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. 18, 2000
Filed:
Dec. 18, 1997
Michael Charles Stich, Rochester, MN (US);
Western Digital Corporation, Irvine, CA (US);
Abstract
A method to adaptively reduce error introduced by the coil current rise time. A disk drive with a moving arm actuator driven by a voice coil motor is controlled by periodically modeling the coil current rise time. An adjustment to a commanded current value is based on the model of the coil current rise time and a magnitude change in commanded value. The model of the coil current is based on a linear approximation to the exponential rise time of the coil current. The commanded value is adjusted to compensate for the error in the control effort. For small commanded value differences no compensation is made for the coil current rise time. For medium command value differences a slope intercept equation is used to compute the compensated commanded value. For large commanded value differences half of an estimate of the maximum largest physical current change is used. The adjustment is made by the estimator in a position error signal feedback control system. The voice coil rise time adjustment is made to a voice coil motor control signal. The actuator velocity estimate is also improved with the model of the coil current rise time.