Shaft mounted energy harvesting for wireless sensor operation and data transmission

• US 7,256,505 B2
• Filed: 01/31/2004
• Issued: 08/14/2007
• 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: Arms, Steven W., Townsend, Christopher P, Hamel, Michael J., Churchill, David L.
• Primary Examiner(s): Waks; Joseph
• Application Number:
  US10/769,642
• Publication Number:
  US 20050017602A1
• Time in Patent Office: 1,291 Days
• Field of Search: 290/1.R
• US Class Current: 290/1.00R
• 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

A device for monitoring a rotating shaft is provided. The device measures strain in the shaft and provides angular velocity and torque in the shaft. The device includes a sensor, sensor conditioning circuitry, a microprocessor, and a transmitter, all located on a rotating shaft. The device obtains power by harvesting mechanical energy of the rotating shaft itself. Coils are provided rotating with the shaft and permanent magnets are mounted adjacent the rotating shaft so electrical energy is induced in the coils as they rotate through the magnetic field of the permanent magnets. A battery or capacitor is connected to the coils for storing energy. A microprocessor is connected to the sensors, the storage device, and the transmitter for managing power consumption and for monitoring the amount of electrical energy stored in the storage device and for switchably connecting the storage device to the transmitter when the stored energy exceeds a threshold.

Claims

1. A device, comprising:

a rotatable shaft mounted for rotating around an axis;

an energy harvesting device having a first portion and a second portion, said first portion mounted to rotate with said rotatable shaft, said second portion mounted on fixed supports relative to said rotatable shaft so as to be non-rotatable around said axis when said rotatable shaft rotates around said axis, said energy harvesting device for converting motion of said first portion with respect to said second portion into electricity; and

a radio frequency communications device mounted to rotate with said rotatable shaft, said radio frequency communications device connected to be powered with electricity derived from said first portion, wherein all electricity for powering said radio frequency communications device is derived from said first portion.

2. A device as recited in claim 1, wherein said first position includes an inductor and wherein said second portion includes a magnet for providing a magnetic field arranged adjacent said rotatable shaft, wherein said inductor is capable of being magnetically coupled to said magnet during rotation of said rotatable shaft, wherein said energy harvesting device harvests energy from a pulse of electricity induced in said inductor by rotation of said inductor through said magnetic field.

3. A device as recited in claim 2, wherein said magnet comprises a permanent magnet.

4. A device as recited in claim 2, wherein said inductor comprises at least one from the group including a coil and a Weigand device.

5. A device as recited in claim 4, further comprising a plurality of said coils or said Weigand devices.

6. A device as recited in claim 1, wherein said rotatable shaft composes a measurable parameter, further comprising a sensor mounted to rotate with said rotatable shaft for measuring said measurable parameter, further wherein said radio frequency communications device comprises a transmitter, said transmitter for transmitting at least one from the group including said measurement and data derived from said measurement.

7. A device as recited in claim 6, wherein said sensor comprises at least one from the group including a temperature sensor, a strain gauge, a torque sensing device, a pressure sensor, and an accelerometer.

8. A device as recited in claim 7, wherein said strain gauge comprises resistance devices sensitive to strain.

9. A device as recited in claim 8, wherein said resistance devices are arranged in a chevron pattern.

10. A device as recited in claim 7, wherein said strain gauge is configured for measuring at least one from the group consisting of torque, bending, tension, and compression of said shaft.

11. A device as recited in claim 1, further comprising a rechargeable source of power mounted to rotate with said rotatable shaft, said rechargeable source of power connected for receiving and storing charge from said energy harvesting circuit.

12. A device as recited in claim 11, wherein said rechargeable source of power comprises at least one from the group including a battery and a capacitor.

13. A device as recited in claim 1, wherein a receiver is mounted to rotate with said rotatable shaft.

14. A device as recited in claim 13, wherein said receiver comprises a transceiver.

15. A device as recited in claim 1, further comprising a processor mounted to rotate with said rotatable shaft.

16. A device as recited in claim 15, further comprising a sensor and an A/D converter mounted to rotate with said rotatable shaft wherein said a/d converter is for converting sensor data to digital data.

17. A device as recited in claim 16, further comprising a memory device mounted to rotate with said rotatable shaft for storing said digital sensor data.

18. A device as recited in claim 17, wherein said memory device is integral with said processor.

19. A device as recited in claim 17, wherein said memory device contains a unique address to identify data transmitted from said memory device.

20. A device as recited in claim 16, wherein said processor contains a program to process said sensor data before transmitting.

21. A device as recited in claim 20, wherein said processor is configured to use said sensor data to calculate torque of said shaft and to calculate at least one from the group including angular velocity of said shaft and rate of rotation of said shaft.

