Wireless Brake Temperature Sensor Using SAW Technology
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Solution Overview
Problem
Current aircraft brake temperature measurement systems using thermocouples face challenges such as thermal lag, limited robustness, and variability in readings due to air gaps and brake design differences, leading to unnecessary delays in take-off procedures.
Innovation Solution
A wireless sensor apparatus comprising a temperature sensor attached to the brake disc and a relay that wirelessly transmits measurement signals, using surface acoustic wave technology and piezoelectric transducers, allowing for direct attachment to the brake disc and minimizing interference, with an interrogation apparatus that generates and receives signals to determine brake disc temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermocouples are installed in the torque tube for robust installation, then installation robustness is improved, but thermal lag increases and measurement precision deteriorates due to air gap between thermocouple and brake discs
Solution Approach 1:
The temperature sensor is extracted from the torque tube location and directly attached to the brake disc surface, eliminating the air gap problem while maintaining installation robustness through direct mounting on the disc itself
Solution Approach 2:
A wireless sensor apparatus with relay is introduced as an intermediary system, allowing the temperature sensor to be positioned directly on the brake disc while transmitting data wirelessly to the monitoring system, thus eliminating thermal lag without compromising installation robustness
2Measurement precision
If thermocouples are placed close to brake discs for better temperature measurement, then measurement precision is improved, but installation robustness deteriorates due to brake design constraints and wear movement
Solution Approach 1:
The temperature sensor is extracted from the torque tube and directly mounted on the brake disc, allowing optimal positioning for temperature measurement while the wireless relay handles the robust communication connection separate from the moving brake components
Solution Approach 2:
The system is segmented into two parts: a temperature sensor directly attached to the brake disc for accurate measurement, and a wireless relay mounted on the torque tube or aircraft structure for robust signal transmission, separating the measurement function from the communication function
3Reliability
If significant safety margins are built into dispatch procedures to account for measurement uncertainties, then reliability is improved, but productivity deteriorates due to longer waiting times before take-off
Solution Approach 1:
The wireless temperature monitoring system provides real-time feedback on actual brake disc temperatures, allowing dispatch procedures to be based on accurate current temperature data rather than conservative estimates, thus reducing unnecessary waiting times while maintaining safety
Solution Approach 2:
The mechanical thermocouple system with inherent thermal lag is replaced by a wireless sensor system that directly measures brake disc temperature and transmits data electronically, eliminating the thermal delay and providing timely temperature information for dispatch decisions
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 system provides accurate, robust, and timely temperature measurements, reducing the need for safety margins and minimizing delays in aircraft take-off by directly attaching sensors to the brake disc and using wireless communication to overcome the limitations of traditional thermocouple systems.
Implementation Method 1
The temperature sensor comprises a transducer configured to transduce the received wireless interrogation signal into a surface acoustic wave, SAW, and to transduce the SAW into the measurement signal
Implementation Method 2
The transducer may comprise a piezoelectric transducer comprising at least one interdigitated electrode
Data Source
AI summary
A brake temperature sensing system for an aircraft including a sensor apparatus and an interrogation apparatus. The sensor apparatus includes a temperature sensor for attachment to a brake disc of an aircraft brake, and a relay for attachment to the brake. The temperature sensor is configured to wirelessly transmit a measurement signal containing information relating to a temperature of the brake disc, responsive to receiving a wireless interrogation signal. The relay is configured to receive an interrogation signal from the interrogation apparatus; wirelessly transmit the interrogation signal to the temperature sensor; receive the wireless measurement signal from the temperature sensor; and transmit the received measurement signal. The interrogation apparatus comprises a controller configured to generate an interrogation signal; and a transceiver configured to transmit the generated interrogation signal to the sensor apparatus; and receive the measurement signal transmitted by the sensor apparatus.