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:
Jul. 22, 2003
Filed:
May. 01, 2000
Russell Wilson-Jones, Warwickshire, GB;
Anthony Walter Burton, Birmingham, GB;
Andrew James Stephen Williams, West Midlands, GB;
John Michael Ironside, Birmingham, GB;
TRW LucasVarity Electric Steering Ltd., West Midlands, GB;
Abstract
A method of calculating the position of the rotor of a motor ( ) in for example an electrical power assisted steering assembly is disclosed. The method comprises the steps of measuring the output shaft ( ) (i.e. steering column) position, and scaling the measured value to produce an estimated motor rotor position value. This estimated value will be relative to an arbitrary datum point, and so the method further includes steps of adding an offset value derived from low resolution measurements of rotor position obtained using Hall effect sensors provided on the motor. Offsets for compensating for backlash and (in a second embodiment) compliance can also be included. Thus, the method allows high resolution information from an output shaft sensor (e.g. a torque sensor with a position dependent output) to be combined with the low resolution output from the Hall effect sensors to produce a high resolution rotor position signal. A correction is also made to allow for “staleness” in the Hall effect sensor output when calculating the offsets by monitoring rotor speed.