Design And Implementation Of A Wireless Bridge Vibration Monitor System Based On PQCR-PSI Sensor

As a large-scale basic transportation facility with great cost,a long design and construction period and a long service life,the bridge plays an extremely important role in promoting national economic construction,regional cultural exchange and promoting social development.The vibration of bridge structure is one of the important factors that affect the use and safety of bridge.Real-time monitoring of bridge vibration is of great significance to avoid the occurrence of bridge accident and prolong its service life.PQCR-PSI sensor,developed by the laboratory,is an inductive sensor with a simple structure and a large frequency response traction rate,it achieves a digital frequency output to overcome some defects of the inductive sensor using the AC bridge and LC resonant circuit as the oscillation circuit,and it will be applied as a sensor probe to the bridge vibration and other low-frequency vibration measurement.Through the analysis of the vibration characteristics of the bridge and the advantages and disadvantages of the existing vibration sensors,a set of bridge vibration monitoring system are proposed and designed for the monitoring of vibration signals of large span bridges based on the PQCR-PSI sensor.According to the requirements of bridge vibration monitoring system and the principle of ZigBee technology,the system hardware is composed of three parts:vibration monitoring node,stress-strain monitoring node and coordinator node.The vibration monitoring node uses the FPGA to collect the frequency of the Pierce oscillation circuit where the PQCR-PSI structure is located,and realize the functions of temperature data acquisition,data processing,USB storage and serial data transmission.Stress-strain monitoring node is mainly composed of the full-armi bridge circuit,voltage amplifier circuit and analog-to-digital conversion circuit.The vibration data and stress-strain data are sent to the coordinator node via ZigBee wireless communication,and the coordinator receives the data and sends it to the computer via the serial port.The upper computer compiled by C#has a mixed programming with MATLAB to apply the fuzzy reasoning fusion theory to the evaluation of simulated bridge state and early warning.At the same time,the upper computer achieves the dynamic curve rendering of the data,MySQL database storage and other functions.The feasibility of applying the inductive sensor probe based on PQCR-PSI structure to bridge vibration measurement is verified by experimenting and testing on the simulation platform.The monitoring system can clearly reflect the simulated vibration of the bridge and realize the non-contact ·ireless real-time monitoring of low-frequency vibration signals.