Study On Laser Displacement Sensor For Pavement Detection

The laser displacement sensor is a key part in the laser pavement detective equipment. Because of different road materials having different reflectivity, it may lead the CCD in the state of saturation, and bring on the metrical errors. Therefore, researching laser displacement sensor which is suit for all road reflectivity is becoming the hotspot in pavement detection.After checking a great deal of literature and analyzing the laser displacement sensor for pavement detection at home and abroad, an architecture based on the symmetrical inverted arrangement had been proposed. It fixed a laser parts in the middle of the sensor, and fixed two zygomorphic imaging lens and CCD. When the reflectivity of detective pavement was high, the two CCD were all in the state of saturation. Because of zygomorphism, one side displacement was more than the actual's, the other side was on the contraty. So averaging two sides'displacements, it could eliminate the error caused by the saturation of CCD.The design process of the road using laser displacement sensor was stated in detail in aspect of the hardware and software.The design project of the components selected and related circuit of the hardware was presented.The hardware part included the design of CCD driving circuit,the pretreatment design of deferent signal and the design of data acquisition. The idea of modularization and object-oriented programming technology were adopted to develop the software part.According to the function of program, the software system was divided into four different modules, which including data acquisition module, data manipulation module, data showing module and interface module.The function and the design processes of each module were introduced in particularly, procedure flow chart and the design of the programming.It made a whole test of hardware and software of the system, made actual measure, and the error of the measured results were discussed and analyzed.The experimental results had indicated that the laser displacement sensor based on symmetrical inverted arrangement could solve the problem of saturation, and it achieved the anticipated request. Therefore, the architecture which had been proposed was accurate and feasible. The research of this paper has great theoretical and practical value.