METHOD AND SYSTEM FOR OPERATING A ROBOT

Abstract

In a method and system for operating a robot, at least one first direction, in which an external load acting on a reference is not reliably detectable on the basis of detected joint loads due to the vicinity to a singular position of the robot, is displayed as not being monitored on the basis of detected joint loads, and/or at least one second direction, in which an external load acting on the reference is reliably detectable on the basis of detected joint loads despite the vicinity to the singular position, is displayed as being monitorable on the basis of detected joint loads. Additionally or alternatively, at least one first direction is blocked if an external load acting on the reference in said direction is not reliably detectable on the basis of detected joint loads due to the vicinity to a singular position of the robot, and if at least one direction is blocked and multiple joints of the robot are simultaneously actuated, a monitoring process is carried out on the basis of detected joint loads for an external load acting on the reference in at least one second direction, in which an external load acting on the reference is reliably detectable on the basis of detected joint loads despite the vicinity to the singular position.

Claims

1-10. (canceled)

11. A method for operating a robot for planning and/or performing a movement of a robot-fixed reference, the method comprising at least one of: visually displaying an indication that at least one first direction of movement of the robot fixed reference is not being monitored by a controller on the basis of detected joint loads, in which first direction an external load at the robot-fixed reference is not reliably detectable on the basis of detected joint loads due to the vicinity of the robot pose to a singularity position of the robot, or visually displaying an indication that at least one second direction of movement of the robot fixed reference is monitorable on the basis of detected joint loads, in which second direction an external load at the robot-fixed reference is reliably detectable on the basis of detected joint loads despite the vicinity of the robot pose to the singularity position.

12. The method of claim 11, wherein at least one of: at least two first directions are visually displayed as not being monitored on the basis of detected joint loads, in each of which first directions an external load at the robot fixed reference is not reliably detectable on the basis of detected joint loads due to the vicinity of the robot pose to a singularity position; or at least two second directions are visually displayed as being monitorable on the basis of detected joint loads, in each of which second directions an external load at the robot-fixed reference is reliably detectable on the basis of detected joint loads despite the vicinity of the robot pose to a singularity position.

13. The method of claim 11, further comprising: outputting a warning when an external load at the robot-fixed reference in the at least one first direction is not reliably detectable on the basis of detected joint loads due to the vicinity of the robot pose to the singularity position of the robot.

14. The method of claim 11, wherein visually displaying an indication with respect to at least one of the at least one first direction of movement or the at least one second direction of movement comprises visually displaying the indication on at least one of: the robot; a control device for controlling the robot; or a simulation environment for simulating movement of the robot-fixed reference.

15. The method of claim 14, wherein visually displaying comprises graphically displaying.

16. The method of claim 13, wherein outputting a warning comprises visually displaying the warning on at least one of: the robot; a control device for controlling the robot; or a simulation environment for simulating movement of the robot-fixed reference.

17. The method of claim 11, further comprising: during a movement of the robot-fixed reference, monitoring an external load at the robot-fixed reference in the at least one second direction on the basis of detected joint loads.

18. The method of claim 11, further comprising: blocking the robot-fixed reference against movement in the at least one first direction in response to an external load at the robot-fixed reference in the at least one first direction being not reliably detectable on the basis of detected joint loads due to the vicinity of the robot pose to a singularity position; and carrying out a monitoring process of an external load at the robot-fixed reference in the at least one second direction on the basis of detected joint loads in response to multiple joints of the robot being simultaneously actuated.

19. The method of claim 18, wherein at least one of: blocking against movement in the at least one first direction comprises blocking at least two first directions; carrying out the monitoring process in the at least one second direction comprises carrying out the monitoring process in at least two second directions.

20. The method of claim 11, wherein at least one of: the at least one first direction has at least one of a translational direction or a rotational direction; the at least one second direction has at least one of a translational direction or a rotational direction; the at least one first direction is determined on the basis of a Jacobian matrix between velocities of the robot-fixed reference and joint velocities; the at least one second direction is determined on the basis of a Jacobian matrix between velocities of the robot-fixed reference and joint velocities; or the robot-fixed reference is a robot end flange-fixed reference.

