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. 24, 2002
Filed:
Jun. 29, 1998
Susumu Ito, Hino, JP;
Masao Kamiguchi, Minamitsuru-gun, JP;
Hisao Ishii, Tokyo, JP;
Masanobu Takemoto, Oshino-mura, JP;
Susumu Maekawa, Oshino-mura, JP;
Kunio Kojima, Oshino-mura, JP;
Fanuc Ltd., Yamanashi, JP;
Abstract
The position of a feed shaft is monitored, the mean moving speed and moving frequency of the feed shaft are measured with every unit time for position correction, and a correction amount &dgr;n is determined from the speed and frequency according to an approximation formula and updated (c and c ). A position correction amount for a commanded position is determined from this correction amount, and the commanded position is corrected by the position correction amount (c to c ). The position correction amount for the commanded position is determined from this correction amount, and the commanded position is corrected by this position correction amount. Since the correction amount is determined according to the approximation formula, thermal displacement correction can be effected at all times without requiring any sensor. When the correction amount changes substantially (c ), the thermal displacement is measured by means of a sensor and used as the correction amount (c and c ), whereby accuracy is improved. The frequency of measurement by means of sensors is reduced, so that the machining time can be reduced.