22. A device as recited in claim 21, wherein said processor is configured to calculate power transmitted by said shaft by calculating the product of torque and rate of rotation.

23. A device as recited in claim 21, further comprising a data base of said torque calculations for comparing to a present calculation of torque for detecting a change in torque.

24. A device as recited in claim 20, wherein said processor is configured to use said sensor data to calculate torque of said shaft and wherein said processor is configured to calculate power transmitted by said shaft from said torque and from rate of rotation of said shaft as sensed by said rate of rotation detector.

25. A device as recited in claim 16, wherein said processor is configured to determine a change in a parameter related to at least one from the group including said shaft, a support for said shaft, a device powering said shaft, and a device powered by said shaft based on a change in said sensor data.

26. A device as recited in claim 16, wherein said processor is configured to determine a change in a parameter related to at least one from the group including said shalt, a support for said shaft, a device powering said shaft, and a device powered by said shaft based on a change in at least one from the group including torque and power of said shaft.

27. A device as recited in claim 16, further comprising a feedback mechanism to adjust operation of said shaft based on said sensor data.

28. A device as recited in claim 15, wherein said processor controls operation of said transmitter.

29. A device as recited in claim 1, wherein said shaft is part of a machine for delivering torque.

30. A device as recited in claim 29, wherein said machine includes at least one from the group including a motor, a vehicle, a pump, a valve, a compressor, a polishing machine, a grinder, a lathe, and a milling machine.

31. A device as recited in claim 30, wherein said vehicle includes an aircraft.

32. A device as recited in claim 1, further comprising a rate of rotation detector mounted to rotate with said rotatable shaft.

33. A device as recited in claim 32, wherein said energy harvesting device includes said rate of rotation detector.

34. A device as recited in claim 32, wherein said energy harvesting device includes a mechanism for counting electrical pulses.

35. A device, comprising:

a rotatable shaft;

an energy harvesting circuit mounted to rotate with said rotatable shaft, said energy harvesting circuit for convening mechanical energy of motion of said rotatable shaft into electricity;

a sensor including at least one from the group consisting of a strain gauge, a torque sensing device, and an accelerometer, said sensor mounted to rotate with said rotatable shaft; and

a radio frequency communications device mounted to rotate with said rotatable shaft, said radio frequency communications device connected to be powered with electricity derived from said energy harvesting circuit wherein all electricity for powering said radio frequency communications device is derived from said energy harvesting circuit.

36. A device as recited in claim 35, further comprising a controlling circuit mounted to rotate with said rotatable shaft for operating said radio frequency communications device, wherein said controlling circuit is connected to receive all its electricity derived from said energy harvesting device.

37. A device as recited in claim 36, wherein said controlling circuit includes a digital circuit.

38. A device as recited in claim 36, wherein said controlling circuit includes a processor.

39. A device as recited in claim 38, wherein said processor is connected for receiving data derived from said sensor.

40. A device as recited in claim 39, further comprising an A/D converter for rotating with said rotatable shaft, wherein said A/D converter is connected for converting sensor data to digital data.

41. A device as recited in claim 40, further comprising a memory device for rotating with said rotatable shaft, wherein said memory device is connected for storing said digital data.

42. A device as recited in claim 41, wherein said memory device is integral with or connected to said processor.

43. A device as recited in claim 41, wherein said memory device contains a unique address to identify data transmitted from said memory.

44. A device as recited in claim 39, wherein said processor contains a program to process said data before providing said data to said radio frequency communications device.

45. A device as recited in claim 39, wherein said processor is configured to calculate torque of said shaft and at least one from the group including angular velocity of said shaft and rate of rotation of said shaft.

46. A device as recited in claim 45, wherein said processor is configured to calculate power transmitted by said shaft by calculating the product of torque and rate of rotation.

47. A device as recited in claim 45, further comprising a data base of said torque calculations for comparing to a present calculation for detecting a change in torque.

48. A device as recited in claim 39, wherein said processor is configured to determine a change in a parameter related to at least one from the group including said shaft, a support for said shaft, a device powering said shaft, and a device powered by said shaft, based on said sensor measurement.

49. A device as recited in claim 39, wherein said processor is configured to determine a change in a parameter related to at least one from the group including said shaft, a support for said shaft, a device powering said shaft, and a device powered by said shaft based on a change in at least one from the group including torque and power of said shalt.

50. A device as recited in claim 39, further comprising a feedback mechanism capable of receiving said sensor data, said feedback mechanism capable of adjusting operation of said shaft based on said sensor data.

51. A device as recited in claim 39, wherein said processor is configured to use said sensor data to calculate torque of said shaft and wherein said processor is configured to calculate power transmitted by said shaft from said torque and from rate of rotation of said shaft as sensed by said rate of rotation detector.

