Acoustic Time-Reversal Based Multi-Sensor Communication For Autonomous Structural Health Monitoring Of Aerial Vehicles

The recurrent monitoring of an aerial vehicle for structural damage detection and identification by acoustic sensors increases its reliability and remaining useful lifetime. In order to reach full structural health monitoring (SHM) autonomy, there is a need to combine sensing and communication functions into smart multifunctional sensors. Through this fusion, the information gathered by the SHM sensors could be transmitted in real time to a central processing unit without any human intervention. To that end, this research paper proposes reusing the existing network of acoustic SHM sensors mounted or embedded in the structure to enable acoustic multi-sensor wireless communication through the structure itself using elastic waves as the carrier signals. By doing so, the proposed acoustic communication system does not generate additional radio-frequency (RF) interference to other RF communication systems on board such as those used for vehicle control and safety-related services. This paper describes the design of the proposed acoustic wireless sensor network for autonomous SHM of aerial vehicles. First, the network topology and sensors placement are described along with the data routing algorithm. Then, the time-reversal based time division multiple access technique is introduced for multi-sensor communication using elastic waves. The data transmission across the elastic channel using time-reversal pulse position modulation is also presented. Finally, the system is evaluated based on the acoustic channel response of the horizontal stabilizer of an Ercoupe 415-C aircraft.