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:
Aug. 18, 2009
Filed:
Feb. 22, 2007
Takenori Atsumi, Ibaraki, JP;
Atsushi Okuyama, Kanagawa, JP;
Takenori Atsumi, Ibaraki, JP;
Atsushi Okuyama, Kanagawa, JP;
Hitachi Global Storage Technologies Netherlands B.V., Amsterdam, NL;
Abstract
Embodiments in accordance with the present invention relate to a positioning control system of a magnetic disk drive. Even if there is no phase correlation in a specific vibration component before and after a seek operation of a magnetic head, a resonance filter in accordance with an embodiment of the present invention follows the vibration at the frequency at high speed. A frequency showing a periodic disturbance is selected as a target frequency Ft[Hz]. A resonance filter showing a peak gain at a frequency Ft is designed. For an input to the resonance filter, a time-variable gain K(t) is used that varies depending on the time lapsed after the completion of a seek operation. This time-variable gain K(t) takes a value larger than 1 when the resonance filter starts operating, and after the lapse of a fixed length of time, the value becomes 1 by degrees.