# US 11,992,951 B2 · Control method, control device, robot system, program, and recording medium > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,992,951 B2 - Document ID: US11992951B2 - Status: Granted - Kind: B2 - Application number: 17/767,058 - Filed: 2020-10-07 - Published: 2022-12-01 - Granted: 2024-05-28 - Earliest claimed: 2019-10-09 - Assignees: Kawasaki Jukogyo Kabushiki Kaisha - Applicants: Kawasaki Jukogyo Kabushiki Kaisha - Inventors: Jun Takebayashi; Toshihiko Miyazaki; Yusuke Fujimoto; Masaya Yoshida; Atsushi Kameyama - Web page: https://patentgrep.com/patent/US11992951B2 ## CPC - B25J 9/1664: {characterised by motion, path, trajectory planning} - G05B 2219/50042: Return to origin, reference point, zero point, homing - B25J: MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES ({manipulators specially adapted for use in surgery A61B34/70; manipulators used in cleaning hollow articles B08B9/04}; manipulators associated with rolling mills B21B39/20; manipulators associated with forging machines B21J13/10; {manipulators associated with picking-up and placing mechanisms B23P19/007}; means for holding wheels or parts thereof B60B30/00; {vehicles with ground-engaging propulsion means, e.g. walking members B62D57/02, B62D57/032; devices for picking-up and depositing articles or materials between conveyors B65G47/90, B65G47/91; manipulators with gripping or holding means for transferring packages B65H67/065}; cranes B66C; {manipulators used in the protection or supervision of pipe-line installations F17D5/00; walking equipment adapted for nuclear steam-generators F22B37/006}; manipulators specially adapted for, or associated with, nuclear reactors G21C; {apparatus used for handling wafers during manufacture or treatment of semiconductor H10P72/50}) - G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G) ## Abstract A control method includes: recording information of an operation target point that is a destination, each time an end effector of a robot moves to the operation target point on an operation path; acquiring a present position of the end effector upon receiving an origin return command; detecting information of a return target point on a return path for returning the end effector to an origin; detecting information of the operation target point already reached immediately before a kth return target point or having a distance closest to the kth return target point, as a (k+1)th return target point; repeating detection of the information of the return target point to detect information of second to (n+1)th return target points; and moving the end effector along the return path passing through the first to (n+1)th return target points and returning to the origin. ## Claims ### Claim 1 A control method for a robot that performs operation of moving an end effector sequentially to operation target points on an operation path, the control method comprising: recording information of the operation target point that is a destination, each time the end effector moves to the operation target point; acquiring a present position of the end effector upon receiving an origin return command to return the end effector to an origin of the operation path; detecting information of a first return target point that is the operation target point already reached immediately before the present position or the operation target point having a distance closest to the present position among information of the operation target points already reached by the end effector before the present position, as information of a point on a return path for returning the end effector to the origin; detecting information of a (k+1)th return target point that is the operation target point already reached immediately before a kth return target point or the operation target point having a distance closest to the kth return target point among information of the operation target points already reached by the end effector before the kth return target point, as information of a point on the return path, wherein k is a natural number from 1 to n and n is a natural number of 1 or more: repeating detection of the information of the (k+1)th return target point to detect information of a second return target point to an (n+1)th return target point; determining the return path passing through the first return target point to the (n+1)th return target point in this order and returning to the origin; and moving the end effector along the return path. ### Claim 2 (depends on 1) The control method according to claim 1, including: determining the earliest reached operation target point as the return target point when detecting the operation target points as candidates for the return target point. ### Claim 3 (depends on 1) The control method according to claim 1, including: detecting a target point distance that is a distance between the recorded operation target point and the present position; and when the target point distance is within a first threshold, regarding the present position as being located at the operation target point whose target point distance is within the first threshold. ### Claim 4 (depends on 1) The control method according to claim 1, including: detecting a separation distance that is a distance between the present position and the operation path; executing detection of the return target point when the separation distance is within a second threshold; and stopping detection of the return target point when the separation distance exceeds the second threshold. ### Claim 5 (depends on 1) The control method according to claim 1, wherein a distance between the present position or the return target point and the operation target point is a distance along the operation path. ### Claim 6 (depends on 1) The control method according to claim 1, including: regarding positions of the two operation target points as being the same when a distance between the two operation target points is equal to or less than a third threshold. ### Claim 7 (depends on 1) The control method according to claim 1, wherein the information of the operation target point includes information of a position of the operation target point, a section operation path that is a path from the immediately previous operation target point to the operation target point, a state of the end effector, and a position of the robot. ### Claim 8 (depends on 7) The control method according to claim 7, wherein the position of the operation target point includes a three-dimensional position of the operation target point and a posture of a reference axis at the operation target point. ### Claim 9 (depends on 8) The control method according to claim 8, wherein the distance between the present position or the return target point and the operation target point includes a distance between a three-dimensional position of the present position or the return target point and the three-dimensional position of the operation target point and a distance between a posture of the reference axis at the present position or the return target point and the posture of the reference axis at the operation target point. ### Claim 10 (depends on 7) The control method according to claim 7, moving the end effector from the kth return target point to the (k+1)th return target point, including: determining a position of the (k+1)th return target point as a target position for the end effector; determining a path that is reverse to the section operation path included in information of the kth return target point as a target operation path for the end effector; determining the state of the end effector included in the information of the kth return target point as a target state for the end effector; and determining the position of the robot included in the information of the (k+1)th return target point as a target position for the robot. ### Claim 11 (depends on 7) The control method according to claim 7, when moving the end effector from the present position thereof to the first return target point, including: determining a position of the first return target