Browse Prior Art Database

Velocity Control Track Access Method for Optical Drive

IP.com Disclosure Number: IPCOM000104574D
Original Publication Date: 1993-May-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 4 page(s) / 70K

Publishing Venue

IBM

Related People

Kagami, N: AUTHOR

Abstract

Disclosed is a method for an optical disk drive to control the optical pickup head Voice Coil Motor (VCM) to obtain the reliable and faster track access by using additional state feedback which corresponds to minimizing the integral of the velocity error.

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This is the abbreviated version, containing approximately 56% of the total text.

Velocity Control Track Access Method for Optical Drive

      Disclosed is a method for an optical disk drive to control the
optical pickup head Voice Coil Motor (VCM) to obtain the reliable and
faster track access by using additional state feedback which
corresponds to minimizing the integral of the velocity error.

      Generally speaking, micro processor digital controlled track
access method uses velocity feedback control method.  This method
usually has the velocity error during constant deceleration period.
In order to minimize the velocity error, the disclosed method uses
additional state feedback which corresponds to minimizing the
integral of the velocity error.  The method is widely applicable to
all Voice Coil Motor (VCM) actuator pickup system whose current or
voltage is periodically controlled by Micro Processor during track
access.

      The method will be best understood with reference to the flow
chart (Fig. 1) which shows a digital track access control flow in
general method.  The optical pickup head VCM control current or
voltage is calculated from the feedback of the deference between
profile velocity and the head moving velocity.  If the profile
velocity is calculated with constant deceleration in order to get
faster access, there will be the velocity error during constant
deceleration period.  Compared with the general method, the disclosed
method uses additional state feedback shown in Fig. 2.

      Step (1) is measuring the opti...