Seagate Technology Incorporated

Maxtor Corporation

Dwight Russell Kinney

Kenneth A Haapala

Reed David Hanson

XingHui Huang

Yu Sun

David Jeppson

Systems and methods for compensating for hysteresis in a disc drive are described. In one embodiment, a method may use an inverse hysteresis model to linearize effects of hysteresis of a microactuator in the disc drive. The hysteresis model may be a Coleman-Hodgdon hysteresis model. The hysteresis of the microactuator may be characterized, and the inverse hysteresis model may be based at least in part on the characterization. The inverse hysteresis model may be used to implement a digital filter. The digital filter may be employed in series with the microactuator to linearize the effects of hysteresis.

Hysteresis compensation in a disc drive

A disk drive includes an actuator assembly and a controller. The actuator assembly generally includes an actuator having a velocity and a voice coil motor that has a detectable back electromotive force (BEMF). The actuator assembly is configured to position a read/write head. The controller is coupled to the actuator assembly and is configured to detect a catastrophic event occurring within the disk drive. In response to the detection of the catastrophic event, the controller activates a closed loop controlled slowing of the velocity using the detected BEMF as a control parameter.

BEMF closed loop control of disk drive actuator during a catastrophic event

Methods, servo controllers, disk drives, and computer program products are provided for adapting compensation for repeatable runout (RRO) of sectors of a disk in a disk drive. RRO of a plurality of sectors of the disk is compensated. A status of whether the RRO compensation has been adapted is tracked for at least some of the sectors of the disk, and corresponding records are formed based on the statuses. The RRO compensation of the tracked sectors is selectively adapted or not adapted based on the records.

Growing community of inventors

Longmont, CO, United States of America

Dwight Russell Kinney