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Integrator Table Adjustment Method Before First Seek at Power-On Reset

IP.com Disclosure Number: IPCOM000118885D
Original Publication Date: 1997-Aug-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 4 page(s) / 92K

Publishing Venue

IBM

Related People

Uchiike, H: AUTHOR [+2]

Abstract

Disclosed is a method of adjustment of an integrator table in a Hard Disk Drive (HDD) which has read/write heads and disks and a Voice Coil Motor (VCM) actuator with flexible cable and Load/Unload function assembly.

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This is the abbreviated version, containing approximately 71% of the total text.

Integrator Table Adjustment Method Before First Seek at Power-On Reset

      Disclosed is a method of adjustment of an integrator table in a
Hard Disk Drive (HDD) which has read/write heads and disks and a
Voice Coil Motor (VCM) actuator with flexible cable and Load/Unload
function assembly.

      At the first stage of power-on sequence, the hard disk drive
must seek a certain target cylinder with a default initial integrator
value which is supposed to be a nominal tension value of the flexible
cable in HDD.  But, in the case of some stress condition which will
affect flexible cable tension, the nominal tension value is no longer
valid for the safe first seek.  In other words, the value is no
longer suitable for the first seek.  The value can be adjusted to a
desired value for a successful seek.  This adjustment can be done in
the first  actuator Loading from the ramp.  Once the head is
travelling on the disk,  the VCM output value during this loading
sequence shows a combined force  of the flexible tension and a
dragging force between the heads and the  disks because the loading
speed is a constant value.  Once the Digital  to Analog Converter
(DAC) value is given at cylinder=x (see Fig. 3), the  integrator
value can be adjusted in a following equation:
  Integ * Coef_neutral = I_VCM.....(*)
  Where
  Integ...integrator value at cylinder x
  Coef_neutral...servo control parameter for an integrator term
  I_VCM...DACOUT value at cylinder x

    ...