Technology Of Vision Measurement For Large Size Axle Based On Light Transmission

With the continuous development of high-speed railway in China,the requirement of quality and safety of high speed EMU are getting higher and higher.As one of the important parts of wheel set system the axle of the motor vehicle plays a role of connecting the wheels and transmitting power to the wheels.Therefore,the measurement of the size of the axle has been an important step.With the continuous improvement of the manufacturing level,the traditional method will be unsuitable gradually for the industrial level.In order to solve the above problems,this paper presents the vision measurement technology of axle based on transmission with double light paths.The accurate on-line measurement is realized by scanning the axle edge.The method has high measuring efficiency,and it can meet the requirement of measurement after the experiment.First,the thesis describes the technical principles of transmission measurement with single-path parallel light and double light paths.And by comparison,it illustrates the necessity and advantages for large size axle measurement adopting the transmission measurement of double light paths.Second,the whole transmission measurement system is designed,and the function of each part is analyzed.The main attention is paid on the design of the core of the system double light paths sensor.By means of theoretical derivation,the propagation mode of the Gauss beam through the collimated beam expanding system is analyzed.The effect of reflected beam on the measurement accuracy is studied.and the parameters of the lens are deduced and simulated.Then,the data of the collected images are processed to locate the edge accurately.As for the noise caused in the process of acquring images,the filtering and noise reduction is necessary;and then the axle edges are tested with a sub-pixel precision.After the axis of the axle is scanned by the transmission system,the edge data of each axle section is obtained,and the edge data of the axle is combined with the segment to obtain the diameter parameters of each axle section.Finally,calibrate the designed light transmission measurement system,and test the axle for repeated measurement to verify the feasibility of the system.Analyze the causes of error based on the measurement results and optimize the overall system.