DOPPLER SENSOR FOR THE DERIVATION OF TORSIONAL SLIP, FRICTION AND RELATED PARAMETERS

• US 20080137062A1
• Filed: 06/19/2007
• Published: 06/12/2008
• Est. Priority Date: 06/20/2006
• Status: Active Grant

• Current Assignee: Virginia Tech Intellectual Properties, Inc. (Virginia Polytechnic Institute and State University)
• Original Assignee: Virginia Tech Intellectual Properties, Inc. (Virginia Polytechnic Institute and State University)
• Inventors: HOLTON, Carvel, Ahmadian, Mehdi
• Granted Patent: US 7,705,972 B2
• Time in Patent Office: Days
• US Class Current: 356/28
• CPC Class Codes: B60W 40/06 Road conditions
• CPC Class Codes: G01P 3/366 by using diffraction of light for measuring speed of fluids G01P5/26
• CPC Class Codes: G01S 17/58 Velocity or trajectory determination systems; Sense-of-movement determination systems
• CPC Class Codes: G01S 17/88 Lidar systems specially adapted for specific applications

Abstract

An optical method and apparatus are described for the measurement of properties of a travel vehicle or a travel surface upon which the travel vehicle travels, which includes providing an incident light from a light source to the travel surface, collecting light reflected from the travel surface, determining a surface induced Doppler shift from the incident and collected light and determining at least one of a motion property of the travel vehicle and a surface property of the travel surface based on the determined surface induced Doppler shift.

Claims

1. A method for measuring properties of a travel vehicle or a travel surface, upon which the travel vehicle travels, comprising:

providing an incident light from a light source to the travel surface;

collecting light reflected from the travel surface;

determining a surface induced Doppler shift from the incident and collected light; and

determining at least one of a motion property of the travel vehicle and a surface property of the travel surface based on the determined surface induced Doppler shift.

2. The method as in claim 1, wherein the step of determining at least one of a motion property of the travel vehicle and a surface property of the travel surface comprises determining a torsional slip of a rotating surface of a contact between the travel vehicle and travel surface.

3. The method as in claim 1, wherein the step of determining at least one of a motion property of the travel vehicle and a surface property of the travel surface comprises determining surface feature aspect ratio of the travel surface.

4. The method as in claim 1, wherein the step of determining at least one of a motion property of the travel vehicle and a surface property of the travel surface comprises determining a degree of curvature of the travel surface.

5. A method for measuring torsional slip, comprising:

measuring a tangential velocity of a surface rotating about an axis via a Doppler shifted return of a first laser beam;

measuring a translational velocity of the axis via a Doppler shifted return of a second laser beam; and

deriving a torsional slip of the rotating surface from the difference between the tangential velocity and the translational velocity.

6. A method as in claim 5, wherein the rotating surface is a drive surface of a wheel mounted on an axle of a vehicle carriage, the axle being the axis.

7. A method as in claim 6, wherein the wheel is a steel wheel of a locomotive.

8. A method as in claim 6, wherein the first and second laser beams are generated by respective optical units mounted on said vehicle carriage, the first laser beam being directed to a rotating side surface of the wheel and the second laser beam being directed to a surface being driven by said wheel.

9. A method as in claim 7, wherein the first and second laser beams are generated by respective optical units mounted at trackside, the first laser beam being directed to a rotating side surface of the wheel and the second laser beam being directed to an axle mount of the wheel.

10. A method as in claim 8, wherein the Doppler shifted return of the first laser beam is used to calculate the angular velocity of the wheel, and the tangential velocity is calculated from the angular velocity and a radius of the wheel.

11. A method as in claim 5, further comprising extracting a measurement of a wheel diameter the torsional characteristics and velocity characteristics.

12. A method as in claim 5, further comprising extracting a frictional value from the torsional slip of the rotating surface.

13. A method for measuring torsional slip, comprising:

using first and second laser beams to simultaneously generate respective first and second Doppler shifted return beams from a first surface rotating about an axis and from a second surface, wherein movement of the second surface corresponds to the translational velocity of the axis;

processing the respective Doppler shifted return beams to determine, respectively, a tangential velocity of the rotating surface and a translational velocity of the axis; and

deriving the torsional slip of the rotating surface from the difference between the tangential velocity and the translational velocity.

