Precise measurement method for static geometric state of large-span bridge railway track

Abstract

The invention discloses a method for precisely measuring the static geometric state of a large-span bridge railway track, and the method comprises the steps: enabling a track measurement trolley to move forwards along the track, collecting the track shape data, and transmitting the data to a terminal; synchronously tracking and observing the track measurement trolley by adopting a plurality of total stations, acquiring three-dimensional coordinate data of the track measurement trolley, and sending the three-dimensional coordinate data to the terminal; the terminal performs spatial splicing on the three-dimensional coordinate data acquired by the plurality of total stations to obtain spliced three-dimensional coordinate data, and performs time synchronization on the IMU data and the spliced three-dimensional coordinate data; and the terminal carries out fusion processing and smoothing processing on the IMU-odometer data after time synchronization and the spliced three-dimensional coordinate data to obtain track geometric state data. According to the rapid and precise measurement method for the static geometric state of the large-span bridge railway track, the geometric state of the track can be rapidly and accurately measured, and the efficiency of measuring the static set state of the large-span bridge railway track is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering measurement, and in particular to a precise measurement method and system for the static geometric state of a railway track on a long-span bridge. Background Art

[0002] Bridges are an important part of railway tracks. With the popularization of railways in recent years, more and more long-span railway bridges have emerged. As the length of railway bridges increases, the difficulty of ensuring the stability and safety of the bridges themselves is also increasing, which also increases the difficulty of track safety maintenance. The static geometric state of the track includes the shape of the track, the three-dimensional position coordinates of the track, etc. The geometric state can be used to calculate parameters such as track unevenness, which has a significant impact on the operating safety, driving speed, stability, and component life of the wheel-rail system.

[0003] At present, there are several methods for measuring the geometric state of bridge tracks, but they are not suitable for measuring railway tracks on large-span bridges, and have problems such as difficult measurement, low measurement efficiency, and susceptibility to environmental influences:

[0004] 1) Through long-term observation by camera-based visual sensors, the geometric state of the bridge track is calculated based on photos. It has the advantages of simple installation, no need for special targets, and flexible measurement positions. However, this method requires good lighting conditions and the effective measurement distance is also short, so it is only suitable for small-span bridges.

[0005] 2) Large inspection vehicles are used for dynamic measurement of railway tracks and cannot be used as a means of measuring the static geometric state of railway tracks on long-span bridges. In addition, large inspection vehicles are expensive, there are few of them, and the inspection time needs to be planned in advance, making it difficult to use them as soon as they are inspected.

[0006] 3) The track inspection car has the following shortcomings:

[0007] 1. Low efficiency. When setting up stations, the track inspection vehicle needs to be re-set every 70 meters or so. Each time the station is set up, 6 to 8 CPIII control points need to be observed, and each rail sleeper must be stationary for 10 seconds during measurement. As a result, the operating speed of the track inspection vehicle is about 150m / h, and the geometric state measurement of only about 300m of track can be completed within the 2h window time.

[0008] Second, the absolute position accuracy is highly dependent on the CPIII control points, but the CPIII points have high maintenance costs, and the accuracy is difficult to guarantee. Moreover, the CPIII points will move with the deformation of the bridge, and the relative position change can be as high as 6mm.

[0009] 3. Frequently changing the total station will cause "overlap error" and affect the accuracy of the final result.

[0010] 4) The advantage of the track inspection vehicle based on GNSS positioning is that it does not need to frequently transfer stations, thereby improving measurement efficiency and having a relative measurement accuracy better than 1mm. However, the absolute accuracy of this method is limited by the GNSS positioning accuracy, which is generally in the centimeter level, and the GNSS signal is easily interfered or blocked in complex scenes such as bridges, tunnels, and valleys.

[0011] Therefore, the existing technology is difficult to fully adapt to the rapid and precise measurement of the geometric state of railway tracks on large-span bridges, and a measurement method with high efficiency, high accuracy and little environmental impact is needed.

[0012] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0013] The main purpose of the present invention is to provide a method and system for accurately measuring the static geometric state of a railway track on a long-span bridge, aiming to solve the technical problems in the prior art of difficult measurement of the geometric state of a railway track on a bridge, low measurement efficiency and susceptibility to environmental influences.

[0014] To achieve the above object, the present invention provides a method for accurately measuring the static geometric state of a railway track on a long-span bridge, and the method for accurately measuring the static geometric state of a railway track on a long-span bridge comprises the following steps:

[0015] The track measurement vehicle moves forward along the track to collect track shape data and send it to the terminal. The track measurement vehicle is integrated with a high-precision IMU and an odometer. The high-precision IMU is used to collect the acceleration and angular velocity of the track measurement vehicle. The odometer is used to collect the speed of the track measurement vehicle. The track shape data includes IMU data and odometer data.

