Deflection Basin Detection of Pavements Based on Linear Array Charge-Coupled Device (CCD) Photoelectric Sensors

Abstract

Deflection is an important indicator of the overall pavement strength, and it is generally detected using the Falling Weight Deflectometer (FWD). In response to the shortcomings of FWD in use, a pavement deflection detection method based on a linear array charge-coupled device (CCD) photoelectric displacement sensor is proposed. Firstly, a detailed description is given of the working principle of the deflection detection photoelectric sensor for the center point of the deflection basin and other points. Secondly, a photoelectric displacement sensor using linear array CCD deflection detection is designed, including a laser, CCD signal processing module, CCD and its driver module, and upper computer communication module. Among them, the EPF10K20TC144-4 device of the FLEX 10K series from ALTERA company is used to generate CCD driving pulses; Two DM54LS245 are selected as the driving interface for CCD photoelectric sensors, and corresponding filtering and signal amplification circuits are designed to address the noise problem of CCD photoelectric signal injection. Finally, the fixed threshold method separates the background and image signals in the CCD photoelectric signal, and the microcontroller is connected to the serial port of the upper computer through the MAX232 chip. The displacement measurement experiment uses the designed linear array CCD photoelectric displacement sensor. The results show that the road deflection basin detection method by the linear array CCD photoelectric displacement sensor fully meets the actual detection requirements and can obtain dynamic deformation information of the tested road surface. It is helpful for a detailed understanding of the changes in the deflection basin of the road surface under load.