System And Method For Determining A Work Offset

• US 20180029231A1
• Filed: 10/11/2017
• Published: 02/01/2018
• Est. Priority Date: 07/23/2015
• Status: Active Grant

• Current Assignee: X Development LLC (Alphabet Inc.)
• Original Assignee: X Development LLC (Alphabet Inc.)
• Inventors: Davis, Benjamin M.
• Granted Patent: US 10,456,914 B2
• Time in Patent Office: Days
• CPC Class Codes: B25J 9/1664 characterised by motion, path, trajectory planning
• CPC Class Codes: B25J 9/1697 Vision controlled systems
• CPC Class Codes: G05B 19/4083 Adapting programme, configuration
• CPC Class Codes: G05B 2219/33271 Convert workpiece to machine coordinates
• CPC Class Codes: G05B 2219/36503 Adapt program to real coordinates, software orientation
• CPC Class Codes: G05B 2219/39032 Touch probe senses constraint known plane, derive kinematic calibration

Abstract

Example systems and methods are disclosed for determining work offset data for a robot in a work environment. A robot operating in a work environment may receive an indication to determine a work offset. The work offset may describe the location and angular orientation of a working plane of the work environment relative to a base plane of the robot. In response to the indication, the robot may identify the working plane. The robot may be controlled to contact one or more points of the working plane. The robot may determine respective point locations of the contacted points relative to the base plane based on the respective positions of the robot at respective times of contact. The robot may determine the location and angular orientation of the working plane relative to the base plane based on the determined respective point locations of the contacted points.

Claims

1. A method comprising:

receiving an indication to determine a work offset for a robot operating in a work environment, wherein the work offset describes a location and an angular orientation of a working plane of the work environment relative to a base plane of the robot;

in response to the indication, identifying the working plane within the work environment;

providing instructions by a processor to control an arm of the robot to position a proximity sensor on the arm within a threshold distance of one or more points of the working plane;

determining one or more respective positions of the robot when the proximity sensor on the arm of the robot is within the threshold distance of the one or more points of the working plane;

based on the one or more respective positions of the robot, determining respective point locations of the one or more points of the working plane relative to the base plane; and

determining the location and angular orientation of the working plane relative to the base plane based on the determined respective point locations of the one or more points of the working plane.

2. The method of claim 1, wherein the arm of the robot is controlled to sequentially move the proximity sensor on the arm of the robot within the threshold distance of three separate, non-collinear points on the working plane.

3. The method of claim 1, wherein the proximity sensor is an optical sensor.

4. The method of claim 1, wherein the proximity sensor is an inductive sensor.

5. The method of claim 1, wherein the proximity sensor is a capacitive sensor.

6. The method of claim 1, wherein the angular orientation of the working plane comprises an angular displacement of the working plane relative to the base plane.

7. The method of claim 1, wherein the location of the working plane comprises a shift distance between a point on the base plane and a corresponding point on the working plane along a vertical axis perpendicular to the base plane of the robot.

8. The method of claim 1, wherein the working plane is a ground plane of the work environment.

9. The method of claim 1, further comprising:

after determining the work offset a first time, detecting a change in the base plane; and

in response to the detected change in the base plane, determining the work offset a second time.

10. The method of claim 1 further comprising:

after determining the work offset a first time, detecting a change in the working plane; and

in response to the detected change in the working plane, determining the work offset a second time.

11. The method of claim 1, wherein the indication to determine the work offset is generated in response to detection of an initial startup of the robot.

12. The method of claim 1, wherein the indication to determine the work offset is generated in response to detection of an error associated with robot operation.

13. The method of claim 1, wherein identifying the working plane within the work environment further comprises:

identifying the working plane within the work environment based on image data from a camera, wherein the image data comprises at least a portion of the working plane.

14. The method of claim 1, wherein the angular orientation of the working plane comprises angular displacement of the working plane relative to a first axis of the base plane and angular displacement of the working plane relative to a second axis of the base plane, wherein the second axis is perpendicular to the first axis.

15. The method of claim 1, wherein the one or more respective positions of the robot are determined based on encoded joint angles.

16. The method of claim 1, wherein the working plane is a surface, wherein one or more objects for the robot to manipulate are located on the surface.

17. A non-transitory computer-readable medium storing instructions that are executable by one or more computing devices, wherein executing the instructions causes the one or more computing devices to perform functions comprising:

receiving an indication to determine a work offset for a robot operating in a work environment, wherein the work offset describes a location and an angular orientation of a working plane of the work environment relative to a base plane of the robot;

in response to the indication, identifying the working plane within the work environment;

controlling an arm of the robot to position a proximity sensor on the arm within a threshold distance of one or more points of the working plane;

determining one or more respective positions of the robot when the proximity sensor on the arm of the robot is within the threshold distance of the one or more points of the working plane;

based on the one or more respective positions of the robot, determining respective point locations of the one or more points of the working plane relative to the base plane; and

determining the location and angular orientation of the working plane relative to the base plane based on the determined respective point locations of the one or more points of the working plane.

18. The non-transitory computer-readable medium of claim 17, wherein controlling the arm of the robot to position the proximity sensor on the arm within the threshold distance of one or more points of the working plane comprises controlling the arm of the robot to sequentially move the proximity sensor on the arm of the robot within the threshold distance of three separate, non-collinear points on the working plane.

19. A system comprising:

a processor; and

a memory storing instructions that when executed by the processor cause the system to perform functions comprising;

receiving an indication to determine a work offset for a robot operating in a work environment, wherein the work offset describes a location and an angular orientation of a working plane of the work environment relative to a base plane of the robot;

in response to the indication, identifying the working plane within the work environment;

controlling an arm of the robot to position a proximity sensor on the arm within a threshold distance of one or more points of the working plane;

determining one or more respective positions of the robot when the proximity sensor on the arm of the robot is within the threshold distance of the one or more points of the working plane;

based on the one or more respective positions of the robot, determining respective point locations of the one or more points of the working plane relative to the base plane; and

determining the location and angular orientation of the working plane relative to the base plane based on the determined respective point locations of the one or more points of the working plane.

20. The system of claim 19, wherein controlling the arm of the robot to position the proximity sensor on the arm within the threshold distance of one or more points of the working plane comprises controlling the arm of the robot to sequentially move the proximity sensor on the arm of the robot within the threshold distance of three separate, non-collinear points on the working plane.