Multirate state-space digital controller for sector servo systems

Chiang, W.-W.

doi:10.1109/cdc.1990.203951

Cited by 71 publications

(11 citation statements)

References 3 publications

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“…Moreover, its sampling frequency is limited since increasing the number of embedded position data results in losing the available data capacity. Under such conditions, utilization of multi-rate feedback control for HDDs was proposed (Chiang 1990), and since then many authors have discussed this issue for track following control (Hara and Tomizuka 1998;Takiguchi et al 2002;Ishikawa 2000;Semba 2001;Ohno et al 2001) and it is successfully used in industry. However, as (Ishikawa and Tomizuka 1998) pointed out, the compensation of nonlinearity and uncertainty remains a key concern for further performance enhancement.…”

Section: Introductionmentioning

confidence: 99%

A pivot nonlinearity compensation by use of variable structure estimator for hard disk drives

Ohno

Horowitz

2005

Microsyst Technol

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This paper discusses robust seeking control of hard disk drives by the use of a variable structure multirate estimator (VSME). Compensation of pivot nonlinearity is one concern in the design of the seeking control, systems. Pivot nonlinearity is subject to uncertainties, and is difficult to deal with by a linear controller. The VSME estimates a class of uncertain disturbances and nonlinearities and yields compensation current through the linear feedback gain, which reduces the residual vibration and error during settling. Several experiments were carried out on several drives including a 3.5 in. 7,200 rpm drive. These experiments confirmed that the off-track probability after settling, which is defined by the number of seek failures over all trials, is much reduced to less than 1% when the drive is operated under a special temperature condition that increases pivot nonlinearity while the corresponding performance of a conventional linear controller is 12%. The seek failure is defined as the case when the position cannot be maintained within ±2.5% of a track pitch for a certain duration after track seeking mode.

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Section: Introductionmentioning

confidence: 99%

A pivot nonlinearity compensation by use of variable structure estimator for hard disk drives

Ohno

Horowitz

2005

Microsyst Technol

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“…In [3,4], multirate redesign methods have been proposed. The control outputs in the redesigned system are calculated based only on the state estimates at sampling instants, and thus the computation burden is greatly eased.…”

Section: Introductionmentioning

confidence: 99%

“…With the fast development of micro-electronics and digital signal processing techniques, control system designers have long been resorting to multirate control techniques to deal with the problem of limited sampling frequency [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. It has been shown that multirate sampling technique may greatly improve the system performance such as improving the transient system behavior, improving the system stability margins by relocating the plant zeros and enhancing the disturbance rejection property.…”

Section: Introductionmentioning

confidence: 99%

A new method of multirate state feedback control with application to an HDD servo system

Qing¹

2008

Mechatronics

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“…In order to maximize the efficiency of the use of the disk surface for user data, a technique to increase the servo bandwidth solely using a servo control method is desirable. Therefore the use of a multi-rate sampling technique has been proposed [1]. However, product implementations are rare since the effectiveness is limited and the servo design method is complicated.…”

Section: Introductionmentioning

confidence: 99%

A design method of a multi-rate servo controller using H/sub ∞/

Semba

2000

IEEE Trans. Magn.

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A method of designing a multi-rate servo controller for a HDD that operates at a higher sampling frequency than that of the position error signal (PES) is proposed. Multi-rate sampling has an advantage for increasing the track density of a HDD without increasing the overhead of the servo information on the disk. A plant model for a design with a higher sampling rate is obtained by adding a zero-interpolator at the output of the position error signal. The controller is calculated by the H method to suppress the noise at the PES sampling frequency that is created by the use of multi-rate sampling. The servo bandwidth and margins of the method are studied for 2.5 and 3.5 HDD's, and for a HDD with a dual-stage actuator. The multi-rate sampling is especailly effective for the dual-stage actuator because the MEMS actuator's transfer function is very clean.

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Multirate state-space digital controller for sector servo systems

Cited by 71 publications

References 3 publications

A pivot nonlinearity compensation by use of variable structure estimator for hard disk drives

A pivot nonlinearity compensation by use of variable structure estimator for hard disk drives

A new method of multirate state feedback control with application to an HDD servo system

A design method of a multi-rate servo controller using H/sub ∞/

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