A laser-ultrasonic based sensor fusion framework for height measurement during the stone crushing process

Abstract

It is a challenging work to monitor the height of the material pile via laser measurement due to the influence of high-concentration dust in a moving crushing line. At present, although the error of using only ultrasonic radar is small, the monitoring range is limited, while using only laser radar to monitor materials is highly affected by dust environments and may fail in high dust environments. To overcome this limitation, a height measurement based on the laser-ultrasonic radar fusion method was proposed to monitor material height in mobile crushing line. Firstly, the proposed method used laser scanning to obtain the three-dimensional point cloud of the material surface through point cloud preprocessing and calculated the material height. Secondly, considering that the concentration of dust has a great impact on the monitoring of the material level height, the experimental data on the change of the material level height with the concentration of dust were obtained, and the monitoring error was fitted to improve the accuracy of the material level height detection. Finally, in order to further reduce the error, the monitoring data of the ultrasonic radar was integrated to reduce the influence of dust on the detection of the material level height. The results showed that the average error was reduced to 22.65 mm when the dust concentration was below 200 mg m−3, and the average error was reduced to 32.14 mm when the dust concentration was higher than 200 mg m−3. The experimental results in different dust concentration environments demonstrated that the proposed method can effectively detect the point cloud shape and material level height of the material in real applications, which effectively improves the accuracy of material height detection by combining the three-dimensional laser points of the laser radar and the penetrability of the ultrasonic radar in high-concentration dust.