Robot calibrating apparatus and robot calibrating method, and robot apparatus and method of controlling robot apparatus

• US 10,279,479 B2
• Filed: 04/18/2017
• Issued: 05/07/2019
• Est. Priority Date: 09/26/2013
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Suzuki, Hideaki, Amano, Shingo
• Primary Examiner(s): Mancho, Ronnie M
• Application Number:
  US15/490,638
• Publication Number:
  US 20170217020A1
• Time in Patent Office: 749 Days
• Field of Search: 700245, 700254, 901 9, 901 47
• CPC Class Codes: B25J 9/1692 Calibration of manipulator
• CPC Class Codes: B25J 9/1697 Vision controlled systems
• CPC Class Codes: G05B 2219/39008 Fixed camera detects reference pattern held by end effector
• CPC Class Codes: G05B 2219/39044 Estimate error model from error at different attitudes and points
• CPC Class Codes: G05B 2219/39045 Camera on end effector detects reference pattern

Abstract

A robot calibrating apparatus calibrating a command value for a robot body 2 whose position and orientation is controlled based on the command value, includes an operating unit configured to calculate a calibrating function of calibrating the command value, based on the difference between an ideal position and orientation of the robot body 2 and an actual position and orientation of the robot body 2. The ideal position and orientation is operated based on a command value ^RH_T^com for calibration used during calibration or on a control result value which is a result of control according to the command value. The actual position and orientation is operated based on a measurement value ^RH_T′^meas for calibration acquired by a camera 3 arranged at a prescribed relative position and orientation with respect to the robot body 2 during the robot body 2 being controlled according to the command value for calibration.

Claims

1. A controlling apparatus for a robot system including a robot body and a camera which is positioned relative to the robot body, the robot body including a plurality of joints and supporting a hand, the controlling apparatus comprising a processing apparatus including a processor configured to execute:

a process of acquiring a plurality of measurement values of a reference object for calibration of the robot system, by the camera taking images of a plurality of markers included in the reference object for calibration of the robot system while controlling the robot body to move through a plurality of positions and orientations based on a plurality of command values for calibration of the robot system;

a process of acquiring a first calibration value representing a relationship between a camera coordinate system and a hand tip coordinate system, and a second calibration value representing a relationship between a coordinate system of a base end part of the robot body and a coordinate system of the reference object for calibration of the robot system from the plurality of command values for calibration of the robot system and the plurality of measurement values of the reference object for calibration of the robot system; and

a process of acquiring a calibrating function that represents a relationship between a command value for the robot body and a prediction value of an actual position and orientation of the robot body, based on a difference between a plurality of positions and orientations of the robot body based on the plurality of command values for calibration of the robot system and the prediction value of the actual position and orientation of the robot body calculated using the plurality of measurement values, the first calibration value and the second calibration value.

2. The controlling apparatus for the robot system according to claim 1, wherein the processor is further configured to execute:

a process of acquiring a measurement value of an object by taking an image of the object with the camera; and

a process of calibrating a command value used for controlling a position and orientation of the robot body in operating the robot body with respect to the object, using the measurement value of the object, the first calibration value and the calibrating function.

3. A robot system comprising:

the controlling apparatus according to claim 1;

the robot body including the plurality of joints; and

the camera fixed to the robot body.

4. The robot system according to claim 3, wherein the controlling apparatus is further configured to execute:

a process of acquiring a measurement value of an object by taking an image of the object with the camera; and

a process of calibrating a command value used for controlling a position and orientation of the robot body in operating the robot body with respect to the object, using the measurement value of the object, the first calibration value and the calibrating function.

5. The robot system according to claim 4, wherein the controlling apparatus is configured to control the robot body based on the calibrated command value.

11. The controlling apparatus for the robot system according to claim 1, wherein the calibrating function includes a rotational component.

