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:
Mar. 03, 2015
Filed:
Dec. 18, 2013
Western Digital Technologies, Inc., Irvine, CA (US);
Qing Wei Jia, Singapore, SG;
Hui Li, Singapore, SG;
Shuyu Cao, Singapore, SG;
Guoxiao Guo, Irvine, CA (US);
Jie Yu, Irvine, CA (US);
Western Digital Technologies, Inc., Irvine, CA (US);
Abstract
A disk drive is disclosed comprising a servo control system configured to control an actuator for actuating a head over a disk. Servo sectors are sampled at a servo sample frequency fto generate a position error signal PES(k) that is filtered with a compensator to generate a first control signal u(k). A first discrete-time sinusoid comprising a sinusoid frequency of f+Δf is added to the first control signal u(k) to generate a second control signal u(k). The second control signal u(k) is applied to the actuator, and a frequency response of the actuator is determined at the frequency |Δf|. The frequency response of the actuator is determined at the frequency f+Δf based at least in part on the frequency response of the actuator at the frequency |Δf| and a measured signal of the servo control system when applying the second control signal u(k) to the actuator.