Denso Wave Corporation

Hiroaki Shiratori

Daisuke Kawase

Yuto Kawachi

Takafumi Fukuoka

In an eccentricity error correction method for an angle detector, an output shaft angle is determined in at least three measurement positions. A difference between an arm angle value at each measurement position and the output shaft angle detected at each measurement position is determined as an eccentricity error. An error curve indicates a relationship between the arm angle value and the eccentricity error, and is determined as a function of the arm angle value by approximating the eccentricity error at each measurement position with a sine wave of which a single cycle is a single rotation of the arm. A correction formula that associates the output shaft angle and the arm angle value is determined using the error curve. A correction value corresponds to the detected output shaft angle, and is determined based on the correction formula and correcting the eccentricity error when the arm is rotated.

Eccentricity error correction method for angle detector and robot system

A deflection angle detection device includes an input shaft encoder, a disk attached to an output shaft of a speed reducer, an output shaft encoder having detection elements disposed at mutually different positions with respect to the disk to detect angular positions of the disk. A basic angular position of the output shaft is calculated based on an angular position of the input shaft detected by the input shaft encoder, a first, a second, and a third angular positions of the output shaft are calculated based on the angular positions of the disk detected by a plurality of detecting elements, and the deflection angle of the output shaft is calculated based on a first, a second, and a third differences, which are differences between the basic angular position and the first, the second, and the third angular positions, respectively, and positions of the detection elements with respect to the disk.

Deflection angle detection device

In an industrial robot, correction is made for change in position and attitude of an arm distal end due to mechanical deflection of the robot. In the robot, a moment applied to the first axis in its non-rotation direction opposite to its rotation direction is calculated from a load torque applied to the second axis in its rotation direction, a moment due to a second-axis-side self-weight, and a ratio of a distance between the rotation centers of the first and second axes, to a distance between the rotation centers of the second axis and a tool. A deflection amount indicating an angle of the first axis tilting in the non-rotation direction is calculated from the moment applied to the first axis and the rigidity of the first axis in the non-rotation direction. A control value is corrected based on the deflection amount to control the robot.

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Chita-gun, Japan

Hiroaki Shiratori