Calculating a calibration parameter for a robot tool

• US 10,723,028 B2
• Filed: 11/30/2017
• Issued: 07/28/2020
• Est. Priority Date: 11/30/2016
• Status: Active Grant

• Current Assignee: Siemens Healthineers AG (Siemens AG)
• Original Assignee: Siemens Healthcare GMBH (Siemens AG)
• Inventors: Mewes, Philip, Gulhar, Abhinav
• Primary Examiner(s): Marc, McDieunel
• Application Number:
  US15/827,020
• Publication Number:
  US 20180147727A1
• Time in Patent Office: 971 Days
• CPC Class Codes: A61B 2017/00725 Calibration or performance testing
• CPC Class Codes: A61B 2034/2059 Mechanical position encoders
• CPC Class Codes: A61B 2034/2065 Tracking using image or pattern recognition
• CPC Class Codes: A61B 2090/374 NMR or MRI
• CPC Class Codes: A61B 2090/376 using X-rays, e.g. fluoroscopy
• CPC Class Codes: A61B 2090/3762 using computed tomography systems [CT]
• CPC Class Codes: A61B 2090/3966 Radiopaque markers visible in an X-ray image
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 34/30 Surgical robots
• CPC Class Codes: A61B 90/37 Surgical systems with images on a monitor during operation
• CPC Class Codes: B25J 9/1692 Calibration of manipulator
• CPC Class Codes: B25J 9/1697 Vision controlled systems
• CPC Class Codes: G05B 2219/37555 Camera detects orientation, position workpiece, points of workpiece
• CPC Class Codes: G05B 2219/39016 Simultaneous calibration of manipulator and camera
• CPC Class Codes: G05B 2219/39026 Calibration of manipulator while tool is mounted
• CPC Class Codes: G05B 2219/39446 Display of manipulator and workpiece and jog directions
• CPC Class Codes: G05B 2219/39466 Hand, gripper, end effector of manipulator

Abstract

A method calculates a calibration parameter for a robot tool. The method is based on the reception of an image dataset from medical imaging of an image volume via a first interface. The image volume contains a part of the robot tool and the robot tool is attached to a robot. A robot dataset is received by a second interface. The robot dataset contains a position of a movable axis of the robot during the recording of the image dataset. The position and/or orientation of a marking in the image dataset are determined by a computing unit. An image-based position and/or orientation of the tool center point of the robot tool are calculated by transforming the position and/or orientation of the marking. The calibration parameter is calculated based on the robot dataset and on the image-based position and/or orientation of the tool center point via the computing unit.

Claims

1. A method for calculating a calibration parameter for a robot tool, which comprises the following method steps of:

receiving an image dataset from medical imaging of an image volume via a first interface, the image volume comprising a part of the robot tool, and the robot tool being attached to a robot;

receiving a robot dataset via a second interface, the robot dataset comprising a position of at least one movable axis of the robot during a recording of the image dataset;

determining at least one of a position and an orientation of a marking in the image dataset via a computing unit;

calculating at least one of an image-based position and an image-based orientation of a tool center point of the robot tool by transforming at least one of the position and the orientation of the marking via the computing unit; and

calculating the calibration parameter based on the robot dataset and on at least one of the image-based position and the image-based orientation of the tool center point via the computing unit.

2. The method according to claim 1, wherein the image dataset contains a two-dimensional X-ray projection of the image volume.

3. The method according to claim 1, wherein the image dataset contains a three-dimensional volume image reconstructed from a plurality of two-dimensional X-ray projections of the image volume.

4. The method according to claim 3, wherein a reconstructed three-dimensional volume image is reconstructed from two-dimensional radiographic X-ray projections of the image volume.

5. The method according to claim 1, wherein a structure of the robot tool is depicted in the image dataset and the marking is embodied as the structure of the robot tool.

6. The method according to claim 5, wherein the step of calculating at least one of the image-based position and the image-based orientation of the tool center point is performed by registering the image dataset with a three-dimensional model of the robot tool.

7. The method according to claim 1, wherein the marking contains a plurality of marking elements, and the marking elements are disposed at least on one of an outside of the robot tool and inside the robot tool.

