Wireless Online Impact Source Localization on a Composite

Abstract

We describe a self-sensing composite capable of making online estimations on the location of an impact within its structure without the need for wires or offline data processing. We embed a network of piezoelectric sensors in the material during manufacturing and connect each sensor to a dedicated micro-controller and power source. Triangulation is performed by each sensor in the network through wireless distributed computation and communication. By making the computation of the sensors distributed, the system is scalable with regard to the number of sensors and robust with regard to individual failure. One of the key challenges of distributed structural health monitoring is the need for multiple sensor signals in order to calculate the impact’s location. This requires that every sensor makes an appropriate choice of neighboring sensors whose signals will be used during the computation. We address this problem by performing selective pairing of a given sensor with the neighbors that it believes provide the most reliable data at a given time. This reliability depends on how close in time the event detection occurred in other sensors compared to the given sensor. Experimental results on a composite with 12 embedded sensors show that this approach is robust against failure of individual sensors and that it is accurate enough to provide a good guess, but not an exact location of the impact when the sensors are too close together.