator for Rejecting Periodic Eccentricity Disturbance in Optical Disc Drive

  • Shim, Hyung-Bo;Kim, Hyung-Jong;Chung, Chung-Choo
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.452-457
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    • 2003
  • An add-on type output regulator is proposed in this paper. By an add-on controller we mean an additional controller which operates harmonically with a pre-designed one. The role of the add-on controller is to reject a sinusoidal disturbance of unknown magnitude and phase but with known frequency. Advantages of the proposed controller include that (1) it can be used only when the performance of disturbance rejection needs to be enhanced, (2) when it is turned on or off, unwanted transient can be avoided (i.e., bumpless transfer), (3) it is designed for perfect disturbance rejection not just for disturbance reduction, (4) ability for perfect rejection is preserved even with uncertain plant model. This design may be promising for optical disc drive (ODD) systems in which disc eccentricity results in a sinusoidal disturbance. For ODD systems, the sensitivity function obtained by the pre-designed controller, which may have been designed by the lead-lag, $H_{\infty}$, or DOB (disturbance observer) technique, does not change much with the add-on controller except at the frequency of the disturbance. Since the add-on controller does the job of rejecting major eccentricity disturbance, the gain of the pre-designed controller does not have to be too high.

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Compensation of Sinusoidal Disturbance in Pendubot System using Disturbance Observer (외란 추정기를 이용한 펜듀봇 시스템의 사인파형 외란 보상)

  • Jeon, Jeong-Hyo;Kim, Cheol-Joong;Chwa, Dong-Kyoung
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.12
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    • pp.2278-2283
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    • 2010
  • This paper deals with the pendubot control using disturbance observer. Experimental results for the motion of pendubot with balancing control show that the limit cycle can be attributed to the disturbance. Therefore, we propose the disturbance compensation method using by disturbance observer to compensate for the disturbance. Through the experimental results, the effectiveness of the proposed method is verified.