Master/slave electroactive polymer systems

• US 20030067245A1
• Filed: 05/31/2002
• Published: 04/10/2003
• Est. Priority Date: 10/05/2001
• Status: Active Grant

• Current Assignee: SRI International, Inc.
• Original Assignee: SRI International, Inc.
• Inventors: Kornbluh, Roy D., Pelrine, Ronald E.
• Granted Patent: US 6,876,135 B2
• Time in Patent Office: Days
• US Class Current: 310/311
• CPC Class Codes: A43B 3/34 with electrical or electronic arrangements
• CPC Class Codes: H10N 30/1071 with electrical and mechanical input and output, e.g. having combined actuator and sensor parts
• CPC Class Codes: H10N 30/802 Drive or control circuitry or methods for piezoelectric or electrostrictive devices not otherwise provided for
• CPC Class Codes: H10N 30/857 Macromolecular compositions
• CPC Class Codes: Y10S 310/80 Piezoelectric polymers, e.g. PVDF

Abstract

The present invention relates to improved devices, systems and methods that convert between electrical and mechanical energy. An electroactive polymer transducer converts between electrical and mechanical energy. An active area is a portion of an electroactive polymer transducer. The active area comprises a portion of an electroactive polymer and at least two electrodes that provide or receive electrical energy to or from the portion. The present invention relates to transducers and devices comprising multiple active areas that are in electrically communication. More specifically, the present invention relates to master/slave arrangements for multiple active areas disposed on one or more electroactive polymers. In a master/slave arrangement, a first active area deflects (a ‘master’), and a second active area reacts (a ‘slave’). Communication electronics in electrical communication with electrodes for the first active area and in electrical communication with electrodes for the second active area transfer electrical energy between the two active areas.

Claims

1. A device for converting between electrical and mechanical energy, the device comprising:

a first active area that converts between electrical energy and mechanical energy, the first active area comprising a first portion of at least one electroactive polymer and at least two first active area electrodes in electrical communication with the first portion;

a second active area that converts between electrical energy and mechanical energy, the second active area comprising a second portion of the at least one electroactive polymer and at least two second active area electrodes in electrical communication with the second portion; and

communication electronics, in electrical communication with the first active area and in electrical communication with the second active area, that transfer at least a portion of an electrical energy change from one of the first active area and the second active area to the other of the first active area and the second active area.

2. The device of claim 1 wherein the communication electronics are passive.

3. The device of claim 2 wherein the communication electronics comprise a wire.

4. The device of claim 1 wherein the communication electronics introduce a time delay before transferring the portion of the electrical energy change between the first active area and the second active area.

5. The device of claim 1 wherein the communication electronics comprise a capacitor.

6. The device of claim 1 wherein the communication electronics comprise a diode.

7. The device of claim 6 wherein the diode prevents backflow of current from the other of the first active area and the second active area.

8. The device of claim 7 wherein the diode allows electrical energy to accumulate in the other of the first active area and the second active area.

9. The device of claim 1 further comprising conditioning electronics in electrical communication with the at least two first or second active area electrodes and designed or configured to add or remove electrical energy from the at least two first or second active area electrodes.

10. The device of claim 1 wherein the communication electronics provide electrical energy generated by one of the first active area and the second active area to the other of the first active area and the second active area.

11. The device of claim 1 wherein the first active area is configured to generate electrical energy in response to external deflection and the communication electronics provide at least a portion of the generated electrical energy to the second active area.

12. The device of claim 11 wherein the second active area uses the portion of electrical energy to produce mechanical energy.

13. The device of claim 1 wherein the first active area and second active area are configured to form a logic function.

14. The device of claim 1 wherein the first or the second active area is configured for one of actuation, generation, sensing, or changing the stiffness for a portion of the device.

15. The device of claim 1 further comprising one or more mechanical transmission mechanisms that are designed or configured to receive external mechanical energy and to transfer a portion of the external mechanical energy to the first active area or the second active area, wherein the transferred portion of the mechanical energy results in a deflection in the active area receiving the external mechanical energy..

16. The device of claim 15 wherein the one or more mechanical transmission mechanisms are designed or configured to receive biologically-generated mechanical energy.

17. The device of claim 1 wherein the electroactive polymer is a dielectric elastomer.

18. The device of claim 17 wherein the dielectric elastomer is pre-strained.

19. The device of claim 1 wherein the polymer has an elastic modulus below about 100 MPa.

20. The device of claim 1 further comprising a substantially rigid member coupled to a third portion of the at least one electroactive polymer.

21. The device of claim 1 wherein one of the first and the second active areas is included in footwear.

22. The device of claim 1 wherein the at least one electroactive polymer is a monolithic polymer and the first and second active area are disposed on the monolithic polymer.

23. The device of claim 1 wherein the first active area and the second active area are electrically connected in series.

24. A device for converting between electrical and mechanical energy, the device comprising:

a first active area that converts mechanical energy to electrical energy, the first active area comprising a first portion of at least one electroactive polymer and at least two first active area electrodes in electrical communication with the first portion;

a second active area that converts electrical energy to mechanical energy, the second active area comprising a second portion of the at least one electroactive polymer and at least two second active area electrodes in electrical communication with the second portion; and

communication electronics, in electrical communication with the first active area and in electrical communication with the second active area, that transfer at least a portion of the electrical energy generated by the first active area to the second active area.

