| Overloading of vehicles has caused great harm to the environment,traffic safety and road facilities.It has greatly threatened the health of basic transportation facilities such as bridges,roads and tunnels,greatly shortened its service period,even caused road collapse and bridge collapse,it causes harmed to people’s life and property.Real-time monitoring of the load capacity of vehicles running on the road will effectively curb this phenomenon,However,the vehicle dynamic weighing technology is still at the development stage in China,Last several years some progress has been made.Nevertheless,the vehicle dynamic weighing systems used in the market have some problems,such as large occupied area of equipment,complicated installation,and larger digging area for buried line.Therefore,this thesis takes the piezoelectric sensor as the research object,designs a set of vehicle dynamic weighing sensor with small volume,high sensitivity and high reliability.The specific research contents of this thesis are as follows:1.Analyzed the Status and trend of domestic road and bridge development,and expounded the harm of vehicle overrun and overload and the importance of vehicle weigh in motion,Research on vehicle weigh in motion system at home and abroad with the analysis of the merits and demerits of various sensors,finally,the overall scheme of the sensor was analyzed;2.Considering the influence of road deformation,flatness and defects on the road load caused by tire during the vehicle running,MATLAB and ADAMS Car were used to establish the truck and road model,and the truck at different levels of road or different speeds was simulated,and The deviation between static wheel load and dynamic wheel load was obtained;3.Combined with piezoelectric ceramic sensor technology,the front-end dynamic weighing sensor unit was designed,and the overall structure design was completed.In the meantime,the piezoelectric analysis and intensity analysis of the designed_sensor unit and the overall structure were conducted by using ANSYS Workbench;4.Combined with the demands of system,the hardware of the system was devised from the respects of signal amplification circuit,acquisition circuit,wireless transmission module,power conversion module,etc.Using Altium Designer to draw the schematic diagram of each circuit,and then make the system hardware object.5.In order to verify the effect of the sensor,the impact load experiment and cyclic loading experiment were accomplished.In addition,the relevant experimental data were analyzed.By cyclically loading the whole dynamic weight cell to simulate the load caused by the vehicle in the process of driving.The experimental data shows that the vehicle dynamic weighing sensor designed in this thesis has stable data transmission,fast dynamic response,excellent signal curve effect,and the relative error of measurement meets the technical requirements of highway vehicle dynamic weighing system in China Therefore,it can meets the actual requirements. |
