| Wheel set is one of the most important rolling components in the vehicle. It affects the safety of railway transportation directly. Our country's train vehicle departments have specific standards about wear and tear limit of all kinds of wheels. Measuring parameters of wheel set is a necessary step for protecting transportation safety. But in our country, the measurement was done by using hands mostly. With the speedup of train, the current detecting methods could not meet the requirements of wheel maintenance. A more accurate and reliable automatic detecting method and system of wheel set parameters was necessary. In many developed countries, a lot of advanced researches had been done. Many static and dynamic measuring equipments were developed. Recently, lots of researches and developments in our country had also been done. The contacted, non-contacted and the measuring by digital camera were the typical methods. The contacted method leaded to wear of sensors and affected the stability of result, thus maintenance became more difficult.. The non-contacted method used laser displacement sensor to scan the object. It was difficult to measure different geometrical profiles of the wheel set flange because the optical axis should be vertical to the surface of flange. It would lead to much more errors and complex scanning structure set. Measuring wheel set flange by digital camera needed confirming rim inside plane by special object. It was difficult to measure running wheels because data transmission speed was slow.According to requirements of different parameters of wheel set, this paper introduced corresponding detecting principles and methods. The line structure light and optoelectronic image detecting method were used to measure the geometrical parameters of the flange. The most difficult detecting parameters were measured accurately. Optical triangulation method was used to measure geometrical dimension parameters by laser displacement sensor scanning. Both laser displacement sensor scanning and image processing technology were used to measure failure parameters. The detecting results of parameters of wheel set met the requirements of vehicle maintaining. In the structure design of system, the position of sensors was controlled by step motor accurately. And the running wheel set drove the detected wheels running in certain speed. For the safety, protecting sets were used to avoid the system from hitting with other wheel sets. Optoelectronic switches were used to protect the movement units and sensors. Self-detecting program could detect the status of sensors and wheel set.Detecting results were displayed real-time and transmitted to database automatically. The database had the function of saving, inquiring, copying and statistics. The detecting results could be printed according to requirement format. The operation system platform was windows 2000 professional edition.Measurement and control system was programmed by visual C++6.0 language. The database were developed by SQL and PowerBuilder. The software used module structure designing method The system designed friend man-machine interface. Experiment equipment-was designed and results were obtained. Factors affecting the measuring accuracy were analyzed and the error correction method were also discussed. Laser and photoelectric technology, digital image processing technology and exact measurement and control technology were used in the system. Wheel set parameters could be measured by non-contacted and automatic way. The accuracy, stability and reliability of the system can meet the demand of wheel sets maintainingT... |
PDF Full Text Request