Tactile sensing method and apparatus having grids as a means to detect a physical parameter

• US 4,839,512 A
• Filed: 01/27/1987
• Issued: 06/13/1989
• Est. Priority Date: 01/27/1987
• Status: Expired due to Term

• Current Assignee: Tactilitics Incorporated 1021 Pearl St Ste D Boulder Company
• Original Assignee: Tactilitics, Inc.
• Inventors: Speck, Richard P.
• Primary Examiner(s): Nelms, David C.
• Assistant Examiner(s): Ballen, Stephone B.
• Application Number:
  US07/007,256
• Time in Patent Office: 868 Days
• Field of Search: 250/227, 250/231 P, 250/231 R, 340/347 P, 340/780, 901/46, 901/47, 901/33, 364/558, 73/861.47, 73/861.53
• US Class Current: 250/231.1
• CPC Class Codes: G01L 1/146 for measuring force distributions, e.g. using force arrays G01L1/148 takes precedence
• CPC Class Codes: G01L 1/205 using distributed sensing elements
• CPC Class Codes: G01L 1/247 using distributed sensing elements, e.g. microcapsules along a single optical fibre G01L1/242
• CPC Class Codes: G01L 5/228 using tactile array force sensors
• CPC Class Codes: H03K 17/9622 using a plurality of detectors, e.g. keyboard
• CPC Class Codes: H03K 17/9625 using a force resistance transducer

Abstract

Apparatus for sensing locations and magnitudes of forces applied on a surface includes a grid comprised of energy input devices running in one direction and energy output devices running another direction with the input and output devices crossing each other. Transducers that meter energy from the input devices to the output devices as a function of the magnitude of forces applied thereon are positioned at the intersections of the input devices with the output devices. Interrogation apparatus is also included, along with energy output detectors and measuring devices, for sensing and determining locations, as well as magnitudes, of forces applied on the grid. Several embodiments of energy input and energy output devices are shown and described, as well as several embodiments of transducers.

Claims

1. Tactile sensing apparatus, comprising:

a grid having a plurality of elongated linear input means positioned in spaced apart relation to each other over a surface area for conducting input power to selected locations on said surface area and a plurality of elongated output means positioned in spaced apart relation to each other over the surface area for conducting power from said selected locations on said surface area, said output means intersecting said input means at said selected locations;

input energy feeder means connectable to said input means for feeding energy into said input means;

output energy detection means for detecting and measuring energy in said output means;

a plurality of transducer means positioned at said intersecting locations, each transducer means being connected one of said input means and to one of said output means for transferring energy from the input means to the output means in such a manner that the amount of energy transferred by the transducer means from an input means to an output means is a function of force applied to said transducer means;

input control means connected to said input energy feeder means for causing said input energy feeder means to feed energy to only selected ones of said input means at a time; and

data processing means for correlating output energy detected by said output energy detection means with said input control means for determining magnitudes and locations of forces applied to said respective transducers.

2. The tactile sensing apparatus of claim 1, wherein said linear input means include input electrical conductors, said linear output means include output electrical conductors, and said input energy feeder means includes an electric current source.

3. The tactile sensing apparatus of claim 2, wherein said transducer means includes variable resistance means in which the resistivity varies as a function of force applied to the variable resistance means, wherein said variable resistance means connects said input electrical conductor to said output electrical conductor.

4. The tactile sensing apparatus of claim 1, wherein said input control means includes input switch means connected between each of said input means and said input energy feeder means and input program means connected to said input switch means for connecting said input means one at a time sequentially to said input energy feeder means, and wherein said output energy detection means includes output switch means connected to each of said output means and output program means connected to said output switch means for connecting said output means one at a time sequentially to said output energy detection means.

5. The tactile sensing apparatus of claim 2, wherein said transducer means includes variable capacitance means in which the capacitance varies as a function of force applied to the variable capacitance means, wherein said variable capacitance means is connected between said input electrical conductor and said output electrical conductor.

6. The tactile sensing apparatus of claim 5, wherein said variable capacitance means includes two electrodes spaced apart from each other, a conductive plate positioned a spaced distance from said electrodes, and a compressible material positioned between said conductive plate and said electrodes in such a manner that a force applied on said transducer causes said material to compress and allow said conductive plate to move toward said electrodes.

7. The tactile sensing apparatus of claim 2, wherein said output energy detection means includes op-amp means connected to said output means for converting electric current in said output means to voltage output data that varies as a function of the current flowing in said output means.

