• Title/Summary/Keyword: disturbance system

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Analysis of Discrete-Time Disturbance Observer for Second-Order Systems (2차 시스템에 대한 이산시간 외란 관측기의 분석)

  • 양광진;최영진;정완균
    • Journal of Institute of Control, Robotics and Systems
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    • v.9 no.6
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    • pp.425-434
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    • 2003
  • The disturbance observer(DOB) has been widely used in high speed and high precision motion control applications and the characteristics of DOB have been investigated in depth. Though most of DOB's have been implemented as the discrete-time form in digital devices, we are still short of the researches on discrete-time DOB (DDOB) in spite of rich references on continuous-time DOB. In this paper, we discuss about the disturbance rejection property and measurement noise effect of discrete-time DOB. Especially, we will focus on revealing the role of sampling time in designing the discrete-time DOB and show the validity of analysis through simulations and experiments for optical disk drive systems.

Design and Implementation of a Robust Controller Using DSP (DSP를 이용한 강인 제어기의 설계 및 구현)

  • Yeo Hee-Joo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.7 no.3
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    • pp.325-331
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    • 2006
  • This paper suggests the design methodology of a robust controller based on disturbance rejection controller using DSP. In this paper, we discuss process to put the disturbance rejection controller into practice, and examine the performance of disturbance rejection controller by implementing it on DSP based hardware to evaluate usefulness of controller. As a result, the proposed robust controller can not only stabilize system against disturbance ,but it improve controlling performance. And also, it shows convenient to put into practical use of industrial sites due to its easy implementation on the hardware.

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Fuzzy Estimator for Gain Scheduling and its Appliation to Magnetic Suspension

  • Lee, Seon-Ho;Lim, Jong-Tae
    • Transactions on Control, Automation and Systems Engineering
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    • v.3 no.2
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    • pp.106-110
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    • 2001
  • The external force disturbance is the one of the main causes that deteriorate the performance of the magnetic suspension. Thus, this paper develops a fuzzy estimator for gain scheduling control of magnetic suspension system suffering from the unknown disturbance. The propose fuzzy estimator computes the disturbance injected to the plant the gain scheduled controller generates the corresponding stabilizing control input associated with estimated disturbance. In the simulation results we confirm the novelty of the proposed control scheme comparing with the other method using a feedback linearization.

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Development of New Smith Predictor Controller and a Disturbance Observer for Control of the Superheater and the Steam Pressure (보일러 과열기 및 증기 압력 제어를 위한 외란 관측기 및 새로운 스미스 예측제어기 개발)

  • Lee, Soon-Young;Shin, Hwi-Beom;Park, Soo-Yong;Jang, Eun-Syeung
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.1687-1688
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    • 2008
  • The steam superheater and the steam pressure systems are time delay systems that have poles near the origin in the left half plane or a pure integrator. Smith predictor can't be applied to these systems any more, because of occurring the steady state error for the step disturbance. In this paper, a new Smith predictor controller for the steam superheater and the steam pressure is proposed. A disturbance observer to estimate an input disturbance and a new controller to eliminate an effect of a disturbance are proposed. The computer simulation results are shown the efficiency of the proposed system.

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Neural-networks-based Disturbance Observer and Tracker Design in the Presence of Unknown Control Direction and Non-affine Nonlinearities (미지의 제어 방향성과 비어파인 비선형성을 고려한 신경망 기반 외란 관측기와 추종기 설계)

  • Kim, Hyoung Oh;Yoo, Sung Jin
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.4
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    • pp.666-671
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    • 2017
  • A disturbance-observer-based adaptive neural tracker design problem is investigated for a class of perturbed uncertain non-affine nonlinear systems with unknown control direction. A nonlinear disturbance observer (NDO) design methodology using neural networks is presented to construct a tracking control scheme with the attenuation effect of an external disturbance. Compared with previous control results using NDO for nonlinear systems in non-affine form, the major contribution of this paper is to design a NDO-based adaptive tracker without the sign information of the control coefficient. The stability of the closed-loop system is analyzed in the sense of Lyapunov stability.

