Wireless structural health monitoring system with synchronized timekeeper

• US 9,090,339 B2
• Filed: 08/02/2011
• Issued: 07/28/2015
• Est. Priority Date: 09/09/2005
• Status: Expired due to Fees

• Current Assignee: Hottinger Bruel & Kjaer Incorporated
• Original Assignee: Lord Corporation (Parker-Hannifin Corporation)
• Inventors: Arms, Steven W., Townsend, Chris Pruyn, Churchill, David Lawrence, Hamel, Michael John
• Primary Examiner(s): BLOUNT, ERIC
• Application Number:
  US13/196,031
• Publication Number:
  US 20110285527A1
• Time in Patent Office: 1,456 Days
• Field of Search: 340/539.1, 340/593.11, 340/945, 340/946, 340/665, 340/668, 340/3.1, 340/3.2
• US Class Current: 1/1
• CPC Class Codes: B64C 2027/002 mounted between the rotor drive and the fuselage
• CPC Class Codes: B64C 27/006 Safety devices
• 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: G07C 5/085 using electronic data carriers

Abstract

A method of obtaining data about a structure includes providing a plurality of sensor modules on the structure. Each of the sensor modules includes a sensor, a processor, a sensor module precision timekeeper, and a sensor module transceiver. One of the plurality of sensor modules includes an energy harvesting device. The processor and the sensor module transceiver of this one of the plurality of sensor modules are powered solely with electricity derived from the energy harvesting device. The method further includes providing a base station. The method further includes periodically wirelessly receiving a broadcast resynchronization timing packet with each of the sensor module transceivers, wherein the broadcast resynchronization timing packet received by each of the sensor module transceivers includes a common resynchronization time value. The method further includes periodically resynchronizing each of the sensor module precision timekeepers based on a signal derived from the resynchronization time value. The method further includes digital sampling of the sensor module sensor in each of the sensor modules to provide digital sensor data, and providing a time stamp to the digital sensor data wherein time in the time stamp is provided by the sensor module precision timekeeper. The method further includes wirelessly transmitting data from each of the plurality of sensor modules to the base station, wherein the data is derived from the time stamped digital sensor data. The method further includes receiving and aggregating the data from each of the plurality of sensor modules in the base station.

Claims

1. A method of obtaining data about a structure, comprising:

a. providing a plurality of sensor modules on the structure, wherein each said sensor module includes a sensor, a processor, a sensor module precision timekeeper, and a sensor module transceiver, wherein said sensor provides data related to loading;

b. providing a base station;

c. periodically wirelessly receiving a broadcast resynchronization timing packet with each said sensor module transceiver, wherein said broadcast resynchronization timing packet received by each said sensor module transceiver includes a common resynchronization time value;

d. periodically resynchronizing each of said sensor module precision timekeepers based on a signal derived from said resynchronization time value;

e. digital sampling of said sensor module sensor in each said sensor module to provide digital sensor data, and providing a time stamp to said digital sensor data wherein time in said time stamp is provided by said sensor module precision timekeeper;

f. wirelessly transmitting data from each of said plurality of sensor modules to said base station, wherein said data is derived from said time stamped digital sensor data; and

g. receiving and aggregating said data from each of said plurality of sensor modules in said base station.

2. A method as recited in claim 1, wherein each said sensor module includes a memory, further comprising logging said time stamped digital sensor data in said memory.

3. A method as recited in claim 2, wherein said memory includes a volatile memory portion and a non-volatile memory portion.

4. A method as recited in claim 3, further comprising providing data directly from said sensor to said volatile memory portion and then transferring said data to said non-volatile memory.

5. A method as recited in claim 2, further comprising providing at least one from the group consisting of configuration, calibration, and compensation coefficients in said memory and providing said coefficients from said memory to said data in said processor.

6. A method as recited in claim 1, wherein said memory is connected for direct memory access, further comprising an input circuit, wherein said input circuit includes a high speed analog to digital converter, wherein an output of said analog to digital converter is directly connected to said memory for said direct memory access, further comprising storing data derived from said sensor by said direct memory access.

7. A method as recited in claim 1, further comprising replacing said structure if information derived from said data shows that said structure experienced a load history indicating damaging usage.

8. A method as recited in claim 7, wherein said load history indicating damaging usage includes at least one from the group consisting of a load exceeding a threshold and fatigue inducing cyclic loading.

