SYSTEM TO MONITOR THE HEALTH OF A STRUCTURE, SENSOR NODES, PROGRAM PRODUCT, AND RELATED METHODS

• US 20070118335A1
• Filed: 11/23/2005
• Published: 05/24/2007
• Est. Priority Date: 11/23/2005
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Berkcan, Ertugrul, Andarawis, Emad, Delgado, Eladio, Rao, Samantha
• Granted Patent: US 7,343,265 B2
• Time in Patent Office: Days
• US Class Current: 702/188
• 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: G01M 5/0041 by determining deflection or stress
• CPC Class Codes: G01M 5/0066 by exciting or detecting vibration or acceleration vibration testing of structures G01M7/00
• CPC Class Codes: G01M 5/0091 by using electromagnetic excitation or detection
• CPC Class Codes: G05B 23/0213 Modular or universal configuration of the monitoring system, e.g. monitoring system having modules that may be combined to build monitoring program; monitoring system that can be applied to legacy systems; adaptable monitoring system; using different communication protocols
• CPC Class Codes: H04Q 2209/10 using a centralized architecture

Abstract

A system to monitor the health of a structure, health monitoring sensor nodes, program product, and associated methods are provided. The system includes an array of health monitoring sensor nodes connected to or embedded within a structure to monitor the health of the structure. Each health monitoring sensor node includes sensor elements positioned to sense parameters of the structure and to provide data related to the parameters to a health monitoring sensor node interrogator. Each health monitoring sensor node has a tunable antenna arrangement individually tunable to minimize data collisions between each other of the health monitoring sensor nodes. Each health monitoring sensor node also includes a processor and memory in communication with the processor storing a parameter processing program product adapted to control tuning the antenna arrangement and providing data to the health monitoring sensor node interrogator.

Claims

1. A passive communication health monitoring sensor node connected to or embedded within a body of a structure to monitor data related to parameters of a portion of the body of the structure, the node comprising:

a processor;

a sensor element coupled to the processor and adapted to sense parameters of a portion of a body of the structure to be monitored to define sensed parameters;

an antenna arrangement including an antenna and coupled to the processor to receive interrogation signals and having at least one tuned and a detuned state;

a memory coupled to the processor to store operating instructions therein; and

a parameter processing program product stored in the memory and including instructions that when executed by the processor perform the operations of processing the sensed parameters to define processed sensor data, selectively tuning the antenna arrangement to at least one preselected data receive frequency of a health monitoring sensor node interrogator responsive to receiving a power and interrogation signal from the interrogator to thereby enable data transfer to the interrogator, providing the processed sensor data to the interrogator, and selectively detuning the antenna arrangement from the preselected data receive frequency of the interrogator.

2. The node as defined in claim 1,

wherein the node includes an antenna arrangement tuner in communication with the processor and positioned to tune the antenna arrangement to the at least one preselected data receive frequency of the interrogator;

and

wherein the parameter processing program product further includes instructions to perform the operations of enabling the antenna arrangement tuner to change the inductance of the antenna to thereby tune the antenna arrangement responsive to passage of a delay period after receiving the power and interrogation signal.

3. The node as defined in claim 2,

wherein the parameter processing program product further includes instructions to perform the operations of iteratively tuning to enable data transfer and detuning the antenna arrangement to define a data transmission cycle responsive to receiving the power and interrogation signal;

and

wherein the delay period resets to a different delay period after each data transmission cycle.

4. The node as defined in claim 3, wherein the delay period is pseudorandom within a preselected range.

5. The node as defined in claim 2,

wherein the node further includes a capacitive arrangement having a variable capacitance;

and

wherein the antenna arrangement tuner is positioned to change the capacitance of the capacitive arrangement to thereby tune the antenna arrangement.

6. The node as defined in claim 1,

wherein the memory includes a node identification;

wherein the node is directly addressable by the interrogator using a node identification; and

wherein the node includes an antenna arrangement tuner in communication with the processor and positioned to tune the antenna arrangement to the at least one preselected data receive frequency of the interrogator responsive to receiving the node identification in the power and interrogation signal.

7. The node as defined in claim 1,

wherein the node includes an antenna arrangement tuner in communication with the processor and positioned to tune the antenna arrangement to the at least one preselected data receive frequency of the interrogator;

and

wherein the antenna arrangement tuner is positioned to provide a substantially short circuit condition to a portion of the antenna to thereby tune or to detune the antenna arrangement.