Characteristics of a Sliding Mode Controller with Disturbance Estimator (외란 추정기를 갖는 슬라이딩 모드 제어기의 특성)

  • Choe, Seung-Bok;Ham, Jun-Ho;Park, Jong-Seong
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.1
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    • pp.165-171
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    • 2002
  • The conventional sliding mode control(SMC) technique requires a priori knowledge of the upperbounds of disturbances or/and modeling uncertainties to assure robustness. This, however, may not to be easy to obtain in practical situation. This paper presents a new methodology, sliding mode control with disturbance estimator(SMCDE), which offers a robust control performance without a priori knowledge about the disturbance. The proposed technique is featured by an average value of the imposed disturbance over a certain period. A nonlinear spring-mass-damper system is adopted as an illustrative example, and a comparative work between the conventional technique and the present one is undertaken.

Joint disturbance torque analysis for 2 DOF robots and its application (2자유도 로봇의 관절외란해석과 응용)

  • Choi, Myoung Hwan
    • Journal of Industrial Technology
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    • v.18
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    • pp.289-293
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    • 1998
  • In a independent joint servo control of robots, the performance of the control is influenced greatly by the joint interaction torques including Coriolis and centrifugal forces. These act as disturbance torques to the control system. As the speed of the robot increases, the effect of this disturbance torque increase, and makes the high speed - high precision control more difficult to achieve. In this paper, a solution to the optimal path placement problem is presented that minimizes the joint disturbance torque during a straight line motion. The proposed method is illustrated using computer simulation. The proposed solution method can be applied to the class of robots that are controlled by independent joint servo control, which includes the vast majority of industrial robots.

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A Study on the Influence of Q-filter on Disturbance Observer Controller for Electro-Magnetic Suspension Systems (자기부상시스템의 외란관측기 제어기에 Q 필터가 미치는 영향에 관한 연구)

  • Jeon, Chanyoung;Jang, Sohyun;Jo, Nam-Hoon
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.10
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    • pp.104-110
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    • 2015
  • The disturbance observer (DOB) controller has been widely used in various industrial applications since it is capable of achieving robust stability and disturbance rejection. In this paper, we study the effect of Q-filter on disturbance observer controller for Electro-Magnetic suspension (EMS) systems. We consider three Q-filters and analyze their effects on the robust stability against parameter uncertainties due to mass variation. Moreover, we investigate the influence of sensor noise for three Q-filters. According to our study, robust stability improves as the order of Q-filter decreases. On the other hand, the larger the order of Q-filter, the more the effect of sensor noise can be removed.

Control Systems Design Based on Disturbance Cancellation via LTR Technique

  • Inooka, Hikaru;Ichirou, Komatsu Ken
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.87.1-87
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    • 2001
  • For a plant subject to several kinds of disturbances in the plant input side, we consider a problem of designing a controller based on the disturbance cancellation. The conventional loop transfer recovery (LTR) technique can not be used since the extended system consisting of the plant and the disturbance model is not necessarily stabilizable. We propose a new LTR technique that can be applied for our problem. As a target of the LTR, we choose a state feedback controller using a disturbance estimator. We find an LTR procedure based on the Riccati equation formalism where the stochastic model contains the filter gain matrix of the disturbance estimator in the target. The procedure recovers the target feedback ...

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Design of Disturbance Observer for Track-following Controller of Optical Disk Drive

  • Ryoo, Jung-Rae;Doh, Tae-Yong;Chung, Myung-Jin
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.87.4-87
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    • 2001
  • In this paper, a design guideline of disturbance observer(DOB) for track-following controller is presented. In the track-following control system(TFCS) of optical disk drive(ODD), disturbance rejection is the key issue for the overall performance. DOB gives an excellent advantage of disturbance rejection within its bandwidth determined by a low-pass filter. In general, design of DOB requires a tradeoff between performance and stability, which should be based on quantitative analysis. The external disturbance is well-defined in the frequency domain, which provides the base of the analysis. In addition to a DOB, a proper feedback controller is utilized for guaranteeing overall stability. Some computer simulations and experiments are conducted and some of the results are presented.

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