Acoustic Air Data System for Icing-Resistant Flight Control
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Solution Overview
Problem
Traditional air data systems in vehicles, such as aircraft, are susceptible to failures due to icing and particulate buildup, which degrade the accuracy of angle of attack and airspeed measurements.
Innovation Solution
An acoustic air data sensing system that uses an acoustic transmitter and receivers located at various angles and distances to determine airflow velocity components and speed of sound, allowing for the calculation of true airspeed and relative wind angle without direct pressure measurements or vane rotation, thereby mitigating the effects of icing and particulates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional pneumatic probes and rotating vane sensors are used, then air data parameters can be measured, but the sensors are susceptible to icing and particulate buildup which degrades measurement accuracy
Solution Approach 1:
The patent replaces mechanical pneumatic probes and rotating vane sensors with an acoustic measurement system that uses sound wave propagation to determine air data parameters. The acoustic transmitter emits sound waves that travel through the airflow to multiple receivers, and the variations in signal velocity and time of flight are used to calculate airflow velocity and angle of attack, eliminating mechanical components that are susceptible to icing and particulate buildup
Solution Approach 2:
The patent introduces acoustic waves as an intermediary medium to measure air data parameters. Instead of directly measuring pressure with pneumatic probes or angle with rotating vanes, the system uses sound wave propagation characteristics (velocity, time of flight) as an intermediary to indirectly determine airflow properties, which are not affected by icing or particulates
2Object-affected harmful factors
If ice buildup occurs on the sensor, then the sensor becomes protected from direct airflow exposure, but rotation is prevented and measurement accuracy decreases
Solution Approach 1:
The patent eliminates the mechanical rotating vane system entirely and replaces it with acoustic transducers that have no moving parts. The acoustic transmitter and receivers are fixed in position, and angle of attack is determined through signal processing of acoustic wave propagation characteristics rather than mechanical rotation, so ice buildup cannot affect the measurement mechanism
3Measurement precision
If pneumatic probes are used to measure air pressure, then air data parameters can be obtained, but particulate buildup within the probe degrades performance
Solution Approach 1:
The patent replaces pneumatic pressure measurement probes with acoustic transducers that measure air data parameters through sound wave propagation. The acoustic transmitter and receivers detect variations in acoustic signal velocity and time of flight caused by airflow properties, eliminating the need for pneumatic probes that can accumulate particulates and block airflow
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
The system provides accurate air data parameters for operational control of vehicles, even at high wind velocities, reducing susceptibility to common failure modes of traditional sensors like ice accumulation and particulate buildup.
Implementation Method 1
The acoustic transmitter is located to transmit an acoustic signal into airflow about an exterior of a vehicle. Each of the plurality of acoustic receivers is located at a respective angle from a wind angle reference line and a respective distance from the acoustic transmitter to receive the acoustic signal transmitted by the acoustic transmitter.
Implementation Method 2
determine a speed of sound in the airflow about the exterior of the vehicle based on the signal velocities and the respective angles of the acoustic receivers from the wind angle reference line
Implementation Method 3
The control circuitry is configured to determine respective times of flight of the acoustic signal from the acoustic transmitter to each of the plurality of acoustic receivers
Implementation Method 4
determine signal velocities of the acoustic signal to each of the plurality of acoustic receivers based on the respective distances and respective times of flight of the acoustic signal from the acoustic transmitter to the acoustic receivers
Data Source
Figure 1
Figure 2
AI summary
An acoustic air data sensing system includes an acoustic transmitter (T) and a plurality of acoustic receivers (R1-RN). The acoustic transmitter (T) is located to transmit an acoustic signal into airflow about an exterior of a vehicle. Each of the acoustic receivers (R1-RN) is located at a respective angle from a wind angle reference line and a respective distance from the acoustic transmitter (T). Planar components of a velocity of the airflow are determined based on signal velocities of the acoustic signal to each of the plurality of acoustic receivers (R1-RN) and the respective angles of the acoustic receivers (R1-RN) from the wind angle reference line. Based on the planar components, the acoustic transmitter (T(determines one or more of true airspeed and relative wind angle of the airflow about the exterior of the vehicle. The acoustic transmitter outputs the one or more of the true airspeed and the relative wind angle for operational control of the vehicle.