[0016] Use multiple total stations to synchronously track and observe the track measurement trolley, obtain the three-dimensional coordinate data of the track measurement trolley, and send it to the terminal;

[0017] The terminal spatially stitches the three-dimensional coordinate data collected by multiple total stations to obtain stitched three-dimensional coordinate data, and synchronizes the IMU data with the stitched three-dimensional coordinate data in time;

[0018] The terminal fuses and smoothes the time-synchronized IMU-odometer data with the spliced ​​three-dimensional coordinate data to obtain the track geometry status data.

[0019] Optionally, the method for precisely measuring the static geometric state of a railway track on a long-span bridge, wherein the step of using multiple total stations to synchronously track and observe a track measuring vehicle to obtain three-dimensional coordinate data of the track measuring vehicle, specifically includes:

[0020] Multiple total stations are set up on the approach bridge deck near the expansion joints, and the stations are set up through the CPIII control points on the approach bridge;

[0021] While the track measuring trolley moves along the bridge track and collects track shape data, multiple total stations track and observe the prisms on the track measuring trolley to obtain the three-dimensional coordinate data of the track measuring trolley.

[0022] Optionally, in the method for precisely measuring the static geometric state of a railway track on a long-span bridge, the total station comprises a first total station and a second total station; the first total station and the second total station are respectively arranged at the bridge head and the bridge tail near the expansion joint;

[0023] The motion process of the track measuring trolley includes:

[0024] The initial position of the track measurement trolley is on the rail of the bridge body close to the first total station, with the prism facing the first total station. After the data acquisition instrument is turned on, the track measurement trolley is pushed along the track toward the second total station on the opposite bank.

[0025] Change the direction of the prism at the first rotation point so that the prism faces the second total station and continue to move in the original direction;

[0026] When the track measuring trolley reaches the telescopic joint near the second total station, keep the prism direction unchanged, turn the travel direction of the track measuring trolley and push it towards the first total station;

[0027] When the track measuring trolley reaches the second mirror rotation point, the direction of the prism is changed again so that the prism faces the first total station, and the track measuring trolley is continued to be pushed until it returns to the initial position;

[0028] The movement route of the track measuring trolley is divided into three parts by the positions of the first mirror rotation point and the second mirror rotation point. The process of the track measuring trolley from the initial position telescopic joint to the first mirror rotation point is named the first movement process, the process from the first mirror rotation point to the second mirror rotation point is named the second movement process, and the process from the second mirror rotation point to the initial position telescopic joint is named the third movement process.

[0029] Optionally, the method for precisely measuring the static geometric state of a railway track on a long-span bridge, wherein the three-dimensional coordinate data collected by a plurality of total stations are spatially spliced ​​to obtain spliced ​​three-dimensional coordinate data, specifically comprises:

[0030] The three-dimensional coordinate data acquired by multiple total stations are preprocessed by mileage correction, mileage normalization and corresponding point relationship determination, and the preprocessed three-dimensional coordinate data are rotated to obtain the rotated orbital space coordinates;

[0031] The rotated orbital space coordinates are translated according to the translation distance to obtain spliced ​​three-dimensional coordinate data.

[0032] Optionally, in the method for precise measurement of the static geometric state of railway tracks on long-span bridges, the translation operation is used to minimize the squared difference in elevation residuals of corresponding points in overlapping parts of two point cloud mileages.

[0033] Optionally, the method for precisely measuring the static geometric state of a railway track on a long-span bridge, wherein the step of time synchronizing the IMU data with the spliced ​​three-dimensional coordinate data, specifically comprises:

[0034] The prism movement speed is calculated based on the three-dimensional coordinate data and timestamps observed by multiple total stations, the timestamp of the prism speed curve is adjusted, and the high-precision IMU and odometer system timestamps are slid. The Pearson correlation coefficient between the prism speed and the odometer speed in the same time interval is calculated, and the functional relationship between the time adjustment amount and the correlation coefficient is obtained. The time adjustment amount corresponding to the maximum correlation coefficient is taken;

[0035] The time stamps of multiple total stations are adjusted as a whole by a time adjustment amount to complete the time synchronization of the multiple total stations and the high-precision IMU and odometer system.

[0036] Optionally, the method for precisely measuring the static geometric state of a railway track on a long-span bridge, wherein the time-synchronized IMU-odometer data and the spliced ​​three-dimensional coordinate data are fused and smoothed to obtain the track geometric state data, specifically comprising:

[0037] Use Kalman filtering to fuse the time-synchronized IMU-odometer data with the spliced ​​3D coordinate data to obtain fused orbital space data;

[0038] The RTS algorithm is used to smooth the fused orbital space data to obtain the orbital geometric state data.

