MOTION MONITORING OF A ROBOT MANIPULATOR

Abstract

A device and method for monitoring a motion of a robot manipulator, including operations of: defining a forbidden position for the robot manipulator, defining a curve running along the robot manipulator with a one-dimensional running coordinate s, wherein at least a subset of all locations of the curve is moved together with a current pose of the robot manipulator, and determining a distance d between a location of a current curve and/or a predicted curve and the forbidden position.

Claims

1. A method of monitoring a motion of a robot manipulator, the method comprising: defining a forbidden position for the robot manipulator; defining a curve running along the robot manipulator with a one-dimensional running coordinate s, wherein at least a subset of all locations of the curve is moved together with a current pose of the robot manipulator; and determining a distance d between a location of a current curve and/or a predicted curve and the forbidden position.

2. The method according to claim 1, further comprising: defining a radius r(s) around the curve, the radius r(s) indicating a safety distance to be maintained between the curve and the forbidden position; and verifying whether the distance d between the location of the current curve and/or the predicted curve and the forbidden position is less than the radius r(s).

3. The method according to claim 1, wherein the curve is defined by interpolation based on a finite number of prespecified locations on the robot manipulator as supporting points.

4. The method according to claim 1, wherein the curve is defined as a Bézier curve based on a finite number of prespecified locations on the robot manipulator as supporting points.

5. The method according to claim 4, wherein a tangent of a cubic Bézier curve is determined from each orientation of the robot manipulator at each of the prespecified locations.

6. The method according to claim 2, wherein the radius r(s) varies over the one-dimensional running coordinate s based on at least one of the following dependencies: dependence on a time: r(s,t); dependence on the local diameter of the robot manipulator: r(s); dependence on an opening state of a gripper at a distal end of the robot manipulator: r(s); dependence on a current effective velocity: r(v(s)); and dependence on an operating mode and/or an environment of the robot manipulator.

7. The method according to claim 1, wherein the forbidden position is arranged at a location on the robot manipulator and is moved together with a motion of the robot manipulator.

8. The method according to claim 1, wherein the curve runs through an axis of rotation of an articulated joint of the robot manipulator.

9. The method according to claim 1, wherein the distance d is a shortest distance between the current curve and/or the predicted curve and the forbidden position.

10. A device to monitor a motion of a robot manipulator, the device comprising a computing unit configured to: define a forbidden position for the robot manipulator; define a curve running along the robot manipulator with a one-dimensional running coordinate s, wherein at least a subset of all locations of the curve is moved together with a current pose of the robot manipulator; and determine a distance d between a location of a current curve and/or a predicted curve and the forbidden position.

11. The device according to claim 10, wherein the computing unit is further configured to: define a radius r(s) around the curve, the radius r(s) indicating a safety distance to be maintained between the curve and the forbidden position; and verify whether the distance d between the location of the current curve and/or the predicted curve and the forbidden position is less than the radius r(s).

12. The device according to claim 10, wherein the curve is defined by interpolation based on a finite number of prespecified locations on the robot manipulator as supporting points.

13. The device according to claim 10, wherein the curve is defined as a Bézier curve based on a finite number of prespecified locations on the robot manipulator as supporting points.

14. The device according to claim 13, wherein a tangent of a cubic Bézier curve is determined from each orientation of the robot manipulator at each of the prespecified locations.

15. The device according to claim 11, wherein the radius r(s) varies over the one-dimensional running coordinate s based on at least one of the following dependencies: dependence on a time: r(s,t); dependence on the local diameter of the robot manipulator: r(s); dependence on an opening state of a gripper at a distal end of the robot manipulator: r(s); dependence on a current effective velocity: r(v(s)); and dependence on an operating mode and/or an environment of the robot manipulator.

16. The device according to claim 10, wherein the forbidden position is arranged at a location on the robot manipulator and is moved together with a motion of the robot manipulator.

17. The device according to claim 10, wherein the curve runs through an axis of rotation of an articulated joint of the robot manipulator.

18. The device according to claim 10, wherein the distance d is a shortest distance between the current curve and/or the predicted curve and the forbidden position.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In the drawings:

[0047] FIG. 1 is a device for monitoring a motion of a robot manipulator according to an embodiment of the invention, and

[0048] FIG. 2 is a method for monitoring a motion of a robot manipulator according to a further embodiment of the invention.

DETAILED DESCRIPTION

[0049] The illustrations in the drawings are schematic and not to scale. FIG. 1 and FIG. 2 complement each other here. In particular in the description of FIG. 2, FIG. 1 can therefore also be used for a better understanding.

[0050] FIG. 1 shows a device 10 for monitoring a motion of a robot manipulator 1, including a computing unit 7 which is designed to define a forbidden position 3 for the robot manipulator 1, to define a curve 5 running along the robot manipulator 1 with a one-dimensional running coordinate s, wherein at least a subset of all locations of the curve 5 is moved together with a current pose of the robot manipulator 1, and to determine a distance d between a location of a current curve and/or a predicted curve 5 and the forbidden position 3, the distance d being the shortest distance between the current curve and/or predicted curve 5 and the forbidden position 3. The curve 5 is defined here as a Bézier curve based on a finite number of prespecified locations on the robot manipulator 1 as supporting points. FIG. 1 shows a cubic Bézier curve as a curve 5 with five supporting points, each of which lies on the axis of rotation of a joint between two links of the robot manipulator 1, and also at a base point and at a point on the end effector of the robot manipulator. The corresponding tangents of the Bézier curve are also defined for each of these supporting points. The radius r(s) is defined for the one-dimensional running coordinate s based on the dependence on a current effective velocity: r(v(s)).

[0051] FIG. 2 shows a method of monitoring a motion of a robot manipulator 1, wherein the method includes: [0052] defining S1 a forbidden position 3 for the robot manipulator 1, [0053] defining S2 a curve 5 running along the robot manipulator 1 with a one-dimensional running coordinate s, wherein at least a subset of all locations of the curve 5 are moved together with a current pose of the robot manipulator 1, and [0054] determining S3 a distance d between a location of a current curve and/or a predicted curve 5 and the forbidden position 3, [0055] defining S4 a radius r(s) around the curve 5, the radius r(s) specifying a safety distance to be maintained between the curve 5 and the forbidden position 3, and [0056] verifying S5 whether a distance d between a location of the current curve and/or the predicted curve 5 and the forbidden position 3 is less than the radius r(s).

[0057] Although the invention has been illustrated and explained in greater detail by means of preferred embodiments, the invention is not limited by the disclosed examples and other variations may be derived therefrom by a person skilled in the art without departing from the scope of protection of the invention. It is therefore clear that there are a plurality of possible variations. It is also clear that embodiments cited by way of example actually only constitute examples that are not to be interpreted in any way as a limitation of the scope, of the potential applications, or of the configuration of the invention. Rather, the preceding description and the description of the figures enable the person skilled in the art to specifically implement the embodiments, wherein the person skilled in the art, having knowledge of the disclosed inventive concept, is able to make numerous modifications—for example, with respect to the function or the arrangement of individual elements cited in an embodiment—without departing from the scope of protection, which is defined by the claims and their legal equivalents, such as a further explanation in the description.

LIST OF REFERENCE NUMERALS

[0058] 1 Robot manipulator

[0059] 3 Forbidden position

[0060] 5 Curve

[0061] 7 Computing unit

[0062] 10 Device

[0063] S1 Defining

[0064] S2 Defining

[0065] S3 Determining

[0066] S4 Defining

[0067] S5 Verifying