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Adaptive Integrator Calibration

IP.com Disclosure Number: IPCOM000119146D
Original Publication Date: 1997-Dec-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 4 page(s) / 63K

Publishing Venue

IBM

Related People

Yoneda, I: AUTHOR [+3]

Abstract

In order to cancel the bias force of a flex cable tension, integral feedback parameter (integrator) is used for the Voice Coil Motor (VCM) servo control system. This bias force changes by temperature, rested time, and the position of the head. To achieve smooth and fast seek/settling operation, the system needs to know the values of this bias force as the function of head position.

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Adaptive Integrator Calibration

      In order to cancel the bias force of a flex cable tension,
integral feedback parameter (integrator) is used for the Voice Coil
Motor (VCM) servo control system.  This bias force changes by
temperature, rested time, and the position of the head.  To achieve
smooth and fast seek/settling operation, the system needs to know the
values of this bias force as the function of head position.

      As for a conventional Hard Disk Drive (HDD), these values are
given by an initial 'integrator table', which is located on Read Only
Memory (ROM) code.  When the HDD is powered on, the head moves onto
the data tracks (initial seek) by the initial 'integrator table'.
Then, the HDD calibrates the 'integrator table' by measuring the bias
force acting on every head's position (integrator calibration).  Fig.
1 shows  the process of the updating 'integrator table' and Fig. 2
shows the format of the integrator table.

      During the process of initial seek and integrator calibration,
seek is done with initial 'integrator table'.  The values in this
table are given as immediate values; therefore, when actual bias
force is different with this table by the condition, the seek
performance becomes  degraded during the process.  Fig. 3 shows the
current integrator calibration method.

      To avoid the degradation of seek performance, an adaptive
integrator calibration method is useful.  This method uses only two
integrator values(I(X1)...