[0039] Optionally, the method for precisely measuring the static geometric state of a railway track on a large-span bridge, wherein the track geometric state data includes the track shape and the three-dimensional position coordinates of the track.

[0040] Optionally, in the method for precisely measuring the static geometric state of a railway track on a large-span bridge, the total station comprises a TS60 total station with a tracking measurement function.

[0041] In addition, to achieve the above-mentioned purpose, the present invention also provides a precision measurement system for the static geometric state of a railway track on a long-span bridge, which is applied to the precision measurement method for the static geometric state of a railway track on a long-span bridge, wherein the precision measurement system for the static geometric state of a railway track on a long-span bridge comprises: a track measurement trolley, a plurality of total stations and a terminal; the track measurement trolley is integrated with a high-precision IMU and an odometer, the high-precision IMU is used to collect the acceleration and angular velocity of the track measurement trolley, the odometer is used to collect the speed of the track measurement trolley, and the track shape data comprises IMU data and odometer data;

[0042] The track measurement vehicle moves along the track to collect track shape data and then sends it to the terminal;

[0043] A plurality of said total stations synchronously track and observe the track measurement trolley, obtain the three-dimensional coordinate data of the track measurement trolley, and send it to said terminal;

[0044] The terminal spatially stitches the three-dimensional coordinate data collected by multiple total stations to obtain stitched three-dimensional coordinate data, time synchronizes the IMU data with the stitched three-dimensional coordinate data, and fuses and smoothes the time-synchronized IMU-odometer data with the stitched three-dimensional coordinate data to obtain track geometry state data.

[0045] In the present invention, the track measurement trolley moves forward along the track to collect track shape data and sends it to the terminal. The track measurement trolley is integrated with a high-precision IMU and an odometer. The high-precision IMU is used to collect the acceleration and angular velocity of the track measurement trolley, and the odometer is used to collect the speed of the track measurement trolley; multiple total stations are used to synchronously track and observe the track measurement trolley, obtain the three-dimensional coordinate data of the track measurement trolley, and send it to the terminal; the terminal spatially splices the three-dimensional coordinate data collected by multiple total stations to obtain spliced ​​three-dimensional coordinate data, and synchronizes the IMU data with the spliced ​​three-dimensional coordinate data in time; the terminal fuses and smoothes the time-synchronized IMU-odometer data with the spliced ​​three-dimensional coordinate data to obtain track geometry data. The present invention proposes a new method for rapid and precise measurement of the static geometry of large-span bridge railway tracks, which can quickly and accurately measure the geometry of the track and improve the efficiency of measuring the static aggregate state of large-span bridge railway tracks. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a flow chart of a preferred embodiment of the method for accurately measuring the static geometric state of a railway track on a long-span bridge of the present invention;

[0047] Figure 2 It is a flow chart of data acquisition and data calculation in a preferred embodiment of the method for accurately measuring the static geometric state of a railway track on a long-span bridge of the present invention;

[0048] Figure 3 It is a diagram showing the relationship between the positions of the on-site instruments in a preferred embodiment of the method for accurately measuring the static geometric state of the railway track of a long-span bridge of the present invention;

[0049] Figure 4 It is a schematic diagram of a measurement route in a preferred embodiment of a method for accurately measuring the static geometric state of a railway track on a long-span bridge of the present invention;

[0050] Figure 5 It is a schematic diagram of spatial splicing-rotation in a preferred embodiment of the method for accurately measuring the static geometric state of a railway track on a long-span bridge of the present invention;

[0051] Figure 6 It is a schematic diagram of spatial splicing-translation in a preferred embodiment of the method for accurately measuring the static geometric state of a railway track on a long-span bridge of the present invention;

[0052] Figure 7 It is a schematic diagram of completing spatial splicing in a preferred embodiment of the method for accurately measuring the static geometric state of a railway track on a long-span bridge of the present invention;

[0053] Figure 8 It is a schematic diagram of time synchronization in a preferred embodiment of the method for accurately measuring the static geometric state of a railway track on a long-span bridge of the present invention;

[0054] Fig. 9 It is a structural diagram of a preferred embodiment of the precise measurement system for the static geometric state of the railway track of a long-span bridge according to the present invention. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the present invention clearer and more specific, the present invention is further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0056] The precise measurement method of the static geometric state of the railway track of a long-span bridge described in the preferred embodiment of the present invention is as follows: Figure 1 and Figure 2 As shown, the method for precisely measuring the static geometric state of the railway track of a long-span bridge comprises the following steps:

[0057] Step S10, the track measurement vehicle moves forward along the track to collect track shape data and send it to the terminal. The track measurement vehicle is integrated with a high-precision IMU and an odometer. The high-precision IMU is used to collect the acceleration and angular velocity of the track measurement vehicle. The odometer is used to collect the speed of the track measurement vehicle. The track shape data includes IMU data (such as the acceleration and angular velocity of the track measurement vehicle) and odometer data (such as the speed of the track measurement vehicle).

