Apparatus for the automated handling of workpieces

Patent metadata

Field	Value
Publication number	US-9302396-B2
Application number	US-201313929652-A
Country	US
Kind code	B2
Filing date	Jun 27, 2013
Priority date	Jun 29, 2012
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

An apparatus for the automated handling of workpieces comprising an object recognition device for detecting the workpiece and a gripper arranged at a gripping arm for picking the workpieces and a control for evaluating the data of the object recognition device, for track planning and for controlling the gripping arm and the gripper and comprising a compensation unit which allows an evasion movement of the gripper, wherein the compensation unit only allows an evasion movement of the gripper on the exceeding of a predefined first load of the gripping arm and remains rigid below the first load, wherein the first load is larger than a load exerted on the gripping arm solely by the gripper and/or the picked workpiece.

First claim

The invention claimed is:

1. An apparatus for automated handling of workpieces, comprising
an object recognition device for detecting the workpieces;
a gripper arranged at a gripping arm for picking up the workpieces;
a control for evaluating data of the object recognition device, for track planning and for controlling the gripping arm and the gripper; and
a compensation unit which allows an evasion movement of the gripper, wherein
the compensation unit only allows the evasion movement of the gripper on the exceeding of a predefined first load of the gripping arm and remains rigid below the first load, wherein the first load is larger than a load exerted on the gripping arm solely by the gripper and the picked up workpieces at least in a travel position of the gripper.

2. The apparatus in accordance with claim 1 , wherein the compensation unit has a sensor arrangement which recognizes an evasion movement occurring due to a collision, wherein the control comprises a first overload function that detects and monitors, based on the sensor arrangement, an occurrence of a collision state, wherein the first overload function permits, upon a detection of a collision state, a continuation of a normal travel operation of the gripping arm for a permitted travel path, and stops the normal travel operation of the gripping arm and restarts a new picking up procedure if the collision state persists and the normal travel operation of the gripping arm exceeds the permitted travel path.

3. The apparatus in accordance with claim 2 , wherein the apparatus comprises two compensation units connected in series, with a first compensation unit being a compensation unit having a spherical compensation movement and a second compensation unit being a compensation unit having a linear compensation movement; wherein the two compensation units are preloaded via separate preloading means and deflect at different loads of the gripping arm.

4. The apparatus in accordance with claim 3 , wherein the control is configured so that it changes an orientation of the gripper after picking up of a workpiece with a slanted gripper such that static forces acting on the compensation unit by a gripper's own weight and a weight of the workpiece are reduced.

5. The apparatus in accordance with claim 4 , wherein the gripper is directed downwardly into a travel position.

6. The apparatus in accordance with claim 4 , wherein the change in the orientation takes place on lifting of the workpiece and wherein a deflection of the compensation unit on lifting of the workpiece is not treated as a collision state.

7. The apparatus in accordance with claim 2 , wherein the permitted travel path corresponds to a second load of the gripping arm and wherein the control has a second overload function which intervenes on the exceeding of a predefined third load of the gripping arm, with the third load being larger than the first load and the second load.

8. The apparatus in accordance with claim 7 , wherein the second overload function caries out an emergency stop on recognition of an overload so that the gripping arm can only be released again by a manual user intervention.

9. The apparatus in accordance with claim 7 , wherein the second overload function monitors a load on one or more drives of the gripping arm for detecting a load that exceeds the predefined third load.

10. The apparatus in accordance with claim 2 , wherein the first overload function, if it detects that the collision state is no longer present and the permitted travel path is not exceeded, allows the normal travel operation of the gripping arm to continue without interruption.

11. The apparatus in accordance with claim 2 , wherein the first overload function monitors, on detection of the collision state, travel path information of the gripping arm provided by the control of the gripping arm for monitoring whether the normal travel operation of the gripping arm exceeds the permitted travel path.

12. The apparatus in accordance with claim 2 , wherein the permitted travel path is smaller than a compensation path provided by the compensation unit.

13. The apparatus in accordance with claim 12 , wherein the first overload function initiates, once the normal travel operation of the gripping arm exceeds the permitted travel path, a braking operation, and the permitted travel path is chosen such that the braking operation brings the gripping arm to a stop before it exceeds the compensation path provided by the compensation unit, taking into account processing time of the control and reaction times of drives of the gripping arm.

14. The apparatus in accordance with claim 1 , further comprising a base unit and a compensation plate which is engaged around by a holding region of the base unit and is preloaded against the base unit and the holding region via a spring arrangement such that the compensation unit only allows an evasion movement between the base unit and the compensation plate on the exceeding of a predefined first load and remains rigid below the first load, with one or more sensors advantageously being provided which monitor a placing of the compensation plate at the holding region, with the one or more sensors advantageously being arranged in the holding region.

15. The apparatus in accordance with claim 14 , wherein the compensation plate is round and/or an edge of the compensation plate is rounded; and/or wherein the evasion movement between the base unit and the compensation plate allows a spherical compensation movement and the compensation unit furthermore has a second compensation unit which allows a linear compensation movement, with the two compensation units advantageously being preloaded via separate preloading means and/or deflecting at different loads of the gripping arm; and/or wherein the second compensation unit advantageously has one or more bars which are linearly guided in a guide and are preloaded via a spring.

16. A method of operating an apparatus for automated handling of workpieces, wherein the apparatus comprises:
an object recognition device for detecting the workpieces;
a gripper arranged at a gripping arm for picking the workpieces;
a control for evaluating data of the object recognition device, for track planning and for controlling the gripping arm and the gripper;
and a compensation unit which allows an evasion movement of the gripper on the exceeding of a first load of the gripping arm, comprising
selecting the first load to be larger than forces occurring in normal operation due to a gripper's own weight and a weight of a workpiece at least in a travel position of the gripper, wherein the compensation unit remains rigid below the first load so that evasion movements of the gripper are prevented in normal operation.

17. The method in accordance with claim 16 , wherein after the picking up of a workpiece with a slanted gripper, an orientation of the gripper is changed such that static forces acting on the compensation unit by the gripper's own weight and the weight of the workpiece are reduced.

18. The method in accordance with claim 17 , wherein the gripper is directed downwardly into a travel position.

19. The method in accordance with claim 17 , wherein the change in the orientation takes place on lifting of the workpiece and wherein a deflection of the compensation unit on lifting is not treated as a collision state.

20. An apparatus for the automated handling of workpieces, comprising:
an object recognition device for detecting the workpieces;
a gripper arranged at a gripping

Assignees

• Liebherr Verzahntech Gmbh

Inventors

• Mattern Thomas
• Haenschke David
• Riedmiller Bernhard
• Mundt Alois

Classifications

• B25J17/0233

  with radial compliance, i.e. perpendicular to the longitudinal wrist axis · CPC title

• B25J9/1612

  characterised by the hand, wrist, grip control · CPC title

• B25J17/0225

  with axial compliance, i.e. parallel to the longitudinal wrist axis · CPC title

• G05B2219/40559

  Collision between hand and workpiece, operator · CPC title

• B25J13/08 Primary

  by means of sensing devices, e.g. viewing or touching devices · CPC title