Design of an ultra-low power device for aircraft structural health monitoring

One of the popular structural health monitoring (SHM) applications of both automotive and aeronautic fields is devoted to the non-destructive localization of impacts in plate-like structures. The aim of this paper is to develop a miniaturized, self-contained and low power device for automated impact detection that can be used in a distributed fashion without central coordination. The proposed device uses an array of four piezoelectric transducers, bonded to the plate, capable to detect the guided waves generated by an impact, to a STM32F4 board equipped with an ARM Cortex-M4 microcontroller and a IEEE802.15.4 wireless transceiver. The waves processing and the localization algorithm are implemented on-board and optimized for speed and power consumption. In particular, the localization of the impact point is obtained by cross-correlating the signals related to the same event acquired by the different sensors in the warped frequency domain. Finally the performance of the whole system is analysed in terms of localization accuracy and power consumption, showing the effectiveness of the proposed implementation.