Research On Three-Dimensional Restriction Measurement Technology Of Track Static Geometry State

In recent years,the high-speed railway in China has been rapidly developed and a number of world-famous high-speed rail lines has been built.With the increasing speed of the train,higher requirements for the track regularity are proposed,and the geometric position error of the track line should be strictly controlled at millimeter level.Therefore,the track static state detection has become one of the necessary projects in the stage of railway construction,acceptance,maintenance and others.The detection parameters includ internal geometric parameters,such as track direction,track height,versine,gauge,level,and the external parameters,such as the horizontal deviation,vertical deviation and coordinates.There are two generic methods to detect the static geometric state of the track.A electronic total station(ETS)is used to measure the control points on the line restriction pile to complete the free-stationing.The three-dimensional coordinates of the the prism on the car are measured,combining the track level and gauge,and then the absolute position parameters of the line are obtained.That is represented by the track measuring instrument for passenger dedicated line,it is usually called absolute measurement method.The other is based on the principle of inertial measurement of fiber optic gyroscope,combined with tilt sensor and displacement sensor to measure the relative track trajectory and posture,and obtain the relative irregularity of the track.That is represented by the railway inspecting instrument,which is usually called relative measurement method.The two methods are essential works for detection and maintenance.The 3D coordinate measurement of the track and the relative position are the main feature of the former method,operation complex,low efficiency.Since the optical equipment is affected by environment,light,wind and rain,it is difficult to adapt to the construction,operation and maintenance of railway lines,especially the time course of "window".The latter is mainly characterized by measuring the relative position of the track to control the regularity.The method has the advantages of operation simplicity,high efficiency and small influence from environment.It can only measure the internal parameters of the track,and lack control of the line coordinates.Based on the introduction of the characteristics of the existing measurement methods of the static geometry of the track.In this paper,the general idea of 3D restriction measurement technology is elaborated.It is proposed that relative measurement system acquire the relative irregularity information of the track and simultaneously measure the fewer points,such as 3D coordinates,horizontal deviation and vertical deviation,which can effectively measure and control the three-dimensional coordinates and regularity of the track line.Therefore,on the premise of Inheriting the existing relative measurement methods in this paper,a mechanistic measurement method is studied,which is used to measure the horizontal(vertical)deviation and three-dimensional coordinates of the coordinate control point(restriction point)simply and rapidly,and a triangulation mathematical model used to measure the horizontal(vertical)deviation between the constrained reference point and constrained line is built.An iterative algorithm on the error correction of the measure line guide wheel,and a orthogonal search algorithm for the Perpendicular of the constrained point are deduced.Taken the design line parameters and line restriction reference point coordinates as the known conditions,and taken the the horizontal deviation,gauge and level measured as input parameters,The center line coordinate calculation model of the line restriction point is built.Based on above of all,a mathematic model of relative measurement inertial trajectory constrained by constrained point coordinates is established,so that the non-optical method can directly and accurately measure the 3D coordinates of the center line on the constrained point,and then calculate the 3D coordinates of center line,left and right line at any position.Since the measurement accuracy and stability of the relative measurement part of the track have a direct impact on the final effect of the track 3D restriction measurement.The paper works a special study of the typical problems in the practical application of the relative measurement project.In order to solve the precision measure of angle accumulated error caused by the temperature drift of the fiber optic gyroscope on the measurement accuracy of the relative measurement inertial track is analyzed.Aiming at the defects of the traditional neural network hidden layer mapping function of the neural network,a wavelet neural network temperature drift error compensation model of fiber optic gyroscope is proposed.And time series analysis method is used to establish the Kalman filter Algorithm which can improve effectively suppress the random noise in the zero drift of fiber gyroscope and improve the data quality of inertial trajectory measurement.At the same time,to solve the influence of the signal distortion of tilt sensor caused by transient impact on the horizontal measurement accuracy,the MEMS horizontal dynamic correction gyroscope and tilt sensor are used to measure simultaneously.The data fusion algorithm of the two sensors is established to improve the dynamic state of the measurement accuracy of the parameter.In order to verify the effectiveness of the research results,the paper also completed the design of measuring institutions,such as restriction measurement column,pulley blocks and so on,as well as the construction of constrained control point pile,the adapter of the pile.At the same time,the influence of mechanical structure on the measurement error is analyzed,and then the measurement accuracy of the track 3D constrained geometric state is calculated and evaluated from the uncertainty of the measurement system.Finally,the line test is carried out on the left line of Zhang Hu passenger dedicated line,from K28182.500 to 285057.500,and the measuring results are used to guide the Large tamping machine for line adjustment operation.The experimental results show that the system constructed by the three dimensional track static geometry state restriction measurement technology meets the needs of engineering field.In order to solve the prominent contradiction between measurement accuracy and efficiency of track positioning,a new integrated measurement method used to measure the three-dimensional coordinates and track regularity fast and accurately is found.