6. A calibrating method of calibrating a robot system including a robot body and a camera which is positioned relative to the robot body, the robot body including a plurality of joints and supporting a hand, the method, executed by a processor of a processing apparatus, comprising:

acquiring a plurality of measurement values of a reference object for calibration of the robot system, by the camera taking images of a plurality of markers included in the reference object for calibration of the robot system while controlling the robot body to move through a plurality of positions and orientations based on a plurality of command values for calibration of the robot system;

acquiring a first calibration value representing a relationship between a camera coordinate system and a hand tip coordinate system and a second calibration value representing a relationship between a coordinate system of a base end part of the robot body and a coordinate system of the reference object for calibration of the robot system from the plurality of command values for calibration of the robot system and the plurality of measurement values of the reference object for calibration of the robot system; and

acquiring a calibrating function that represents a relationship between a command value for the robot body and a prediction value of an actual position and orientation of the robot body based on a difference between a plurality of positions and orientations of the robot body based on the plurality of command values for calibration of the robot system and the prediction value of the actual position and orientation of the robot body calculated using the plurality of measurement values, the first calibration value and the second calibration value.

7. The calibrating method of calibrating the robot system according to claim 6, wherein the method further comprises:

acquiring a measurement value of an object by taking an image of the object with the camera; and

calibrating a command value used for controlling a position and orientation of the robot body in operating the robot body with respect to the object, using the measurement value of the object, the first calibration value and the calibrating function.

8. A non-transitory computer-readable recording medium storing a program for executing each step of the calibrating method of calibrating the robot system according to claim 6.

9. A controlling method of controlling a robot system including a robot body and a camera which is positioned relative to the robot body, the robot body including a plurality of joints and supporting a hand, a processor of a controlling apparatus executing the method, comprising:

acquiring a plurality of measurement values of a reference object for calibration of the robot system, by the camera taking images of a plurality of markers included in the reference object for calibration of the robot system while controlling the robot body to move through a plurality of positions and orientations based on a plurality of command values for calibration of the robot system;

acquiring a first calibration value representing relationship between a camera coordinate system and a hand tip coordinate system, and a second calibration value representing a relationship between a coordinate system of a base end part of the robot body and a coordinate system of the reference object for calibration of the robot system from the plurality of command values for calibration of the robot system and the plurality of measurement values of the reference object for calibration of the robot system; and

acquiring a calibrating function that represents a relationship between a command value for the robot body and a prediction value of an actual position and orientation of the robot body based on a difference between a plurality of positions and orientations of the robot body based on the plurality of command values for calibration of the robot system and the prediction value of the actual position and orientation of the robot body calculated using the plurality of measurement values, the first calibration value and the second calibration value.

10. The controlling method of controlling the robot system according to claim 9, wherein method further comprises:

acquiring a measurement value of an object by taking an image of the object with the camera; and

calibrating a command value used for controlling a position and orientation of the robot body in operating the robot body with respect to the object, using the measurement value of the object, the first calibration value and the calibrating function.

12. A controlling apparatus for a robot system including a robot body and a camera which is positioned relative to a platform to which a base end part of the robot body is fixed, the robot body including a plurality of joints and supporting a hand, the controlling apparatus comprising a processing apparatus including a processor configured to execute:

a process of acquiring a plurality of measurement values of a reference object for calibration of the robot system, by the camera taking images of a plurality of markers included in the reference object for calibration of the robot system while controlling the robot body supporting in the reference object for calibration of the robot system to move through a plurality of positions and orientations based on a plurality of command values for calibration of the robot system;

a process of acquiring a third calibration value representing a relationship between a camera coordinate system and a coordinate system of the base end part of the robot body and a fourth calibration value representing a relationship between a hand tip coordinate system and a coordinate system of the reference object for calibration of the robot system from the plurality of command values for calibration of the robot system and the plurality of measurement values of the reference object for calibration of the robot system; and

a process of acquiring a calibrating function that represents a relationship between a command value for the robot body and a prediction value of an actual position and orientation of the robot body, based on a difference between a plurality of positions and orientations of the robot body based on the plurality of command values for calibration of the robot system and the prediction value of the actual position and orientation of the robot body calculated using the plurality of measurement values, the third calibration value and the fourth calibration value.