8. The method according to claim 1, wherein the step of calculating the calibration parameter is based on the robot dataset such that at least one of a predicted position and orientation of the tool center point is calculated from the robot dataset, and that the calibration parameter contains deviations of at least one of the predicted position and orientation from at least one of the image-based position and the image-based orientation.

9. The method according to claim 1, wherein the robot dataset furthermore contains an influencing variable of an environment of the robot, the influencing variable influences a measurement of at least one of the robot dataset and the position of the tool center point.

10. The method according to claim 9, wherein the influencing variable contains at least one of the following variables:

an ambient temperature;

a force acting on the robot tool; and

loading of the robot tool.

21. A computer program product with computer executable non-transitory instructions, which when loaded directly into a memory of a calibration unit, carrying out the steps of a method according to claim 1.

22. A non-transitory computer-readable storage medium comprising computer executable instructions to be read and executed by a calibration unit for carrying out all steps of method claim 1 when the computer executable instructions are executed by the calibration unit.

11. A calibration unit for calculating a calibration parameter for a robot tool, the calibration unit comprising:

a first interface embodied for a first reception of an image dataset from medical imaging of an image volume, the image volume comprising a part of the robot tool and the robot tool is attached to a robot;

a second interface embodied for a second reception of a robot dataset, the robot dataset comprising a position of at least one movable axis of the robot during a recording of the image dataset; and

a computing unit embodied for determining at least one of a position and an orientation of a marking in the image dataset, said computing unit embodied for;

calculating at least one of an image-based position and image-based orientation of a tool center point of the robot tool by transforming at least one of the position and the orientation of the marking; and

calculating the calibration parameter based on the robot dataset and on at least one of the image-based position and the image-based orientation of the tool center point.

12. The calibration unit according to claim 11, wherein the image dataset contains a two-dimensional X-ray projection of the image volume.

13. The calibration unit according to claim 11, wherein the image dataset contains a three-dimensional volume image reconstructed from a plurality of two-dimensional X-ray projections of the image volume.

14. The calibration unit according to claim 13, wherein a reconstructed three-dimensional volume image is reconstructed from two-dimensional radiographic X-ray projections of the image volume.

15. The calibration unit according to claim 11, wherein a structure of the robot tool is depicted in the image dataset and the marking is embodied as the structure of the robot tool.

16. The calibration unit according to claim 15, wherein the step of calculating at least one of the image-based position and the image-based orientation of the tool center point is performed by registering the image dataset with a three-dimensional model of the robot tool.

17. The calibration unit according to claim 11, wherein the marking contains a plurality of marking elements, and the marking elements are disposed at least on one of an outside of the robot tool and inside the robot tool.

18. The calibration unit according to claim 11, wherein the step of calculating the calibration parameter is based on the robot dataset such that at least one of a predicted position and an orientation of the tool center point is calculated from the robot dataset, and that the calibration parameter contains deviations of at least one of the predicted position and the orientation from at least one of the image-based position and the image-based orientation.

19. The calibration unit according to claim 11, wherein the robot dataset furthermore contains an influencing variable of an environment of the robot, the influencing variable influences a measurement of at least one of the robot dataset and the position of the tool center point.

20. The calibration unit according to claim 19, wherein the influencing variable contains at least one of the following variables:

an ambient temperature;

a force acting on the robot tool; and

loading of the robot tool.

23. A robot, comprising:

a calibration unit for calculating a calibration parameter for a robot tool, said calibration unit comprising;

a first interface embodied for a first reception of an image dataset from medical imaging of an image volume, the image volume comprising a part of the robot tool and the robot tool is attached to a robot;

a second interface embodied for a second reception of a robot dataset, the robot dataset comprising a position of at least one movable axis of the robot during a recording of the image dataset; and

a computing unit embodied for determining at least one of a position and an orientation of a marking in the image dataset, said computing unit embodied for;

calculating at least one of an image-based position and an image-based orientation of a tool center point of the robot tool by transforming at least one of the position and the orientation of the marking; and

calculating a calibration parameter based on the robot dataset and on at least one of the image-based position and the image-based orientation of the tool center point.