Operating machine with redundant axes and resolution of the redundancy in real time

Patent metadata

Field	Value
Publication number	US-9555546-B2
Application number	US-201414481479-A
Country	US
Kind code	B2
Filing date	Sep 9, 2014
Priority date	Sep 10, 2013
Publication date	Jan 31, 2017
Grant date	Jan 31, 2017

Abstract

A program for a numerical control device is disclosed that determines path points to be approached by an end effector. A control signal group is ascertained for each path point that contains its set point value for each position-controlled axis. Those values are output to the axes, moving the end effector. The degrees of freedom are fewer than the position-controlled axes. The control signal groups are ascertained so that the end effector approaches the path points at least approximately. The control signal groups are ascertained gradually during the activation of the axes. The set point values are ascertained by minimizing an objective function. The objective function that is minimized includes at least the set point values for a path point only to be approached in the future. The sequence between the currently approached point and the point approached in the future has at least one further path point.

First claim

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims and includes equivalents of the elements recited therein:

1. A control method that determines a sequence of path points to be approached by an end effector of an operating machine in a given number of degrees of freedom, comprising the steps of:
ascertaining a control signal group for each of the path points in the sequence, so that the respective control signal group for each path point contains respective position set points for a number of position-controlled axes of the operating machine for that path point, wherein the given number of degrees of freedom is smaller than the number of position-controlled axes;
ascertaining position set point values of the control signal groups by minimizing a respective objective function while currently approaching a path point of one of the control signal groups, at that time the respective objective function including at least the position set point values for a path point only to be approached in the future and one other path point between the path point currently being approached and the path point to be approached in the future in the sequence of path points; and
activating ascertained position set point values by providing the ascertained position set point values to the axes, each control signal group being ascertained such that the end effector approaches respective path points at least approximately during the activation of the position-controlled axes, and control signal groups are ascertained gradually during the activation of the position-controlled axes; and
moving the end effector with the axes using the ascertained position set point values.

2. The control method of claim 1 , further comprising the step of ascertaining position set point values for the path point to be approached next by minimizing the respective objective function.

3. The control method of claim 2 wherein a respective objective function also includes the position set point values of path points that are in the sequence of path points between the path point to be approached in the future and the path point to be approached next.

4. The control method of claim 1 , wherein each of the position set point values is ascertained for the path point to be approached in the future by minimizing the respective objective function.

5. The control method of claim 1 , wherein position set point values for several path points are ascertained by minimizing the respective objective function and form a coherent group within the sequence of path points to be approached that contains the path point to be approached in the future.

6. The control method of claim 1 , wherein path points are spaced at distances from each other, defined by time or by the path defined by the sequence of path points.

7. The control method of claim 1 , wherein a respective objective function also includes time derivatives of the position set point values included in the respective objective function.

8. The control method of claim 1 , wherein the objective function is determined such that it takes into account the rigidity of the end effector.

9. The control method of claim 1 , wherein singularities and software limits are taken into account in the objective function.

10. The control method of claim 1 , wherein the objective function includes deviations of an actual path produced by the position set point values from a desired path defined by the sequence of path points.

11. A system program for enabling an operating machine to determine a sequence of path points to be approached by an end effector of the operating machine in a given number of degrees of freedom, said program comprising:
a control signal group ascertained for each of the path points in the sequence, so that the respective control signal group for each path point contains respective position set points for a number of position-controlled axes of the operating machine for that path point, wherein the given number of degrees of freedom is smaller than the number of position-controlled axes;
position set point values of respective control signal groups, said position set point values being ascertained by minimizing a respective objective function while currently approaching a path point of one of the control signal groups, at that time the respective objective function including at least the position set point values for a path point only to be approached in the future and one other path point between the path point currently being approached and the path point to be approached in the future in the sequence of path points; and
activated ascertained position set point values that are activated by being provided to the axes that move the end effector, each control signal group being ascertained such that the end effector approaches respective path points at least approximately during the activation of the position-controlled axes, and control signal groups are ascertained gradually during the activation of the position-controlled axes.

12. The system program of claim 11 , further comprising a data medium on which the system program is stored in machine-readable form.

13. The system program of claim 11 , further comprising ascertained position set point values for the path point to be approached next that are ascertained by minimizing the respective objective function.

14. The system program of claim 13 , wherein a respective objective function also includes the position set point values of path points that are in the sequence of path points between the path point to be approached in the future and the path point to be approached next.

15. The system program of claim 11 , wherein each of the position set point values is ascertained for the path point to be approached in the future by minimizing the respective objective function.

16. The system program of claim 11 , wherein position set point values for several path points are ascertained by minimizing the respective objective function and form a coherent group within the sequence of path points to be approached that contains the path point to be approached in the future.

17. The system program of claim 11 , wherein path points are spaced at distances from each other, defined by time or by the path defined by the sequence of path points.

18. The system program of claim 11 , wherein a respective objective function also includes time derivatives of the position set point values included in the respective objective function.

19. The system program of claim 11 , wherein the objective function is determined such that it takes into account the rigidity of the end effector.

20. The system program of claim 11 , wherein singularities and software limits are taken into account in the objective function.

21. The system program of claim 11 , wherein the objective function includes deviations of an actual path produced by the position set point values from a desired path defined by the sequence of path points.

22. A programmed numerical control device using a system program for determining a sequence of path points to be approached by an end effector of an operating machine in a given number of degrees of freedom, comprising:
a control signal group ascertained for each of the path points in the sequence, so that the respective control signal group for each path point contains respective position set points for a number of position-controlled axes of the operating machine for that path point, wherein the given num

Assignees

• Siemens Ag

Inventors

• Hamm Carsten
• Tauchmann Sven

Classifications

• G05B2219/40336

  Optimize multiple constraints or subtasks · CPC title

• B25J9/1643 Primary

  redundant control · CPC title

• B25J9/1664 Primary

  characterised by motion, path, trajectory planning · CPC title

• G05B2219/40367

  Redundant manipulator · CPC title

• G05B2219/40333

  Singularity, at least one movement not possible, kinematic redundancy · CPC title