Tactile sensor
First Claim
1. A tactile sensor for identifying the magnitudes and locations of pressures applied substantially contemporaneously thereto at a plurality of locations thereon, comprising:
- a resilient platen having upper and lower surfaces;
a plurality of laterally spaced pressure sensing sites underlying said lower surface;
each of said pressure sensing sites including emitter electrode means and companion collector electrode means surrounding said emitter electrode means in spaced relation therewith;
flexible conductive means on said lower surface of said platen overlying said pressure sensing sites and cooperable therewith when said platen is deflected downwardly against a selected site to receive current emitted from said emitter electrode means and to conduct to said companion collector electrode means substantially all of the current flowing into the conductive means from said emitter electrode means; and
control means for measuring, and for determining the locations of said sites constituting the source of, the current conducted from said emitter electrode means to said collector electrode means at each of said sites.
2 Assignments
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Accused Products
Abstract
A sensitive, durable, high resolution tactile sensor particularly suited for use as a robot end effector in an automated manufacturing process. The tactile sensor has an array of pressure sensing sites provided by a series of current emitter electrodes surrounded by a series of companion current collector electrodes both of which engage a rough conductive layer carried on the underside of a resilient platen. The emitters are electrically connected together in parallel rows, and the collectors are electrically connected together in parallel columns above and across the rows. The emitters and collectors are electrically insulated from one another as are the rows and columns. When the platen engages an object to apply pressure at one of the sites, and a positive voltage is applied to an emitter electrode, current flows from the emitter electrode and through the conductive layer to the companion collector electrode from which it is collected and measured. Cross-multiplexing circuitry scans the rows and columns periodically to provide a readout of both the location and magnitude of applied pressure.
79 Citations
30 Claims
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1. A tactile sensor for identifying the magnitudes and locations of pressures applied substantially contemporaneously thereto at a plurality of locations thereon, comprising:
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a resilient platen having upper and lower surfaces; a plurality of laterally spaced pressure sensing sites underlying said lower surface; each of said pressure sensing sites including emitter electrode means and companion collector electrode means surrounding said emitter electrode means in spaced relation therewith; flexible conductive means on said lower surface of said platen overlying said pressure sensing sites and cooperable therewith when said platen is deflected downwardly against a selected site to receive current emitted from said emitter electrode means and to conduct to said companion collector electrode means substantially all of the current flowing into the conductive means from said emitter electrode means; and control means for measuring, and for determining the locations of said sites constituting the source of, the current conducted from said emitter electrode means to said collector electrode means at each of said sites. - View Dependent Claims (2, 3, 4, 5)
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6. A tactile sensor for identifying the locations of pressures applied substantially contemproaneously thereto at a plurality of locations thereon, comprising;
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a series of sensing sites arranged in a predetermined pattern; one of said sites including first current emitter means, and first current collector means surrounding said first current emitter means; another of said sensing sites including second current emitter means spaced laterally from said first current emitter means, and second current collector means surrounding said current emitter means; a resilient platen having an obverse contact surface and a reverse surface; flexible conductive means on said reverse surface of said platen cooperating therewith to provide microprotrusions transverse thereto, said conductive means engaging said current emitter and collector means and providing a portion of a circuit the resistance of which varies inversely with pressure applied across the conductive means; mounting means extending along the reverse surface of said platen for mounting said first and second current collector means in laterally spaced electrically insulated relation to define through said flexible conductive means a higher resistance to current flow between said first emitter means and said second collector means and between said second emitter means and said first collector means than provided between either current emitter means and its companion current collector means; whereby substantially all of the current flowing into the flexible conductive means from one emitter means is collected in its companion collector means. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A tactile sensor for generating a machine image of an object engaging and exerting pressures at a plurality of locations upon said sensor, comprising:
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an electrically substantially non-conductive elastomeric member having a top surface adapted to contact an object and a bottom surface; a flexible conductive layer on said bottom surface providing a plurality of microprotrusions transverse thereto, said conductive layer providing a portion of a circuit having an electrical resistance which varies inversely with pressure applied transversely thereto; an electrically insulated panel underlying said elastomeric member and having a topside and a bottomside; a first series of current emitter electrodes mounted in spaced relation in a first column on the topside of said panel; at least a second series of current emitter electrodes mounted in spaced relation on the topside of said panel in a second column extending alongside said first column; a first current collector means mounted on said panel in said first column and surrounding each of said emitter electrodes in said first column in coplanar relation therewith; at least a second current collector means mounted on said panel in said second column and surrounding each of said emitter electrodes in said second column in coplanar relation therewith; each of said emitter electrodes in said first and second columns being spaced laterally from their respective first and second collector means to provide electrical insulation therebetween; said first current collector means being spaced laterally from the second current collector means to provide electrical isolation therebetween; current supply means disposed in spaced rows on the underside of said panel transverse to said columns for supplying current to said current emitter electrodes in said columns; and frame means mounting said elastomeric member and panel in parallel relation with said emitter electrodes and said collector means engaged with said conductive layer; whereby substantially all of the current supplied to each current emitter electrode flows transversely into the conductive layer, laterally therethrough, and transversely into its companion current collector means when pressure is applied to the elastomeric member superadjacent thereto. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. Apparatus for use in providing a machine image of an object, comprising:
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means providing a plurality of closely-spaced pressure sensing sites; each of said pressure sensing sites including; a current emitter electrode, and a companion current collector electrode surrounding and spaced from said emitter electrode, means electrically connecting a series of said emitter electrodes together in a row; means electrically connecting an array of said current collector electrodes together in a column disposed at an angle to said row; said emitter and collector electrode connecting means each being arranged with like rows and columns of connecting means; a resilient platen having a topside adapted to contact an object and an underside with a rough flexible electrically conductive layer engaging said emitter and collector electrodes; said layer providing along the platen between each emitter electrode and its companion collector electrode a resistance which is less than the resistance between each emitter electrode and adjacent non-companion collector electrodes; control means for applying to the current emitter electrodes in a selected row a predetermined positive voltage potential and for simultaneously applying to the current collector electrodes in a series of selected columns a lower voltage potential to cause, at each pressure-receiving site situated along said selected row, current flow through said layer from said emitter electrode to said collector electrode of said site, said current flow being proportional to the pressure applied to said layer engaging said electrodes of said site; said control means including multiplexing means for effecting said voltage application in a predetermined sequence among said columns and rows and said control means including means for sequentially monitoring said current flow in said columns and for identifying the locations of the applied pressure among said pressure sensing sites; whereby both location and magnitude of pressure applied to the platen by the object can be determined. - View Dependent Claims (27, 28, 29)
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30. A method of producing a machine readable image of an object, comprising the steps of:
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applying pressure to the object with a sensor having a resilient platen with a pressure responsive conductive layer contacting a series of current emitter electrodes electrically connected in laterally spaced rows and surrounded by spaced current collector electrodes electrically connected in laterally spaced columns providing an array of sensing sites; applying to a selected one of said current emitter electrode rows a predetermined positive voltage potential and simultaneously applying to said collector electrode columns a lower voltage potential for causing current to flow from one emitter electrode in said selected row and through said layer only to an immediately adjacent current collector electrode in a selected column; collecting substantially all of said current flow from said collector electrode of said selected column; and repeating said voltage applying step periodically among said rows and columns and periodically repeating said current collecting step among selected ones of said columns to provide an electrical output related to the shape of the object and the pressure with which it engages the platen.
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Specification