Method and apparatus for correcting actuator positioning error
AssigneeHarmonic Drive Systems Inc.
InventorsNaoki Kanayama, Kozo Sasaki
Life of this patent
Estimating the term…
Abstract
A method of correcting positional error in an actuator that is equipped with a motor and a wave gear reduction drive that transmits a motor output to the target load. Positioning error relative to the absolute position of the actuator output shaft is measured, to compile error correction data relating to each position on the rotation of the motor shaft. The rotational position of the motor shaft is detected and rotational position correction information produced by adding error correction values assigned to the position concerned. The rotational positional error information thus produced is used as position feedback information for controlling the positioning of the output shaft.
Claims6
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.
Dependencies are inferred from the claim text.