METHOD AND SYSTEM FOR TRANSFERRING AN END EFFECTOR OF A ROBOT BETWEEN ONE END EFFECTOR POSE AND A FURTHER END EFFECTOR POSE

Abstract

A method for transferring an end effector of a robot between an end effector pose and a further end effector pose, for at least one axis of the robot includes specifying the same uniform progression of the position of the axis, particularly in advance, for the transfer between the one end effector pose and the one further end effector pose, and for transfers between the one end effector pose and a group of other further end effector poses, more particularly in dependence on activation of a control operating mode. For at least one further axis of the robot, different progressions of the position of the further axis are commanded, more particularly during the transferring, for the transfer between the one end effector pose and the one further end effector pose and the transfer between the one end effector pose and the at least one of the further end effector poses.

Claims

1-10. (canceled)

11. A method for transferring an end effector of a robot between a first end effector pose and a second end effector pose, the method comprising: for at least one first axis of the robot, specifying the same, uniform progression of a position of the at least one first axis for the transfer between the first end effector pose and one second end effector pose, and for transfers between the first end effector pose and a group of other second end effector poses; and for at least one second axis of the robot, commanding different progressions of a position of the at least one second axis for the transfer between the first end effector pose and the one second end effector pose, and for the transfer between the first end effector pose and at least one of the other second end effector poses.

12. The method of claim 11, wherein at least one of: the uniform progression of the position of the first axis is specified in advance of the transfer; different progressions of the position of the at least one second axis are commanded during the transfer; or specifying the uniform progression of the position of the at least one first axis or commanding progressions of the position of the at least one second axis is performed as a function of an activation of a control operating mode of the robot.

13. The method of claim 11, further comprising: commanding positions of the at least one first axis and/or the at least one second axis on the basis of the uniform progression.

14. The method of claim 11, further comprising commanding positions of the at least one first axis on the basis of specified end effector poses.

15. The method of claim 11, wherein positions of the at least one second axis are commanded on the basis of at least one of: specified positions of the at least one first axis; or specified end effector poses.

16. The method of claim 11, characterized in that the at least one first axis is specified on the basis of a user selection.

17. The method of claim 11, further comprising: ascertaining a permissible range for the uniform progression of the position of the at least one first axis; wherein the uniform progression is specified within the permissible range.

18. The method of claim 17, wherein the permissible range is ascertained on the basis of a specified restriction.

19. The method of claim 17, wherein at least one of: the permissible range is ascertained based on at least one of: extreme positions for the second end effector pose, a specified area of second end effector poses, virtual transfers between the first end effector pose and the extreme positions of the second end effector poses, or an intersection of permissible individual ranges for a second end effector pose at each extreme position; or the uniform progression is specified on the basis of a specified quality criterion.

20. The method of claim 19, wherein the specified area of second end effector poses is defined by a convex envelope.

21. The method of claim 11, further comprising parameterizing the uniform progression based on a running parameter.

22. The method of claim 21, wherein at least one of: parameterizing the uniform progression comprises discretizing the uniform progression; or the running parameter is an end effector coordinate or a path section length.

23. A system for transferring an end effector of a robot between a first end effector pose and a second end effector pose, the system comprising: means for specifying, for at least one first axis of the robot, the same, uniform progression of the position of the at least one first axis for the transfer between the first end effector pose and one second end effector pose, and for transfers between the first end effector pose and a group of other second end effector poses; and means for commanding, for at least one second axis of the robot, different progressions of the position of the at least one second axis for the transfer between the first end effector pose and the one second end effector pose, and for the transfer between the first end effector pose and at least one of the other second end effector poses.

24. The system of claim 23, wherein at least one of: the uniform progression of the position of the FIRST axis is specified in advance of the transfer; different progressions of the position of the at least one second axis are commanded during the transfer; or specifying the uniform progression of the position of the at least one FIRST axis or commanding progressions of the position of the at least one second axis is performed as a function of an activation of a control operating mode of the robot.

25. A computer program product for transferring an end effector of a robot between a first end effector pose and a second end effector pose the computer program product including machine-readable program code stored on a non-transitory storage medium, the program code, when executed by a computer, causing the computer to: for at least one first axis of the robot, specify the same, uniform progression of the position of the at least one first axis for the transfer between the first end effector pose and one second end effector pose, and for transfers between the first end effector pose and a group of other second end effector poses; and for at least one second axis of the robot, command different progressions of the position of the at least one second axis for the transfer between the first end effector pose and the one second end effector pose, and for the transfer between the first end effector pose and at least one of the other second end effector poses.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the principles of the invention.

[0054] FIG. 1 depicts a system according to one embodiment of the present invention including a robot with a linear axis and a robot arm arranged thereon with an end effector;

[0055] FIG. 2 illustrates a permissible range for the uniform progression of the position of the linear axis; and

[0056] FIG. 3 is a flow chart that illustrates a method for transferring the end effector between one end effector pose and one further end effector pose according to one embodiment of the present invention.

