US 12,472,624 B2
Spring constant correction device, method therefor, and recording medium
Takashi Yamada, Kobe (JP); Yoshiharu Nishida, Kobe (JP); Yoshihisa Tamase, Kakogawa (JP); Naoki Kida, Fujisawa (JP); and Kenichiro Kanao, Fujisawa (JP)
Assigned to Kobe Steel, Ltd., Kobe (JP)
Appl. No. 18/261,010
Filed by Kobe Steel, Ltd., Kobe (JP)
PCT Filed Jan. 13, 2022, PCT No. PCT/JP2022/000958
§ 371(c)(1), (2) Date Jul. 11, 2023,
PCT Pub. No. WO2022/176456, PCT Pub. Date Aug. 25, 2022.
Claims priority of application No. 2021-024925 (JP), filed on Feb. 19, 2021.
Prior Publication US 2024/0083024 A1, Mar. 14, 2024
Int. Cl. B25J 9/16 (2006.01); B25J 13/08 (2006.01)
CPC B25J 9/1633 (2013.01) [B25J 9/1664 (2013.01); B25J 13/088 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A spring constant correction device applied to an articulated robot in which a speed reducer acts as a spring element and elastically deforms, the articulated robot being operated in a state where elastic deformation is compensated based on a spring constant of the spring element by an elastic deformation compensation unit included in a robot controller,
the spring constant correction device comprising:
a measurement unit that measures a position and attitude of a distal end of the articulated robot when the articulated robot is operated in a state where the elastic deformation is compensated;
a comparison unit that compares measurement values of the position and attitude, of the distal end of the articulated robot, measured by the measurement unit and target values of the position and attitude of the distal end of the articulated robot; and
a correction unit that corrects the spring constant, based on a result obtained by comparison by the comparison unit,
wherein the correction unit corrects, at a predetermined position, the spring constant based on at least three of: an angle of an end point attitude based on the attitude, of the distal end of the articulated robot, measured by the measurement unit; a torque of the distal end of the articulated robot in the end point attitude; an angle of the distal end of the articulated robot in a target attitude; and a torque of the distal end of the articulated robot in the target attitude,
the predetermined position is an end point position of a weaving motion, and
the spring constant is expressed, at the predetermined position, by a functional expression using the torque τ1 of the distal end of the articulated robot in the end point attitude, the angle θd of the distal end of the articulated robot in a target attitude, and the torque τd of the distal end of the articulated robot in the target attitude, the functional expression being:

OG Complex Work Unit Math
where Knew denotes a corrected spring constant, Kold denotes a current spring constant, and dθd denotes an angular error.