8. The node as defined in claim 1, wherein each node includes a bistable switch positioned to vary the antenna arrangement between tuned and detuned states, the bistable switch requiring power to actuate and substantially not requiring power when stabilized.

9. The node as defined in claim 1, wherein the at least one tuned state is a plurality of detuned states, wherein the antenna includes a plurality of antenna taps, and wherein each node includes a multistable switch operatively connected to the plurality of antenna taps and positioned to vary the antenna arrangement between the plurality of tuned states and the detuned state, the multistable switch requiring power to actuate and substantially not requiring power when stabilized.

10. A system to monitor the health of a structure, the system comprising:

a structure to be monitored having a body;

a plurality of separate health monitoring sensor nodes each connected to or embedded within the body of the structure to monitor data related to parameters of a respective portion of the body of the structure, each node having a processor, a sensor element coupled to the processor and positioned to sense parameters of the respective portion of the body of the structure to define sensed parameters, an antenna arrangement including an antenna and coupled to the processor to receive interrogation signals and having an active tuned state and an inactive detuned state, a power harvester coupled to the processor and the antenna arrangement to harvest power received therefrom, a power storage device to store harvested power, and a memory coupled to the processor to store operating instructions and data therein;

a plurality of health monitoring sensor node interrogators each having an antenna arrangement and positioned to transmit a request for data to a subset of the plurality of health monitoring sensor nodes and to receive requested data therefrom and having a preselected power and interrogation signal transmission frequency spectrum and a preselected data signal receive frequency spectrum having a preselected data receive frequency substantially coinciding with the active tuned state of the respective subset of the plurality of health monitoring sensor nodes; and

a parameter processing program product separately stored in the memory of each of the plurality of health monitoring sensor nodes and including instructions that when executed by the respective processor perform the operations of processing the sensed parameters to define processed sensor data, selectively tuning the antenna arrangement to the preselected data receive frequency of at least one of the plurality of interrogators responsive to receiving a power and interrogation signal from the interrogator to thereby enable data transfer to the respective interrogator via passive radiofrequency communication, providing the processed sensor data to the respective interrogator, and selectively detuning the antenna arrangement from the preselected data receive frequency of the respective interrogator to thereby minimize data collisions with other ones of the plurality of health monitoring sensor nodes.

11. The system as defined in claim 10, wherein each node includes an antenna arrangement tuner positioned to tune the respective antenna arrangement to the preselected data receive frequency of at least one of the plurality of interrogators responsive to passage of a delay period after receiving the power and interrogation signal.

12. The system as defined in claim 11, wherein each node has a different delay period to thereby minimize the data collisions.

13. The system as defined in claim 11,

wherein the parameter processing program product further includes instructions to perform the operations of iteratively tuning and detuning the antenna arrangement of the respective node to define a data transmission cycle responsive to receiving the power and interrogation signal, the tuning performed to enable data transfer, the detuning performed to reduce saturation of the respective preselected data receive frequency of each of the plurality of interrogators;

and

wherein the delay period resets to a different delay period after each data transmission cycle to thereby minimize the data collisions.

14. The system as defined in claim 13, wherein the delay period is pseudorandom within a preselected range.

15. The system as defined in claim 10,

wherein the memory of each of the plurality of nodes includes a unique node identification;

wherein each of the plurality of nodes is directly addressable by at least one of the plurality of interrogators using the respective node identification; and

wherein each of the plurality of nodes includes a switch arrangement in communication with the respective processor and positioned to tune the antenna arrangement to the preselected data receive frequency of the at least one of the plurality of interrogators responsive to receiving the node identification in the power and interrogation signal.

16. The system as defined in claim 10,

wherein each of the plurality of nodes includes an antenna arrangement tuner in communication with the respective processor and positioned to tune the respective antenna arrangement to and detune the respective antenna arrangement from the preselected data receive frequency of at least one of the plurality of interrogators;

and

wherein the antenna arrangement tuner is positioned to provide a substantially short circuit condition to a portion of the respective antenna to thereby tune or to detune the antenna.