DETAILED DESCRIPTION

[0057] FIG. 1 shows a system according to one embodiment of the present invention including a robot with a base 11 which may be moved on a linear axis with travel limitations 21, 22, a robot arm 10 with a swivel joint 12, which is situated in a further swivel joint 13 on the base 11 and comprises an end effector 14, and a robot controller 15.

[0058] The end effector 14 is to be transferred from arbitrary initial end effector poses x within a specified initial range A into the same target end effector pose without colliding with an obstacle H, these poses each being (defined) (by) the two-dimensional position of the end effector 14 in the image plane of FIG. 1 and the robot with the two swivel joints 12, 13 and the linear axis or these three axes being redundant with regard to this task.

[0059] In a first offline step S10, the initial range A is specified, a convex envelope U is placed around this range A, and all four corner points E1-E4 of this envelope, which form the extremes of the group of possible or permitted initial end effector poses, are virtual transfers B1-B4 planned between the extremes and the target end effector pose are planned, taking into account the travel limitations 21, 22 and avoiding a collision with the obstacle H.

[0060] For clarification, the robot is delineated in FIG. 1 by way of example in two positions of its linear axis, in which its end effector assumes or includes the end effector x.sub.B1(s=0.1) or x.sub.B1(s=1).

[0061] In a second offline step S20, a permissible individual range for the positions of the linear axis is ascertained for each of these virtual transfers B1-B4 or extremes E1-E4.

[0062] For this purpose, the limits q.sub.1, min, q.sub.1, max of the permissible individual range for the transfer B1 or from the extremum E1 to the target end effector pose for two values s=0.1, s=1 of a running parameter are shown in FIG. 1 in the form of a normalized path section length 0≤s≤1.

[0063] In FIG. 2, these limits are indicated by dash-dotted lines above the running parameter s, the corresponding limits of the permissible individual ranges for the other transfers B2-B4 or from the extremes E2-E4 to the target end effector pose are indicated by dashes, dots or double-dashes. They are ascertained in discrete steps ds=0.1.

[0064] Then, in step S20, a permissible (total) range for a uniform progression q.sub.1(s) of the position of the linear axis is ascertained as the intersection of these permissible individual ranges, which is indicated by hatching in FIG. 2.

[0065] In a third offline step S30, the uniform progression q.sub.1(s) is subsequently specified on the basis of a specified quality criterion, for example in such a way that an average distance from the limits of the permissible (overall) range is maximal or the like.

[0066] If the end effector 14 is then to be transferred from any of the group of permitted initial end effector poses A to the target end effector pose, a path is planned therefor in a first online step S40 and parameterized (x(s)) with the running parameter 0≤s≤1.

[0067] In a second online step S50, the respective position of the linear axis is ascertained for discrete steps ds of this running parameter in each case from the predefined uniform progression q.sub.1(s), the positions of the two rotary joints are ascertained from this position of the linear axis and from the corresponding end effector pose x(s) 12, 13 and these positions are commanded.

[0068] In this way, it is ensured that the linear axis has the same, predictable or reproducible behavior for each transfer from any of the initial end effector poses A into the target end effector pose. In addition, the offline specification of the uniform progression q.sub.1(s) may reduce the computing load.

[0069] Although exemplary embodiments have been explained in the preceding description, it is noted that a large number of modifications are possible. It is also noted that the exemplary embodiments are merely examples that are not intended to restrict the scope of protection, the applications and the structure in any way. Rather, the preceding description provides the person skilled in the art with guidelines for implementing at least one exemplary embodiment, with various changes, in particular with regard to the function and arrangement of the described components, being able to be made without departing from the scope of protection as it arises from the claims and from these equivalent combinations of features.

[0070] In addition or alternatively, for example, arbitrary target end effector poses may also be provided within a specified target range.

[0071] Instead of a standardized path section length s, an end effector coordinate may advantageously also be used directly, for example, the so-called kick angle of an end effector of a patient positioning robot about a reference direction of an irradiation unit.

[0072] In one embodiment, a uniform progression of the position of the linear axis of the patient positioning robot may similarly be specified offline, as explained above with reference to S10-S30, then a path of the six degrees of freedom of the end effector including this kick angle may be planned as explained above with reference to S40, and then for this path or kick angle in each case the associated position of the linear axis and from this the position of the arm of the patient positioning robot or its axis divisions are ascertained and commanded in each case from the predetermined uniform progression of the position of the linear axis for discrete kick angle changes.

[0073] While the present invention has been illustrated by a description of various embodiments, and while these embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such de-tail. The various features shown and described herein may be used alone or in any combination. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method, and illustrative example shown and described. Accordingly, departures may be made from such details without departing from the spirit and scope of the general inventive concept.

LIST OF REFERENCE NUMERALS

[0074] 10 Robot arm [0075] 11 Robot base [0076] 12, 13 Robot arm swivel joint (further or second axis) [0077] 14 End effector [0078] 15 Robot controller [0079] 21, 22 Linear axis travel limitation [0080] A Initial range [0081] B1-B4 Virtual transfer [0082] E1-E4 Extreme [0083] H Obstacle [0084] U Envelope [0085] X 2-D position of the end effector (end effector pose) [0086] s Path section length (run parameter) [0087] q.sub.1 Position of the first or linear axis