14. A method as in claim 13, wherein the rotating surface is a side surface of a wheel mounted on an axle of a vehicle carriage, the axle being the axis.

15. A method as in claim 14, wherein the wheel is a steel wheel of a locomotive.

16. A method as in claim 14, wherein the first and second laser beams are generated by respective optical units mounted on the vehicle carriage, the first laser beam being directed to the side surface of the wheel and the second laser beam being directed to a surface being driven by the wheel.

17. A method as in claim 15, wherein the first and second laser beams are generated by respective optical units mounted at trackside, the first laser beam being directed to the side surface of the wheel and the second laser beam being directed to an axle mount of the wheel.

18. A method as in claim 16, wherein the Doppler shifted return of the first laser beam is used to calculate the angular velocity of the wheel, and the tangential velocity is calculated from the angular velocity and a radius of the wheel.

19. An apparatus for measuring torsional slip, comprising:

means for using a Doppler shifted return of a first laser beam to measure tangential velocity of a surface rotating about an axis;

means for using a Doppler shifted return of a second laser beam to measure translational velocity of the axis; and

means for deriving the torsional slip of the rotating surface from the difference between the tangential velocity and the translational velocity.

20. An apparatus as in claim 19, wherein the rotating surface is a drive surface of a wheel mounted on an axle of a vehicle carriage, the axle being the axis.

21. An apparatus as in claim 20, wherein said wheel is a steel wheel of a locomotive.

22. An apparatus as in claim 20, wherein the first and second laser beams are generated by respective optical units mounted on said vehicle carriage, the first laser beam being directed to a rotating side surface of the wheel and the second laser beam being directed to a surface being driven by the wheel.

23. An apparatus as in claim 21, wherein said first and second laser beams are generated by respective optical units mounted at trackside, said first laser beam being directed to a rotating side surface of said wheel and said second laser beam being directed to an axle mount of said wheel.

24. An apparatus as in claim 22, wherein the Doppler shifted return of the first laser beam is used to calculate the angular velocity of the wheel, and the tangential velocity is calculated from the angular velocity and a radius of the wheel.

25. An apparatus as in claim 24, wherein a spectral processor is used to determine velocity data from the Doppler shifted return of the first laser beam, and the velocity data from the spectral processor is used to calculate the angular velocity of the wheel.

26. An apparatus as in claim 20, further comprising:

mean for using a Doppler shifted return of a third laser beam to measure tangential velocity of a second wheel mounted on the axis, wherein the first and third laser beams are generated by respective optical units mounted on the vehicle carriage, the first laser beam being directed to a rotating side surface of the wheel and the second laser beam being directed to a rotating side surface of the second wheel; and

means for deriving the relative torsional slip of the wheel and the second wheel from the respective tangential velocities of the wheel and the second wheel.

27. A method for determining characteristics of a travel surface while traveling on the travel surface, the method comprising the steps of:

providing an incident light from a light source to travel surface;

collecting light reflected from the travel surface;

determining a surface induced Doppler shift from the incident and collected light; and

determining surface feature aspect ratio based on the determined surface induced Doppler shift.

28. The method of claim 27, wherein the travel surface is a highway surface and the step of collecting light comprises collecting light reflected from the highway surface.

29. The method of claim 27, wherein the travel surface is a railroad surface and the step of collecting light comprises collecting light reflected from the railroad surface.

30. The method of claim 27, further comprising determining slip, resistance or friction for the travel surface based on the determined surface feature aspect ratio.

31. An apparatus for determining characteristics of a travel surface while traveling on the travel surface, comprising:

means for providing all incident light from a light source to travel surface;

means for collecting light reflected from the travel surface;

means for determining a surface induced Doppler shift from the incident and collected light; and

means for determining surface feature aspect ratio based on the determined surface induced Doppler shift.

32. The apparatus of claim 31, wherein the travel surface is a highway surface and the means for collecting light comprises means for collecting light reflected from the highway surface.

33. The apparatus of claim 31, wherein the travel surface is a railroad surface and the means for collecting light comprises means for collecting light reflected from the railroad surface.

