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Dead-Beat Servo Control by Interleaved Sampling for Hard Disk Drive

IP.com Disclosure Number: IPCOM000100700D
Original Publication Date: 1990-May-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 3 page(s) / 91K

Publishing Venue

IBM

Related People

Arai, K: AUTHOR [+4]

Abstract

This method aims at gaining the following advantages for dead-beat servo control of Hard Disk Drive (HDD) with interleaved sampling. (Interleaved sampling means that one of two samples are not subject to process, or one of three, etc.): (1) CPU processing time reduction for servo control (2) Decreased sensitivity for mechanical resonances (3) Easy control of servo bandwidth

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Dead-Beat Servo Control by Interleaved Sampling for Hard Disk Drive

       This method aims at gaining the following advantages for
dead-beat servo control of Hard Disk Drive (HDD) with interleaved
sampling.  (Interleaved sampling means that one of two samples are
not subject to process, or one of three, etc.):
      (1)  CPU processing time reduction for servo control
      (2)  Decreased sensitivity for mechanical resonances
      (3)  Easy control of servo bandwidth

      Background: A digitally controlled dead-beat type servo has a
bandwidth up to about the Nyquist frequency.  With increased sample
rate, the bandwidth increases accordingly and the servo system
becomes more sensitive to mechanical resonances which resides from
around 1KHz to upper region.  The low cost HDD, on the other hand,
usually uses one CPU for processing all the internal functions of
HDD, such as servo, interface, etc.  For such HDD, the increased rate
of sampling means the increased occupancy of CPU power by servo
processing.  The recent trend for more sectors per track (high
capacity drives) increases the sample rate for sector servo system.

      Method: In order to solve the above two difficulties, that is,
(1) sensitivity to mechanical resonances, and (2) CPU power reduction
by increased servo processing, the method to use only interleaved
sample information leads us to the solution.  For the sector servo
system where the position information is located...