Online measuring method and system for diameter parameters of wheel set

The measuring of diameter parameters of wheel set is an important step for the safety of train vehicle running. The wear degree of wheel increases with the speedup of train. The paper introduced an online measuring method of diameter parameters of running wheel set based on optoelectronic detecting technique while the train is running in low-speed within 5–10km/h. The method used precision laser displacement sensor, high speed and high resolution CCD and digital image processing technology to realize the non-contact automatic measuring of wheel set parameters. These parameters include the diameter, roundness and diameter difference. The main influence factors for measuring accuracy, including movement, vibration and trigger error were analyzed. The automatic measuring system was designed. The system included wheel detector, laser displacement sensor, semiconductor laser source, CCD, online image acquisition and processing circuits. Theoretic and experimental results showed that the measuring accuracy of diameter parameters was within 1.0mm. The accuracy meets the demand of online diameter measurement.