8. The tactile sensing apparatus of claim 7, wherein said data processing means includes analog-to-digital converter means connected to said op-amp means for converting said voltage output data to digital form and a digital computer connected to said analog-to-digit converter means for processing, storing, and outputting force magnitude and location data.

9. The tactile sensing apparatus of claim 2, wherein said transducer means includes said input and output electrical conductors passing in close, non-contacting proximity to each other and wherein said input and output electrical conductors are movable toward and away from each other in response to a force applied on the transducer means.

10. The tactile sensing apparatus of claim 2, wherein said linear input means includes light-producing means connected to said input electrical conductors for converting electrical energy from said electric current source to light energy.

11. The tactile sensing apparatus of claim 10, wherein said linear input means includes an elongated input optical fiber that receives light from said light-producing means and transmits the light to said transducer means.

12. The tactile sensing apparatus of claim 11, wherein said linear output means includes an elongated output optical fiber, and said transducer means includes a portion of said input optical fiber that is positioned in parallel contacting relation with said output optical fiber creating a contacting surface area between said input and output optical fibers at which light is transferable from the input optical fiber to the output optical fiber in such a manner that the contacting surface area varies as a function of force applied on said transducer means, and including photovoltaic conversion means connected to said output optical fiber for converting light energy in said output optical fiber to electrical energy.

13. The tactile sensing apparatus of claim 10, wherein said transducer means includes photovoltaic conversion means for converting light energy to electrical energy and incident light control means for varying the intensity of light from said light-producing means incident on said photovoltaic conversion means as a function of a force applied on said transducer means.

14. The tactile sensing apparatus of claim 13, wherein said light control means includes said light-producing means and said photovoltaic conversion means being positioned a spaced distance apart from each other, a mask with a hole therethrough positioned in the space between said light-producing means and said photovoltaic conversion means, and yieldable resilient spacer means positioned in contact with both said light-producing means and said photovoltaic conversion means for yieldably holding said light-producing means and said photovoltaic conversion means apart.

15. The tactile sensing apparatus of claim 13, wherein said light control means includes said light-producing means and said photovoltaic conversion means positioned adjacent each other with an opaque barrier positioned between said light-producing means and said photovoltaic conversion means, reflective mirror means positioned a variable spaced distance over both said light producing means and said photovoltaic conversion means in such a manner that light produced by said light-producing means is reflected on said mirror to said photovoltaic conversion means and said mirror means is movable toward said light-producing means and said photovoltaic conversion means in response to a force applied on said transducer means.

16. The tactile sensing apparatus of claim 13, wherein said light-producing means includes an elongated electroluminescent strip capable of producing light along its entire length when connected to said electric current source.

17. The tactile sensing apparatus of claim 13, wherein said light-producing means includes a plurality of light-emitting diodes (LED'"'"'s).

18. The tactile sensing apparatus of claim 13, wherein said photovoltaic conversion means includes a semiconductor photovoltaic cell device in which electric current is produced by light incident thereon.

19. The tactile sensing apparatus of claim 13, wherein said photovoltaic conversion means includes an elongated photoconductor in which electric current is produced by light incident thereon.

20. The tactile sensing apparatus of claim 3, wherein said variable resistance means includes two electrical contacts spaced apart from each other and a compressible semiconductor material positioned between said contacts, wherein the resistivity of said semiconductor material varies as a function of the extent to which the material is compressed and wherein the extent to which the material is compressed varies as a function of the magnitude of compressive force applied to the material.

21. The tactile sensing apparatus of claim 3, wherein said variable resistance means includes two electrical contacts spaced apart from each other, each of said contacts having a surface area, and a semiconductor material positioned between and in contact with said electrical contact surface areas in such a manner that the area of semiconductor material that contacts one of said electrical contacts varies as a function of force applied to the transducer means.

22. The tactile sensing apparatus of claim 3, wherein said variable resistance means includes two electrodes positioned a spaced distance apart from each other, a stretchable, resilient sleeve attached to said electrodes and enclosing the space between said electrodes, and a semiconductor fluid filling said enclosed space.

23. The tactile sensing apparatus of claim 4, wherein said input program means and said output program means are coordinated together such that energy is fed into each of said input means sequentially as energy in each of said output means is detected and measured.