52. A device as recited in claim 35, further comprising a memory device having an address.

53. A device as recited in claim 35, wherein said energy harvesting circuit includes an inductor.

54. A device as recited in claim 53, wherein said inductor comprises at least one from the group including a coil and a Weigand device.

55. A device as recited in claim 54, further comprising a plurality of said coils or said Weigand devices.

56. A device as recited in claim 53, further comprising a device for generating a magnetic field located adjacent said rotatable shaft.

57. A device as recited in claim 56, wherein said device for generating a magnetic field includes a permanent magnet.

58. A device as recited in claim 35, further comprising at least one from the group consisting of a temperature sensor, and a pressure sensor.

59. A device as recited in claim 35, wherein said strain gauge comprises resistance devices sensitive to strain.

60. A device as recited in claim 59, wherein said resistance devices are arranged in a chevron pattern.

61. A device as recited in claim 35, wherein said strain gauge is configured for measuring at least one from the group including torque, bending, tension, and compression of said shaft.

62. A device as recited in claim 35, further comprising a rechargeable source of power mounted to rotate with said rotatable shaft and connected for receiving and storing electricity derived from said energy harvesting circuit.

63. A device as recited in claim 62, wherein said rechargeable source of power includes at least one from the group including a battery and a capacitor.

64. A device as recited in claim 35, wherein said radio frequency communications device includes a transmitter.

65. A device as recited in claim 35, wherein said radio frequency communications device includes a transceiver.

66. A device as recited in claim 35, wherein said rotatable shaft is part of a machine for delivering torque.

67. A device as recited in claim 66, wherein said machine includes at least one from the group including a motor, a vehicle, a pump, a valve, a compressor, a polishing machine, a grinder, a lathe, and a milling machine.

68. A device as recited in claim 67, wherein said vehicle includes an aircraft.

69. A device as recited in claim 35, further comprising a rate of rotation detector mounted to rotate with said rotatable shaft.

70. A device as recited in claim 69, wherein said energy harvesting device includes said rate of rotation detector.

71. A device as recited in claim 70, wherein said energy harvesting device includes a mechanism for counting electrical pulses.

72. A device, comprising:

a rotatable shaft;

a power supply including a circuit and a rechargeable source of power, said circuit and said rechargeable source of power mounted to rotate with said rotatable shaft, said circuit for convening mechanical energy of motion of said rotatable shaft into electricity, said rechargeable source of power for receiving and storing electricity derived from said circuit;

a radio frequency communications device mounted to rotate with said rotatable shaft wherein all electricity for powering said radio frequency communications device is derived from at least one from the group consisting of said circuit and said rechargeable source of power; and

a control circuit for disconnecting power to said radio frequency communications device when said power supply does not have sufficient electricity stored for operating said radio frequency communications device, said control circuit for reconnecting power to said radio frequency communications device when said power supply has sufficient electricity stored for operating said radio frequency communications device.

73. A device as recited in claim 72, wherein said rechargeable source of power includes at least one from the group including a battery and a capacitor.

74. A device as recited in claim 72, wherein said circuit includes a rate of rotation detector.

75. A device as recited in claim 74, further comprising a torque sensor and a processor, wherein said processor is configured to use torque sensor data to calculate torque of said shaft, and wherein said processor is configured to calculate power transmitted by said shalt from said torque and from rate of rotation of said shaft as sensed by said rate of rotation detector.

76. A device as recited in claim 72, further comprising a sensor and a data storage device, said data storage device for logging data, wherein said control circuit provides data derived from said storage device for transmission in said radio frequency communications device.

77. A device as recited in claim 76, wherein said data storage device is capable of logging data while power is disconnected from said radio frequency communications device.

78. A device as recited in claim 72, wherein said control circuit includes a monitoring device and a switch.

79. A device as recited in claim 72, wherein said rotatable shaft is part of a machine for delivering torque.

80. A device as recited in claim 79, wherein said machine includes at least one from the group including a motor, a vehicle, a pump, a valve, a compressor, a polishing machine, a grinder, a lathe, and a milling machine.

81. A device as recited in claim 80, wherein said vehicle includes an aircraft.

82. A device, comprising:

a rotatable shaft;

an energy harvesting circuit mounted to rotate with said rotatable shaft, said energy harvesting circuit for converting mechanical energy of motion of said rotatable shaft into electricity;

a sensor for providing sensor data mounted to rotate with said rotatable shaft,

a feedback mechanism capable of receiving said sensor data, said feedback mechanism capable of adjusting operation of said rotatable shaft based on said sensor data; and

a radio frequency communications device mounted to rotate with said rotatable shaft said radio frequency communications device connected to be powered with electricity derived from said energy harvesting circuit, wherein all electricity for powering said radio frequency communications device is derived from said energy harvesting circuit.