25. The device of claim 24 further comprising one or more mechanical transmission mechanisms that are designed or configured to receive mechanical energy and to transfer a portion of the mechanical energy to the first portion, wherein the transferred portion of the mechanical energy results in a deflection in the first portion.

26. The device of claim 25 wherein the one or more transmission mechanisms are designed or configured to receive biologically-generated mechanical energy.

27. The device of claim 24 wherein electrical energy transferred to the second active area is used for actuation of the second active area.

28. The device of claim 24 wherein electrical energy transferred to the second active area is used for changing the stiffness of the second active area.

29. The device of claim 24 further comprising conditioning electronics in electrical communication with the at least two first active area electrodes and designed or configured to add or remove electrical energy from the at least two first active area electrodes.

30. The device of claim 29 wherein the conditioning electronics are designed or configured to perform one or more of the following functions:

voltage step-up, voltage step-down and charge control.

31. The device of claim 24 further comprising:

a battery for storing electrical energy generated by the first active area or for providing electrical energy to the first active area.

32. The device of claim 24 wherein the communication electronics further comprise:

a logic device in electrical communication with the at least two first active area electrodes or the at least two second active area electrodes.

33. The device of claim 32 wherein the logic device is a microprocessor or a microcontroller.

34. The device of claim 24 wherein the communication electronics are passive.

35. The device of claim 24 wherein the communication electronics introduce a time delay before transferring electrical energy between the first active area and the second active area.

36. The device of claim 24 wherein the communication electronics comprise a diode.

37. The device of claim 36 wherein the diode prevents backflow of current from the second active area to the first active area.

38. The device of claim 37 wherein the diode allows electrical energy to accumulate in the second active area.

39. The device of claim 24 wherein the first portion and the second portion are included in a monolithic electroactive polymer.

40. The device of claim 24 wherein the electroactive polymer is a dielectric elastomer.

41. The device of claim 24 wherein the first active area is disposed on a first electroactive polymer of a first polymer type and the second active area is disposed on a second electroactive polymer of a second polymer type

42. A method for using multiple electroactive polymer active areas, the method comprising:

deflecting a first portion of at least one electroactive polymer, the first portion associated with a first active area;

receiving an electrical energy change in response to the first portion deflection; and

transferring at least a portion of the electrical energy change from the first active area to a second active area.

43. The method of claim 42 wherein the multiple electroactive polymer active areas are disposed on a monolithic electroactive polymer.

44. The method of claim 42 further comprising providing electrical energy to the first active area before the first portion deflection.

45. The method of claim 44 wherein the electrical energy provided to the first active area is less than the electrical energy needed to deflect the first portion.

46. The method of claim 45 wherein the first portion deflection increases the electrical field in the first active area.

47. The method of claim 42 further comprising storing the electrical energy change in a battery or capacitor.

48. The method of claim 42 wherein the second active area deflects in response to the electrical energy transferred from the first active area.

49. The method of claim 42 wherein the second active area increases in stiffness in response to the electrical energy transferred from the first active area.

50. The method of claim 42 further comprising regulating the rate of electrical energy transfer from the first active area to the second active area.

51. A device included in footwear for converting between electrical and mechanical energy during human bipedal motion, the device comprising:

a first active area that converts between electrical energy and mechanical energy, the first active area comprising a first portion of at least one electroactive polymer mounted in footwear and at least two first active area electrodes in electrical communication with the first portion;

a second active area that converts between electrical energy and mechanical energy, the second active area comprising a second portion of the at least one electroactive polymer and at least two second active area electrodes in electrical communication with the second portion;

communication electronics, in electrical communication with the first active area and in electrical communication with the second active area, that transfer at least a portion of an electrical energy change from one of the first active area and the second active area to the other of the first active area and the second active area; and

one or more transmission mechanisms that are designed or configured to receive mechanical energy generated during human bipedal motion and to transfer a portion of the mechanical energy to one of the first or second active area, wherein the transferred portion of the mechanical energy results in a deflection in the portion corresponding to the active area receiving the mechanical energy.

52. The device of claim 51 further comprising conditioning electronics connected to the at least two first active area electrodes and designed or configured to add or remove electrical energy from the first or the second active area.

53. The device of claim 51 wherein the one or more transmission mechanisms receives mechanical energy when a portion of the footwear contacts a surface during the human bipedal motion.

54. The device of claim 51 wherein the first or the second active area increases stiffness for a portion of the footwear.

55. The device of claim 51 wherein the first or the second active tightens a portion of the footwear.

56. The device of claim 51 wherein the footwear is one of a walking shoe, running shoe, athletic shoe for a particular sport, or fashion footwear.

57. The device of claim 51 wherein the first and the second active areas are disposed on a monolithic electroactive polymer.

58. The device of claim 51 wherein the second active area is also disposed in the footwear.

59. The device of claim 51 wherein the first active area is disposed on a first electroactive polymer of a first polymer type and the second active area is disposed on a second electroactive polymer of a second polymer type.