Study On Non-contact And Automatical Measuring System For Measurment Of Wheelset Geometric Parameters

The study on non-contact and automatical measuring system for measurement of wheelset geometric parameters is very important, which can not only help to improve the quality of wheelset test, to increase the development of digital-railway, but also can give much information on studying wheel-rail geometric contract.There are two kinds of way to measure the wheelset geometric parameters. One is the static measurement which uses the mechanical ruler, electro-testing apparatus and device equipped with CCD. Another is the dynamic measurement which mainly depends on the technology of ultrasonic and CCD. The device equipped with CCD and other equipment will be large and expensive, the maintenance of the equipments are quite difficult. Because of these, a new method for measuring the wheelset geometric parameters is given in this paper. First, the wheelset is fixed and rotated by the device used hi vehicle depot as usual. Second, the center line of wheelset axis is determined by a device called axis-center probe. Last, the acting device for sensor can draw a whole felloe profile, which is made up of parallel-pole device and rotating-probe. Thus, the geometric parameters of wheelset will be get. So this device is simple, cheap and easy to be widely used.In this paper, after the kinematics of parallel-pole device are analyzed, the parameters of this device are given and the design of this machine are finished. As well as, the sources and the characters of errors are analyzed, and the method of error compensation are found out. Thus the accuracy is greatly improved though the acting-device is made as usual.With the help of the idea of virtual instrumentation, the scheme of testing system is determined: First, high resolution and measuring accuracy are get by the grating ruler and the photoelectricity coder. The second, the stepping motor make the real-time control system better. The third, the temperature testing device make the errors reduce. The forth, there are two grade computer management in this testing system. The main computer is programmed under WINDOWS, while the assistant computer is programmed under DOS. The last, based on the idea of module-structure , the software of the testing system are designed, thus thissoftware system is compatible and transplantable to design again.The experiment of measuring principle is taken: Take the XY flat of lathe as the parallel-pole device and adjust the angle of sensor, the rotating-probe can test the felloe mould in scanning way. In this experiment, the data collecting and processing are finished by computer. According to the experiment, two conclusions can be drawn: first, not only to laser sensor but to inductance sensor, it is a good method for measuring the wheelset geometric parameters when the wheelset are made in factory or tested in the last working procedure in vehicle depot. Second, when the inductance sensor is selected, the first working procedure in car section can be well done too. So the experiment is a good experience for the measuring system of the wheelset geometric parameters to be put into practice.