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. 29, 2009
Filed:
Jul. 22, 2008
Adrian E. Cerda, San Jose, CA (US);
Amir Hossein Chaghajerdi, San Jose, CA (US);
Bryan Scott Rowan, San Jose, CA (US);
Adrian E. Cerda, San Jose, CA (US);
Amir Hossein Chaghajerdi, San Jose, CA (US);
Bryan Scott Rowan, San Jose, CA (US);
Hitachi Global Storage Technologies Netherlands B.V., Amsterdam, NL;
Abstract
A magnetic recording disk drive has compensation for both mechanical disturbances and electrical disturbances. The disk drive's servo control system includes mechanical disturbance (MD) feedforward compensation and electrical disturbance (ED) feedforward compensation, of which either or both can be selectively enabled and disabled. In the operation of the disk drive, it is first determined that there is some disturbance that is causing track misregistration (TMR). The system is then tested to determine if the ED is greater than an ED threshold by measuring an averaged ED sensor signal. If ED is greater than the ED threshold, the system is then tested for a reduction in TMR by selectively turning MD compensation and ED compensation on and off, and determining changes in the position error signal (PES). Depending on the test results from the PES measurements, one or both of MD compensation and ED compensation is left on, and maintained on until the TMR falls below the predetermined threshold.