21. A system for operating a robot, the system comprising at least one of: means for visually displaying at least one of: an indication that at least one first direction of movement of the robot fixed reference is not being monitored by a controller on the basis of detected joint loads, in which first direction an external load at the robot-fixed reference is not reliably detectable on the basis of detected joint loads due to the vicinity of a pose of the robot to a singularity position of the robot, or an indication that at least one second direction of movement of the robot fixed reference is monitorable on the basis of detected joint loads, in which second direction an external load at the robot-fixed reference is reliably detectable on the basis of detected joint loads despite the vicinity of the robot pose to the singularity position; or means for: blocking the robot-fixed reference against movement in the at least one first direction in response to an external load at the robot-fixed reference in the at least one first direction being not reliably detectable on the basis of detected joint loads due to the vicinity of the robot to a singular position, and carrying out a monitoring process of an external load at the robot-fixed reference in the at least one second direction on the basis of detected joint loads in response to the at least one first direction being blocked and multiple joints of the robot being simultaneously actuated.

22. A computer program product for operating a robot, the computer program product comprising a program code stored on a non-transitory, computer-readable medium, the program code, when executed on a computer, causing the computer to at least one of: visually display at least one of: an indication that at least one first direction of movement of a robot fixed reference is not being monitored by a controller on the basis of detected joint loads, in which first direction an external load at the robot-fixed reference is not reliably detectable on the basis of detected joint loads due to the vicinity of a pose of the robot to a singularity position of the robot, or an indication that at least one second direction of movement of the robot fixed reference is monitorable on the basis of detected joint loads, in which second direction an external load at the robot-fixed reference is reliably detectable on the basis of detected joint loads despite the vicinity of the robot pose to the singularity position; or perform the following: block the robot-fixed reference against movement in the at least one first direction in response to an external load at the robot-fixed reference in the at least one first direction being not reliably detectable on the basis of detected joint loads due to the vicinity of the robot pose to a singularity position, and carry out a monitoring process of an external load at the robot-fixed reference in the at least one second direction on the basis of detected joint loads in response to the at least one first direction being blocked and multiple joints of the robot being simultaneously actuated.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0074] 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.

[0075] FIG. 1 schematically depicts a system for operating a robot according to one embodiment of the present invention; and

[0076] FIG. 2 is a flow chart of a method for operating the robot according to one embodiment of the present invention.

DETAILED DESCRIPTION

[0077] FIG. 1 shows, by way of example, a six-axis or six-jointed robot (arm) 10, the joint positions or loads thereof are indicated by q.sub.1, . . . , q.sub.6 (joint positions or rotational angles) or .sub.1, . . . , .sub.6 (detected joint loads or torques), wherein the joint positions q.sub.1, . . . , q.sub.6 determine the pose of its end flange and therefore of the TCP 11.

[0078] By way of example, an external load in the form of a horizontal force f.sub.x, the line of action of which runs through the axes of rotation of the joints, and a vertical force f.sub.z are indicated at the TCP 11.

[0079] 12 designates a robot controller with which a handheld control device 13 communicates.

[0080] In the vicinity of the illustrated singular position of the robot 10, the force f.sub.x can no longer be reliably detected on the basis of the detected joint loads .sub.1, . . . , .sub.6; in the depicted singular position, it cannot be detected at all and therefore also cannot be reliably detected. This force direction can be determined on the basis of a Jacobian matrix between velocities of the reference and joint velocities, since the corresponding (first) column of the transposed Jacobian matrix J.sup.T has zeros in the singular position, since a force f.sub.x does not cause a non-zero torque in any of the joints.

