Shaft mounted energy harvesting for wireless sensor operation and data transmission

• US 8,011,255 B2
• Filed: 08/14/2007
• Issued: 09/06/2011
• Est. Priority Date: 03/05/2003
• Status: Expired due to Term

• Current Assignee: Lord Corporation (Parker-Hannifin Corporation)
• Original Assignee: MicroStrain, Inc. (Spectris PLC)
• Inventors: Hamel, Michael J., Arms, Steven W., Townsend, Christopher P, Churchill, David L.
• Primary Examiner(s): Caputo; Lisa
• Assistant Examiner(s): DAVIS, OCTAVIA L
• Application Number:
  US11/891,957
• Publication Number:
  US 20080047363A1
• Time in Patent Office: 1,484 Days
• Field of Search: 738/623.25, 290/1.R, 307/151
• US Class Current: 73/862.325
• CPC Class Codes: B60C 23/0411 Piezoelectric generators
• CPC Class Codes: B60C 23/0413 Wireless charging of active radio frequency circuits
• CPC Class Codes: B60C 23/0433 Radio signals
• CPC Class Codes: G01D 21/00 Measuring or testing not otherwise provided for
• CPC Class Codes: G01D 5/185 using piezoelectric sensors
• CPC Class Codes: G01L 3/108 involving resistance strain gauges
• CPC Class Codes: G01M 5/00 Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings G01M9/00 takes precedence
• CPC Class Codes: H02J 7/32 for charging batteries from a charging set comprising a non-electric prime mover rotating at constant speed
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: H02K 11/21 Devices for sensing speed or position, or actuated thereby specially adapted for machines having non-mechanical commutating devices H02K29/06, H02K29/14
• CPC Class Codes: H02K 11/24 Devices for sensing torque, or actuated thereby H02K11/27 takes precedence
• CPC Class Codes: H02K 11/25 Devices for sensing temperature, or actuated thereby
• CPC Class Codes: H02K 11/26 Devices for sensing voltage, or actuated thereby, e.g. overvoltage protection devices
• CPC Class Codes: H02K 7/1846 structurally associated with wheels or associated parts dynamos arranged in the wheel hub of cycles B62J6/12
• CPC Class Codes: H02N 11/002 Generators
• CPC Class Codes: H02N 2/186 Vibration harvesters

Abstract

One embodiment of the present patent application is a method of monitoring a rotating part. The method includes providing a shaft, a sensor, a processor, an energy storage device, and a transmitter. The method further includes mounting the sensor directly on the shaft and mounting said processor, said energy storage device, and said transmitter to rotate with said shaft. The method further includes rotating the shaft and waking the processor for a period of time and drawing energy to the processor from the energy storage device to provide the processor in an active mode during the period of time. The method also includes sampling the sensor during the period of time. It also includes returning the processor to sleep mode. The method also includes transmitting data derived from the sensor.

Claims

1. A method of monitoring a rotating part, comprising:

a. providing a shaft, a sensor, a processor, an energy storage device, and a wireless transmitter;

b. mounting said sensor, said processor, said energy storage device, and said wireless transmitter to rotate with said shaft;

c. rotating said shaft;

d. waking said processor for a period of time while said shaft is rotating, wherein said processor draws energy from said energy storage device during said period of time, wherein said processor is in an active mode during said period of time;

e. sampling said sensor during said period of time;

f. returning said processor to sleep mode; and

g. transmitting data derived from said sensor with said wireless transmitter while said shaft is rotating, wherein energy for operating said wireless transmitter is provided from said energy storage device.

2. A method as recited in claim 1, wherein said shaft is on a machine for delivering torque.

3. A method as recited in claim 2, wherein said machine is one from the group consisting of a motor, a vehicle, a pump, a valve, a compressor, a polishing machine, a grinder, a lathe, or a milling machine.

4. A method as recited in claim 1, wherein said sensor comprises at least one from the group consisting of a temperature sensor, a strain gauge, a torque sensing device, and an accelerometer.