17. The system as defined in claim 10,

wherein each of the plurality of nodes includes an antenna arrangement tuner in communication with the respective processor and positioned to tune the respective antenna arrangement to and to detune the respective antenna arrangement from the preselected data receive frequency of at least one of the plurality of interrogators;

and

wherein the antenna arrangement tuner of at least one of the plurality of health monitoring sensor nodes is positioned to change a radiation pattern of a data signal provided to the at least one of the plurality of interrogators.

18. The system as defined in claim 17,

wherein the antenna of at least one of the plurality of health monitoring sensor nodes includes a plurality of segments each having a polarity;

and

wherein the antenna arrangement tuner is adapted to change the polarity of one of the plurality of segments to thereby change the radiation pattern of the data signal.

19. The system as defined in claim 17,

wherein the antenna of at least one of the plurality of health monitoring sensor nodes includes a plurality of segments;

and

wherein the antenna arrangement tuner is adapted to change the phase or amplitude of the data signal to thereby change the radiation pattern of the data signal.

20. A method of monitoring the health of a structure, the method comprising the steps of:

positioning each of a plurality of separate wireless health monitoring sensor nodes on or within a portion of a body of a structure, each node including an antenna arrangement having an active tuned state and an inactive detuned state;

receiving a power and interrogation signal from an interrogator by each of the plurality of health monitoring sensor nodes to thereby power each respective node;

selectively tuning the antenna arrangement of each node to a preselected data receive frequency of the interrogator responsive to the power and interrogation signal to thereby enable data transfer to the interrogator; and

selectively detuning the antenna arrangement of the each respective node from the preselected data receive frequency of the interrogator to thereby minimize data collisions with other ones of the plurality of health monitoring sensor nodes.

21. The method as defined in claim 20, the method further comprising the step of modulating an impedance of the antenna arrangement of each respective node to thereby provide to the interrogator processed sensor data processed by each node.

22. The method as defined in claim 20, the method further comprising the step of modulating a resonant frequency of the antenna arrangement of each respective node to thereby provide to the interrogator processed sensor data processed by each node.

23. The method as defined in claim 20, wherein the step of selectively tuning the antenna arrangement of each node further includes the step of delaying for a delay period tuning the respective antenna arrangement to the preselected data receive frequency of the interrogator responsive to at least one of the following:

receiving the power and interrogation signal and detuning the antenna arrangement.

24. The method as defined in claim 23, wherein each node has a different delay period to thereby minimize the data collisions.

25. The method as defined in claim 23,

wherein the steps of selectively tuning the antenna arrangement of each node, and selectively detuning the antenna arrangement of each node includes iteratively tuning and detuning the antenna arrangement of the respective node to define a data transmission cycle responsive to receiving the power and interrogation signal, the tuning performed to enable data transfer, the detuning performed to reduce saturation of the preselected data receive frequency of the interrogator.

26. The method as defined in claim 25,

wherein the method further includes the step of resetting the delay period to a different delay period after each data transmission cycle so that no two nodes of the plurality of nodes continuously have the same delay period to thereby minimize the data collisions.

27. The method as defined in claim 26, wherein the delay period is pseudorandom within a preselected range.

28. The method as defined in claim 20,

wherein the method further includes the step of directly addressing each of the plurality of health monitoring sensor nodes by the interrogator using a respective unique node identification;

and

wherein the step of selectively tuning the antenna arrangement of each node to a preselected data receive frequency of the interrogator includes performing such step individually for each node responsive to receiving the respective unique node identification in the power and interrogation signal.

29. The method as defined in claim 20, the method further comprising the step of forming a substantially short circuit condition to a portion of the antenna of at least one of the plurality of health monitoring sensor nodes to thereby tune the respective antenna arrangement to or to detune the respective antenna arrangement from the preselected data receive frequency of the interrogator.

30. The method as defined in claim 20, the method further comprising the step of varying capacitance of the antenna arrangement of at least one of the plurality of health monitoring sensor nodes to thereby tune the respective antenna arrangement to or to detune the respective antenna arrangement from the preselected data receive frequency of the interrogator.

31. The method as defined in claim 20, the method further comprising the step of varying a radiation vector of the antenna arrangement of at least one of the plurality of health monitoring sensor nodes to thereby tune the respective antenna arrangement to or to detune the respective antenna arrangement from the preselected data receive frequency of the interrogator.