US 10,864,639 B2Granted

Simultaneous kinematic and hand-eye calibration

AssigneeCognex Corporation

InventorsLifeng Liu, Cyril C. Marrion, Tian Gan, David Michael, Han Xiao

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Abstract

Described are machine vision systems and methods for simultaneous kinematic and hand-eye calibration. A machine vision system includes a robot and a 3D sensor in communication with a control system. The control system is configured to move the robot to poses, and for each pose: capture a 3D image of calibration target features and robot joint angles. The control system is configured to obtain initial values for robot calibration parameters, and determine initial values for hand-eye calibration parameters based on the initial values for the robot calibration parameters, the 3D image, and joint angles. The control system is configured to determine final values for the hand-eye calibration parameters and robot calibration parameters by refining the hand-eye calibration parameters and robot calibration parameters to minimize a cost function.

Claims16

Dependent claims

A machine vision system comprising:

a robot;
a 3D sensor;
and
a control system in communication with the robot and the 3D sensor, the control system configured to:
move the robot to a plurality of poses, and for each pose of the plurality of poses:
capture, with the 3D sensor, a 3D image of one or more features on a calibration target;
and
capture a plurality of robot joint angles;
obtain a plurality of initial values for a plurality of robot calibration parameters;
determine a plurality of initial values for a plurality of hand-eye calibration parameters based on the plurality of initial values for the plurality of robot calibration parameters, and the 3D image and the plurality of robot joint angles captured for each of the plurality of poses;
determine a plurality of final values for the plurality of hand-eye calibration parameters and a plurality of final values for the robot calibration parameters by refining one or more of the plurality of hand-eye calibration parameters and one or more of the plurality of robot calibration parameters to minimize a cost function.

8 more elements

A machine vision system-implemented calibration method comprising:

moving, by a control system, a robot to a plurality of poses, and for each pose of the plurality of poses:
capturing, by a 3D sensor, a 3D image of one or more features on a calibration target;
and
capturing, by the control system, a plurality of robot joint angles;
obtaining, by the control system, a plurality of initial values for a plurality of robot calibration parameters;
determining, by the control system, a plurality of initial values for a plurality of hand-eye calibration parameters based on the plurality of initial values for the plurality of robot calibration parameters, and the 3D image and the plurality of robot joint angles captured for each of the plurality of poses;
determining, by the control system, a plurality of final values for the plurality of hand-eye calibration parameters and a plurality of final values for the plurality of robot calibration parameters by refining one or more of the plurality of hand-eye calibration parameters and one or more of the plurality of robot calibration parameters to minimize a cost function.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/448,925Filed 21 Jun 2019 · continuation in part
Priority: 28 Sep 2016
Published: US 2019/0015991 A110 Oct 2019
Granted: 15 Dec 2020
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

B25J 9/1697
Characterised by use of sensors other than normal servo-feedback from position, speed or acceleration sensors, perception control, multi-sensor…:…
B25J 9/1692
Characterised by the tasks executed: calibration of manipulator
G06T 7/70
Image analysis: determining position or orientation of objects or cameras
G06T 7/73
Determining position or orientation of objects or cameras: using feature-based methods

Family

Application15/278,156Parent of this continuation · filed 28 Sep 2016
Application16/133,324Parent of this continuation-in-part · filed 17 Sep 2018
US 10,076,842 B2Parent of this continuation · filed 18 Sep 2018
US 2019/0308326 A1Pre-grant publication · published 10 Oct 2019
Application16/133,324Parent of this continuation
US 2018/0089831 A1Published application
US 2019/0015991 A1Published application
US 10,864,639 B2This patent

From the US filing history. Foreign family members aren’t listed.

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