Browse Prior Art Database

Adaptive Velocity Profile for Direct Access Storage Devices

IP.com Disclosure Number: IPCOM000106345D
Original Publication Date: 1993-Oct-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 2 page(s) / 58K

Publishing Venue

IBM

Related People

Purkett, JC: AUTHOR [+3]

Abstract

A method for adjusting the Seek velocity profile to correct for variations in disk drive electrical and mechanical parameters and operating conditions is disclosed. The adjustments are based on periodic measurements of actuator acceleration while applying full saturated coil current.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 62% of the total text.

Adaptive Velocity Profile for Direct Access Storage Devices

      A method for adjusting the Seek velocity profile to correct for
variations in disk drive electrical and mechanical parameters and
operating conditions is disclosed.  The adjustments are based on
periodic measurements of actuator acceleration while applying full
saturated coil current.

      During the deceleration phase of an actuator movement, coil
current is applied to make the actuator velocity follow a velocity
profile chosen to give good performance under a selected set of
electrical, mechanical, and environmental conditions.  This invention
adjusts the velocity profile function to correct for variations in
the operating conditions.  The adjustments are based on periodic
measurements of actuator acceleration while applying full saturated
coil current.

      The profile velocity is a monotonically decreasing function of
distance from the target location, and can be expressed as

          PVEL = f (DIST_TO_GO).

      One implementation of this method involves multiplying the
profile velocity by an adjustment factor, PROFILE_ADJUST, i.e.,

         PVEL = PROFILE_ADJUST * f (DIST_TO_GO).

      The adjustment factor is determined by comparing the nominal
acceleration time, ACCEL_TIME_NOM, with the measured acceleration
time, ACCEL_TIME_MEAS, as follows:

       PROFILE_ADJUST= 1 + (ACCEL_TIME_NOM - ACCEL_TIME_MEAS) *
ADJ_GAIN

      The values of ACCEL_TIME...