5. A method as recited in claim 1, wherein said waking said processor comprises waking said processor at a frequency in the range from 1 Hz to 1 kHz.

6. A method as recited in claim 1, wherein said sampling said sensor comprises a frequency less than 1 Hz to a frequency of about 1 kHz.

7. A method as recited in claim 1, wherein said processor further comprises controlling power to said sensor and wherein said processor sends a signal to provide power to said sensor only during said period of time.

8. A method as recited in claim 1, wherein said processor further comprises controlling power to said transmitter wherein said processor provides power to said transmitter only during said active mode period of time.

9. A method as recited in claim 1, wherein said mounting further comprises mounting sensor signal conditioning to rotate with said rotating shaft, wherein said processor further comprises controlling power to said sensor signal conditioning, wherein said processor provides power to said sensor signal conditioning only during said period of time.

10. A method as recited in claim 9, wherein said mounting further comprises mounting a sensor signal conditioning power supply to rotate with said shaft for powering said sensor signal conditioning, wherein said sensor signal conditioning power supply comprises an enable pin, wherein said processor further comprises controlling operation of said sensor signal conditioning power supply by sending a signal to said enable pin.

11. A method as recited in claim 10, wherein said mounting further comprises mounting a transmitter power supply to rotate with said shaft, wherein said processor has separate controls to enable said sensor signal conditioning power supply and to enable said transmitter power supply wherein said processor further comprises enabling said signal conditioning power supply independently of enabling said transmitter power supply.

12. A method as recited in claim 11, wherein said mounting further comprises mounting a sensor power supply to rotate with said shaft, wherein said processor has an additional separate control to enable said sensor power supply wherein said processor further comprises independently enabling said sensor power supply.

13. A method as recited in claim 1, wherein said processor further comprises computing strain of said rotating shaft.

14. A method as recited in claim 1, wherein said processor further comprises computing torque of said rotating shaft.

15. A method as recited in claim 1, wherein said processor further comprises computing at least one from the group consisting of angular velocity and RPM of said rotating shaft.

16. A method as recited in claim 1, wherein said processor further comprises computing instantaneous mechanical power of said rotating shaft.

17. A method as recited in claim 1, wherein said mounting further comprises mounting a receiver to rotate with said shaft.

18. A method as recited in claim 17, further comprising receiving a command through said receiver to wake up said processor.

19. A method as recited in claim 18, further comprising receiving a command to log data, transmit data, or return to sleep mode.

20. A method as recited in claim 1, further comprising providing power to said processor and to said transmitter to transmit data at preset time intervals.

21. A method as recited in claim 1, wherein said energy storage device comprises a battery.

22. A method as recited in claim 1, wherein said mounting further comprises mounting an energy harvesting circuit to rotate with said shaft.

23. A method as recited in claim 22, wherein said energy harvesting circuit is connected to provide power to recharge said energy storage device.

24. A method as recited in claim 22, further comprising providing a magnetic field adjacent said shaft, wherein said energy harvesting circuit comprises an inductor for harvesting energy from rotation of said shaft in said magnetic field.

25. A method as recited in claim 1, wherein said mounting further comprises providing a circuit for measuring state of charge of said energy storage device to rotate with said shaft, said method further comprising providing a first measurement of said state of charge of said energy storage device.

26. A method as recited in claim 25, further comprising providing a second measurement of said state of charge of said energy storage device and comparing said second measurement to said first measurement to determine if charge stored in said energy storage device is depleting or charging.

27. A method as recited in claim 25, further comprising using said first measurement of state of charge in said processor to determine one from the group consisting of:

rate of sampling data from said sensor, how long to sample data from said sensor, time between samplings of data from said sensor, how long to keep said processor in sleep mode, when to awaken said processor, how long to keep said processor awake, time for providing power to said sensor, and time for providing power to said transmitter.

28. A method as recited in claim 1, wherein said mounting further comprises mounting a non-volatile memory to rotate with said shaft.

29. A method as recited in claim 28, wherein said non-volatile memory includes a unique address to identify data transmitted from said rotating shaft.