[0058] In the present invention, the precise measurement method of the static geometric state of the railway track of a long-span bridge is applied to a terminal, and the terminal includes but is not limited to: a computer and a mobile terminal, such as a computer.

[0059] Specifically, the track measurement vehicle is equipped with an IMU / odometer combined measurement system. The accuracy of the IMU reaches 0.01° / h. The odometer encoder is installed on the wheels of the track measurement vehicle and connected to the system. Figure 2 As shown, the track measurement vehicle integrates a high-precision IMU and an odometer. The high-precision IMU is used to collect the acceleration and angular velocity of the track measurement vehicle, and the odometer is used to collect the speed of the track measurement vehicle. IMU specifically refers to an inertial measurement unit (Inertial Measurement Unit), which is a device that includes three single-axis accelerometers and three single-axis gyroscopes to measure the three-axis attitude angle (or angular rate) and three-axis acceleration of an object. The odometer is a measuring instrument that uses data from a motion sensor to estimate the change of posture over time. Among them, the wheel odometer is based on the photoelectric encoder installed on the robot to track the rotation speed of each wheel, and then the robot's kinematic model is used to determine the relative position of the robot relative to the starting point. In addition, the track measurement vehicle is provided with a column for placing a prism to facilitate the total station to obtain the three-dimensional coordinates of the track measurement vehicle itself.

[0060] Step S20: Use multiple total stations to synchronously track and observe the track measurement vehicle, obtain the three-dimensional coordinate data of the track measurement vehicle, and send it to the terminal.

[0061] Total station specifically refers to an Electronic TotalStation, which is a high-tech measuring instrument that integrates optics, mechanics and electronics. It is a surveying and mapping instrument system that integrates horizontal angle, vertical angle, distance (slant distance, horizontal distance) and height difference measurement functions. It is called a total station because it can complete all measurement work at the survey station by setting up the instrument once. It is widely used in precision engineering measurement or deformation monitoring fields such as large-scale ground buildings and underground tunnel construction.

[0062] The total station in the present invention preferably adopts the TS60 total station with tracking measurement function. When the electronic level is used, the station setting accuracy reaches 2 seconds. The continuous tracking measurement point accuracy of TS60 is 0.5 seconds in angle and 3mm+1.5ppm in distance. For a 1000m long long-span railway bridge, a single total station tracks and observes half of the distance, and its point position accuracy is 3mm+1.5ppm*0.5km=3.75mm, which meets the accuracy required by the method.

[0063] Before collecting data, the track measurement vehicle and the total station are placed on the bridge deck. The position relationship diagram is shown in the figure below. Figure 3 As shown. Total stations, such as TS01 (i.e., the first total station) and TS02 (i.e., the second total station), are placed on the approach bridge deck near the expansion joint (bridge expansion joint refers to the expansion joint of the bridge deck, which is usually set between the two beam ends, between the beam end and the abutment, or at the hinged position of the bridge to meet the requirements of bridge deck deformation. The function of the bridge expansion joint is to adjust the displacement between the superstructure caused by vehicle loads and bridge construction materials and the expansion device connecting the skew bridge. Once it is damaged, it will seriously affect the speed, comfort and safety of driving, and even cause driving safety accidents. Therefore, all bridge decks must be pre-installed with expansion joints) and set up stations through the CPIII control points on the approach bridge (CPIII means the pile control network) (i.e., TS01 and TS02 are respectively set at the bridge head and bridge tail near the expansion joint), so as to avoid CPIII point position errors caused by the shaking of the main part of the bridge. The track measurement trolley is installed on the track of the main part of the bridge, and the prism of the track measurement trolley needs to ensure visibility. While the track measuring trolley moves along the track and collects track shape data, the total station tracks the observation prism to obtain the three-dimensional coordinates of the track measuring trolley.

[0064] The data collection process is as follows Figure 4 As shown, Figure 4 Transfer mirror point 1 (i.e. the first transfer mirror point) and transfer mirror point 2 (i.e. the second transfer mirror point) refer to the positions where the track measurement trolley cannot see through TS01 and TS02 during the pushing process. The initial position of the track measurement trolley is on the rails of the bridge body close to the total station TS01, with the prism facing TS01. After turning on the data acquisition instrument, push the track measurement trolley along the track toward TS02 on the opposite bank. Change the direction of the prism at transfer mirror point 1 so that it faces TS02, and continue to push it in the original direction. When the track measurement trolley reaches the telescopic joint near TS02, that is, the turning point, keep the direction of the prism unchanged, turn the driving direction of the track measurement trolley, and push it toward TS01. When the track measurement trolley reaches transfer mirror point 2, change the direction of the prism again so that it faces TS01, and continue to push the track measurement trolley until it returns to the initial position.

