Design And Implementation Of Multi-point Laser Micro-displacement Measurement System

Bridges play an important role in the modernization drive,however,because of its own weight,carrying object and the ground subsidence,the tiny deformation which the naked eye cannot see will occur.Collapse accidents occur when the shape variables exceed the tolerance range of materials such as reinforced concrete.In view of this,a multi-point laser micro-displacement measurement system is studied.The system is mainly composed of laser emitter,data processing terminal and display terminal,realizing the functions of displacement detection,data processing and displacement display respectively.Compared with the traditional bridge displacement monitoring method,the system installes two TTL modulated laser emitters at each monitoring point,eliminating the error caused by the Angle deviation of the transmitting end.The receiver uses FPGA design acquisition module,filter module and amplitude extraction module to separate the two spots.The spot position module is designed and extracted.According to the height difference of the two spots,the bridge displacement was calculated by using the micro-displacement calculation module.This method can effectively reduce the measurement error of transmitting end,optical long lens and receiving end and greatly improve the system precision.The focus module through the data acquisition function of STM32 MCU gathering feedback signal,design software program to the acquisition of signal processing,resulting in a pulse width modulation wave,implement the timesharing focus monitoring of multiple monitoring points,reduces the system cost;The display terminal uses Eclipse to write an Android APP which are portable to realize real-time display of bridge micro-displacement waveform,and realize functions such as query and alarm.The initial height of the grid on the display interface is 1mm,which can be customized.The number of grids in the vertical direction of the waveform represents the displacement of the bridge,and the monitoring is very intuitive.The experimental results show that the system can measure dynamic deflection curve of single monitoring point and static deflection curve of multiple monitoring points.Significant improvements have been made in accuracy,cost and convenience.