30. A method as recited in claim 28, further comprising storing data derived from said sensor in said non-volatile memory for transmitting by said transmitter at a later time.

31. A method as recited in claim 1, further comprising adjusting operation of said shaft based on said data.

32. A method as recited in claim 1, wherein a machine drives said rotating shaft, further comprising providing a base station for receiving data transmitted by said transmitter and providing an output from said base station to control said machine driving said rotating shaft.

33. A method as recited in claim 32, wherein said control said machine driving said rotatable part includes at least one from the group consisting of switching off said machine driving said rotatable part and sending a signal to change speed of said machine driving said rotatable part.

34. A method as recited in claim 1, wherein said mounting said sensor includes mounting said sensor directly on said rotatable part.

35. A method of monitoring a rotating part, comprising:

a. providing a rotatable part, a sensor, a processor, an energy storage device, a non-volatile memory, and a wireless transmitter;

b. mounting said sensor, said processor, said energy storage device, said non-volatile memory, and said wireless transmitter to rotate with said rotatable part;

c. rotating said rotatable part, wherein said sensor, said processor, said energy storage device, said non-volatile memory, and said transmitter rotate with said rotatable part;

d. waking said processor for a period of time while said shaft is rotating, wherein said processor draws energy from said energy storage device during said period of time, wherein said processor is in an active mode during said period of time;

e. sampling said sensor and storing data derived from said sensor in said non-volatile memory during said period of time;

f. returning said processor to sleep mode; and

g. transmitting information with said wireless transmitter, wherein said information includes data derived from said sensor and stored in said non-volatile memory, wherein said transmitting is accomplished while said rotatable part is rotating.

36. A method as recited in claim 35, wherein said rotatable part is on a machine for delivering torque.

37. A method as recited in claim 36, wherein said machine is one from the group consisting of a motor, a vehicle, a pump, a valve, a compressor, a polishing machine, a grinder, a lathe, or a milling machine.

38. A method as recited in claim 35, wherein said sensor comprises at least one from the group consisting of a temperature sensor, a strain gauge, a torque sensing device, and an accelerometer.

39. A method as recited in claim 35, wherein said waking said processor comprises waking said processor at a frequency in the range from 1 Hz to 1 kHz.

40. A method as recited in claim 35, wherein said sampling said sensor comprises a frequency less than 1 Hz to a frequency of about 1 kHz.

41. A method as recited in claim 35, wherein said processor further comprises controlling power to said sensor and wherein said processor sends a signal to provide power to said sensor only during said period of time.

42. A method as recited in claim 35, further comprising mounting a transmitter to rotate with said rotatable part, wherein said processor further comprises controlling power to said transmitter wherein said processor provides power to said transmitter only during said active mode period of time.

43. A method as recited in claim 35, wherein said mounting further comprises mounting sensor signal conditioning to rotate with said rotatable part, wherein said processor further comprises controlling power to said sensor signal conditioning, wherein said processor provides power to said sensor signal conditioning only during said period of time.

44. A method as recited in claim 43, wherein said mounting further comprises mounting a sensor signal conditioning power supply to rotate with said rotatable part for powering said sensor signal conditioning, wherein said sensor signal conditioning power supply comprises an enable pin, wherein said processor further comprises controlling operation of said sensor signal conditioning power supply by sending a signal to said enable pin.

45. A method as recited in claim 44, wherein said mounting further comprises mounting a transmitter power supply on said rotatable part to rotate with said rotatable part, wherein said processor has separate controls to enable said sensor signal conditioning power supply and to enable said transmitter power supply wherein said processor further comprises enabling said signal conditioning power supply independently of enabling said transmitter power supply.

46. A method as recited in claim 45, wherein said mounting further comprises mounting a sensor power supply to rotate with said rotatable part, wherein said processor has an additional separate control to enable said sensor power supply wherein said processor further comprises independently enabling said sensor power supply.

47. A method as recited in claim 35, wherein said processor further comprises computing strain of said rotatable part.

48. A method as recited in claim 35, wherein said processor further comprises computing torque of said rotatable part.

49. A method as recited in claim 35, wherein said processor further comprises at least one from the group consisting of computing angular velocity and RPM of said rotatable part.

