Patent ID: 7088547
Filing Date: 2006-08-08
Classification: G11B

Abstract:
1. A disk drive comprising: (a) a disk comprising a plurality of data tracks, wherein each data track comprises a plurality of data sectors and a plurality of embedded servo sectors; (b) an actuator arm; (c) a head coupled to a distal end of the actuator arm; (d) a voice coil motor (VCM) for rotating the actuator arm about a pivot in order to actuate the head over the disk; and (e) control circuitry for generating a control signal applied to the VCM in response to a position error signal (PES) generated from reading the embedded servo sectors and a feed-forward compensation value that compensates for a repeatable runout (RRO) disturbance, the feed-forward compensation value generated for each servo sector in response to an RRO estimate Ŝ computed recursively for each servo sector according to:  wherein: