New method for automatically measuring geometric parameters of wheel sets by laser

Abstract

How to automatically and effectively measure geometric parameters and defects of train wheel-sets is a key problem in the maintenance of wheelsets. Currently, there are several methods for this kind of measurements. However, all these methods cannot meet the requirements of high accuracy, low cost, and short measurement periods at the same time. A quite simple and novel method for measuring geometric parameters and defects of wheelsets was proposed in this paper. Most key geometric parameters, such as diameters at any given point of the tread, flange thickness, flange height, rim thickness, rim width, wheel flats, and distance between internal faces etc., can be easily obtained by use of five sets of parallelogram mechanisms together with laser transducers. Wheel-sets are dragged simply by a chain to pass through the measurement system when the measurement results are done, which has totally changed the situation that a measurement platform was required to support a wheelset and makes it rotate in order to take measurements. Methods to calibrate the measurement errors of the system are also discussed, and some in-situ measurement results are given. Experimental results show that the measurement uncertainty within 0.1 mm can be reached by the developed system.