Research On The Precision Measurement Method Of Ballastless Track Based On The Vehicle ETS Without Leveling In High-Speed Railway

In order to ensure the smooth,safe and comfortable running of the train,the precise measurement and precise adjustment of the static geometric state of the railway line are very important.At present,adjustment measurement of ballastless track of high-speed railway in China mainly uses the absolute measurement represented by the track measuring instrument,of which the coordinate positioning control and long-wave regularity control capacity is generally recognized.However,the problem of short wave smoothness control accuracy is insufficient,and the problem of low efficiency and so on,which needs to measure at the position of sleeper one by one,has been criticized.Therefore,the relative measurement represented by the railway inspection instrument is often used as an auxiliary.Its coordinate positioning control capability is missing,but its excellent short wave regularity control ability can provide a good complement for the absolute measurement,and the measurement efficiency is very high.Therefore,the two systems of absolute measurement and relative measurement have some complementary to each one,and has its good points,but two sets of system work independently,which lead to a large measure workload and low degree of information fusion.Explorating and researching a precision measurement method or instrument with high accuracy control of coordinate positioning and high accuracy control of long and short wave ride comfort is the need and development direction of high speed railway track precision adjustment in China.Taking the discrete Fourier transform(DFT)and discrete Fourier inverse transform(IDFT)as the core method,through the data processing and analysis,the feasibility of the information extraction and information fusion,based on the location data of absolute measurement and inertial trajectory data of relative measurement,is demonstrated.On the basis of this,the overall scheme of track precision measurement based on the free-stationing of vehicle electronic total station(ETS)without leveling is proposed.The ETS is installed on the track inspecting instrument with relative measuring function,so as to realize the integration of relative and absolute measurement system in machinery,electronics,software,information and operation.A method of free-stationing without leveling and algorithm model is established to achieve high accuracy and high efficiency of station location and posture measurement without leveling.Taking the ETS station as the car's feature point and combining with vehicle attitude measurement information,the real-time calculation of track center positioning measurement results is implemented.The track center positioning measurement results is used to constraint the relative inertial trajectory of the track inspection instrument as a boundary condition,in order to realize the measurement of the internal and external geometric states of the track.The main research contents of the track precision measurement method based on the free-stationing of vehicle ETS without leveling include.1.The location and posture of vehicle ETS is the core of the precise track scheme,and also the basis for later track location data and inertial trajectory constraint.In engineering applications,the location and posture calculation of ETS(free-stationing)in the traditional methods are based on the prerequisite conditions,that total station have be leveled,of which the algorithm model is simple,mature,stable.The method of free-stationing is adopted for the built-in measuring software of the domestic and foreign total station instruments and the relevant textbooks for the total station measurement.However,the total station leveling operation reduces the measurement efficiency of the total station to a certain extent,and also limits the application of the total station in the vehicle mounted state because it can not always maintain its leveling condition.I have been around the free-stationing of ETS without leveling to guide the postgraduates students Xu Yimin to carry out an initial research,the analysis shows that: because the net shape of CP? control network is very special,the position solving equations of ETS are morbid equations,and the way that the position and the posture are solved step by step lead to the introduction error of the station coordinates is irreconcilable.Therefore,a synchronous solution method for the location and posture of ETS is proposed,which based on space coordinate transformation to solve the initial value.According to the Taylor expansion method of the coordinates,the error equation is obtained,then,the indirect adjustment is implemented with the solution method of function extreme value.At last,the accurate position and posture of the ETS without leveling can be obtained,not constrained by the net shape of the control network.2.The measurement of CP? control points by the unleveled vehicle ETS is an important part of the track precision measurement,carrying out the automation research of measurement represented by the automatic aiming,automatic observing,so as to reduce the dependence on artificial observation,to improve the measurement efficiency and to reduce the intensity of work,has great engineering significance.Based on the basic principle of ETS measurement automation,the premise for the realization of ETS automatic measurement is the correct estimation of station location and posture before the measurement.For the free-stationing problem of the fixed unleveled total station,through reducing the dimensions of measured data and estimation parameters by dimensionality reduction,pose estimation algorithm of twopoint method is established,and the measuring automation based two CP? control points artificial observation is relized.Aiming at the unleveled mobile ETS which takes the track inspection instrument as carrier,based on the posture information of the railway inspection instrument,and the inherent posture relationship between the car and the ETS,a posture estimation of the mobile ETS is implemented.The measurement automation of vehicle ETS without leveling is achieved by only one CP? control point's measurement data.3.The traditional two-step measurement mode,that free-stationing have to be implemented before measuring,is broken.The one-step measurement mode,that free-stationing is the measurement and the station point is set as the feature point,is innovated.The center line coordinates of the track is calculated combined the posture measurement result of the car and the ETS installation parameters,and the positioning point of the track is obtained to restrain the relative trajectory of the gyroscope.In order to ensure the measurement accuracy of the ETS position parameters,a calibration device with a spherical prism and a mechanical alignment function is designed to measure the horizontal and vertical deviation of the center line of the track.An accurate ETS position parameters are solved by redundant observation and least squares adjustment.At last,the prototype manufacture and software developement are carried out according to the system research and algorithm design.The tests and line experiments are carried out for each sub module,such as ETS free-stationing without leveling,vehicle ETS position and posture estimation,ETS position parameters measurement and track positioning point measurement.The test results show that all the sub modules and the whole machine can meet the design requirements.Compared with the existing track measurement technology,the speed is faster and the precision is higher.It can control the geometric state of the inner and outer parts of the track,and meet the needs of the high speed railway track fine adjustment.