Structural Monitoring: Modal Tracking with LoRaWAN Wireless Systems and Automatic Cloud Algorithms

Every structure needs to be monitored throughout its useful life, to ensure an adequate level of safety and due to external events - both natural and not – that can disturb its state of equilibrium. Moving from these demands, in recent years, Move Solutions has implemented a structural monitoring system, static and dynamic, consisting of a variety of completely wireless sensors, operating with LoRaWAN technology, together with a special Cloud platform developed with the aim of facilitating the analysis and visualization of data by the operators in charge of the activities. The system is based on excellent sensor synchronization (500 μs) through which a dataset conforming to OMA (Operational Modal Analysis) is obtained. From the accelerometric data, it is possible to extrapolate the daily frequencies and modal shapes using the FDD (Frequency Domain Decomposition) technique. For long-term monitoring, it is necessary to identify only structure modes of vibration among all those calculated by FDD; this is made possible by a multi-level clustering algorithm, designed by Move Solutions, that can differentiate useful vibrational modes from the “spurious” ones, which will be discarded. The following step is defined as Tracking, where the aim is to monitor the variations of the previously identified vibrational modes over time. The use of a wireless and fully automated monitoring system on the Cloud can give a big boost in simplifying the management of all infrastructures, cutting costs and digitizing processes.