Turnout Surface Modelling Method For High-Speed Railway

During the operation of high-speed railway,the size and geometric shape of each part of the high-speed turnout are easily changed.Therefore,the regulation of turnout disease is an important task for the daily maintenance of the railway engineering department.At present,the main technology for turnout detection is finished by the comparison of standard data and measured data collected by traditional measuring tools such as Track Geometry Measuring Instrument,track gauge,offset scale,feeler gauges,inspection hammers,and strings.But it is difficult to meet the needs of railway development due to external factors and low operational efficiency.In order to improve the detection efficiency and accuracy of turnouts detection,some scholars have tried to use non-contact measurement for turnout detection in recent years.The measurement data of the switch is collected by the non-contact measurement such as digital technology or machine vision technology and compare with the standard switch to further improve the disease of the switch,then the status of turnout disease is visually presented to the staff.The accuracy and reliability of the standard model of turnout will directly affect the diagnosis and remediation of the turnout disease.Therefore,the basis for determining the disease location and formulating the remediation measures through the turnout detection data is the high-precision three-dimensional model of the turnout,so,the premise of turnout model is looking for the method for accurate generation of the three-dimensional surface of the turnout rail.In order to generate a high-precision digital model of the surface of turnout rail,the coordinates of the left and right rails of the straight strand and the curved strand at any position in the turnout zone are calculated according to the design parameters of the turnout.In this paper,a geometric method for generating the digital model of the high-speed railway turnout rail surface is proposed.Taking the No.18 turnout of passenger dedicated line as an example,this paper calculate the node column coordinates of contour and attribute information in any position according to the line type and geometric relationship of the variable section rail,and generate the digital model of switch and nose rail surface by program automated.Finally,the digital model of the whole turnout surface rail is obtained by converting the single section rail model to the section line coordinate system by using the left and right rail working edge coordinates of the sill area.In order to verify the accuracy of the surface model of the turnout rail obtained by the geometric method,the digital model of the rail surface obtained by the geometric method is compared with the existing fitting interpolation method,the loft reconstruction method and the corresponding CAD design model.The result shows: the maximum deviation and standard deviation of the variable turnout section rail digital model generated by geometric method and design model is less than 0.1mm and 0.02 mm.The overall smoothness is better than the fitting interpolation method and stake out method,and the accuracy of the model can fully meet the requirements of disease detection and remediation and scientific research.