13. The controlling apparatus for the robot system according to claim 12, wherein the processor is further configured to execute:

a process of acquiring a measurement value of an object by taking an image of the object with the camera; and

a process of calibrating a command value used for controlling a position and orientation of the robot body in operating the robot body with respect to the object, using the measurement value of the object, the third calibration value and the calibrating function.

14. The controlling apparatus for the robot system according to claim 12, wherein the calibrating function includes a rotational component.

15. A robot system comprising:

the controlling apparatus according to claim 12;

the robot body including the plurality of joints; and

the camera which is positioned relative to the platform to which the base end part of the robot body is fixed.

16. The robot system according to claim 15, wherein the controlling apparatus is further configured to execute:

a process of acquiring a measurement value of an object by taking an image of the object with the camera; and

a process of calibrating a command value used for controlling a position and orientation of the robot body in operating the robot body with respect to the object, using the measurement value of the object, the third calibration value and the calibrating function.

17. The robot system according to claim 16, wherein the controlling apparatus is configured to control the robot body based on the calibrated command value.

18. A calibrating method of calibrating a robot system including a robot body and a camera which is positioned relative to a platform to which a base end part of the robot body is fixed, the robot body including a plurality of joints and supporting a hand, the method, executed by a processor of a processing apparatus, comprising:

acquiring a plurality of measurement values of a reference object for calibration of the robot system, by the camera taking images of a plurality of markers included in the reference object for calibration of the robot system while controlling the robot body supporting in the reference object for calibration of the robot system to move through a plurality of positions and orientations based on a plurality of command values for calibration of the robot system;

acquiring a third calibration value representing a relationship between a camera coordinate system and a coordinate system of the base end part of the robot body and a fourth calibration value representing a relationship between a hand tip coordinate system and a coordinate system of the reference object for calibration of the robot system from the plurality of command values for calibration of the robot system and the plurality of measurement values of the reference object for calibration of the robot system; and

acquiring a calibrating function that represents a relationship between a command value for the robot body and a prediction value of an actual position and orientation of the robot body, based on a difference between a plurality of positions and orientations of the robot body based on the plurality of command values for calibration of the robot system and the prediction value of the actual position and orientation of the robot body calculated using the plurality of measurement values, the third calibration value and the fourth calibration value.

19. The calibrating method of calibrating the robot system according to claim 18, wherein the method further comprises:

acquiring a measurement value of an object by taking an image of the object with the camera; and

calibrating a command value used for controlling a position and orientation of the robot body in operating the robot body with respect to the object, using the measurement value of the object, the third calibration value and the calibrating function.

20. A non-transitory computer-readable recording medium storing a program for executing each step of the calibrating method of calibrating the robot system according to claim 18.

21. A controlling method of controlling a robot system including a robot body and a camera which is positioned relative to a platform to which a base end part of the robot body is fixed, the robot body including a plurality of joints and supporting a hand, a processor of a controlling apparatus executing the method, comprising:

acquiring a plurality of measurement values of a reference object for calibration of the robot system, by the camera taking images of a plurality of markers included in the reference object for calibration of the robot system while controlling the robot body supporting in the reference object for calibration of the robot system to move through a plurality of positions and orientations based on a plurality of command values for calibration of the robot system;

acquiring a third calibration value representing a relationship between a camera coordinate system and a coordinate system of the base end part of the robot body and a fourth calibration value representing a relationship between a hand tip coordinate system and a coordinate system of the reference object for calibration of the robot system from the plurality of command values for calibration of the robot system and the plurality of measurement values of the reference object for calibration of the robot system; and

acquiring a calibrating function that represents a relationship between a command value for the robot body and a prediction value of an actual position and orientation of the robot body, based on a difference between a plurality of positions and orientations of the robot body based on the plurality of command values for calibration of the robot system and the prediction value of the actual position and orientation of the robot body calculated using the plurality of measurement values, the third calibration value and the fourth calibration value.

22. The controlling method of controlling the robot system according to claim 21, wherein the method further comprises:

acquiring a measurement value of an object by taking an image of the object with the camera; and

calibrating a command value used for controlling a position and orientation of the robot body in operating the robot body with respect to the object, using the measurement value of the object, the third calibration value and the calibrating function.