Teaching in a Holding Force for an Object in a Robotic Gripper

Abstract

A method of teaching in a holding force for holding an object by a gripper of a robot manipulator, the gripper having gripper jaws elastically deformable in a reversible manner, the method including: closing the gripper until the gripper jaws contact the object at contact points of the gripper jaws; externally applying a desired closing force at connection points of the gripper jaws to gripper jaw bearings such that the connection points move relative to the contact points, thereby elastically deforming the gripper jaws; actuating a gripper drive to maintain the current position of the connection points and terminating the closing force externally applied onto the connection points; and ascertaining and storing a value of a gripping force or a gripping torque, wherein the gripping force or the gripping torque is produced by elastic deformation of the gripper jaws and is exerted onto the connection points by the gripper jaws.

Claims

1. A method of teaching in a holding force for holding an object by a gripper of a robot manipulator, wherein the gripper has gripper jaws which are elastically deformable in a reversible manner (7), the method comprising: closing the gripper until the gripper jaws contact the object at contact points of the gripper jaws; externally applying a desired closing force at connection points of the gripper jaws to gripper jaw bearings, such that the connection points move relative to the contact points, thereby elastically deforming the gripper jaws; actuating a gripper drive in order to maintain a current position of the connection points, such that after termination of the closing force as externally applied onto the connection points, the connection points maintain their current position; ascertaining and storing a value of a gripping force or a gripping torque, wherein the gripping force or the gripping torque is produced by the elastic deformation of the gripper jaws and is exerted onto the connection points by the gripper jaws.

2. The method according to claim 1, wherein the gripper jaw bearings are portions on a closed belt, and the connection points of the gripper jaws are belt-side ends of the gripper jaws, and wherein the contact points of the gripper jaws with the object are within a region of free ends of the gripper jaws.

3. The method according to claim 2, wherein the gripping force is ascertained in a force sensor, the force sensor ascertaining a force applied to the belt.

4. The method according to claim 2, wherein the gripping force is ascertained in a torque sensor, the torque sensor being arranged on a pulley.

5. The method according to claim 1, wherein the gripping force is ascertained in a torque sensor, the torque sensor being arranged on the gripper drive.

6. The method according to claim 1, wherein closing the gripper jaws of the gripper until the gripper jaws contact the object at contact points of the gripper jaws takes place by actuating the gripper drive.

7. The method according to claim 1, wherein closing the gripper jaws of the gripper until the gripper jaws contact the object at contact points of the gripper jaws takes place by manually guiding the gripper jaws.

8. The method according to claim 1, wherein the externally applied desired closing force is a manually applied force.

9. The method according to claim 1, wherein the externally applied desired closing force is a force applied by a second gripper of a second robot manipulator.

10. A robot system to teach in a holding force for holding an object, the system comprising: a robot manipulator comprising a gripper arranged on the robot manipulator, the gripper having gripper jaws which are elastically deformable in a reversible manner; and a computing unit configured to: close the gripper until the gripper jaws contact the object at contact points of the gripper jaws; externally apply a desired closing force at connection points of the gripper jaws to gripper jaw bearings, such that the connection points move relative to the contact points, thereby elastically deforming the gripper jaws; actuate a gripper drive in order to maintain a current position of the connection points, such that after termination of the closing force as externally applied onto the connection points, the connection points maintain their current position; and ascertain and store a value of a gripping force or a gripping torque, wherein the gripping force or the gripping torque is produced by the elastic deformation of the gripper jaws and is exerted onto the connection points by the gripper jaws.

11. The system according to claim 10, wherein the gripper jaw bearings are portions on a closed belt, and the connection points of the gripper jaws are belt-side ends of the gripper jaws, and wherein the contact points of the gripper jaws with the object are within a region of free ends of the gripper jaws.

12. The system according to claim 11, wherein the gripping force is ascertained in a force sensor, the force sensor ascertaining a force applied to the belt.

13. The system according to claim 11, wherein the gripping force is ascertained in a torque sensor, the torque sensor being arranged on a pulley.

14. The system according to claim 10, wherein the gripping force is ascertained in a torque sensor, the torque sensor being arranged on the gripper drive.

15. The system according to claim 10, wherein closing the gripper jaws of the gripper until the gripper jaws contact the object at contact points of the gripper jaws takes place by actuating the gripper drive.

16. The system according to claim 10, wherein closing the gripper jaws of the gripper until the gripper jaws contact the object at contact points of the gripper jaws takes place by manually guiding the gripper jaws.

