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. 14, 2010
Filed:
Jul. 30, 2007
Bjorn E. B. Jansson, Snohomish, WA (US);
Bjorn E. B. Jansson, Snohomish, WA (US);
Mitutoyo Corporation, Kawasaki-shi, JP;
Abstract
A system and method for real time calibration of a quadrature encoder. Errors from sources such as signal offsets, amplitude mismatches and phase errors are addressed. In one embodiment, the errors are addressed by determining and applying a dynamic operational set of calibration parameters. The process for determining the operational calibration parameters involves minimizing a variation metric that indicates the variations of the magnitudes of a set of corrected vectors Ci″. The corrected vectors Ci″ are defined by using the calibration parameters to provide corrected vector components (Ati″, Bti″) that correspond to a current operational set of quadrature signal samples comprising at least four respective quadrature signal samples (Ati, Bti) having spatial phase angles θti that are distributed over a significant portion of 360 degrees. For well chosen calibration parameters, the resulting corrected vectors define a well-centered circle and the variation metric is minimized.