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:
Mar. 05, 1985
Filed:
Nov. 17, 1982
Ryoichiro Nozawa, Tokyo, JP;
Hidetsugu Komiya, Hino, JP;
Hajimu Kishi, Hino, JP;
Hitoshi Matsuura, Hachioji, JP;
Etsuo Yamazaki, Hachioji, JP;
Hiroshi Sakurai, Hino, JP;
Fanuc Ltd., Minamitsuru, JP;
Abstract
A method and apparatus for sensing the present position of a movable machine element in a position control system when a position control loop in the system is placed in the open state. In the position control system, error storage means computes and stores an error which corresponds to the difference between a command value produced by a control unit and an amount of movement sensed by a position sensor provided on a motor shaft or on the movable machine element. A speed control circuit controls the motor in accordance with the error from the error storage means. The method of sensing the present position includes the steps of reading and storing the error from the error storage means as a steady deviation immediately before the position control loop is switched from the closed to the open state, reading the error in the error storage means when the position control loop is in the open state, updating the content of a present position register on the basis of an arithmetic difference obtained by subtracting the steady deviation from the error read from the error storage means when the position control loop is in the open state, and revising the content of the error storage means in dependence upon the arithmetic difference.