Claims
- 1. A plurality of sensor assemblies embedded in an elastomeric material, each said sensor assembly comprising:
a pair of first strain sensors disposed on first opposed faces of a flexible pyramid-shaped body, said first strain sensors detecting a force in a first direction, wherein said first strain sensors generate corresponding output signals in response to the force in the first direction, and wherein the force in the first direction is generally equal to the difference between the output signals of said first strain sensors; a pair of second strain sensors disposed on second opposed faces of said body, said second opposed faces adjacent to said first opposed faces, and said second strain sensors detecting a force in a second direction generally orthogonal to said first direction, wherein said second strain sensors generate corresponding output signals in response to the force in the second direction, and wherein the force in the second direction is generally equal to the difference between the output signals of said second strain sensors; wherein a sum of the first output signals and the second output signals is indicative of a force in a third direction, and wherein the plurality of sensor assemblies are embedded in a tire in mutually spaced relationship.
- 2. The sensor assembly of claim 1, further including a bus to communicate signals generated by the plurality of sensor assemblies.
- 3. The sensor assembly of claim 2, wherein said bus is a five-wire bus.
- 4. The sensor assembly of claim 1, wherein a contact region is defined at a position where the tire contacts a surface.
- 5. The sensor assembly of claim 4, wherein, when the tire is operation, each of the plurality of sensors passes said contact region at a different time.
- 6. A process of producing a sensor embedded in an elastomeric material, the process comprising:
providing a sensor assembly including a pyramid-shaped body and first and second pairs of strain sensors; disposing the first pair on first opposed faces of the pyramid-shaped body; and disposing the second pair on second opposed faces of the pyramid-shaped body.
- 7. The process of claim 6, further comprising the step of placing the sensor assembly in the elastomeric material when the elastomeric material is in an uncured state.
- 8. The process of claim 6, wherein the elastomeric material comprises a vehicle tire.
- 9. The process of claim 8, further comprising the step of embedding a plurality of three-axis sensor assemblies around the circumference of the vehicle tire.
- 10. The process of claim 9, wherein the sensor assemblies are positioned in mutually spaced relationship.
- 11. The process of claim 10, wherein the sensor assemblies are positioned such that only one of the sensor assemblies passes through the contact patch of the tire during operation at a particular time.
- 12. The process of claim 9, further comprising the step of providing a sensing system including a sensor bus.
- 13. The process of claim 12, wherein the sensor bus includes a plurality of conductors, each of the conductors corresponding to one strain axis to be monitored.
- 14. The process of claim 12, wherein three orthogonal strain axes are monitored.
- 15. The process of claim 12, wherein the outputs of the sensor bus are electrically coupled to a transmitter.
- 16. The process of claim 12, wherein the bus is a passive sensor bus.
- 17. The process of claim 12, wherein the sensing system connects the strain gauges of the sensor assemblies in parallel.
- 18. A tire sensor assembly embedded in an elastomeric tire at a particular radial depth inward from a contact patch of the tire, said sensor assembly comprising:
a flexible generally pyramid-shaped body; a pair of first strain sensors disposed on first opposed faces of said pyramid-shaped body, said first strain sensors detecting a force in a first direction; and wherein each face of said first opposed faces is non-planar.
- 19. The sensor assembly of claim 18, wherein said first opposed faces are curved.
- 20. The sensor assembly of claim 18, further comprising:
a pair of second strain sensors disposed on second opposed faces of said pyramid-shaped body, said second strain sensors detecting a force in a second direction, wherein each face of said second opposed faces is non-planar.
- 21. The sensor assembly of claim 20, wherein said first strain sensors generate corresponding output signals in response to the force in the first direction, and wherein the force in the first direction is generally equal to the difference between the output signals of said first strain sensors, and wherein said second strain sensors generate corresponding output signals in response to the force in the second direction, and wherein the force in the second direction is generally equal to the difference between the output signals of said second strain sensors.
- 22. The sensor assembly of claim 20, wherein said first and second opposed faces are generally symmetrical about an axis extending longitudinally through the apex of said pyramid-shaped body.
- 23. The sensor assembly of claim 20, wherein said first and second opposed faces are curved so as to allow adjustment of the sensitivity of the sensor assembly generally independent of the radial depth.