17. The system according to claim 10, wherein the externally applied desired closing force is a manually applied force.

18. The system according to claim 10, wherein the externally applied desired closing force is a force applied by a second gripper of a second robot manipulator.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In the drawings:

[0034] FIG. 1 shows a method for teaching in a holding force for holding an object by a gripper of a robot manipulator according to an embodiment of the invention,

[0035] FIG. 2 shows a gripper according to a further embodiment of the invention, and

[0036] FIG. 3 shows a robot system with a robot manipulator and with a computing unit and with a gripper arranged on the robot manipulator according to a further embodiment of the invention.

[0037] The illustrations in the figures are schematic and not to scale.

DETAILED DESCRIPTION

[0038] FIG. 1 shows a method for teaching in a holding force for holding an object 9 by a gripper 5 of a robot manipulator 3, the gripper 5 having gripper jaws which can be elastically deformed in a reversible manner 7, the method including: [0039] closing S1 the gripper 5 until the gripper jaws 7 contact the object 9 at contact points 15 of the gripper jaws 7, wherein the gripper jaws 7 of the gripper 5 are closed until the gripper jaws 7 contact the object 9 at contact points 15 of the gripper jaws 7 by actuating the gripper drive 17, [0040] externally applying S2 a desired closing force at connection points 13 of the gripper jaws 7 to gripper jaw bearings 11, such that the connection points 13 move relative to the contact points 15, thereby elastically deforming the gripper jaws 7, [0041] actuating S3 a gripper drive 17 in order to maintain the current position of the connection points 13 and terminating the closing force externally applied onto the connection points 13, and [0042] ascertaining and storing S4 a value of a gripping force or a gripping torque, wherein the gripping force or the gripping torque is produced by the elastic deformation of the gripper jaws 7 and is exerted onto the connection points 13 by the gripper jaws 7.

[0043] FIG. 2 shows a gripper 5. The gripper 5 has elongated gripper jaws 7 made of plastic. The gripper jaws 7 each have a free end and, opposite thereto, a connection point 13 which is connected to the same belt, albeit on opposite sides of the belt. The belt forms the belt bearings 11, wherein the portion of the belt which is located at the corresponding connection point 13 is referred to as the corresponding belt bearing 11. The gripper jaw bearings 11 are therefore certain portions on the closed belt, and the connection points 13 of the gripper jaws 7 are ends of the gripper jaws 7 on the belt side. The contact points 15 of the gripper jaws 7 with the object 9 are in the region of the free ends of the gripper jaws 7. The belt is driven by a gripper drive 17 on which a torque sensor is also arranged.

[0044] FIG. 3 shows a robot system 1 with a robot manipulator 3 and with a computing unit 19 and with a gripper 5 arranged on the robot manipulator 3, as shown in FIG. 2. The robot system 1 is used to teach in a holding force for holding an object 9 using the gripper 5 of the robot manipulator 3. The gripper 5 has gripper jaws 7 made of plastic which can be fully elastically deformed in a reversible manner. The computing unit 19 of the robot manipulator 3 is designed, after an external application of a desired closing force at connection points 13 of the gripper jaws 7 to gripper jaw bearings 11, such that the connection points 13 move relative to the contact points 15, thereby elastically deforming the gripper jaws 7, to actuate a gripper drive 17 in order to maintain the current position of the connection points 13, such that, after the termination of the external force applied to the connection points 13, the connection points 13 maintain their position. Furthermore, the computing unit 19 is designed to ascertain and store a value of a gripping force or a gripping torque, wherein the gripping force or the gripping torque is produced by the elastic deformation of the gripper jaws 7 and is exerted onto the connection points 13 by the gripper jaws 7.

[0045] Even though the invention has been illustrated and explained in greater detail via preferred embodiments, the invention is not limited by the disclosed examples, and other variations can 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 is a plurality of possible variations. It is also clear that embodiments mentioned by way of example actually only constitute examples that are not to be interpreted in any way as a limitation of the scope of protection, of the potential applications, or of the configuration of the invention. Instead, the preceding description and the description of the figures allow a person skilled in the art to specifically implement the example embodiments, wherein a 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 mentioned 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

[0046] 1 Robot system [0047] 3 Robot manipulator [0048] 5 Gripper [0049] 7 Gripper jaws [0050] 9 Object [0051] 11 Gripper jaw bearings [0052] 13 Connection points [0053] 15 Contact points [0054] 17 Gripper drive [0055] 19 Processing unit [0056] S1 Closing [0057] S2 Externally applying [0058] S3 Actuating [0059] S4 Ascertaining and storing