Biomimetic Tactile Sensor

• US 20070227267A1
• Filed: 03/28/2007
• Published: 10/04/2007
• Est. Priority Date: 03/28/2006
• Status: Active Grant

• Current Assignee: University of Southern California
• Original Assignee: The Alfred E. Mann Institute For Biomedical Engineering At The University Of Southern California (University of Southern California)
• Inventors: Loeb, Gerald, Johansson, Roland
• Granted Patent: US 7,658,119 B2
• Time in Patent Office: Days
• US Class Current: 73/862.46
• CPC Class Codes: B25J 13/084 Tactile sensors in general G01L5/16, G01L5/22
• CPC Class Codes: G01D 5/1655 more than one point of contact or actuation on one or more tracks
• CPC Class Codes: G01D 5/2417 by varying separation
• CPC Class Codes: G01L 5/228 using tactile array force sensors

Abstract

Disclosed is a tactile sensory system consisting of set of sensors that work by measuring impedance among plurality of electrodes. The electrodes are deployed on a substantially rigid structure that is protected form the direct contact with external objects by overlying deformable structures. These mechanical structures have similarities to the biological relationships among the distal phalanx, overlying finger pulp and covering skin and nail. Signal information is extracted form these sensors that is related to canonical physical representations used to describe stimuli to be sensed.

Claims

1. ) A biomimetic tactile sensor for providing an electrical indication of contact comprising:

a) a substantially rigid core having a curved surface, configured to hold a plurality of electrodes along the curved surface, wherein each of the electrodes is independently energized;

b) at least one deformable layer, configured to attach to the core, having an inner and an outer surface;

c) a volume of deformable material enclosed between the core and the at least one deformable layer inner surface; and

d) a detection circuitry mounted within the core and electrically coupled to the plurality of the electrodes, configured to independently energize at least one of the electrodes and detect contact information independently from the energized electrode, wherein the contact information corresponds to a local force that is exerted on the deformable layer outer surface.

2. ) The biomimetic tactile sensor of claim 1, wherein the detected contact information from the electrode is a measured impedance.

3. ) The biomimetic tactile sensor of claim 2, wherein the detection circuit is further configured to transmit the measured impedance to an external processor.

4. ) The biomimetic tactile sensor of claim 1, wherein the deformable material is injected through a channel into the space between the deformable layer inner surface and the core.

5. ) The biomimetic tactile sensor of claim 1, wherein the deformable material is inflatable.

6. ) The biomimetic tactile sensor of claim 1, wherein the deformable material is a dielectric material selected from a group including gases, liquids and gels.

7. ) The biomimetic tactile sensor of claim 1, wherein the deformable material is an electrical conducting material selected from a group including aqueous gels;

non-aqueous gels and liquid crystal materials.

8. ) The biomimetic tactile sensor of claim 1, wherein the deformable material is volume-conducting material.

9. ) The biomimetic tactile sensor of claim 1, wherein the core is made from a material selected from group including titanium, aluminum, stainless steel, zirconia ceramic and alumina ceramic.

10. ) The biomimetic tactile sensor of claim 1, wherein the deformable layer is made from a dielectric material.

11. ) The biomimetic tactile sensor of claim 10, wherein the deformable layer is made from dielectric material selected from a group including polymers and polyurethanes.

12. ) The biomimetic tactile sensor of claim 1, wherein the deformable layer further includes bumps and/or ridges on the inner and/or outer surface of the deformable layer.

13. ) The biomimetic tactile sensor of claim 1, wherein the deformable layer is made from electrical conductive material.

14. ) The biomimetic tactile sensor of claim 13, wherein the deformable layer is made from a material including any one of a woven metal fabric, metal-filled polymer and carbon-filled polymer.

15. ) The biomimetic tactile sensor of claim 1, further comprising a plurality of deformable layers.

16. ) The biomimetic tactile sensor of claim 1, wherein the at least one deformable layer is formed by dip-coating.

17. ) The biomimetic tactile sensor of claim 1, wherein the detection circuitry is configured to detect contact information corresponding to a normal force exerted on the deformable layer outer surface.

18. ) The biomimetic tactile sensor of claim 1, wherein the detection circuitry is configured to detect contact information corresponding to a tangential force exerted on the deformable layer outer surface.

19. ) The system of claim 1, wherein the detection circuitry is configured to determine contact information from the plurality of the electrodes that are held by the core.

20. ) The system of claim 1, wherein the detected contact information from the electrode is a measured capacitance.

21. ) A biomimetic tactile sensor for providing an electrical indication of contact comprising:

a) a substantially rigid core having a curved surface, configured to hold a plurality of electrodes along the curved surface;

b) at least one deformable layer having an inner and an outer surface, wherein the inner surface has at least one protruding element configured to attach to the core, and wherein the at least one protruding element is substantially opposed to at least one of the electrodes;

c) a volume of deformable material enclosed between the core and the at least one deformable layer inner surface; and

d) a detection circuitry mounted within the core, configured to detect a contact information from the at least one electrode.

