Patent Number: 7,088,547

Title: Disk drive recursively estimating repeatable runout

Abstract: A disk drive is disclosed comprising control circuitry for generating a control signal applied to a VCM in response to a position error signal (PES) generated from reading embedded servo sectors and a feed-forward compensation value that compensates for a repeatable runout (RRO) disturbance. The feed-forward compensation value is generated for each servo sector in response to an RRO estimate S computed recursively for each servo sector according to: .lamda..function..times..times..times. ##EQU00001## wherein: .lamda. is a predetermined fraction; PES.sub.i is the position error signal generated for a selected servo sector during an ith revolution of the disk; and n represents a number of disk revolutions.

Inventors: Wang; Zhi (San Jose, CA), Chen; Jenghung (Cupertino, CA)

Assignee: Western Digital Technologies, Inc.

International Classification: G11B 5/596 (20060101)

Expiration Date: 8/08/02018