[0065] like Figure 4 As shown, the positions of the two mirror rotations (i.e., mirror rotation point 1 and mirror rotation point 2) divide the movement route of the track measuring trolley into three parts. The process of the track measuring trolley from the initial position telescopic joint 1 to the mirror rotation point 1 is named Run01 (i.e., the first movement process), the process from the mirror rotation point 1 to the mirror rotation point 2 is named Run02 (i.e., the second movement process), and the process from the mirror rotation point 2 to the initial position telescopic joint 1 is named Run03 (i.e., the third movement process).

[0066] Step S30: The terminal spatially stitches the three-dimensional coordinate data collected by multiple total stations to obtain stitched three-dimensional coordinate data, and time-synchronizes the IMU data with the stitched three-dimensional coordinate data.

[0067] The railway track of a bridge is generally a straight line on the horizontal plane, but presents an undulating shape in the elevation direction. Therefore, the track is taken as the X-axis, that is, the mileage is taken as the X-coordinate, the elevation direction is taken as the Z-axis, and the Y-axis is used to establish a coordinate system perpendicular to the track. The shape of a series of three-dimensional point clouds obtained by the total station (three-dimensional point clouds means a series of points with three-dimensional coordinates obtained by the total station) is a curve extending along the mileage direction of the rail. The mileage of the curve is corrected and normalized, so as to unify the mileage of the measurement points of multiple total stations. Therefore, it is believed that the data of multiple total stations do not need to be adjusted in mileage, that is, in X-coordinate. Taking the X-axis as the reference, adjusting the errors in the Y-axis and Z-axis directions can complete the spatial splicing of the total station data. The overlapping part of the mileage of the total station point cloud curve is taken as the area to be registered, and the points with the same mileage are taken as corresponding points.

[0068] After the above-mentioned preprocessing such as mileage correction, mileage normalization, corresponding point relationship determination (for the curves obtained by TS01 and TS02 measurement, it is necessary to determine the two corresponding points with the same mileage in the two curves. This process is called corresponding point relationship confirmation), the total station data spatial splicing can be performed. Taking the mileage-elevation plane coordinate system, that is, the XZ plane, as an example, spatial splicing includes two steps. The first step is rotation, such as Figure 5 As shown in the figure, the reference total station point cloud data is selected, and the target point cloud is rotated counterclockwise by an angle θ along the center point C0 (M0, H0) of the total station itself, where M0 and H0 represent the coordinate values ​​of the center point C0 of the total station, so that the parts of the two point cloud curves with the same mileage are parallel, that is, the variance of the elevation residual of the corresponding points of the point cloud (that is, the distance in the point cloud splicing) is minimized. The formula is:

[0069]

[0070]

[0071]

[0072]

[0073] in, and is the point t in the rotated point cloud T k Mileage coordinates and elevation coordinates, M k is the point t in the point cloud T before rotation k The mileage coordinates of is the point t in the point cloud T before rotation k The elevation coordinates of is the point t in the point cloud R before rotation k The elevation coordinate, ΔH k and is the elevation residual between corresponding points after rotation and its average value, k represents the number of point clouds, Var(ΔH k ) is the variance of the elevation residual.

[0074] The θ value is obtained by solving the above equation, and then the target point cloud curve is rotated according to the θ value.

[0075] like Figure 6 As shown in the figure, after the rotation operation, the target point cloud that has been rotated in the previous step is translated up and down along the elevation direction. The translation distance is τ. The purpose is to minimize the squared residual error f(τ) of the corresponding points in the overlapping part of the two point clouds. The formula is:

[0076]

[0077]

[0078] After the above rotation and translation, the target point cloud curve and the reference point cloud curve are in the best matching state, such as Figure 7 As shown. The curves of the two overlap in the mileage overlap area and are in the same coordinate system of the reference point cloud curve, thus completing the spatial splicing of the total station data on the XZ plane. The spatial splicing process of the total station data on the mileage-two-dimensional plane perpendicular to the track direction, that is, the XY plane, is similar to the XZ plane, but does not require rotation. The target point cloud curve can be translated in the Y-axis direction.

[0079] Generally, the IMU / odometer system on the track measurement vehicle will be powered on throughout the measurement, and the timestamps are continuous and complete. However, each total station only observes a part of the route, and its timestamp only accounts for a part of the total measurement time, and there may be discontinuities. Therefore, the IMU / odometer system is selected as the reference benchmark to adjust the timestamps of each total station for synchronization.

