Browse Prior Art Database

High-Speed Head Actuator of Hard Disk Drives Using Fuzzy Logic Control

IP.com Disclosure Number: IPCOM000118099D
Original Publication Date: 1996-Sep-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 4 page(s) / 99K

Publishing Venue

IBM

Related People

Noda, K: AUTHOR [+4]

Abstract

Disclosed is a method to get a faster access-time head actuator using a fuzzy logic control for future Hard Disk Drives (HDDs) with high track density around 15K-Track Per Inch (TPI) or higher, by which can be compensated to an appropriate function between a Voice Coil Motor (VCM) drive current and head actuator moving speed. In another words, this method can provide an appropriate velocity curve for the head actuator compensating inhibitors of the speed such as friction and hesteresis of the actuator pivot shaft.

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High-Speed Head Actuator of Hard Disk Drives Using Fuzzy Logic Control

      Disclosed is a method to get a faster access-time head actuator
using a fuzzy logic control for future Hard Disk Drives (HDDs) with
high track density around 15K-Track Per Inch (TPI) or higher, by
which can be compensated to an appropriate function between a Voice
Coil Motor (VCM) drive current and head actuator moving speed.  In
another words, this method can provide an appropriate velocity curve
for the head actuator compensating inhibitors of the speed such as
friction and hesteresis of the actuator pivot shaft.

      Fig. 1 shows a block diagram of a head actuator control system
with a fuzzy logic controller as one of the fuzzy logic assistance
applications, which are currently applied to various electronic
products.  A data/servo head reads servo information written by a
servo track writer.

      The data comes to the head velocity estimator through arm
electronics.  Head velocity information goes to the state controller,
and finally to the servo actuator via the VCM current driver for
head-seeking and head-following operations.  At present, for head
movements that involve crossing several tracks, the speed of the head
movement is controlled by both the head velocity estimator and the
state controller according to the head position error; that is, a
speed diagram is managed by the head velocity estimator and the state
controller according to the numbers of tracks crossed.  The head is
accelerated at a certain rate from start-up until it is close to the
desired track, and then decelerated until it reaches the track.  For
single-track movement, both the head velocity estimator and the state
controller operate in the same manner as for multiple-track
movement.  However, a longer settling time is required for
single-track movement, because friction and hesteresis appear...