TrueTrack/sup TM/ servo technology for high TPI disk drives

Sri-Jayantha, Sri M.; Dang, Hien; Sharma, A.; Yoneda, I.; Kitazaki, N.; Yamamoto, Shigehiko

doi:10.1109/20.917634

Cited by 36 publications

(23 citation statements)

References 2 publications

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“…It consists of two parts: 1) a first-order lag section with a crossover frequency of , whose integral state is reset to zero whenever the input goes to zero and 2) a lead section to balance the gain roll-off and certain phase loss due to reset first-order lag mode. The reset controller is described by the following impulsive differential equations: (6) where…”

Section: A Reset Controllermentioning

confidence: 99%

“…The two methods have been proven to be equivalent to the internal-model principle at the disturbance frequencies [4]. The same technology was used to compensate for NRRO disturbances at low frequencies [5], [6], and in the very high-frequency range [7], [9]. A resonant filter was proposed to suppress NRRO with a phase compensator [8], where parameters were carefully selected to ensure stability and efficiency.…”

Section: Introductionmentioning

confidence: 99%

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Reset Control for Midfrequency Narrowband Disturbance Rejection With an Application in Hard Disk Drives

Guo

Wang

2011

IEEE Trans. Contr. Syst. Technol.

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A reset disturbance compensation scheme is developed to reject midfrequency narrowband disturbances, with an application to the hard disk drives (HDDs). Generally, disturbance at the midfrequency band is not effective to reject through the feedback control based on the internal-model principle or high gain control due to phase stability. This paper investigates a reset control scheme and its favorable approximate frequency response using the describing function. The reset control makes its gain-phase frequency response break through the fundamental Bode's constraint of linear time-invariant system and provides a maximal phase lead at desired frequencies without affecting gain's characteristic. With additional phase lead, the issue of phase stability can be solved. A reset midfrequency narrowband compensator is designed by incorporating the reset controller and a narrowband filter. The implementation on a real HDD servo system shows the removal of midfrequency disturbance due to disk vibration is improved by 50% compared with the linear control scheme, resulting in a track misregistration (TMR) reduction of 32%.Index Terms-Bode's gain-phase relationship, disturbance rejection, midfrequency, reset control, hard disk drive (HDD).

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Section: A Reset Controllermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Reset Control for Midfrequency Narrowband Disturbance Rejection With an Application in Hard Disk Drives

Guo

Wang

2011

IEEE Trans. Contr. Syst. Technol.

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“…These kinds of narrowband disturbances near the frequency of a few kHz are critical to improving the positioning accuracy of the read/write head. Conventionally, the narrowband disturbances are rejected with a peak filter [7], [8], [9]. Recently, blending control technique is applied to simultaneously reject two or three narrow-band disturbances at a few kHz [10].…”

Section: Introductionmentioning

confidence: 99%

Analysis of actuator in-phase property in terms of control performance and integrated plant/controller design using a novel model matching method

Gao

Xie

2012

2012 12th International Conference on Control Automation Robotics &Amp; Vision (ICARCV)

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This paper is concerned with resonance in-phase property of a VCM (voice coil motor) plant system in the sense of control performance in HDDs (hard disk drives). Its relationships with the optimal performance level γopt, the stability margins and the disturbance rejection capability are revealed. It is found that the main resonance being in-phase is particularly beneficial to rejection of the narrow-band disturbances with frequencies near plant resonances. In order to meet the requirement on the inphase property, a partial model matching method is proposed. This model matching problem is solved by an H∞ method using an linear matrix inequality approach. The partial model matching method is then applied to the VCM plant system. We especially take into account the in-phase case for the purpose to improve the system ability to attenuate high frequency disturbance. For the new system designed using the proposed model matching method, a feedback controller and a group peak filter are designed to attenuate the disturbance near the plant resonances. The advantages of the in-phase resonances are illustrated, when compared with the original plant.

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“…In this case, d(t) is mainly caused by the RRO after the track seeking control. We compared the proposed method with the conventional one (7) , in which the p(k) and q(k) were not updated during the track-seeking control, and were restarted after the track-seeking control. Figure 18 shows the output signal of the enhanced AFCs, where the dashed-line is that for the conventional enhanced AFC and the solid line is that for the proposed enhanced AFC.…”

Section: Performance Evaluationmentioning

confidence: 99%

“…However, the enhanced AFC cannot improve the transient responses in a track-seeking control because the transient characteristics of the enhanced AFC may worsen the positioning error after the track-seeking control. Therefore, the calculation of enhanced AFC should stop during the track-seeking control, and restart after the track-seeking control (7) . As a result, the control system cannot compensate for RRO and the disk flutter induced positioning errors immediately after track-seeking control.…”

Section: Introductionmentioning

confidence: 99%

Improvement of Convergence for Adaptive Feed-Forward Cancellation Using Variable Gains in a Head Positioning System of Hard Disk Drives

Yabui¹,

Kajiwara

Nakamura³

et al. 2013

JAMDSM

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We present an enhanced adaptive feed-forward cancellation (AFC) with variable gains to be used in the head positioning control system of a hard disk drive (HDD). The variable gains can help to improve the convergence characteristic of the enhanced AFC after the track seeking control. Therefore, the proposed enhanced AFC can improve the transient response of the head positioning after the track seeking control. The track seeking simulation results from HDDs showed that the proposed control method compensated for the disturbances caused by the repeatable run-out (RRO) and airflowinduced vibration immediately after the track seeking control.

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TrueTrack/sup TM/ servo technology for high TPI disk drives

Cited by 36 publications

References 2 publications

Reset Control for Midfrequency Narrowband Disturbance Rejection With an Application in Hard Disk Drives

Reset Control for Midfrequency Narrowband Disturbance Rejection With an Application in Hard Disk Drives

Analysis of actuator in-phase property in terms of control performance and integrated plant/controller design using a novel model matching method

Improvement of Convergence for Adaptive Feed-Forward Cancellation Using Variable Gains in a Head Positioning System of Hard Disk Drives

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