Microphones as Airspeed Sensors for Micro Air Vehicles

Microphones as Airspeed Sensors for Micro Air Vehicles

Makaveev, Momchil (TU Delft Aerospace Engineering)

Smeur, E.J.J. (mentor)

Delft University of Technology

Aerospace Engineering

2023-01-31

This project proposes and evaluates a novel concept for an airspeed instrument aimed at small hybrid unmanned aerial vehicles. The working principle is to relate the power spectra of the wall-pressure fluctuations beneath the turbulent boundary layer formed over the vehicle’s body to its airspeed. The instrument consists of two microphones, flush mounted on the UAV’s nose cone, that capture the pseudo-sound caused by the coherent turbulent structures, and a micro-controller that processes the signals from the microphones and computes the airspeed. Dedicated models were constructed, using data obtained from wind tunnel and flight experiments, that take the power spectra of the microphones’ signals as an input and provide the airspeed as an output. The model structure is a feed-forward neural network with a single hidden layer, trained using a second-order gradient descent algorithm, following a supervised learning approach. The models were validated using only flight data, with the best one achieving a mean approximation error of 0.043 m/s and having a standard deviation of 1.039 m/s. It was also shown that the airspeed could be successfully predicted for a wide range of angles of attack, given that they are known, thus necessitating the vehicle to be equipped with a dedicated angle of attack sensor.

Tail-sitter
Airspeed
Hydrodynamic Pressure Fluctuations
Pseudo-sound
Turbulent boundary layer
Microphones
Power Spectral Density
Artificial Neural Networks

http://resolver.tudelft.nl/uuid:90916a92-95bc-44eb-889e-81555ddd494f

Student theses

master thesis

© 2023 Momchil Makaveev