Device and method for securing apparatuses with parts freely movable in space

• US 20030137219A1
• Filed: 12/17/2002
• Published: 07/24/2003
• Est. Priority Date: 12/19/2001
• Status: Active Grant

• Current Assignee: KUKA Roboter GmbH (Midea Group Co., Ltd)
• Original Assignee: KUKA Roboter GmbH (Midea Group Co., Ltd)
• Inventors: Steininger, Fritz, Heiligensetzer, Peter
• Granted Patent: US 7,031,807 B2
• Time in Patent Office: Days
• US Class Current: 310/328
• CPC Class Codes: B25J 13/084 Tactile sensors in general G01L5/16, G01L5/22
• CPC Class Codes: B25J 13/086 Proximity sensors
• CPC Class Codes: B25J 19/0091 Shock absorbers in general F16F
• CPC Class Codes: B25J 19/027 Electromagnetic sensing devices
• CPC Class Codes: B25J 19/063 working only upon contact with an outside object
• CPC Class Codes: F16P 3/12 with means, e.g. feelers, which in case of the presence of a body part of a person in or near the danger zone influence the control or operation of the machine F16P3/08 takes precedence
• CPC Class Codes: F16P 3/144 using light grids
• CPC Class Codes: F16P 3/148 using capacitive technology

Abstract

The invention relates to a safety device for apparatuses having parts freely movable in space, particularly handling equipment such as industrial robots or driverless transportation means, as well as a method for securing such apparatuses by means of such a safety device. The apparatuses have switching means which in the case of a collision of the moving parts with persons or objects emit a control signal through which the moving parts can be stopped or an emergency program can be started up, which brings about a movement sequence opposing the approach movement. The invention is characterized in that the safety device is constructed in the form of a tactile sensor system formed from optical waveguides and located on moving parts of the apparatus.

Claims

1. A safety device for apparatuses with parts freely movable in space, particularly for handling equipment, such as industrial robots or driverless transportation means, with switching means, which in the case of a collision of the moving parts with persons or objects emit a control signal making it possible to stop the moving parts or start up an emergency program bringing about a movement sequence opposing the approach movement, said device comprising a tactile sensor system formed from optical waveguides and located on movable parts of the apparatus.

2. The safety device according to claim 1, wherein the tactile sensor system is placed directly on housing parts of the apparatus.

3. The safety device according to claim 2, wherein the tactile sensor system is protected relative to the outside against mechanical effects by a shock absorbing, partly elastic layer.

4. The safety device according to claim 1, wherein the tactile sensor system is located outside and on the shock absorbing, partly elastic layer surrounding the housing parts.

5. The safety device according to claim 3, wherein the shock absorbing, partly elastic layer is made from a material with a mechanical efficiency between 0.5 and 0.7 and particularly with a mechanical efficiency of 0.6, the material having damping and resilience characteristics.

6. The safety device according to claim 3, wherein the shock absorbing, partly elastic layer is of soft polyurethane foam.

7. The safety device according to claim 6, wherein the tactile sensor system responds as from a force action of 0.5 to 1.5 N, particularly 1 N.

8. A safety device for apparatuses with parts freely movable in space, particularly for handling equipment, such as industrial robots or driverless transport means, with switching means, which in the case of a collision of the moving parts with persons or objects emit a control signal, particularly according to claim 7, said device comprising a contactless sensor system.

9. The safety device according to claim 8, wherein the further contactless sensor system is constructed as a capacitive sensor system with at least one sensor element formed from two or more electrodes.

10. The safety device according to claim 8, wherein the capacitive sensor system can detect people and other objects with a permittivity coefficient ≧

30, particularly in the range of 50.

11. The safety device according to claim 9, wherein the sensor elements in each case have three electrodes, which are constructed as a grounded electrode, a sensor electrode and a shielding electrode located between them.

12. The safety device according to claim 9, wherein the capacitive sensor system has several junction sensor elements with corresponding junction electrodes.

13. The safety device according to claim 12, wherein the sensor elements are subdivided into sectors.

14. The safety device according to claim 9, wherein the sensor elements can be blocked out individually or in groups, particularly in the case of a permitted approach of safety-relevant components.

