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:
Sep. 02, 2003
Filed:
Mar. 31, 2000
Edgar D. Sheh, Cupertino, CA (US);
Thao P. Trieu, Redwood City, CA (US);
Ara W. Nazarian, Tustin, CA (US);
Richard K. Wong, San Jose, CA (US);
Western Digital Technologies, Inc., Lake Forest, CA (US);
Abstract
Disclosed is a disk drive having a plant with a moveable transducer and a servo controller that more precisely controls the transducer during short to medium seeks by producing a multi-rate feed-forward command effort signal. The servo controller includes a reference position generator that provides a reference position signal that varies as a function of time along a shaped position profile for moving the transducer from a start position to a target position in a smoothly controlled fashion, a feed-forward control path that receives the reference position signal and applies a feed-forward command effort signal at a feed-forward rate that is greater than the servo sampling rate to move the actuator more closely along the shaped position profile between servo samples; and a feedback control path that receives the reference position signal and the indicated position signal and applies a feedback command effort signal at the servo sampling rate based on a difference between the reference position signal and the indicated position signal to make minor corrections to error remaining after application of prior feed-forward command effort signals.