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Hard Disk Acutator Control Method with 2-Delay Control Theory

IP.com Disclosure Number: IPCOM000114369D
Original Publication Date: 1994-Dec-01
Included in the Prior Art Database: 2005-Mar-28
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Ono, H: AUTHOR

Abstract

Disclosed is a closed loop digital control system for head positioning in hard disk drive which employs a discrete Position Error Signal (PES) system to get the current position and a DC motor, for instance, voice coil (VCM) to drive the actuator.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 54% of the total text.

Hard Disk Acutator Control Method with 2-Delay Control Theory

      Disclosed is a closed loop digital control system for head
positioning in hard disk drive which employs a discrete Position
Error Signal (PES) system to get the current position and a DC motor,
for instance, voice coil (VCM) to drive the actuator.

      The block diagram of the control system is shown in Fig. 1.
Head position is sensed as the PES through analog to digital
converter(s).  Then a state estimator estimates the current states
such as head position, velocity, and acceleration.  A controller
generates the DC motor drive signal from the estimated states and
from the previous drive signal.  The drive signal is still digital.
A digital to analog converter and a DC current power amplifier are
applied to drive the DC motor.

      The state estimator generates the estimated states once with
its internal states and with two samples of PES information.  This is
called two delays estimator which is known as a robust estimator
algorithm.  The number of samples and delays are expandable, then we
can call the system multiple delays state estimator.

      Two types of controllers - linear and nonlinear - are employed
to the system.  The nonlinear controller suppress the effect of
parasitic elements which are not considered in the linear model of
the actuator.  Then, the linear controller works better than usual.

      The estimator need nothing about the drive signal information
...