34. The apparatus of claim 31, further comprising means for determining slip, resistance or friction for the travel surface based on the determined surface feature aspect ratio.

35. A method for determining characteristics of a travel surface while traveling on the travel surface, the method comprising the steps of:

providing a first optical sensor on one side of a vehicle traveling on the travel surface;

providing a second optical sensor on an opposite side of the vehicle traveling on the travel surface, where the one side and the opposite side are on opposite sides of the vehicle and perpendicular to a direction of travel;

collecting light reflected from the travel surface by the first and second optical sensors;

determining induced Doppler shifts from the light collected by the first and second optical sensors; and

determining at least one characteristic of the travel surface based on the determined induced Doppler shifts.

36. The method of claim 35, wherein the travel surface is a highway surface and the step of determining at least one characteristic of the travel surface comprises determining a decree of curvature of the highway surface.

37. The method of claim 35, wherein the travel surface is a railroad surface and the step of determining, at least one characteristic of the travel surface comprises determining a degree of curvature of the railroad surface.

38. The method of claim 35, wherein the travel surface is a railroad surface and the step of determining at least one characteristic of the travel surface comprises determining a gauge variance of the railroad surface.

39. A apparatus for determining characteristics of a travel surface while traveling on the travel surface, comprising:

first means for optically sensing reflected light on one side of a vehicle traveling on the travel surface;

second means for optically sensing reflected light on an opposite side of the vehicle traveling on the travel surface, where the one side and the opposite side are on opposite sides of the vehicle and perpendicular to a direction of travel;

means for determining induced Doppler shifts from the light collected by the first and second means for optically sensing reflected light; and

means for determining at least one characteristic of the travel surface based on the determined induced Doppler shifts.

40. The apparatus of claim 39, wherein the travel surface is a highway surface and the means for determining at least one characteristic of the travel surface comprises means for determining a degree of curvature of the highway surface.

41. The apparatus of claim 39, wherein the travel surface is a railroad surface and the means for determining at least one characteristic of the travel surface comprises means for determining a degree of curvature of the railroad surface.

42. The apparatus of claim 39, wherein the travel surface is a railroad surface and the means for determining at least one characteristic of the travel surface comprises means for determining a gauge variance of the railroad surface.

43. A method for measuring patient characteristics, comprising the steps of:

providing an incident light from a light source to a surface of patient'"'"'s body;

collecting light reflected from the surface of patient'"'"'s body;

determining a surface induced Doppler shift from the incident and collected light; and

determining at least one patient characteristic based on the determined surface induced Doppler shift.

44. A method as in claim 43, wherein the at least one patient characteristic is a measurement of heart or pulmonary rate as extracted from the determined surface induced Doppler shift.

45. A method as in claim 43, wherein the at least one patient characteristic is a measurement of a skin surface of the patient from the determined surface induced Doppler shift.

46. A method as in claim 43, wherein the at least one patient characteristic is a measurement of a motional stability of the patient from the determined surface induced Doppler shift.

47. A method as in claim 46, wherein the at least one patient characteristic is a measurement of motion of the patient from the determined surface induced Doppler shift and the method further comprises alerting technicians about motions beyond predetermined limits.

48. A method for measuring characteristics of athletic equipment, comprising the steps of:

providing an incident light from a light source to a surface of the athletic equipment;

collecting light reflected from the surface of the athletic equipment;

determining a surface induced Doppler shift from the incident and collected light; and

determining at least one motion-based characteristic based on the determined surface induced Doppler shift.

49. A method as in claim 48, wherein the athletic equipment is a golf ball and the step of determining at least one motion-based characteristic comprises determining at least one a spin and a trajectory of the golf ball.

50. A method as in claim 48, wherein the athletic equipment is a golf club and the step of determining at least one motion-based characteristic comprises determining at least one a spin and a trajectory of the golf ball.

51. A method as in claim 48, wherein the step of determining at least one motion-based characteristic comprises determining a spin, a trajectory, a torsion or a slip in the athletic equipment.

52. A method as in claim 48, wherein the athletic equipment is sporting footwear and the step of determining at least one motion-based characteristic comprises determining traction of the sporting footwear with a playing surface.