Wireless SAW Temperature Sensor Synchronization for Rotating Platforms
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Solution Overview
Problem
Existing wireless SAW temperature sensors for rotating platforms are unreliable without a tachometer, prone to wear and tear, and misalignment, leading to inconsistent line-of-sight alignment with the interrogating antenna, which affects the accuracy and reliability of temperature measurements.
Innovation Solution
A software-based shaft position indicator using a processor with a field programmable gate array (FPGA) or microcontroller executes a threshold detection algorithm to synchronize RF interrogating signals with rotating SAW sensors, eliminating the need for physical tachometers and ensuring consistent alignment by transmitting signals only when a reflected signal exceeds a threshold magnitude, allowing for accurate temperature measurement across varying angular velocities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If physical tachometers are used to synchronize interrogating signals with rotating sensors, then signal synchronization reliability is improved, but device complexity and susceptibility to wear increase
Solution Approach 1:
The patent replaces mechanical tachometers with a software-based position indicator that uses signal processing and timing algorithms to determine sensor positions. The system uses a processor to track the rotational position of SAW sensors through RF signal analysis, eliminating the need for physical tachometer components while maintaining synchronization reliability.
Solution Approach 2:
The rotating SAW sensors themselves serve as the position indicator by their own RF signal reflections. The system uses the sensors' inherent ability to reflect RF signals to determine their positions, making the sensors self-indicating without requiring external tachometer components. The sensors essentially tell their own position story through their signal characteristics.
2Measurement precision
If physical tachometers are used for synchronization, then measurement precision is improved, but wear and tear increase
Solution Approach 1:
The patent eliminates mechanical contact-based position sensing by using wireless RF signal analysis. The processor determines angular position through signal timing and phase information without any physical contact between sensors and position-indicating components, thereby eliminating wear and tear while maintaining measurement precision.
3Device complexity
If line-of-sight alignment is random and unreliable, then device complexity is reduced, but measurement reliability deteriorates
Solution Approach 1:
The system continuously monitors the RF signal returns from rotating SAW sensors and uses this feedback to dynamically adjust interrogation timing. The processor analyzes signal characteristics to determine sensor positions and adjusts the timing of subsequent RF interrogating signals accordingly, creating a closed-loop system that ensures reliable measurements despite random line-of-sight conditions.
Solution Approach 2:
The system performs preliminary position detection by analyzing RF signal reflections to determine when sensors are in line-of-sight positions. This preliminary information is stored and used to pre-time subsequent interrogating signals, ensuring that when the sensors rotate into position, the interrogating signals are already ready for immediate accurate measurement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution provides a robust and reliable temperature sensing system capable of measuring temperature on rotating platforms with constant or variable speeds, ensuring accurate data collection even at high angular velocities exceeding 100,000 RPM, and reducing wear and tear issues, thereby enhancing the integrity of the temperature sensing system.
Implementation Method 1
The IDT 20 launches incident surface acoustic waves (SAW) 28 onto the piezoelectric substrate 24
Implementation Method 2
an interdigital transducer (IDT) 20 disposed on a piezoelectric substrate 24
Implementation Method 3
A reflector bank 30 generates reflected surface acoustic waves 32 back to the IDT 20 where they are converted to an RF echo signal 34
Data Source
AI summary
A surface acoustic wave sensor system for use with a moving platform. The system comprises an interrogator for producing an RF interrogating signal transmitted from a first antenna. A substrate that supports surface acoustic waves is attached to the moving platform and an interdigital transducer (IDT) and reflector are mounted on the substrate. The IDT produces surface acoustic waves (SAW) responsive to the RF interrogating signal. The reflector produces reflected SAW responsive to the incident SAW and responsive to a characteristic of the moving platform. A position indicator produces a synchronization signal input to the interrogator for triggering the RF interrogating signal. The synchronization signal is timed to trigger the RF interrogating signal when the interdigital transducer is within a field-of-view of the first antenna.