Patent ID: 6664752
Filing Date: 2003-12-16
Classification: G05B

Abstract:
A method of correcting positional error in an actuator having a motor and a wave gear reduction drive that transmits a rotational output of the motor to a load at a reduced speed, said method comprising:measuring positioning error relative to an absolute position of an actuator output shaft to produce error correction data relating to a rotational position of the motor shaft; detecting a rotational position of the motor shaft; producing rotational position correction information by adding an error correction value in the error correction data to the detected rotational position, the error correction value being assigned to the detected rotational position in the error correction data; and using the produced rotational position correction information as position feedback information for controlling the positioning of the output shaft; wherein the error correction data is produced by measuring the positioning error for at least 1/(R+1) revolution of the output shaft, where R is a speed ratio of the wave gear reduction drive.