24. The tactile sensing apparatus of claim 23, wherein said data processing means is connected to said input control means and to said output energy detection means for detecting and correlating which of said input means is being fed energy and on which of said output means energy is being detected and the magnitude of such energy detected and for processing such input and output data into real time measurements of forces on specific transducer locations.

25. The tactile sensing apparatus of claim 24, including display means connected to said data processing means for displaying force magnitude and location data in a manner perceptible to human senses.

26. A method of sensing and measuring forces applied on a plurality of locations on a surface area, comprising the steps of:

forming a grid of energy input and energy output devices on the surface area, which grid includes a plurality of elongated energy input devices in spaced apart relation to each other and generally oriented to run in one direction on the surface and a plurality of elongated energy output devices in spaced apart relation to each other and generally oriented to run in another direction such that the energy input divides intersect the energy output devices;

connecting the energy input devices to the energy output devices at the intersecting locations with transducers that allow energy to flow therethrough from the energy input devices to the energy output devices in amounts that vary as a function of the magnitude of forces applied on the respective transducers;

feeding energy sequentially into selected input devices while isolating the other input devices from energy input and detecting and measuring energy sequentially in selected output devices while isolating the other output devices from energy output;

correlating and processing data indicating the input device to which energy is being fed with data indicating the output device from which energy is being detected and measured at any selected time and determining location of the transducer in the grid through which the detected and measured energy is being transferred from an input device to an output device at such selected time and further determining the magnitude of the force applied on that transducer location as a function of the measured energy at that selected time.

27. The method of claim 26, including the steps of:

using input electrical conductors for said input devices and using output electrical conductors for said output devices;

using variable resistance devices for said transducers in which resistance varies as a function of force applied on the transducer;

converting current flowing in said output conductors to output voltage data in such a manner that the output voltage data varies as a function of the current flowing in the respective output conductors from which such voltage data is produced; and

utilizing said voltage output data to determine that magnitude of respective forces applied on respective transducer locations.

28. The method of claim 26, including the steps of:

using input electrical conductors for said input devices and using output electrical conductors for said output devices;

using variable capacitance devices for transducers in which capacitance varies as a function of force applied on the transducer;

converting current in said output conductors to output voltage data in such a manner that the output voltage data varies as a function of the current in the respective output conductors from which such voltage data is produced; and

utilizing said voltage output data to determine the magnitude of respective forces applied on the respective transducer locations.

29. The method of claim 26, including the steps of:

using input electrical conductors for said input devices and using output electrical conductors for said output devices and feeding electrical energy into said input conductors in such a manner that dynamic magnetic fields are produced around said input conductors;

positioning said input and output conductors in close enough proximity to each other in said transducers that the magnetic field around input conductors induces voltage in the output conductors and in such a manner that the distance between the input and output conductors in each transducer is variable as function of force applied on the transducer;

utilizing voltage induced in the output conductors by the magnetic field around the input conductors to determine the magnitude of respective forces applied on respective transducers.

30. The method of claim 26, including the steps of:

using light producing devices for said input devices and using output electrical conductors for said output devices;

using photovoltaic current producing devices connected to the output electrical conductors for transducers with the photovoltaic current producing devices positioned in such a manner that light intensity incident on said photovoltaic current producing devices is variable as a function of force applied on said transducer;

converting current produced by said photovoltaic current producing devices to output voltage data in such a manner that the output voltage data in such a manner that the output voltage data varies as a function of the current flowing in the respective output conductors from which such voltage data is produced; and

utilizing said voltage output data to determine the magnitude of respective forces applied on respective transducer locations.

31. The method of claim 26, including the steps of:

using input optical fibers for said input devices and using output optical fibers for said output device;

feeding light energy into the input optical fibers;

transferring light from input optical fibers to output optical fibers at the transducer locations, in such a manner that the amount of light transferred from an input optical fiber to an output optical fiber varies as a function of force applied on the transducer;

utilizing the light in the output optical fibers to determine the magnitude of respective forces applied on respective transducer locations.

32. The method of claim 31, including the step of positioning the optical fibers in parallel contact with each other in said transducers in such a manner that light can transfer from an input optical fiber to an output optical fiber and the surface contact area between said input and output optical fibers and in such a manner that the surface contact area varies as a function of force applied on the transducer.

33. The method of claim 31, including the step of converting light energy in said output optical fibers to output electrical energy with photoelectric cells and utilizing the output electrical energy to determine the magnitude of respective forces applied on respective transducer locations.