[0080] The time synchronization method is to first calculate the movement speed of the prism based on the three-dimensional coordinates and timestamps of the points observed by the total station, and then adjust the timestamp of the prism speed curve to slide on the timestamp of the IMU / odometer system, such as Figure 8 As shown on the left side of , the Pearson correlation coefficient between the prism speed and the odometer speed in the same time interval is calculated to obtain the time adjustment t lag Functional relationship with correlation coefficient r, finally taking the maximum correlation coefficient r max The corresponding time adjustment t best ,like Figure 8 The calculation method of Pearson correlation coefficient is:

[0081]

[0082] Among them, V TS , V Od is the speed calculated by the total station and the odometer speed, is the standard deviation of the two, and They represent the average values ​​of the speed calculated by the total station and the odometer speed respectively, and E represents the expected value calculation.

[0083] Adjust the total station timestamp by an amount t best , thereby completing the time synchronization between this total station and the IMU / odometer system.

[0084] Step S40: The terminal fuses and smoothes the time-synchronized IMU-odometer data and the spliced ​​three-dimensional coordinate data to obtain track geometry state data.

[0085] Specifically, the Kalman filter is used to fuse the time-synchronized IMU-odometer data with the spliced ​​three-dimensional coordinate data to obtain the fused orbital space data; the RTS algorithm is used to smooth the fused orbital space data to obtain the orbital geometric state data.

[0086] Among them, the system state model, error model and observation model of Kalman filtering are expressed as:

[0087]

[0088]

[0089]

[0090] Among them, X, P are the system state vector and its covariance matrix at the previous moment, is the system state matrix and its covariance matrix at this moment, A and H are the state transfer matrix and observation matrix, is the observation vector at this moment, w and v are process noise and observation noise, which obey normal distribution with mean 0 and covariance Q and R respectively. N(0,Q) represents normal distribution with covariance Q, and N(0,R) represents normal distribution with covariance R. A T Represents the transpose of the state transition matrix.

[0091] According to the actual situation, the system state matrix x and observation matrix Z are designed, where X contains various errors of the IMU / odometer system and Z is the observation error of the prism.

[0092] X=[δφ δv δr δbg δb a δk d ];

[0093]

[0094] Among them, δφ, δv, δr, δb g , δb a ,δk d is the attitude angle error vector, velocity error vector, position error vector, random walk error vector, acceleration error vector, odometer scale coefficient error, δr p represents the observation error of the prism, are the predicted and measured position coordinates of the prism control point, r INS To predict the IMU position, is the attitude transformation matrix, is the position vector of the prism relative to the IMU center, r TS is the prism position coordinate measured by the total station, ε TS Measuring noise for total stations.

[0095] The Kalman gain matrix K is calculated from the system state matrix and its covariance matrix at the previous moment, thereby obtaining the system state and covariance at this moment. After continuous forward iteration, the system state of the entire track route can be calculated.

[0096] K=APA T H T (HAPA T H T +R) -1 ;

[0097]

[0098]

[0099] Where I represents the identity matrix;

[0100] The RTS (Rauch–Tung–Striebel) algorithm is used to perform back filtering and smoothing on the data. The principle of the RTS algorithm is similar to that of the Kalman filter, but the calculation direction is opposite. The RTS smoothing algorithm calculates the smoothing gain matrix G through the state and covariance X and P at the next moment, and calculates the Right now:

[0101] G=PA T (APA T +Q) -1 ;

[0102]

[0103]

[0104] The δr in the vector X obtained above is the three-dimensional coordinate error of the orbit point. Adding the original three-dimensional coordinate of the orbit point can get the optimal three-dimensional coordinate estimate of the orbit point, so that the static geometric state of the measurement orbit can be obtained through the three-dimensional coordinates of the orbit point.

[0105] The overall process of the precision measurement method of the static geometric state of the railway track of a large-span bridge of the present invention is divided into two parts: data collection and data solution. In the data collection process, the track measurement trolley collects data related to the track line shape, wherein the inertial measurement unit (IMU) collects the acceleration and angular velocity of the track measurement trolley, the odometer collects the speed of the trolley, and the total station observes the three-dimensional coordinates of the track measurement trolley. In the data solution process, it is first necessary to spatially splice the data of multiple total stations, then synchronize the time of multiple total stations and IMU / odometers, and finally fuse and smooth the data of many sensors, that is, the data fusion method based on Kalman filtering and RTS smoothing filtering, and finally obtain the track geometric state parameters.

[0106] The method of the present invention uses a track measurement cart with integrated high-precision IMU and odometer to move forward along the track to collect track shape data, and adopts multiple total stations to synchronously track and observe the track measurement cart to obtain its three-dimensional coordinate data, and then spatially splices and temporally synchronizes the multi-sensor data. After fusion and smoothing, the track geometric state data can be obtained.

