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:
Dec. 01, 1998
Filed:
Dec. 20, 1996
Otis L Funches, Oklahoma City, OK (US);
Seagate Technology, Inc., Scotts Valley, CA (US);
Abstract
Apparatus and method for improved positional control in a disc drive servo loop, wherein the actual velocity of rotary actuator is sensed from the motion-induced back-emf generated by movement of a coil of the actuator through the magnetic field of a voice coil motor. A current sense resistor is used in conjunction with the coil to provide closed loop control of the current applied to the coil. Signals indicative of the voltages across the serial combination of the coil and current sense resistor are provided to a velocity sense circuit, which determines the velocity of the coil by generating and subtracting out values for the dc voltage drops across the coil and the current sense resistor and the ac voltage drop across the coil. A compensation routine is provided to compensate for variations in temperature of the coil during operation. The sensed velocity of the coil is thereafter used in conjunction with other conventionally obtained measurements of estimates of head velocity to improve the accuracy and the reliability of the servo loop.