Wireless Intelligent Sensor and Actuator Network – A Scalable Platform for Time-synchronous Applications of Structural Health Monitoring

Wireless sensor networks have attracted attention as a possible solution for applications of periodic and continuous structural health monitoring. Ensuring synchronous data acquisition across wireless nodes in large networks of sensors spatially distributed on a structure is of critical importance for many methods of structural health monitoring, especially those based on analysis of vibration. In this article we present a novel Wireless Intelligent Sensor and Actuator Network (WISAN) addressing the issue of scalability for applications of structural health monitoring. We also present a novel time synchronization algorithm that can keep the synchronization error between any number of globally distributed sensors nodes less than 23 ms. We show proof of stability for the time synchronization algorithm. We validate WISAN in laboratory experiments, testing the actual time synchronization between randomly selected sensors in a complex network. Finally, we validate WISAN in a field experiment by reconstructing mode shapes of a highway bridge.