9. A method as recited in claim 1, further comprising adjusting operation of said structure so as to avoid damaging usage based on information derived from said data.

10. A method as recited in claim 9, further comprising providing a warning if said information shows that said component is subject to damaging usage to facilitate said adjusting operation.

11. A method of operating a system as recited in claim 9, wherein damaging usage involves a load exceeding a threshold, wherein said adjusting operation involves avoiding exceeding said threshold.

12. A method as recited in claim 1, further comprising using said data to set a time for maintaining said structure.

13. A method as recited in claim 1, further comprising determining accumulated damage from repeated instances of said data indicating loading.

14. A method as recited in claim 1, further comprising determining at least one from the group consisting of strain, load, remaining life, accumulated damage and peak data from said data.

15. A method as recited in claim 1, wherein one of said plurality of sensor modules includes an energy harvesting device, wherein said processor and said sensor module transceiver of said one of said plurality of sensor modules is powered solely with electricity derived from said energy harvesting device.

16. A method as recited in claim 15, wherein said one of said plurality of sensor modules includes a timekeeper-energy-storage device, wherein said timekeeper-energy-storage device is connected for powering said timekeeper.

17. A method as recited in claim 15, wherein said energy harvesting device is configured to convert at least one from the group consisting of vibration of the structure and strain of the structure into electricity.

18. A method as recited in claim 15, wherein said sensor module further includes a rechargeable battery connected for recharging from said energy harvesting device.

19. A method as recited in claim 15, further comprising automatically adjusting rate of said digital sampling to log data at a rate depending on amount of energy harvested by said energy harvesting device.

20. A method as recited in claim 1, wherein said structure includes at least one from the group consisting of an aircraft, a land vehicle, and a water craft.

21. A method as recited in claim 1, wherein said structure comprises a rotating part.

22. A method as recited in claim 21, wherein said structure comprises a helicopter pitch link.

23. A method as recited in claim 1, wherein said sensor includes at least one from the group consisting of a strain gauge, a piezoelectric transducer, a temperature sensor, an accelerometer, a pressure sensor, a load sensor, a force sensor, a moisture sensor, and a magnetic field sensor.

24. A system as recited in claim 23, wherein said sensor of one said sensor module includes a foil strain gauge and a piezoelectric transducer and wherein said data includes a ratio of foil strain gauge amplitude to piezoelectric transducer amplitude.

25. A method as recited in claim 24, wherein said strain gauge includes a triaxial strain gauge, further comprising providing a programmable triaxial strain gauge signal conditioner with integral self calibration.

26. A method as recited in claim 1, wherein said sensor of one said sensor module includes triaxial accelerometers and triaxial rate gyros.

27. A method as recited in claim 26, wherein said sensor of said one said sensor module further includes triaxial magnetometers.

28. A method as recited in claim 27, wherein said sensor of said one said sensor module further includes a GPS and a GPS antenna.

29. A method as recited in claim 1, wherein said processor is connected for controlling operation of said sensor module transceiver.

30. A method as recited in claim 29, wherein said sensor module further includes a plurality of sensors and a multiplexer, wherein said multiplexer is connected to provide data derived from said plurality of sensors to said processor.

31. A method as recited in claim 29, further comprising using said processor to perform calculations before transmitting data.

32. A method as recited in claim 1, further comprising providing a wired sensor module, wherein said wired sensor module has a wired connection to said base station, and further comprising transmitting data from said wired sensor module to said base station.

33. A sensing system as recited in claim 32, further comprising providing a network of wired sensor modules, wherein said wired network includes at least one from the group consisting of a CAN bus, a vehicle bus, and a serial bus.

34. A method as recited in claim 32, wherein said base station includes memory for combining data from said plurality of sensor modules with data from said wired sensor module.

35. A method as recited in claim 1, wherein said processor is capable of sleep mode, further comprising providing a periodic signal to said processor from said sensor module timekeeper for waking said processor from said sleep mode.

36. A method as recited in claim 35, wherein said sleep mode includes power to said processor being turned off, wherein said signal results in power being provided to said processor.

37. A method as recited in claim 36, further comprising providing a plurality of said signals from said timekeeper to said processor, wherein power to said processor is turned off during a portion of time between said signals.