50. A method as recited in claim 35, wherein said processor further comprises computing instantaneous mechanical power of said rotatable part.

51. A method as recited in claim 35, wherein said mounting further comprises mounting a receiver to rotate with said rotatable part.

52. A method as recited in claim 51, further comprising receiving a command through said receiver to wake up said processor.

53. A method as recited in claim 52, further comprising receiving at least one command from the group consisting of log data, transmit data, or return to sleep mode.

54. A method as recited in claim 35, further comprising providing power to said processor and to said transmitter to transmit data at preset time intervals.

55. A method as recited in claim 35, wherein said energy storage device comprises a battery.

56. A method as recited in claim 35, wherein said mounting further comprises mounting an energy harvesting circuit to rotate with said rotatable part.

57. A method as recited in claim 56, wherein said energy harvesting circuit is connected to provide power to recharge said energy storage device.

58. A method as recited in claim 56, further comprising providing a magnetic field adjacent said rotatable part, wherein said energy harvesting circuit comprises an inductor for harvesting energy from rotation of said rotatable part in said magnetic field.

59. A method as recited in claim 58, further comprising using said first measurement of state of charge in said processor to determine at least one from the group consisting of:

rate of sampling data from said sensor, how long to sample data from said sensor, time between samplings of data from said sensor, how long to keep said processor in sleep mode, when to awaken said processor, how long to keep said processor awake, time for providing power to said sensor, and time for providing power to said transmitter.

60. A method as recited in claim 35, wherein said mounting further comprises providing a circuit for measuring state of charge of said energy storage device to rotate with said rotatable part, said method further comprising providing a first measurement of said state of charge of said energy storage device.

61. A method as recited in claim 60, further comprising providing a second measurement of said state of charge of said energy storage device and comparing said second measurement to said first measurement to determine if charge stored in said energy storage device is depleting or charging.

62. A method as recited in claim 35, wherein said non-volatile memory includes a unique address to identify data transmitted from said rotatable part.

63. A method as recited in claim 35, further comprising storing data derived from said sensor in said non-volatile memory for transmitting by said transmitter at a later time.

64. A method as recited in claim 35, further comprising adjusting operation of said rotatable part based on said data.

65. A method as recited in claim 35, wherein a machine drives said rotatable part, further comprising providing a base station for receiving data transmitted by said transmitter and providing an output from said base station to control said machine driving said rotatable part.

66. A method as recited in claim 65, wherein said control said machine driving said rotatable part includes at least one from the group consisting of switching off said machine driving said rotatable part and sending a signal to change speed of said machine driving said rotatable part.

67. A method as recited in claim 35, wherein said mounting said sensor includes mounting said sensor directly on said rotatable part.

68. A method of monitoring a rotating part, comprising:

a. providing a rotatable part, a sensor, a processor, and an energy supplying device;

b. mounting said sensor, said processor, and said energy supplying device to rotate with said rotatable part;

c. rotating said rotatable part, wherein said sensor, said processor, and said energy supplying device rotate with said rotatable part;

d. while said rotatable part is rotating waking said processor for a period of time, wherein said processor draws energy from said energy supplying device during said period of time, wherein said processor is in an active mode during said period of time;

e. sampling said sensor during said period of time;

f. while said rotatable part is rotating automatically adjusting rotation of said rotatable part based on data derived from said sensor; and

g. returning said processor to sleep mode.

69. A method as recited in claim 68, further comprising providing a device driving said rotatable part, wherein said adjusting rotation of said rotatable part based on said data includes adjusting operation of said device driving said rotatable part.

70. A method as recited in claim 69, wherein said device driving said rotatable part is a motor.

71. A method as recited in claim 69, wherein said adjusting operation of said device driving said rotatable part includes at least one from the group consisting of switching off said device driving said rotatable part and sending a signal to change speed of said device driving said rotatable part.

72. A method as recited in claim 68, wherein said mounting said sensor includes mounting said sensor directly on said rotatable part.