# US 2018/0021955 A1 · Robot zero-point calibration device and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0021955 A1 - Document ID: US20180021955A1 - Status: Published application - Kind: A1 - Application number: 15/651,559 - Filed: 2017-07-17 - Published: 2018-01-25 - Earliest claimed: 2016-07-20 - Assignees: Fanuc Corporation - Applicants: Fanuc Corporation - Inventors: Kokoro HATANAKA - Web page: https://patentgrep.com/patent/US20180021955A1 ## CPC - B25J 9/1692: {Calibration of manipulator} - G05B 2219/39045: Camera on end effector detects reference pattern - G05B 2219/39047: Calibration plate mounted on robot, plate comprises sensors for measuring target - 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 robot zero-point calibration device includes an axial position recording unit configured to record positional data of each axis of a robot in each of a plurality of postures when a first positioning point and a second positioning point are made to coincide with each other, the first positioning point being disposed at a predetermined coordinate on a base coordinate system of the robot, and the second positioning point being disposed at a predetermined coordinate on a flange coordinate system of the robot. The device also includes a positional offset calculating unit configured to calculate an offset amount of a zero point of each axis of the robot from a true zero point of the axis based on a plurality of sets of the positional data stored in the axial position recording unit. ## Claims ### Claim 1 A robot zero-point calibration device, comprising: an axial position recording unit configured to record positional data of each axis of a robot in each of a plurality of postures when a first positioning point and second positioning point are made to coincide with each other, the first positioning point being disposed at a predetermined coordinate on a base coordinate system of the robot, and the second positioning point being disposed at a predetermined coordinate on a flange coordinate system of the robot; and a positional offset calculating unit configured to calculate an offset amount of a zero point of each axis of the robot from a true zero point of the axis based on a plurality of sets of the positional data stored in the axial position recording unit. ### Claim 2 (depends on 1) The robot zero-point calibration device according to claim 1, wherein the robot is a seven-axis robot, and the axial position recording unit records the positional data of each axis of the robot when the first positioning point is made to coincide with the second positioning point while the robot is in three postures or more. ### Claim 3 (depends on 1) The robot zero-point calibration device according to claim 1, further comprising: a first calibration jig fixed to a base of the robot to provide the first positioning point; and a second calibration jig fixed to a wrist flange of the robot to provide the second positioning point. ### Claim 4 (depends on 3) The robot zero-point calibration device according to claim 3, wherein the first calibration jig includes a first tip at the first positioning point, and the second calibration jig includes a second tip at the second positioning point. ### Claim 5 (depends on 3) The robot zero-point calibration device according to claim 3, wherein the first calibration jig is provided with three measurement targets measurable by a three-dimensional measurement device, and the second calibration jig is provided with one measurement target measurable by the three-dimensional measurement device. ### Claim 6 (depends on 3) The robot zero-point calibration device according to claim 3, wherein the second calibration jig includes a camera, and the first calibration jig is provided with a geometric characteristic measurable by the camera. ### Claim 7 A robot zero-point calibration method comprising: making a first positioning point and a second positioning point coincide with each other in each of a plurality of postures, the first positioning point being disposed at a predetermined coordinate on a base coordinate system of a robot, and the second positioning point being disposed at a predetermined coordinate on a flange coordinate system of the robot; recording positional data of each axis of the robot when the first positioning point and the second positioning point are made coincide with each other while the robot is in each posture at the positioning step; and calculating an offset amount of a zero point of each axis of the robot from a true zero point of the axis based on a plurality of sets of the positional data stored at the axial position recording step. ### Claim 8 (depends on 7) The robot zero-point calibration method according to claim 7, wherein the robot is a seven-axis robot, and the axial position recording step records the positional data of each axis of the robot when the first positioning point is made to coincide with the second positioning point while the robot is in three postures or more.