38. A method as recited in claim 36, further comprising providing burst mode sampling data from said sensor.

39. A method as recited in claim 38, wherein duty cycle of said burst mode sampling is based on energy available.

40. A method as recited in claim 38, wherein each sensor module includes a memory, further comprising buffering data acquired in said burst mode sampling in said memory before transmitting said data with said wireless communication device.

41. A method as recited in claim 1, further comprising connecting an actuator to said sensor module.

42. A method as recited in claim 41, wherein said actuator is connected for providing a signal to said structure for material testing.

43. A method as recited in claim 1, wherein said plurality of sensor modules is arranged in at least one from the group consisting of a mesh network and wireless multihop network.

44. A method as recited in claim 1, further comprising providing a housing, wherein said processor, said timekeeper, and said sensor module transceiver are included in said housing.

45. A method as recited in claim 44, wherein said sensor is external to said housing.

46. A method as recited in claim 1, further comprising providing calculations for transmission by said sensor module transceiver.

47. A method as recited in claim 1, further comprising providing digital filtering with said processor.

48. A method as recited in claim 1, further comprising providing an input circuit including an instrumentation amplifier with digitally programmable gain and amplifying a signal from said sensor with said instrumentation amplifier.

49. A method of obtaining data about a structure, comprising:

a. providing a plurality of sensor modules on the structure, wherein each said sensor module includes a sensor, a processor, a sensor module precision timekeeper, and a sensor module transceiver, wherein one of said plurality of sensor modules includes an energy harvesting device, wherein said processor and said sensor module transceiver of said one of said plurality of sensor modules are powered solely with electricity derived from said energy harvesting device;

b. providing a base station;

c. periodically wirelessly receiving a broadcast resynchronization timing packet with each said sensor module transceiver, wherein said broadcast resynchronization timing packet received by each said sensor module transceiver includes a common resynchronization time value;

d. periodically resynchronizing each of said sensor module precision timekeepers based on a signal derived from said resynchronization time value;

e. digital sampling of said sensor module sensor in each said sensor module to provide digital sensor data, and providing a time stamp to said digital sensor data wherein time in said time stamp is provided by said sensor module precision timekeeper;

f. wirelessly transmitting data from each of said plurality of sensor modules to said base station, wherein said data is derived from said time stamped digital sensor data; and

g. receiving and aggregating said data from each of said plurality of sensor modules in said base station.

50. A method as recited in claim 49, wherein each said sensor module includes a memory, further comprising logging said time stamped digital sensor data in said memory.

51. A method as recited in claim 49, wherein said one of said plurality of sensor modules includes a timekeeper-energy-storage device, wherein said timekeeper-energy-storage-device is connected for powering said timekeeper.

52. A method as recited in claim 49, wherein said energy harvesting device is configured to convert at least one from the group consisting of vibration of the structure and strain of the structure into electricity.

53. A method as recited in claim 49, wherein said sensor module further includes a rechargeable battery connected for recharging from said energy harvesting device.

54. A method as recited in claim 49, further comprising automatically adjusting rate of said digital sampling to log data at a rate depending on amount of energy harvested by said energy harvesting device.

55. A method as recited in claim 49, wherein each said sensor module includes an energy harvesting device, wherein said processor and said sensor module transceiver of each of said plurality of sensor modules are powered solely with electricity derived from said energy harvesting device.

56. A method of obtaining data about a structure, comprising:

a. providing a plurality of sensor modules on the structure, wherein each said sensor module includes a sensor, a processor, a sensor module precision timekeeper, and a sensor module transceiver;

b. providing a base station;

c. periodically wirelessly receiving a broadcast resynchronization timing packet with each said sensor module transceiver, wherein said broadcast resynchronization timing packet received by each said sensor module transceiver includes a common resynchronization time value;

d. periodically resynchronizing each of said sensor module precision timekeepers based on a signal derived from said resynchronization time value;

e. digital burst mode sampling of said sensor module sensor in each said sensor module to provide burst mode digital sensor data, and providing a time stamp to said burst mode digital sensor data wherein time in said time stamp is provided by said sensor module precision timekeeper;

f. wirelessly transmitting data from each of said plurality of sensor modules to said base station, wherein said data is derived from said time stamped burst mode digital sensor data; and

g. receiving and aggregating said data from each of said plurality of sensor modules in said base station.