Small Business Innovation Research/Small Business Tech Transfer
Wireless SAW Sensor Strain Gauge & Integrated Interrogator Design
Project Description
The proposed Wireless, passive, SAW sensor system operates in a multi-sensor environment with a range in excess of 45 feet. This proposed system offers unique features in two (2) important areas. The first is in the development of a new sensor type, a strain gauge that is based on OFC techniques and implemented with the low loss characteristics of SAW Unidirectional transducers. The second is in the design of an integrated interrogator system that has DSP-based embedded signal processing. Interrogator will also be capable of rapidly performing multiple interrogations which can them be used to make ibration measurements or averaged to extend the operational range of the system. This proposal extends the Phase I and previous work in two major areas; developing a SAW strain sensor, and dramatically increasing interrogation range, which is applicable to both the new strain sensors and the previously developed temperature sensors. In order to increase SAW sensor range, sensitivity and accuracy, the most important device parameters were identified and initial investigation begun in Phase I and will be put into practice in Phase II. To reduce SAW sensor loss and minimize multi-transit acoustic echoes, low loss unidirectional studies were initiated. Phase I produced three alternative low-loss approaches that will be evaluated in the Phase II work. Success will lower the insertion loss by approximately 15 dB, and multi-transit echoes are predicted to be less than -40 dB from the main signal; doubling the system range and reducing the sensors self-noise. Advanced coding techniques were investigated in Phase I that have led to longer delay path lengths, and shorter codes with less inter-sensor interference. During Phase II, the interrogator will improve the following critical capabilities: onboard-fully-integrated DSP, extended connectivity options to customer's computer, and rapid interrogation capabilities. This will allow vibration sensing and signal integration.
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Anticipated Benefits
A wireless, passive, coded sensor that is rugged, cheap and can be remotely interrogated has multiple applications at NASA. Temperature, pressure and acceleration sensors can be installed on the leading edges of wings to monitor temperature, pressure loss and also provide a profile of the forces on the structure. Additional NASA applications include acceleration sensing for monitoring vehicular acceleration and vehicular vibration, vehicular docking, rotation and directional sensing, tilt control, and fall detection. By exploring the future use of SAW devices for monitoring structural integrity, extreme temperature, extreme pressure, toxic or lethal environments, it is highly probable that the wireless SAW can change the future of Airframe safety and the required/planned maintenance process. This technology can allow the feasible embedment of sensors in key structural components of an airframe for persistent monitoring both during flight and as a post flight analysis. Not only could the structural integrity of the airframe be monitored but other critical states of air flight could be instrumented without the increased cost of weight associated with fiber optic or wired communication.
Potential Non-NASA commercial include the Automotive Industry (state of health), Civil Engineering (stress management), Chemical and Biological development (toxic safety monitoring) and Refinery process (safety monitoring). The utilization of a wireless SAW device for remote monitoring of hostile environments will become not only technically feasible but also economically feasible based on the extremely low cost associated with the device. By establishing the WSAW as a passive device and the wireless interrogator as the active portion of the link you have enabled an architecture which can support the monitoring of possibly hundreds of SOH sensors per interrogator. As an example in an automobile the wireless SAW can be deployed as pressure sensors in each tire, liquid contaminant sensors in the fuel and oil supplies, temperature and pressure sensors within the engine, and carbon monoxide sensors within the vehicle. Additionally, highway safety information could be deployed with each informational sign or within construction areas to alert the driver of a status change of speed or other conditions which could be interrogated by the onboard system. More »
Potential Non-NASA commercial include the Automotive Industry (state of health), Civil Engineering (stress management), Chemical and Biological development (toxic safety monitoring) and Refinery process (safety monitoring). The utilization of a wireless SAW device for remote monitoring of hostile environments will become not only technically feasible but also economically feasible based on the extremely low cost associated with the device. By establishing the WSAW as a passive device and the wireless interrogator as the active portion of the link you have enabled an architecture which can support the monitoring of possibly hundreds of SOH sensors per interrogator. As an example in an automobile the wireless SAW can be deployed as pressure sensors in each tire, liquid contaminant sensors in the fuel and oil supplies, temperature and pressure sensors within the engine, and carbon monoxide sensors within the vehicle. Additionally, highway safety information could be deployed with each informational sign or within construction areas to alert the driver of a status change of speed or other conditions which could be interrogated by the onboard system. More »
Primary U.S. Work Locations and Key Partners
| Organizations Performing Work | Role | Type | Location |
|---|---|---|---|
| Mnemonics, Inc. | Lead Organization | Industry | Melbourne, Florida |
Kennedy Space Center
(KSC)
|
Supporting Organization | NASA Center | Kennedy Space Center, Florida |
| University of Central Florida (UCF) | Supporting Organization | Academia | Orlando, Florida |
Primary U.S. Work Locations
-
Florida
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