Nonrepeatable Run-out Rejection Using Online Iterative Control for High-Density Data Storage

Pang, Chee Khiang; Wong, Wai Ee; Guo, Guoxiao; Chen, Ben M.; Lee, Tong Heng

doi:10.1109/tmag.2006.890242

Cited by 11 publications

(9 citation statements)

References 16 publications

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“…In the OBFSOF design, assume that there is no parametric uncertainty in the VCM model while the outer track LFHV model (1), which is regarded as the accurate LFHV model, is estimated with certain parametric variations: ζ c =0 .025,ω c = 2π ×1170 rad/s, k c =1.36. This set of parameters is derived when modeling the inner track LFHV model at the same rotation speed and fly-height by experiment.…”

Section: P Erformance Evaluation B Y Simulationmentioning

confidence: 99%

“…Furthermore, there is no way to extend this method for infinitely many frequency components' suppression in NRRO. It is also reported in [1] that online iterative control algorithm by minimizing the square of the H 2 -norm of the transfer function from NRRO disturbance to the true PES can achieve an improvement of 22% in 3σ NRRO. Obviously, research space was left here to address better NRRO suppression methodologies.…”

Section: Introductionmentioning

confidence: 97%

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Frequency-shaping optimal compensation of low fly-height vibration in high density HDD servo systems

Huang

Venkataramanan

et al. 2011

2011 9th IEEE International Conference on Control and Automation (ICCA)

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In this work, a novel robust observer-based frequency-shaping optimal feedback (OBFSOF) controller is designed to actively compensate low fly height vibration (LFHV) in hard disk drive (HDD) servo systems. LFHV is a new vibration source due to continuous contact of the read/write head with the media in high density HDDs. The main characteristics of LFHV are the time-varying phase and magnitude, and the wideband frequency spectrum. Differing from many existing non-repeatable runout (NRRO) compensation schemes that focus on a finite number of dominant frequency components, the proposed OBFSOF scheme can suppress infinitely many frequency components concurrently, meanwhile keep robust stability to model uncertainties and disturbances. The effectiveness of the proposed OBFSOF scheme is verified by theoretical analysis and numerical simulations on a real HDD model. By replacing the linear part of PTOS controller with the proposed OBFSOF controller, the maximal LFHV magnitude is decreased by 62.8% comparing with the PTOS controller during the track following stage.

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Section: P Erformance Evaluation B Y Simulationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Frequency-shaping optimal compensation of low fly-height vibration in high density HDD servo systems

Huang

Venkataramanan

et al. 2011

2011 9th IEEE International Conference on Control and Automation (ICCA)

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“…Interested readers are kindly referred to Pang et al (2007b) for an example of such an online RRO estimator.…”

Section: Remarkmentioning

confidence: 99%

Improved disturbance rejection with online adaptive pole-zero compensation on a Φ-shaped PZT active suspension

et al. 2009

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In feedback control systems, the anti-resonant zeros cannot be arbitrarily placed, hence degrading tracking performance as well as input disturbance and noise rejection capabilities due to reduced gain at the frequencies of the zeros. In this paper, an online adaptive inverse control with saturation (OAICS) algorithm is proposed for compensating the minimum phase resonant poles and antiresonant zeros of a PZT active suspension using measured position error signal. Experimental results on a U-shaped PZT active suspension using laser Doppler vibrometer (LDV) shows the proposed OAICS is effective in cancelling the first two dominant minimum phase pole-zero pairs to achieve high servo bandwidth and low sensitivity servo system with small overshoot during set-point tracking.

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“…In the HDD industry, the areal density is continuously growing and targeting to achieve more than 1 T b/in 2 through use of perpendicular recording technologies [1]. At such high track density, the fly-height between the slider and the disk has to be lowered, even to the point of permanent contact with the media.…”

Section: Introductionmentioning

confidence: 99%

Adaptive compensation of contact-induced vibration in high density HDD servo systems using peak filter method

Huang

Venkataramanan

2012

2012 IEEE International Symposium on Industrial Electronics

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In this paper, a phase lead peak filter (PLPF) design method is adopted to adaptively compensate contact-induced vibration (CIV) in high density hard disk drive (HDD) servo systems. Such kind of vibration is a new vibration source due to continuous contact of the read/write head with the media in HDDs, and its main characteristics are the time-varying phase and magnitude and the narrow-band frequency spectrum. In the PLPF based controller, a baseline feedback controller is first employed to stabilize the servo loop and add-on peak filters are then connected in parallel with the baseline controller to further suppress the specific vibrations. Meanwhile, a frequency identification algorithm is plugged-in simultaneously to meet the variation of central frequency of CIV. The proposed CIV compensation scheme has simple control structure, is capable of dealing with multiple vibration modes that may not be within the bandwidth of open-loop transfer function, and possesses remarkable robustness to CIV change. In the end, the performance of the proposed method in CIV compensation is validated by simulation and experiment.

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Nonrepeatable Run-out Rejection Using Online Iterative Control for High-Density Data Storage

Cited by 11 publications

References 16 publications

Frequency-shaping optimal compensation of low fly-height vibration in high density HDD servo systems

Frequency-shaping optimal compensation of low fly-height vibration in high density HDD servo systems

Improved disturbance rejection with online adaptive pole-zero compensation on a Φ-shaped PZT active suspension

Adaptive compensation of contact-induced vibration in high density HDD servo systems using peak filter method

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