Rechargeable Wireless Sensor Node Design And Test Platform Development For Rapid Detection And Monitoring Of Bridges

As an important transport hub,the safety of the bridge operation directly affects people's life and property security and national economic constructions.In recent years,wireless sensor network(WSN)applications in bridge structural health monitoring have become a hot topic of research in this area.Its advantages on convenient installation,low maintenance cost and flexible deployment stimulate gradual replacement of the traditionally wired based structural health monitoring system.However,the limited data processing capability and power supply of the sensor node in WSN hinder it wide application.Focusing on precision and accuracy of the data acquisition for WSN nodes and the applications of wireless power charging,and considering the actual application scenarios and requirements,this thesis designs and develops a rechargeable WSN node for fast detection of middle and small bridges and establishes a set of bridge vibration signal acquisition platform.Theoretical analysis,software and hardware design,software simulation and experimental verification are performed to achieve this goal.In summary,the main work of this thesis are listed as follows:Firstly,this thesis performs the hardware design for the WSN nodes based on the requirement of low power consumption and high precision,it can implement bridge vibration signal acquisitions at the low frequency range.Drivers of each module,wireless communication program,the AD conversion,and the software that implements the data display and storage in the computer,are designed as well.Secondly,this thesis designs the wireless power charging module based on electromagnetic radiation principle,where the electromagnetic energy can be converted to electrical energy and stored in lithium-ion batteries.Lithium batteries can be directly connected to the sensor nodes,and eventually form a rechargeable WSN node.Thirdly,this thesis conducts experimental verification on the designed rechargeable WSN node,and analyzes the data acquired from the experiment.The actual measurement and contrast analysis for the accuracy of the bridge vibration signals from WSN nodes and wireless power charging capability has been performed.The experimental results show that the accuracy of bridge vibration signals is high and meets the precision requirement of bridge structural health monitoring.Bridge health assessment results are comparatively accurate.The wireless charging power can reach 4.5 mW which has played a certain make-up effect for power supply of the rechargeable WSN nodes.