[0081] In contrast, despite the vicinity to the illustrated singular position of the robot 10, the force f.sub.z can still be reliably detected on the basis of the detected joint loads .sub.1, . . . , .sub.6, even in the illustrated singular position. This direction can also be determined on the basis of the Jacobian matrix, since the corresponding (third) column of the transposed Jacobian matrix J.sup.T has more than just zeros in the singular position, since the force f.sub.z causes different torques from zero in the second, third and fifth joint.

[0082] In each case, the robot controller 12 determines the Jacobian matrix on the basis of a current position of the robot (FIG. 2: step S10) and from this, (first) directions in which external loads on the reference 11 are not reliably detectable on the basis of detected joint loads due to the vicinity to a singular position of the robot .sub.1, . . . , .sub.6.

[0083] These first directions are then indicated in a step S20 as not being monitored on the basis of detected joint loads, preferably on the robot, as indicated in FIG. 1 by a corresponding (activated) illuminating means S, and/or on the handheld control device 13, as indicated in FIG. 1 by a corresponding graphical visualization. In addition, for example, a visual and/or acoustic warning can be output, preferably on the robot and/or the handheld control device.

[0084] In this way, a user can recognize that forces in the horizontal direction in the vicinity of the position shown in FIG. 1 are not reliably detectable on the basis of detected joint loads.

[0085] If this is unproblematic, it can nevertheless command a movement in (one) of the first direction(s) (in the exemplary embodiment, this is only possible in positions that deviate slightly from the shown singular position).

[0086] However, if it determines, for example, that an obstacle 20 is present in the corresponding direction, there is the possibility that the robot will collide with the obstacle 20 without this being noticed by a collision monitoring system which determines external loads on the TCP 11 on the basis of the detected joint loads .sub.1, . . . , .sub.6 and monitors them for exceeding limit values.

[0087] In a modification, in step S20 the first direction is not or not only indicated but, optionally additionally, blocked so that the user cannot command a movement of the TPC 11 in the horizontal direction in the vicinity of the position shown in FIG. 1.

[0088] In other, second directions, monitoring of external loads on the TCP is carried out, while the first direction is blocked and multiple joints of the robot are simultaneously actuated. For example, the comparison of FIG. 1 to FIGS. 3 and 4 of DE 10 2017 204 211 A1 illustrates that the joints 2, 3 and 5 can be actuated simultaneously, since the force in the second direction f.sub.z can be reliably detected despite the vicinity to the singular position, and the movement options can therefore be significantly expanded compared to DE 10 2017 204 211 A1.

[0089] Although embodiments have been explained in the preceding description, it is noted that a large number of modifications are possible.

[0090] The corresponding first directions can therefore also be displayed analogously when planning a movement, for example in a simulation environment 30. For a more compact illustration, the handheld control device 13 and the simulation environment 30 are illustrated by the same figure element in FIG. 1.

[0091] In addition or alternatively to the display of first directions, in a modification (not shown), second directions in which external loads on the reference are reliably detectable on the basis of detected joint loads despite the vicinity to the singular position can also be displayed (and preferably monitored) as being monitorable on the basis of detected joint loads, for example analogously to the symbol S on the robot 10 or analogously to the graphical visualization on the handheld control device 13 or in the simulation environment 30. As explained elsewhere, it may be advantageous to display only the first or only the second directions. Likewise, both first and second directions can also be displayed, purely by way of example in different colors, preferably first directions in a warning color.

[0092] Likewise, the corresponding first directions can also be blocked when planning a movement.

[0093] It is also noted that the 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 a person skilled in the art with guidelines for implementing at least one exemplary embodiment, wherein various changesin particular with regard to the function and arrangement of the described componentsare able to be made without departing from the scope of protection as it arises from the claims and from these equivalent combinations of features.

[0094] 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 SIGNS

[0095] 10 Robot (arm) [0096] 11 TCP (robot (end flange)-fixed reference) [0097] 12 Robot controller [0098] 13 Control device [0099] 20 Obstacle [0100] 30 Simulation environment [0101] S Illuminating means