point as a target position for the end effector; determining a path that is reverse to the section operation path included in information of a destination operation target point that is the operation target point that is the destination for the present position as a target operation path for the end effector: determining the state of the end effector included in the information of the destination operation target point as a target state for the end effector; and determining the position of the robot included in information of the first return target point as a target position for the robot. ### Claim 12 (depends on 1) The control method according to claim 1, wherein the operation target point is a target point of the operation taught to the robot in a process of teaching the operation to the robot. ### Claim 13 (depends on 1) A controller that executes the control method according to claim 1. ### Claim 14 (depends on 13) A robot system comprising: the controller according to claim 13; and the robot, wherein the controller controls operation of the robot. ### Claim 15 A non-transitory recording medium having recorded therein a program executed by a computer, the program causing the computer to: in a process in which a robot moves an end effector sequentially to operation target points on an operation path, record information of the operation target point that is a destination, each time the end effector moves to the operation target point; acquire a present position of the end effector upon receiving an origin return command to return the end effector to an origin of the operation target points; detect information of a first return target point that is the operation target point already reached immediately before the present position or the operation target point having a distance closest to the present position among information of the operation target points already reached by the end effector before the present position, as information of a point on a return path for returning the end effector to the origin; detect information of a (k+1)th return target point that is the operation target point already reached immediately before a kth return target point or the operation target point having a distance closest to the kth return target point among information of the operation target points already reached by the end effector before the kth return target point, as information of a point on the return path, wherein k is a natural number from 1 to n and n is a natural number of 1 or more; repeat detection of the information of the (k+1)th return target point to detect information of a second return target point to an (n+1)th return target point; and determine the return path passing through the first return target point to the (n+1)th return target point in this order and returning to the origin. ### Claim 16 (depends on 15) The non-transitory recording medium according to claim 15, wherein the program is an application program that runs on a system program of a controller that controls operation of the robot. ### Claim 17 (depends on 16) The non-transitory recording medium according to claim 16, wherein the application program is allowed to run when the application program is installed and incorporated in the system program. ### Claim 18 (depends on 15) The non-transitory recording medium according claim 15, wherein the program causes the computer to: determine the earliest reached operation target point as the return target point when the operation target points are detected as candidates for the return target point. ### Claim 19 (depends on 15) The non-transitory recording medium according to claim 15, wherein the program causes the computer to: detect a target point distance that is a distance between the recorded operation target point and the present position; and when the target point distance is within a first threshold, regard the present position as being located at the operation target point whose target point distance is within the first threshold. ### Claim 20 (depends on 15) The non-transitory recording medium according to claim 15, wherein the program causes the computer to: detect a separation distance that is a distance between the present position and the operation path; execute detection of the return target point when the separation distance is within a second threshold; and stop detection of the return target point when e separation distance exceeds the second threshold. ### Claim 21 (depends on 15) The non-transitory recording medium according to claim 15, wherein a distance between the present position or the return target point and the operation target point is a distance along the operation path. ### Claim 22 (depends on 15) The non-transitory recording medium according to claim 15, wherein the program causes the computer to: regard positions of the two operation target points as being the same when a distance between the two operation target points is equal to or less than a third threshold. ### Claim 23 (depends on 15) The non-transitory recording medium according to claim 15, wherein the information of the operation target point includes information of a position of the operation target point, a section operation path that is a path from the immediately previous operation target point to the operation target point, a state of the end effector, and a position of the robot. ### Claim 24 (depends on 23) The non-transitory recording medium according to claim 23, wherein the position of the operation target point includes a three-dimensional position of the operation target point and a posture of a reference axis at the operation target point. ### Claim 25 (depends on 24) The non-transitory recording medium according to claim 24, wherein the distance between the present position or the return target point and the operation target point includes a distance between a three-dimensional position of the present position or the return target point and the three-dimensional position of the operation target point and a distance between a posture of the reference axis at the present position or the return target point and the posture of the reference axis at the operation target point. ### Claim 26 (depends on 23) The non-transitory recording medium according to claim 23, wherein, in a section return path from the kth return target point to the (k+1)th return target point in the return path, the program causes the computer to: determine a position of the (k+1)th return target point as a target position for the end effector; determine a path that is reverse to the section operation path included in information of the kth return target point as a target operation path for the end effector; determine the state of the end effector included in the information of the kth return target point as a target state for the end effector; and determine the position of the robot included in the information of the (k+1)th return target point as a target position for the robot. ### Claim 27 (depends on 23) The non-transitory recording medium according to claim 23, wherein, in a section return path from the present position to the first return target point in the return path, the program causes the computer to: determine a position of the first return target point as a target position for the end effector; determine a path that is reverse to the section operation path included in information of a destination operation target point that is the operation target point that is the destination for the present position as a target operation path for the end effector; determine the state of the end effector included in the information of the destination operation target point as a target state for the end effector; and determine the position of the robot included in information of the first return target point as a target position for the robot. ### Claim 28 (depends on 15) The non-transitory recording medium according to claim 15, wherein the operation target point is a target point of the operation taught to the robot in a process of teaching the operation to the robot.