15. The safety device according to claim 9, wherein the electrodes of at least one sensor element are asymmetrically arranged.

16. The safety device according to claim 9, wherein at least one sensor element has a crimped on shielding electrode.

17. The safety device according to claim 9, wherein when using several sensor elements at least the moving parts of the apparatus are enveloped in a closed sensor field.

18. The safety device according to claim 9, wherein the components of a given sensor element are wholly or partly located outside the apparatus housing.

19. The safety device according to claim 9, wherein the components of a given sensor element are located completely inside the apparatus housing.

20. The safety device according to claim 18, wherein the housing is made from a low permittivity coefficient material.

21. The safety device according to claim 20, wherein the housing is made from plastic.

22. The safety device according to claim 3, wherein the arrangement of the tactile sensor system, the capacitive sensor system and the shock absorbing, partly elastic layer takes place in the form of layers locally plane-parallel to the housing and whose sequence can also vary at random relative to the housing.

23. The safety device according to claim 22, wherein the two independent sensor systems act directly in an emergency off circuit of the apparatus.

24. The safety device according to claim 23, wherein a cyclic self-control of all the sensor faces is possible by starting a safety program, particularly through the approach of a testpiece during a control run.

25. The safety device according to claim 24, wherein the tactile and capacitive sensor systems are combined with a third system constructed as a motor current monitoring system for monitoring motor currents in electric motors provided for moving the moving parts in the apparatus and if the moving parts collide with persons or objects the control signal is emitted.

26. The safety device according to claim 25, wherein the sensor or monitoring systems are combined with at least one force-moment sensor through which the control signal can be emitted in the case of collisions between moving parts and persons or objects.

27. The safety device according to claim 26 wherein force-moment sensors are provided between the apparatus and tools located on said apparatus.

28. A method for securing apparatuses with parts freely movable in space, particularly for handling equipment, such as industrial robots or driverless transportation means, with switching means, which in the case of a collision of moving parts with persons or objects emit a control signal through which the moving parts can be stopped or an emergency program can be started up bringing about a movement sequence opposing the approach movement, wherein in the case of contact between a moving part of the apparatus, electromagnetic radiation guided by optical waveguides forming a tactile sensor system and located on said part is influenced, so that at least one control signal is emitted for initiating at least one safety-relevant action.

29. The method according to claim 28, wherein an approach of an object or person to the movable part of the apparatus is detected prior to any contact through an additional, contactless sensor system and a control signal is emitted for bringing about at least one safety-relevant action.

30. The method according to claim 29, wherein the control signal is brought about by a change in the capacitance of at least one capacitor located on the part and which forms part of a capacitive sensor system.

31. The method according to claim 29, wherein the safety-relevant action is brought about by the control signal of the tactile sensor system and the control signal of the capacitive sensor system in the sense of a logic OR operation of the two control signals.

32. The method according to claim 29, wherein at least one area of the capacitive sensor system is blocked out, so that no control signal is emitted despite an approach having taken place.

33. The method according to claim 29, wherein the capacitive sensor system detects objects and persons with a high permittivity coefficient.

34. The method according to claim 29, wherein the capacitive sensor system detects persons and objects with a permittivity coefficient ≧

b 30, particularly in the range of 50.

35. The method according to claim 29, wherein through a directivity of the elements of the capacitive sensor system essentially no components of the apparatus are detected.

36. The method according to claim 28, wherein a collision between a moving part of the apparatus and an object or a person is detected by an additional motor current monitoring system, which emits the control signal after measuring currents in electric motors associated with the moving parts of the apparatus and after a comparison of the measurement with theoretically expected currents and in the case of a given deviation.

37. The method according to claim 36, wherein a collision is detected by at least one additional force-moment sensor, which emits the control signal if unusual forces and/or moments occur.

38. The method according to claim 37, wherein the safety-relevant action is brought about the control signal of the motor current monitoring system and the force-moment sensor means in the sense of a logic OR operation of the two control signals.

39. The method according to claim 28, wherein through the control signal one or more of the following safety-relevant actions are initiated:

a) stopping the apparatus,

b) initiating a movement sequence opposing the collision movement, or

c) triggering an optical and/or acoustic alarm.