US 12,000,476 B2
Method of correcting angular transmission error for reducer and robot system
Naoto Murakami, Matsumoto (JP)
Assigned to SEIKO EPSON CORPORATION, (JP)
Filed by Seiko Epson Corporation, Tokyo (JP)
Filed on Jan. 31, 2022, as Appl. No. 17/588,647.
Claims priority of application No. 2021-014201 (JP), filed on Feb. 1, 2021.
Prior Publication US 2022/0243807 A1, Aug. 4, 2022
Int. Cl. B25J 9/16 (2006.01); F16H 61/12 (2010.01); G01B 21/22 (2006.01); G01C 19/00 (2013.01)
CPC F16H 61/12 (2013.01) [B25J 9/1694 (2013.01); G01B 21/22 (2013.01); G01C 19/00 (2013.01); F16H 2061/1232 (2013.01); F16H 2061/1256 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A method of correcting an angular transmission error for a reducer of creating correction data for correction of an angular transmission error of the reducer in a robot system including
an arm,
the reducer having an input shaft and an output shaft coupled to the arm,
a motor coupled to the input shaft and generating power for rotating the arm via the reducer,
an encoder detecting a rotation angular position of the input shaft, and
an inertial sensor provided in the arm and detecting a rotation angular velocity of the arm,
the method comprising:
rotating the arm in an input rotation angular range smaller than a necessary input rotation angular range of the input shaft necessary for creation of the correction data;
when the arm rotates in the input rotation angular range, measuring and recording the angular transmission error of the reducer based on an output value from the encoder and an output value from the inertial sensor;
using a time when the angular transmission error of the reducer is measured or an angular range in which the angular transmission error of the reducer is measured as an index, determining whether or not an accumulated value of the indexes is equal to or larger than a predetermined value;
when the accumulated value of the indexes is smaller than the predetermined value, measuring the angular transmission error of the reducer and updating a record; and
when the accumulated value of the indexes is equal to or larger than the predetermined value, creating the correction data based on the recorded angular transmission error of the reducer.