• 제목/요약/키워드: 트랙추종서보

검색결과 6건 처리시간 0.026초

트랙 추종 서보 시스템에 대한 주기적 외란 보상기의 이득 설정과 구현 (Design and Implementation of Periodic Disturbance Compensators for Track Following Servo Systems)

  • 정준
    • 한국소음진동공학회논문집
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    • 제24권2호
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    • pp.139-145
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    • 2014
  • Periodic disturbance compensators are widely used in track following servo systems. They are commonly designed and implemented by adaptive feedforward compensators or internal model based compensators. In track following servo systems, the gains of the compensators should be determined considering the change of the sensitivity transfer function and the implementation methods should be selected considering the system environment. This paper proposes a guide for determining gains of the periodic disturbance compensators. Various simulation and experimental results are presented to see the effect of gains. In addition, this paper introduces the various types of implementation methods and compares their merits and demerits.

초고밀도 디스크 드라이브를 위한 반 진공 작동 환경에서 서보 트랙 기록 방법에 의한 RRO 저감에 대한 연구 (Repeatable Run-out Reduction by Servo Track Writing in Semi-vacuum Condition for Ultra-high TPI Disk Drive)

  • 한윤식;강심우
    • 한국소음진동공학회논문집
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    • 제14권11호
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    • pp.1176-1181
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    • 2004
  • In high-capacity disk drives with ever-growing track density, the allowable level of position error signal(PES) is becoming smaller and smaller. In order to achieve the high TPI(track per inch) disk drive, it is necessary to improve the writing accuracy during the servo track writing(STW) Process through the reduction of track mis-registration sources. Among the main contributors of the non-repeatable runout(NRRO) PES, the disk vibration and the head-stack assembly vibration is considered to be one of the most significant factors. Also the most contributors of repeatable runout(RRO) come from the contributors of NRRO which is written-in at the time of STW process. In this paper, the effect of NRRO on servo written-in RRO is Investigated by experimentally, and the experimental result shows that the written-in RRO can be effectively reduced through a STW process under low dense medium condition such as semi-vacuum.

외란 관측기를 이용한 근접장 기록 시스템의 트랙킹 서보 성능 향상 (Improvement of Tracking Servo Performance in SIL based Near-field Recording using Disturbance Observer)

  • 강민석;김중곤;신원호;정준;박노철;양현석;박영필
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2008년도 춘계학술대회논문집
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    • pp.609-612
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    • 2008
  • The solid immersion lens (SIL) based near-field recording (NFR) system is considered as one of the high density optical data storage system. For the NFR servo system, tracking servo control is a difficult technology to maintain extremely small gap between SIL and media within one twentieth. This is because the track pitch is decreased for increasing the recording density. In this paper, we propose disturbance observer (DOB) and internal model principle (IMP) for disturbance rejection due to eccentricity of disk. The performance of tracking controller using DOB is increased by about 85%, 94%, 97% using Q filters that have bandwidths of 50Hz, 125Hz, 250Hz, respectively. Moreover, IMP based controller is effectively reduced the residual error.

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광 디스크 드라이브의 트랙 추종 서보 시스템을 위한 반복 제어 (Repetitive Control for the Track-Following Servo System of an Optical Disk Drive)

  • 문정호;이문노;정명진
    • 제어로봇시스템학회논문지
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    • 제5권1호
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    • pp.39-46
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    • 1999
  • Disturbances acting on the track-following servo system of an optical disk drive inherently contain significant periodic components that cause tracking errors of a periodic nature. Such disturbances can be effectively rejected by employing a repetitive controller, which must be implemented carefully in consideration of system stability. Plant uncertainty makes it difficult to design a repetitive controller that will improve tracking performance yet preserve system stability. In this paper, we examine the problem of designing a repetitive controller for an optical disk drive track-following servo system with uncertain plant coefficients. We propose a graphical design technique based on the frequency domain analysis of linear interval systems. This design method results in a repetitive controller that will maintain system stability against all admissible plant uncertainties. We show simulation and experimental results to verify the validity of the proposed design method.

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광디스크 드라이브의 개선된 트래킹 서보 시스템 (An Improved Tracking Servo System in Optical Disk Drives)

  • 이태규;정동슬;정정주
    • 전자공학회논문지SC
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    • 제44권4호통권316호
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    • pp.67-73
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    • 2007
  • 광디스크 드라이브에서 일반적으로 광 픽업은 포커싱과 트래킹 서보 시스템의 결합된 동력한 시스템을 갖는다. 이 결합된 동력학 시스템은 서로의 구동간섭에 의하여 광디스크 드라이브의 성능을 저하시킨다. 특히 디스크의 표면에 결함이 존재할 경우에는 포커싱과 트래킹 서보 시스템의 구동간섭으로 인해 시스템이 안정화하는데 많은 시간이 소요되고 결함구간이 길어질 경우 광학 렌즈가 추종하던 트랙을 이탈할 수 있다. 본 논문에서는 이 문제점을 극복하기 위하여, 트래킹 에러와 포커싱 에러의 관측을 기반으로 광디스크 드라이브의 새로운 제어 방법을 제안한다. 결함이 존재할 경우 결합된 동력학 시스템에 대한 보상을 통하여 시스템의 안정화 시간을 감소시킨다. 동일한 표면 결함에 대하여 제안된 제어 방법의 개선된 성능은 실험을 통하여 검증하였다.

선형 행렬 부등식을 이용한 광 디스크 드라이브의 트랙 추종 서보를 위한 반복 제어 (Repetitive Control for Track-Following Servo of an Optical Disk Drive Using Linear Matrix Inequalities)

  • 도태용;문정호
    • 제어로봇시스템학회논문지
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    • 제9권2호
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    • pp.117-123
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    • 2003
  • Rotational machines such as optical disk drives, hard disk drives, and so on are subject to periodic disturbances caused by their mechanical characteristics. In the meanwhile, it is well known that repetitive control rejects periodic disturbance effectively. This paper presents a practical application of repetitive control to the track-following servo of an optical disk drive. The repetitive control system is composed of two repetitive controllers which compensate for periodic disturbances generated by track geometry and eccentric rotation of disk and a feedback controller stabilizing the feedback loop. A robust stability for all plant uncertainties is proved using linear matrix inequalities (LMIs). In the controller design, a weighting function is introduced for the feedback controller to ensure a minimum loop gain and a sufficient phase margin. The repetitive controllers and the feedback controller are designed by solving an optimization problem which can consider the robust stability condition and the system performance. The developed repetitive control system is implemented in the digital control system with a 16-bit fixed-point digital signal processor (DSP). Through simulation and experiment. The feasibility of the proposed repetitive control system is verified.