University of Catania - Italy D ipartimento di I ngegneria E lettrica, E lettronica e I nformatica An Early Warning System for Structural Monitoring in AAL Context Bruno And, Vincenzo Marletta, Antonio Pistorio University of Catania Italy May 19-22, 2015 PO-FESR Sicilia CUP: G13F University of Catania - Italy D ipartimento di I ngegneria E lettrica, E lettronica e I nformatica An Early Warning System for Structural Monitoring in AAL Context The Traditional Monitoring of Structures The Developed System Experimental Characterization of the System A Wavelet Multiresolution Strategy Results and Conclusions OUTLINE University of Catania - Italy D ipartimento di I ngegneria E lettrica, E lettronica e I nformatica An Early Warning System for Structural Monitoring in AAL Context Multi-Sensor System. A multi-sensor system is a system in which the information of several sensors contribute to define the knowledge of an environment. EWS. An early warning system is a multifunctional system including sensors, signal processing and communication facilities aimed to timely provide information useful to prepare resources and response actions to minimize the impact of the incoming hazard. SHM. The structural health monitoring is the process to detect damage or changes to the material and/or geometric properties of a structural system. The Traditional Monitoring of Structures (1/2) Definitions University of Catania - Italy D ipartimento di I ngegneria E lettrica, E lettronica e I nformatica Quanterra Q330 (for data acquisition and storage) Applied Geomechanics mod. 702 (for tilt measurements) Kinemetrics EpiSensor ES-T (for acceleration measurements) High Costs High Power Supply Monitoring with Low Spatial Resolution T R A D I T I O N A L I N S T R U M E N T S An Early Warning System for Structural Monitoring in AAL Context The Traditional Monitoring of Structures (2/2) University of Catania - Italy D ipartimento di I ngegneria E lettrica, E lettronica e I nformatica An Early Warning System for Structural Monitoring in AAL Context The Traditional Monitoring of Structures The Developed System Experimental Characterization of the System A Wavelet Multiresolution Strategy Results and Conclusions OUTLINE University of Catania - Italy D ipartimento di I ngegneria E lettrica, E lettronica e I nformatica The Developed System (1/4) GOAL. Development of a customized multi-sensor node for the implementation of a distributed EWS for SHM, based on a wireless sensor network. The ability to monitor simultaneously both the seismic and tilt quantities, could be a useful tool for the risk assessment of the population. Specifications: Measure and analysis of acceleration signals, with a resolution of 0.02 g; Measure and analysis of tilt signals, with a resolution of ; Observation of phenomena, having frequency range [0.5 10] Hz; Sampling frequency 200 Hz; Data storage; Wireless communication. An Early Warning System for Structural Monitoring in AAL Context University of Catania - Italy D ipartimento di I ngegneria E lettrica, E lettronica e I nformatica The Developed System (2/4) Commercial Off-the-Shelf (COTS) devices: low cost; low-power consumption. Arduino Uno microcontroller board (based on the ATmega328 microcontroller running at 16 MHz). Wireless SD Shield by Arduino (to communicate wirelessly through the XBee-PRO module from MaxStream and to store data on a micro SD card). MEMS-based accelerometer MMA7361L by Freescale Semiconductor to measure accelerations along the x, y and z axis. MEMS-based inclinometers SCA61T-FAHH1G by Murata Electronics Oy for the monitoring of the tilt. Schematization of the developed system for seismic and tilt monitoring. An Early Warning System for Structural Monitoring in AAL Context University of Catania - Italy D ipartimento di I ngegneria E lettrica, E lettronica e I nformatica The Developed System (3/4) Real views of the wireless multi-sensor node (a), the master node (b), and a panel of the GUI with experimental results obtained during the first assessment survey (c). a b c An Early Warning System for Structural Monitoring in AAL Context University of Catania - Italy D ipartimento di I ngegneria E lettrica, E lettronica e I nformatica The Developed System (4/4) The context adaptive architecture -Continuous data transfer: TX Real-Time Vs Server -Event-triggered: Alert/Messaging, TX Real- Time Vs Server if supra- threshold signals are detected Acquisition Storage Transmission Techniques Two operating mode Continuous data transfer (extract a deep information; more complex infrastructures; high power consumptions). Event-triggered (fast generation of early warnings; low power consumptions; server free operations; limited computational power): tradeoff between low-power consumptions and the extraction of deep informations. An Early Warning System for Structural Monitoring in AAL Context University of Catania - Italy D ipartimento di I ngegneria E lettrica, E lettronica e I nformatica An Early Warning System for Structural Monitoring in AAL Context The Traditional Monitoring of Structures The Developed System Experimental Characterization of the