22. ) The biomimetic tactile sensor of claim 21, wherein the detection circuitry is configured to detect information corresponding to a force exerted on the deformable layer outer surface.

23. ) The biomimetic tactile sensor of claim 22, wherein the detection circuitry is configured to detect contact information corresponding to a normal force exerted on the deformable layer outer surface.

24. ) The biomimetic tactile sensor of claim 22, wherein the detection circuitry is configured to detect contact information corresponding to a tangential force exerted on the deformable layer outer surface.

25. ) The biomimetic tactile sensor of claim 22, wherein the detection circuitry is configured to detect contact information corresponding to a shear force exerted on the deformable layer outer surface.

26. ) The biomimetic tactile sensor of claim 21, wherein the detected contact information from the electrode is a measured impedance.

27. ) The biomimetic tactile sensor of claim 21, wherein the deformable material is injected through a channel into the space between the deformable layer inner surface and the core.

28. ) The biomimetic tactile sensor of claim 21, wherein the deformable material is a dielectric material selected from a group including gas, liquid and gel.

29. ) The biomimetic tactile sensor of claim 21, wherein the deformable material is an electrical conducting material selected from a group including aqueous gel, non-aqueous gel and liquid crystal material.

30. ) The biomimetic tactile sensor of claim 21, wherein the deformable material is a volume-conducting material.

31. ) The biomimetic tactile sensor of claim 21, wherein the core is made from a material selected from a group including titanium, aluminum, stainless steel, zirconia ceramic and alumina ceramic.

32. ) The biomimetic tactile sensor of claim 21, wherein the deformable layer is made from a dielectric material.

33. ) The biomimetic tactile sensor of claim 32, wherein the deformable layer is made from material selected from a group including polymers and polyurethanes.

34. ) The biomimetic tactile sensor of claim 21, wherein the protruding element forms a bump and/or ridge on the inner surface of the deformable layer.

35. ) The biomimetic tactile sensor of claim 21, wherein the deformable layer is made from electrical conductive material.

36. ) The biomimetic tactile sensor of claim 21, wherein the deformable layer is made from a material including any one of a woven metal fabric, metal-filled polymer or carbon-filled polymer.

37. ) The biomimetic tactile sensor of claim 21, further comprising a plurality of deformable layers.

38. ) The biomimetic tactile sensor of claim 21, wherein the at least one deformable layer is formed by dip-coating.

39. ) The biomimetic tactile sensor of claim 21, wherein the detection circuitry is configured to determine contact information from the plurality of the electrodes.

40. ) The biomimetic tactile sensor of claim 21, wherein the detected contact information from the electrode is a measured capacitance

41. ) A biomimetic tactile sensory system for determining the characteristics of contact by an object against a deformable surface comprising:

a) a biomimetic tactile sensor configured to determine a contact information comprising;

i) a plurality of electrodes held on a curved surface of a core, wherein each of the electrodes has a proximal and a distal end;

ii) an energizing circuitry held within the core, configured to energize at least one of the plurality of electrodes,

iii) a volume of deformable material in contact with the plurality of the electrodes distal end;

iv) at least one deformable layer having an inner and outer surface, configured to cover the deformable material;

v) a detection circuitry held within the core, configured to determine a contact information from the at least one energized electrode and sending the determined contact information; and

b) a processor configured to receive the sent contact information in order to identify at least one characteristic of a contact by the object based on the detected contact information and a feature extraction algorithm.

42. ) The system of claim 41, wherein the detected contact information from the electrode is a measured impedance.

43. ) The system of claim 42, wherein the detection circuitry is configured to measure the impedance from the plurality of the electrodes.

44. ) The system of claim 43, wherein the measured impedance from the plurality of the electrodes make a distinct pattern.

45. ) The system of claim 41, wherein the feature extraction algorithm is a trainable algorithm.

46. ) The system of claim 45, wherein the trainable algorithm is a neural network.

47. ) The system of claim 41, wherein the characteristic of the contact is identified based at least on one feature of the object and spatiotemporal distribution of applied forces against the deformable layer.

48. ) The system of claim 41, further comprising a channel located within the core, configured to inject the deformable material.

49. ) The system of claim 48, further including a pressure transducer located within the core to monitor the pressure of the space occupied by the deformable material.

50. ) The system of claim 49, wherein the deformable material is inflated through the channel.

51. ) The system of claim 43, wherein the detecting circuitry is configured to detect changes in measured impedances among and/or from the plurality of the electrodes.

52. ) The system of claim 41, wherein the characteristic of the contact corresponds to any one of contact force, centroid and area of force, eccentricity of force, vector of force, vernier detection of force shifts, or contact transients and vibration.

53. ) The system of claim 41, wherein the deformable material is a dielectric.

54. ) The system of claim 41, wherein the deformable material is an electrical conductive material.

55. ) The system of claim 54, wherein the measured impedance is capacitance between the deformable layer and the electrode that are separated by a dielectric deformable material.

56. ) The system of claim 54, wherein the measured impedance is resistance between a deformable layer and the electrode separated by a weakly conductive deformable material.

57. ) The system of claim 41, wherein the deformable layer is a dielectric.