[0107] The advantages of this method are: First, the track measurement vehicle can collect trajectory geometry data with high precision and high frequency; second, multiple total stations track and observe the track measurement vehicle in sections to achieve line of sight everywhere and absolute positioning of the track measurement vehicle throughout the entire process; third, after using the algorithm to perform spatial stitching and time synchronization of data, the track geometry state is obtained by fusing multi-sensor data, and inertial navigation positioning is achieved through multiple total stations and odometers, thereby effectively suppressing the divergence error of the IMU.

[0108] Field tests have shown that the multi-total station-assisted IMU / odometer-based measurement method proposed in the present invention has obvious advantages in accuracy and efficiency. It can measure the geometric state of a 1000m long bridge railway track with millimeter-level accuracy within 1 hour. It is an effective new measurement solution with good practical significance.

[0109] Furthermore, if Fig. 9As shown, the present invention also provides a precision measurement system for the static geometric state of a railway track on a long-span bridge, which is applied to the precision measurement method for the static geometric state of a railway track on a long-span bridge, wherein the precision measurement system for the static geometric state of a railway track on a long-span bridge comprises: a track measurement trolley, a plurality of total stations and a terminal; the track measurement trolley is integrated with a high-precision IMU and an odometer, the high-precision IMU is used to collect the acceleration and angular velocity of the track measurement trolley, the odometer is used to collect the speed of the track measurement trolley, and the track shape data comprises IMU data and odometer data;

[0110] The track measurement vehicle moves along the track to collect track shape data and then sends it to the terminal;

[0111] A plurality of said total stations synchronously track and observe the track measurement trolley, obtain the three-dimensional coordinate data of the track measurement trolley, and send it to said terminal;

[0112] The terminal spatially stitches the three-dimensional coordinate data collected by multiple total stations to obtain stitched three-dimensional coordinate data, time synchronizes the IMU data with the stitched three-dimensional coordinate data, and fuses and smoothes the time-synchronized IMU-odometer data with the stitched three-dimensional coordinate data to obtain track geometry state data.

[0113] In summary, the present invention provides a method and system for precisely measuring the static geometric state of a railway track on a long-span bridge. The method comprises: a track measuring trolley moves forward along the track to collect track shape data and send it to a terminal. The track measuring trolley is integrated with a high-precision IMU and an odometer. The high-precision IMU is used to collect the acceleration and angular velocity of the track measuring trolley, and the odometer is used to collect the speed of the track measuring trolley; multiple total stations are used to synchronously track and observe the track measuring trolley, obtain the three-dimensional coordinate data of the track measuring trolley, and send it to the terminal; the terminal spatially splices the three-dimensional coordinate data collected by the multiple total stations to obtain spliced ​​three-dimensional coordinate data, and time synchronizes the IMU data with the spliced ​​three-dimensional coordinate data; the terminal performs fusion processing and smoothing processing on the time-synchronized IMU-odometer data and the spliced ​​three-dimensional coordinate data to obtain track geometric state data. The present invention proposes a new method for rapidly and precisely measuring the static geometric state of railway tracks on long-span bridges, which can quickly and accurately measure the track geometric state and improve the efficiency of measuring the static collective state of railway tracks on long-span bridges.

Claims

1. A method for accurately measuring the static geometric state of a railway track on a long-span bridge, characterized in that: The method for precisely measuring the static geometric state of the railway track of the long-span bridge comprises: The track measurement vehicle moves forward along the track to collect track shape data and send it to the terminal. The track measurement vehicle is integrated with a high-precision IMU and an odometer. The high-precision IMU is used to collect the acceleration and angular velocity of the track measurement vehicle. The odometer is used to collect the speed of the track measurement vehicle. The track shape data includes IMU data and odometer data. Use multiple total stations to synchronously track and observe the track measurement vehicle, obtain the three-dimensional coordinate data of the track measurement vehicle, and send it to the terminal; The terminal spatially stitches the three-dimensional coordinate data collected by multiple total stations to obtain stitched three-dimensional coordinate data, and time-synchronizes the IMU data with the stitched three-dimensional coordinate data; The terminal fuses and smoothes the time-synchronized IMU-odometer data with the spliced ​​three-dimensional coordinate data to obtain the track geometry status data.

2. The method for accurately measuring the static geometric state of a railway track on a long-span bridge according to claim 1 is characterized in that: The method of using multiple total stations to synchronously track and observe the track measurement vehicle to obtain the three-dimensional coordinate data of the track measurement vehicle specifically includes: Multiple total stations are set up on the approach bridge deck near the expansion joints, and the stations are set up through the CPIII control points on the approach bridge; While the track measuring trolley moves along the bridge track and collects track shape data, multiple total stations track and observe the prisms on the track measuring trolley to obtain the three-dimensional coordinate data of the track measuring trolley.

