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:
Feb. 11, 2014
Filed:
Mar. 28, 2012
Brandon P. Smith, San Jose, CA (US);
Wenli Yang, Los Angeles, CA (US);
Brandon P. Smith, San Jose, CA (US);
Wenli Yang, Los Angeles, CA (US);
Western Digital Technologies, Inc., Irvine, CA (US);
Abstract
A disk drive is disclosed comprising a head actuated over a disk, a spindle motor operable to rotate the disk, and control circuitry comprising a speed control loop operable to control a rotation speed of the disk. A rotation speed of the disk is measured, and a speed error is generated in response to the measured rotation speed. The speed error is processed with a compensator to generate a control signal, a disturbance is injected into the control signal to generate a modified control signal, and the modified control signal is applied to the spindle motor. An amplitude of the disturbance is ramped, and after ramping the amplitude of the disturbance, an open-loop gain of the speed control loop is estimated at a frequency of the disturbance, and at least one parameter of the compensator is adjusted in response to the estimated open-loop gain.