Design and Application of Pavement Structure Depth Calibration Device

The depth of pavement structure is an important indicator of pavement detection, which can evaluate the anti-skid performance and drainage performance of the pavement, and plays a decisive role in the safety of pavement traffic. The traditional pavement structure depth measurement method has problems such as poor measurement accuracy and unintuitive measurement results. The laser measurement pavement structure depth measurement method has been widely used. In the process of calibrating the laser structural depth instrument, a calibration device is urgently needed, which can provide a stable rotation speed and drive the rotation of the simulated road surface turntable. The turntable has standard values and different structural depths, thereby completing the verification of the structural depth instrument. A depth calibration device for pavement structure proposed in this paper meets the above requirements. The device prototype is composed of mechanical system and control system. The mechanical system consists of a control box and a turntable rotating base. This paper describes the structure of the turntable rotating base. The main controller of the control system is based on the Mitsubishi FX3U PLC design and controls the speed of the direct drive motor through the analog voltage. During the experiment on the system linearity, due to the poor linearity of the motor driver, it caused greater inconvenience to the speed design, so the program control logic designed the speed feedback loop, and the negative feedback logic was introduced to ensure the stability of the turntable speed and the system speed. The error is within ±15r/min. Through system testing and actual industrial field experiments, the system performance meets the requirements.