3. The method for accurately measuring the static geometric state of a railway track on a long-span bridge according to claim 2 is characterized in that: The total station includes a first total station and a second total station; the first total station and the second total station are respectively arranged at the bridge head and the bridge tail close to the telescopic joint; The motion process of the track measuring trolley includes: The initial position of the track measurement trolley is on the rail of the bridge body close to the first total station, with the prism facing the first total station. After the data acquisition instrument is turned on, the track measurement trolley is pushed along the track toward the second total station on the opposite bank. Change the direction of the prism at the first rotation point so that the prism faces the second total station and continue to move in the original direction; When the track measuring trolley reaches the telescopic joint near the second total station, keep the prism direction unchanged, turn the travel direction of the track measuring trolley and push it towards the first total station; When the track measuring trolley reaches the second mirror rotation point, the direction of the prism is changed again so that the prism faces the first total station, and the track measuring trolley is continued to be pushed until it returns to the initial position; The movement route of the track measuring trolley is divided into three parts by the positions of the first mirror rotation point and the second mirror rotation point. The process of the track measuring trolley from the initial position telescopic joint to the first mirror rotation point is named the first movement process, the process from the first mirror rotation point to the second mirror rotation point is named the second movement process, and the process from the second mirror rotation point to the initial position telescopic joint is named the third movement process.

4. The method for accurately measuring the static geometric state of a railway track on a long-span bridge according to claim 2 is characterized in that: The spatial splicing of the three-dimensional coordinate data collected by multiple total stations to obtain spliced ​​three-dimensional coordinate data specifically includes: The three-dimensional coordinate data acquired by multiple total stations are preprocessed by mileage correction, mileage normalization and corresponding point relationship determination, and the preprocessed three-dimensional coordinate data are rotated to obtain the rotated orbital space coordinates; The rotated orbital space coordinates are translated according to the translation distance to obtain spliced ​​three-dimensional coordinate data.

5. The method for accurately measuring the static geometric state of a railway track on a long-span bridge according to claim 4 is characterized in that: The translation operation is used to minimize the squared difference of the elevation residuals of the corresponding points in the overlapping parts of the two point clouds.

6. The method for precisely measuring the static geometric state of a railway track on a long-span bridge according to claim 4 is characterized in that: The time synchronization of the IMU data and the spliced ​​three-dimensional coordinate data specifically includes: The prism movement speed is calculated based on the three-dimensional coordinate data and timestamps observed by multiple total stations, the timestamp of the prism speed curve is adjusted, and the high-precision IMU and odometer system timestamps are slid. The Pearson correlation coefficient between the prism speed and the odometer speed in the same time interval is calculated, and the functional relationship between the time adjustment amount and the correlation coefficient is obtained. The time adjustment amount corresponding to the maximum correlation coefficient is taken; The time stamps of multiple total stations are adjusted as a whole by a time adjustment amount to complete the time synchronization of the multiple total stations and the high-precision IMU and odometer system.

7. The method for precisely measuring the static geometric state of a railway track on a long-span bridge according to claim 6 is characterized in that: The time-synchronized IMU-odometer data and the spliced ​​three-dimensional coordinate data are fused and smoothed to obtain track geometry state data, specifically including: Use Kalman filtering to fuse the time-synchronized IMU-odometer data with the spliced ​​3D coordinate data to obtain fused orbital space data; The RTS algorithm is used to smooth the fused orbital space data to obtain the orbital geometric state data.

8. The method for precisely measuring the static geometric state of a railway track on a long-span bridge according to claim 7 is characterized in that: The track geometry data includes track shape and track three-dimensional position coordinates.

9. The method for accurately measuring the static geometric state of a railway track on a long-span bridge according to any one of claims 1 to 8, characterized in that: The total station includes a TS60 total station with a tracking measurement function.

10. A precision measurement system for the static geometric state of a railway track on a long-span bridge, applied to the precision measurement method for the static geometric state of a railway track on a long-span bridge as claimed in any one of claims 1 to 9, characterized in that: The precision measurement system for the static geometric state of the railway track of a long-span bridge comprises: a track measurement trolley, a plurality of total stations and a terminal; the track measurement trolley is integrated with a high-precision IMU and an odometer, the high-precision IMU is used to collect the acceleration and angular velocity of the track measurement trolley, the odometer is used to collect the speed of the track measurement trolley, and the track shape data includes IMU data and odometer data; The track measurement vehicle moves along the track to collect track shape data and then sends it to the terminal; A plurality of said total stations synchronously track and observe the track measurement trolley, obtain the three-dimensional coordinate data of the track measurement trolley, and send it to said terminal; The terminal spatially stitches the three-dimensional coordinate data collected by multiple total stations to obtain stitched three-dimensional coordinate data, time synchronizes the IMU data with the stitched three-dimensional coordinate data, and fuses and smoothes the time-synchronized IMU-odometer data with the stitched three-dimensional coordinate data to obtain track geometry state data.

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