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. 21, 2010
Filed:
Nov. 14, 2007
Kenichi Kuramoto, Kanagawa, JP;
Shinya Sakamoto, Kanagawa, JP;
Nobuhiko Wasa, Kanagawa, JP;
Sayaka Nojiri, Kanagawa, JP;
Hidefumi Tominaga, Tokyo, JP;
Kenichi Kuramoto, Kanagawa, JP;
Shinya Sakamoto, Kanagawa, JP;
Nobuhiko Wasa, Kanagawa, JP;
Sayaka Nojiri, Kanagawa, JP;
Hidefumi Tominaga, Tokyo, JP;
Hitachi Global Storage Technologies Netherlands B.V., Amsterdam, NL;
Abstract
Embodiments of the present invention help to prevent destabilization in voice coil motor (VCM) velocity control. According to one embodiment, a hard disk controller/multiprocessing unit (HDC/MPU) calibrates a correction operational coefficient of a detected back electromotive force (EMF) voltage before unloading. The calibration is carried out in a state that an actuator is pivoting. The HDC/MPU calibrates the correction coefficient according to a motion equation of the actuator using VCM current applied to a VCM and a detected value of a back EMF voltage detection circuit.