System A Wavelet Multiresolution Strategy Results and Conclusions OUTLINE University of Catania - Italy D ipartimento di I ngegneria E lettrica, E lettronica e I nformatica Shake Shaker Vibration Controller Displacemente transducer Power amplifier Functions generator PC for data Acquisition board A/D Conditioning circuit Mobile platform Actuator Schematization of the experimental set-up Real view of the experimental set-up Experimental Characterization of the System (1/2) The 3 axis accelerometer An Early Warning System for Structural Monitoring in AAL Context University of Catania - Italy D ipartimento di I ngegneria E lettrica, E lettronica e I nformatica Amplitude: [ ] g Frequency: [ ] Hz Comparison between acceleration signals by the reference sensor (solid) and the wireless multi- sensor node (dotted): (a)without solicitations, and (b)with a vertical solicitations of about Hz. (c) Frequency response of the acceleration module embedded in the multi-sensor node. 1 level = g Noise 1 Hz = g/Hz (a) (b) (c) Experimental Characterization of the System (2/2) The 3 axis accelerometer An Early Warning System for Structural Monitoring in AAL Context University of Catania - Italy D ipartimento di I ngegneria E lettrica, E lettronica e I nformatica An Early Warning System for Structural Monitoring in AAL Context The Traditional Monitoring of Structures The Developed System Experimental Characterization of the System A Wavelet Multiresolution Strategy Results and Conclusions OUTLINE University of Catania - Italy D ipartimento di I ngegneria E lettrica, E lettronica e I nformatica A wavelet multiresolution strategy has been adopted to discriminate the structural response to seismic sources from other exogenous inertial components. The processing paradigm runs in the remote server collecting data from the WSN implementing the monitoring system. A Wavelet Multiresolution Strategy (1/4) An Early Warning System for Structural Monitoring in AAL Context University of Catania - Italy D ipartimento di I ngegneria E lettrica, E lettronica e I nformatica acceleration signal used to stimulate the wireless multi-sensor node in the vertical direction time-frequency image of the vertical acceleration signal acquired with the wireless multi-sensor node after the application of the mechanical solicitations A Wavelet Multiresolution Strategy (2/4) An Early Warning System for Structural Monitoring in AAL Context University of Catania - Italy D ipartimento di I ngegneria E lettrica, E lettronica e I nformatica The vertical component of the acceleration signal provided by the multisensory node has to be decomposed in an approximation level and several details levels using the Discrete Wavelet Transform (DWT). Each detail level is compared with amplitude/frequency modes typical of the human activity. A Wavelet Multiresolution Strategy (3/4) An Early Warning System for Structural Monitoring in AAL Context University of Catania - Italy D ipartimento di I ngegneria E lettrica, E lettronica e I nformatica As a further step, detail levels showing a high correlation with the typical environment vibrations have to be removed. Successively, the remaining components of the vertical acceleration signal has to be reassembled from the residual detail levels. The latter is expected to be really informative on possible seismic response of the structure. By comparing such residuals with pre- determined threshold, candidates anomalous seismic response of the structure can be highlighted. candidate seismic sources A Wavelet Multiresolution Strategy (4/4) An Early Warning System for Structural Monitoring in AAL Context University of Catania - Italy D ipartimento di I ngegneria E lettrica, E lettronica e I nformatica An Early Warning System for Structural Monitoring in AAL Context The Traditional Monitoring of Structures The Developed System Experimental Characterization of the System A Wavelet Multiresolution Strategy Results and Conclusions OUTLINE University of Catania - Italy D ipartimento di I ngegneria E lettrica, E lettronica e I nformatica In this work a wireless multi-sensor architecture for a distributed monitoring of seismic and tilt data for Early Warning in Structural Monitoring has been developed. AccelerationTilt Operating range: 1.5 gOperating range: 30 Resolution: gResolution: Major outcomes of the proposed methodology: smart dust approach (high resolution maps of the health status of the structures with a high number of low cost wireless multi-sensor nodes). Future work: test the whole system performances in real environments for a long observation time. Results and Conclusions An Early Warning System for Structural Monitoring in AAL Context ACKNOWLEDGMENT This work is developed under the project Attivit di sviluppo sperimentale finalizzata alla riduzione del rischio sismico nella Sicilia orientale, CUP: G13F , funded by the PO-FESR Sicilia program University of Catania - Italy D ipartimento di I ngegneria E lettrica, E lettronica e I nformatica An Early Warning System for Structural Monitoring in AAL Context Installation: Protezione Civile (ME) 09 Apr 2015, (GMT) (Terrazzo)