58. ) The system of claim 41, wherein the deformable layer is an electrical conductor.

59. ) The system of claim 41, wherein the energizing comprises applying a direct voltage or current.

60. ) The system of claim 41, wherein the energizing comprises applying an alternate voltage or current.

61. ) A biomimetic tactile sensory system for activating a prosthetic/disabled hand to grip an object comprising:

a) a biomimetic tactile sensor configured to determine a contact information comprising;

i) a plurality of electrodes held on a curved surface of a core, wherein each of the electrodes has a proximal and a distal end;

ii) an energizing circuitry configured to energize at least one of the plurality of electrodes,

iii) a volume of deformable material in contact with the plurality of the electrodes distal end;

iv) at least one deformable layer having an inner and outer surface, configured to cover the deformable material;

v) a detection circuitry configured to determine a contact information from the at least one energized electrode and sending the determined contact information;

b) a processor configured to receive the sent contact information in order to identify at least one characteristic of a contact by the object based on the detected contact information and a feature extraction algorithm; and

c) at least one actuator configured to activate the prosthetic/disabled hand based on an output data generated by the feature extraction algorithm in order to grip the object.

62. ) The system of claim 61, wherein the detected contact information from the electrode is a measured impedance.

63. ) The system of claim 62, wherein the detection circuitry is configured to measure impedance from the plurality of electrodes.

64. ) The system of claim 61, wherein the feature extraction algorithm is a trainable neural network.

65. ) The system of claim 63, wherein the biomimetic tactile sensor is an anatomical finger-like structure that is integrated into the prosthetic/disabled hand.

66. ) The system of claim 65, wherein the finger-like structure configured to exert more force on the object in order to grip the object.

67. ) The system of claim 65, wherein measured impedance from the plurality of electrodes change when the object is gripped.

68. ) The system of claim 61, wherein the characteristic of the contact corresponds to any one of contact force, centroid and area of force, eccentricity of force, vector of force, vernier detection of force shifts, or contact transients and vibration.

69. ) The system of claim 61, wherein the deformable material is a dielectric.

70. ) The system of claim 61, wherein the deformable material is an electrical conductor.

71. ) The system of claim 62, wherein the measured impedance is capacitance between the deformable layer and the electrode separated by a dielectric deformable material.

72. ) The system of claim 62, wherein the measured impedance is resistance between the deformable layer and the electrode separated by a weakly conductive deformable material.

73. ) The system of claim 61, wherein the deformable layer is a dielectric.

74. ) The system of claim 61, wherein the deformable layer is an electrical conductor.

75. ) The system of claim 62, wherein the biomimetic sensor further comprising a plurality of deformable layers.

76. ) The system of claim 61, wherein the deformable layer further comprising at least one protruding element positioned onto the inner surface, wherein the protruding element is substantially opposed to at least one of the electrodes.

77. ) The system of claim 76, wherein the detection circuitry produces a large change in impedance based on a lateral shift of the protruding element.

78. ) The system of claim 61, wherein the processor further is configured to determine if a slip of the object is imminent.

79. ) The system of claim 66, further comprising a plurality of biomimetic tactile sensors having anatomical finger-like structure that are integrated into the prosthetic/disabled hand.

80. ) A method of determining the characteristics of contact by an object against a deformable surface of a biomimetic tactile sensor comprising:

a) energizing at least one electrode from a plurality of electrodes held on a curved surface of a substantially rigid core of a the tactile sensor, wherein the electrode has a proximal and a distal end and wherein the at least one electrode distal end is in contact with a deformable material;

b) detecting contact information from the at least one energized electrode; and

c) sending the contact information to a processor in order to identify at least one characteristic of a contact based on the detected contact information and a feature extraction algorithm.

81. ) The method of claim 80, wherein the detected contact information from the electrode is a measured impedance.

82. ) The method of claim 80, wherein the energizing includes energizing a plurality of the electrodes and detecting contact information from them.

83. ) The method of claim 80, wherein the feature extraction algorithm is a trainable algorithm.

84. ) The method of claim 83, wherein the trainable algorithm is a neural network.

85. ) The method of claim 81, wherein the characteristic of the contact is identified based at least on one feature of the object and spatiotemporal distribution of applied forces by the object against the deformable layer.

86. ) The method of claim 80, wherein the characteristic of the contact corresponds to any one of contact force, centroid and area of force, eccentricity of force, vector of force, vernier detection of force shifts, or contact transients and vibration.

87. ) The method of claim 82, wherein the measured impedance comprises capacitance between a conductive deformable layer of the tactile sensor and the electrodes, and wherein the deformable layer and the electrodes are separated by a dielectric deformable material.

88. ) The method of claim 82, wherein the measured impedance is resistance between a conductive deformable layer and the electrodes separated by a weakly conductive deformable material.

89. ) The method of claim 82, wherein the detecting comprises detection of impedances between one electrode and other electrodes.

90. ) The method of claim 82, wherein the detecting comprises measurement of impedance between combination of the electrodes.

91. ) The method of claim 82, wherein the detecting comprises measurement of impedances from each of the electrodes.