An online wheel size detecting technology based on laser displacement sensors for urban rail vehicles

In order to improve the efficiency of wheel size detection and the measurement accuracy, an online wheel size detecting technology based on 2D laser displacement sensors is proposed. The 2D laser displacement sensors are installed on both sides of the track, then scan the wheel tread of the detected region dynamically. Next, use coordinate transformation and data fusion to preprocess the collected data and finally calculate flange height, flange width and wheel diameter. The system was installed on site to online measure the wheel-set size to verify the feasibility of the system. Comparing the system results with manual results, the experiment results show that the system can online detect wheel-set size accurately. The errors of flange height and flange width was ±0.2mm and the error of the wheel diameter was ±0.5mm. The accuracy of the system meets the field requirements and it has high feasibility. The system can completely replace manual measurement to improve the efficiency.