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:
May. 20, 2008
Filed:
Mar. 17, 2006
Tetsuo Semba, San Jose, CA (US);
Matthew T. White, Mountain View, CA (US);
Kevin I. Tzou, San Jose, CA (US);
Tetsuo Semba, San Jose, CA (US);
Matthew T. White, Mountain View, CA (US);
Kevin I. Tzou, San Jose, CA (US);
Hitachi Global Storage Technologies Netherlands B.V., Amsterdam, NL;
Abstract
A disk drive has multiple feedforward controllers for handling external disturbances, such as rotational vibration (RV), that have different external disturbance frequency spectra. Each feedforward controller is designed to be optimal for a canceling a specific associated RV spectrum. The actual RV spectrum acting on the disk drive is determined and the proper feedforward controller is then selected and used to generate a compensation signal for canceling the RV. Each feedforward controller may be tested when the disk drive is experiencing the RV, and the resulting compensation signal and PES measured. The feedforward controller that produces the best external disturbance cancellation is then selected as the feedforward controller. A signal from a RV sensor may be used to detect the peak frequency of the actual RV spectrum. This detected peak frequency is then matched to a peak frequency in a plurality of peak frequencies in a lookup table, and the feedforward controller associated with the matching peak frequency is selected as the feedforward controller.