- 24. The sensor assembly of claim 20, wherein the sensor assembly is more sensitive to a tensile strain than to a shear strain.
- 25. The sensor assembly of claim 24, wherein said first and second opposed faces are concave.
- 26. The sensor assembly of claim 20, wherein said first and second opposed faces are convex.
- 27. The sensor assembly of claim 18, wherein said first pair of strain sensors are resistive strain sensors.
- 28. The sensor assembly of claim 18, wherein said first pair of strain sensors generate said first and second output signals differentially.
- 29. The sensor assembly of claim 18, wherein said first pair of strain sensors are arranged in a Wheatstone bridge circuit to detect said forces in said first direction.
- 30. The sensor assembly of claim 18, further including a second material that encapsulates said first pair of strain sensors, said second material being different than the material of the elastomeric tire.
- 31. The sensor assembly of claim 30, wherein a ratio of elastic moduluses between the material of the elastomeric tire and the second material correspondingly scales the strain forces sensed by the strain sensors.
- 32. The sensor assembly of claim 30, wherein the second material is one of polyimide and epoxy.
- 33. The sensor assembly of claim 18, further including an adhesive to couple the first pair of strain sensors to the pyramid-shaped body.
- 34. The sensor assembly of claim 33, further including a potting material disposed on the sensor assembly.
- 35. The sensor assembly of claim 34, wherein said potting material and said adhesive are the same.
- 36. The sensor assembly of claim 34, further including a topping layer disposed on said potting material so as to scale strain forces sensed by the first pair of strain sensors.
- 37. The sensor assembly of claim 20, wherein the forces in the first and second directions are indicative of tire traction.
- 38. A method of embedding a sensor in a tire, the method comprising:
providing a sensor assembly including a first pair of strain sensors disposed on first opposed faces of a generally pyramid-shaped body; and shaping the first opposed faces of the pyramid-shaped body so that each face of the first opposed faces is non-planar.
- 39. The method of claim 38, wherein the sensor assembly is a three-axis sensor assembly including a second pair of strain sensors disposed on second opposed faces of the pyramid-shaped body, and further including the step of shaping the second opposed faces so that each face of the second opposed faces is non-planar.
- 40. The method of claim 39, wherein the first and second opposed faces of the pyramid-shaped body are curved.
- 41. The method of claim 38, wherein said shaping step includes shaping the first opposed faces of the pyramid-shaped body so the faces are concave.
- 42. The method of claim 38, wherein said shaping step includes shaping the first opposed faces of the pyramid-shaped body so the faces are convex.
- 43. The method of claim 38, wherein said shaping step is based on a desired sensitivity of the sensor.
- 44. The method of claim 43, wherein the desired sensitivity is greater sensitivity to a tensile strain and less sensitivity to a shear strain.
- 45. A sensor assembly embedded in an elastomeric material of a vehicle tire at a depth radially inward from a contact patch of the tire, the sensor assembly comprising:
a flexible body; a strain sensing element disposed on said flexible body; and wherein said body includes curved faces that are shaped so as to allow adjustment of the sensitivity of the sensor assembly generally independent of the radial depth.
- 46. The sensor assembly of claim 45, wherein said flexible body is generally pyramid-shaped.
- 47. A sensor assembly comprising:
a first pair of strain sensors, each strain sensor detecting an associated first force, wherein the vector difference of the associated first forces is shear strain in a first direction; a second pair of strain sensors each strain sensor detecting an associated second force, wherein the vector difference of the associated second forces is shear strain in a second direction; and wherein the vector sum of the associated first and second forces is tensile strain in a third direction.
- 48. A tire sensor comprising:
a plurality of sensor assemblies, each sensor assembly adapted to measure forces along multiple axes that correspond among the sensor assemblies, wherein each sensor assembly includes at least one strain sensor that measures a force along one of the corresponding axes; and a summing circuit that sums the measured forces along the one of the corresponding axes.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. Ser. No. 09/724,655 filed on Nov. 28, 2000, and entitled “THREE-AXIS SENSOR ASSEMBLY FOR USE IN AN ELASTOMERIC MATERIAL.”
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
09724655 |
Nov 2000 |
US |
Child |
09844193 |
Apr 2001 |
US |