Technique Research Onwireless Measurement System For Bridges Based On The Existing Sensor

As an important part of national infrastructure, bridge plays a more andmore important role in the national economy and social life. Now people paymore attention to safety, durability and normal function of large-scale bridges.Examination, monitor, damage, aging, plant disease and accidents of thebridge structure are more prominent along with the world scope. Especiallyrecently, significant accidents have happened on many domestic and foreignbridges. The bridge safety faces serious challenge. In order to ensure the bridgesafety during service time, bridges should be scientifically tested. Bridges arepresently tested with wire data transmission. Although this technique is efficientand mature, for test of long span bridges, wire data transmission technique coststoo much time on wire setting and removing and its installation expense is high.The bridge wireless measurement system has solved the above problems, whichuses the wireless communication method to replace wire transmission. Thereforeit is essential to develop wireless examination technology for long span bridgestructure.In this thesis, a bridge wireless measurement system is presented whichcombines bridge structure detection technique, computer technology, modernsensor technology, wireless communication and system technology. The wirelessmeasurement system consists of hardware and software. The hardware systemstructure is composed of a master station and several substations. The masterstation is composed of control center subsystem and data transmission subsystem.The substation is composed of data transmission subsystem and gatheringsubsystem. The software system consists of controlling, data and Single ChipMicyoco processing.In data acquisition subsystem, the data collecting node of secondary stationapplying for the sensor of resistance strain, vibrating string and 941B typevibration sensor for bridge static and dynamic test is researched and exploited.Multiple sensors can be controlled by single collecting node and data of multiplesensors can be collected, stored by single collecting node and transmitted withsingle transmitting device. Software and hardware of power supporting, circuit and testing element circuit are designed and debugged for data collection nodeand finally integrated into wireless data collection module of secondary station.Experimental result shows that this static data collection module can meet therequirement of detection precision for bridge engineering.In data transmission subsystem, wireless correspondence agreement isdesigned by drawing lessons from the OSI of ISO, considering complexity ofwireless measurement system for bridge. Its validity of agreement and stability oftransmission is analyzed. The independent communications platform isconstructed, but not using existing wireless communication module or existingcommunication network. Wireless communications are simplified into threeagreements to enhance the communication protocol of the transmission efficiency,accuracy and flexibility.In control center subsystem, the software system is designed and realized,which includes design, realization and experiments of Single Chip Micyococontrol procedure, master control program, database procedure and wireless datapost-processing algorithmic routine.Finally, the wireless measurement system is tested by indoors and outdoorsexperiments. The result of load experiment shows that the wireless measurementsystem is accurate, reliable, easily operational and stable. It is capable of fulfilldetection of structure static strain, deflection and dynamic acceleration, andspeed signal measurement.