Browse Prior Art Database

Compensation Algorithm for Hysteretic Stationary External Force

IP.com Disclosure Number: IPCOM000102314D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Arai, K: AUTHOR [+2]

Abstract

Disclosed is an algorithm which compensates a hysteretic stationary external force in a Hard Disk Drive servo system. This function is achieved by software (microprocessor). This function is divided mainly into two portions. The first portions is the measurement of the external force, and the other one is the compensation for it. The feature of this function may be described as follows: 1) The integrated value of a position error signal is used for measurement. 2) This measurement is done in both seek directions at several tracks which are equally distributed within the whole track range. 3) Each measurement result is saved in two compensation tables: an inner seek compensation table and an outer seek compensation table. These two tables are used for each seek direction.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 53% of the total text.

Compensation Algorithm for Hysteretic Stationary External Force

       Disclosed is an algorithm which compensates a hysteretic
stationary external force in a Hard Disk Drive servo system. This
function is achieved by software (microprocessor). This function is
divided mainly into two portions.  The first portions is the
measurement of the external force, and the other one is the
compensation for it.  The feature of this function may be described
as follows:
   1) The integrated value of a position error signal is used for
measurement.
   2) This measurement is done in both seek directions at several
tracks which are equally distributed within the whole track range.
   3) Each measurement result is saved in two compensation tables:
an inner seek compensation table and an outer seek compensation
table.  These two tables are used for each seek direction.
   4) The compensation is done by adding the table value to the servo
control output.

      a) The measurement of the hysteretic stationary external force.
The stationary external force is caused, for example, by the tension
of a flex cable, an offset of digital/analog (D/A) converter, and so
on.  These values have a hysteretic characteristic; thus, they are
different in seek direction.  To measure these values, integration of
the position error signal value is used.  Equation (1) shows the
servo control law.  In this equation, the amount of the first term,
which is the integration of pes (position er...