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Browse Prior Art Database

Control of Spindle Motor Velocity in Load/Unload Hard Disk Drive

IP.com Disclosure Number: IPCOM000117136D
Original Publication Date: 1995-Dec-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Koyanagi, I: AUTHOR [+5]

Abstract

Disclosed is a method to improve the stability of a slider while it is merged or demerged with a disk, by control of spindle motor velocity. Furthermore, power consumption reduction and acoustic output reduction is expected as a result of lower spindle velocity at idle.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 89% of the total text.

Control of Spindle Motor Velocity in Load/Unload Hard Disk Drive

      Disclosed is a method to improve the stability of a slider
while it is merged or demerged with a disk, by control of spindle
motor velocity.  Furthermore, power consumption reduction and
acoustic output reduction is expected as a result of lower spindle
velocity at idle.

      The Hard Disk Drive (HDD) has a mechanism of ramp Load/Unload
(L/UL) for the purpose of removing the heads from the disk surface
when the HDD is at rest.  By parking the heads off of the disk, shock
resistance is improved and stiction between the head and disk is
eliminated.  The Figure shows an example of the L/UL mechanism.

      The negative air bearing slider has a vibration problem which
will cause damage to the disk and the slider itself during the L/UL
motion.  Spindle motor velocity control reduces the vibration of the
slider during the L/UL motion.  The effectiveness was this method was
observed means of a high speed camera.

Examples of methods for spindle motor velocity control are as
follows:
  1.  Vary the spindle motor velocity as any function.
  2.  Establish spindle motor velocity as a function of actuator
       position or velocity.
  3.  Construct a feedback loop for spindle motor control by VCM
       current.
  4.  Construct an open loop to start or stop the spindle motor by
time
       step.
  5.  Slow down the spindle motor gradually during the L/UL motion.

   ...