The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 22, 2002
Filed:
Apr. 19, 2000
Travis E. Ell, Oklahoma City, OK (US);
Seagate Technology LLC, Scotts Valley, CA (US);
Abstract
Apparatus and method for improved servo control in a disc drive. The disc drive includes a rotatable disc, a moveable actuator which supports a head adjacent the disc, and a stationary active magnetic bearing assembly which uses bearing coils to levitate the actuator. An active magnetic bearing control circuit applies currents to the bearing coils, and a servo control circuit applies current to an actuator motor to position the head with respect to the disc. The active magnetic bearing control circuit outputs a disturbance signal when a disturbance affects the relative positioning of the actuator and the bearing assembly, and this disturbance signal is fed forward into the servo control circuit. Conversely, the servo control circuit provides a seek expectancy signal to the bearing control circuit to enable the bearing control circuit to compensate for torque forces applied by the actuator motor.