MEASUREMENT OF SLIDING FRICTION-INDUCED VIBRATIONS FOR BIOMIMETIC TACTILE SENSING
First Claim
1. A biomimetic tactile sensor system comprising:
- a rigid core having a surface;
an elastomeric skin surrounding at least a portion of the core and having an inner and outer surface, and configured and arranged to form a space for confining a fluid between the surface of the core and the inner surface;
a fluid disposed within the space between the elastomeric skin and the core, wherein the fluid comprises a hydraulic fluid;
a pressure sensor configured and arranged to detect pressure variations in the fluid produced by vibrations of the skin; and
a processing system configured and arranged to receive an output from the pressure sensor.
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Accused Products
Abstract
Tactile sensors are disclosed that mimic the human fingertip and its touch receptors. The mechanical components are similar to a fingertip, with a rigid core surrounded by a weakly conductive fluid contained within an elastomeric skin. The deformable properties of the finger pad can be used as part of a transduction process. Multiple electrodes can be mounted on the surface of the rigid core and connected to impedance measuring circuitry within the core. External forces deform the fluid path around the electrodes, resulting in a distributed pattern of impedance changes containing information about those forces and the objects that applied them. Strategies are described for extracting features related to the mechanical inputs and using this information for reflexive grip control. Controlling grip force in a prosthetic having sensory feedback information is described. Pressure transducers can provide sensory feedback by measuring micro-vibrations due to sliding friction.
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Citations
30 Claims
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1. A biomimetic tactile sensor system comprising:
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a rigid core having a surface; an elastomeric skin surrounding at least a portion of the core and having an inner and outer surface, and configured and arranged to form a space for confining a fluid between the surface of the core and the inner surface; a fluid disposed within the space between the elastomeric skin and the core, wherein the fluid comprises a hydraulic fluid; a pressure sensor configured and arranged to detect pressure variations in the fluid produced by vibrations of the skin; and a processing system configured and arranged to receive an output from the pressure sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A biomimetic tactile sensor system comprising:
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a rigid core having a surface; an elastomeric skin surrounding at least a portion of the core and having an inner and outer surface, and configured and arranged to form a space for confining a fluid between the surface of the core and the inner surface; a fluid disposed within the space between the elastomeric skin and the core, wherein the fluid comprises a hydraulic fluid; and a pressure sensor subsystem disposed within the core and configured and arranged to detect pressure variations in the fluid produced by vibrations of the skin and provide an electrical output indicative of the vibrations. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method of sensing vibration of a biomimetic sensor surface, the method comprising:
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causing relative movement between a biomimetic tactile sensor, having an elastomeric skin, and an object in contact with the elastomeric skin; detecting pressure fluctuations in a hydraulic fluid in contact with the elastomeric skin; and matching the detected pressure fluctuations to one or more entries in a database of pressure fluctuations corresponding to conditions of the interface between the elastomeric skin and the object. - View Dependent Claims (22, 23, 24, 25, 26)
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27. A method of adjusting the grip force of a manipulator, the method comprising:
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causing relative movement between a biomimetic tactile sensor, having an elastomeric skin, and an object in contact with the elastomeric skin; detecting pressure fluctuations in a hydraulic fluid in contact with the elastomeric skin; and adjusting the force between the object and the sensor based on the electrical signal indicative of pressure fluctuations.
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28. The method of 27, wherein the pressure fluctuations are used to determine the onset of slip.
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29. The method of 28, wherein the grip force is reduced until the onset of slip occurs in order to estimate the coefficient of static friction.
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30. The method of 29, wherein the coefficient of static friction is used to compute an adequate grip force according to a safety factor and the estimated coefficient of static friction.
Specification