83. A device as recited in claim 82, wherein said energy harvesting circuit includes an inductor and a rechargeable source of power.

84. A device as recited in claim 82, further comprising a magnet for magnetically coupling to said inductor.

85. A device as recited in claim 84, wherein said rotatable shaft is mounted for rotating around an axis, wherein said magnet is mounted adjacent said rotatable shaft so as to be non-rotatable around said axis when said rotatable shaft rotates around said axis.

86. A device as recited in claim 82, further comprising a wireless base station.

87. A device as recited in claim 82, further comprising a motor, a motor controller, and a wireless base station, said motor connected for driving said shaft, said motor controller connected for controlling operation of said motor, wherein said feedback mechanism includes said wireless base station and said motor controller.

88. A device as recited in claim 82, further comprising a rate of rotation detector mounted to rotate with said rotatable shaft.

89. A device as recited in claim 88, wherein said energy harvesting device includes said rate of rotation detector.

90. A device as recited in claim 89, wherein said energy harvesting device includes a coil and a circuit for counting electrical pulses in said coil.

91. A device as recited in claim 88, further comprising a processor, wherein said processor is configured to use said sensor data to calculate torque of said shaft and wherein said processor is configured to calculate power transmitted by said shaft from said torque and from rate of rotation of said shaft.

92. A device as recited in claim 82, wherein said rotatable shaft is part of a machine for delivering torque.

93. A device as recited in claim 92, wherein said machine includes at least one from the group including a motor, a vehicle, a pump, a valve, a compressor, a polishing machine, a grinder, a lathe, and a milling machine.

94. A device as recited in claim 93, wherein said vehicle includes an aircraft.

95. A device, comprising:

a rotatable object;

an energy harvesting device and an energy consuming device, said energy harvesting device having a circuit mounted to rotate with said rotatable object, said energy consuming device mounted to rotate with said rotatable object, said circuit converting mechanical energy of motion of said rotatable object into electricity available for use in said energy consuming device; and

a rate of rotation detector mounted to rotate with said rotatable object and provide information about rate of rotation of said rotatable object.

96. A device as recited in claim 95, wherein said rate of rotation detector is integrated with said energy harvesting circuit.

97. A device as recited in claim 95, wherein said energy consuming device includes a radio frequency communications device.

98. A device as recited in claim 97, wherein all electricity for powering said radio frequency communications device is derived from said energy harvesting circuit.

99. A device as recited in claim 97, wherein said radio frequency communications device is connected to transmit data derived from said information about rate of rotation of said rotatable object.

100. A device as recited in claim 95, wherein said rotatable shaft is part of a machine for delivering torque.

101. A device as recited in claim 100, wherein said machine includes at least one from the group including a motor, a vehicle, a pump, a valve, a compressor, a polishing machine, a grinder, a lathe, and a milling machine.

102. A device as recited in claim 101, wherein said vehicle includes an aircraft.

103. A device, comprising:

a rotatable shaft;

an energy harvesting device includes a first portion and a second portion, said first portion mounted to rotate with said, rotatable shaft, said second portion mounted on fixed supports relative to said rotatable shaft, said energy harvesting device for converting mechanical energy of motion of said rotatable shaft into electricity;

a radio frequency communications device mounted to rotate with said rotatable shaft, said radio frequency communications device connected to be powered with electricity derived from said first portion, wherein all electricity for powering said radio frequency communications device is derived from said first portion.

104. A device as recited in claim 103, wherein said first portion includes an inductor and wherein said second portion includes a magnet arranged adjacent said rotatable shaft, said magnet for providing a magnetic field wherein said inductor is capable of being magnetically coupled to said magnet during rotation of said rotatable shaft, wherein said energy harvesting device harvests energy from a pulse of electricity induced in said inductor by rotation of said inductor through said magnetic field.

105. A device as recited in claim 104, wherein said first portion includes a plurality of said inductors.

106. A device as recited in claim 103, further comprising a sensor mounted to rotate with said rotatable shaft, wherein said sensor comprises at least one from the group including a temperature sensor, a strain gauge, a torque sensing device, a pressure sensor, and an accelerometer.

107. A device as recited in claim 106, wherein said strain gauge is configured for measuring at least one from the group consisting of torque, bending, tension, and compression of said shaft.

108. A device as recited in claim 103, further comprising a rechargeable source of power mounted to rotate with said rotatable shaft, said rechargeable source of power connected for receiving and storing charge from said energy harvesting device.

109. A device as recited in claim 103, further comprising a processor mounted to rotate with said rotatable shaft.

110. A device as recited in claim 109, wherein said processor is configured to calculate power transmitted by said shaft by calculating the product of torque and rate of rotation.