Construction lofting method and device based on unmanned aerial vehicle RTK

Abstract

The invention discloses a construction lofting method based on an unmanned aerial vehicle RTK, and the method comprises the following steps: obtaining an aerial image of a concrete-filled steel tube arch bridge construction region through a man-machine, and carrying out the preprocessing of the aerial image, so as to obtain a corresponding construction region mapping; aiming at the concrete-filled steel tube arch bridge in the construction area mapping, constructing an arch axis coordinate system under a corresponding preset camber, collecting an arch axis control point coordinate under the arch axis coordinate system and converting the arch axis control point coordinate into a geodetic coordinate system so as to obtain a hovering coordinate of the unmanned aerial vehicle; and controlling the unmanned aerial vehicle to carry out lofting acquisition through the hovering coordinates so as to obtain construction lofting data. The invention further provides a construction lofting device. According to the method provided by the invention, aiming at the construction lofting task of the large-span overwater concrete-filled steel tube arch bridge, the three-dimensional space coordinates can be obtained without or with less use of ground image control points in a complex terrain environment, and the arch axis construction lofting is realized.

Description

Technical Field

[0001] The invention belongs to the field of civil engineering surveying, and in particular relates to a construction layout method and device based on unmanned aerial vehicle RTK. Background Art

[0002] The accuracy and efficiency of the construction and layout of the arch axis of a large-span overwater steel tube concrete arch bridge directly affect the quality, cost and progress of the arch bridge construction, and are the key issues for the correct closure of the arch bridge. Existing bridge and tunnel modeling usually uses third-party modeling software to pre-generate a three-dimensional model of the road, bridge and tunnel, and reflects the construction progress through some annotations and chart information, but cannot intuitively display the three-dimensional model of the current construction status. Parametric modeling technology provides a way to automatically generate models, but the parametric model lacks association with construction progress data and cannot generate a construction stage model. The collision with the terrain is often manually edited through third-party plug-ins, and the relevant technology has a low degree of automation and low efficiency.

[0003] Patent document CN118686433A discloses a polar coordinate floor plane layout system and method based on a rotary-wing UAV. The system includes a rotary-wing UAV, a laser radar device, a laser coder, a remote control, a polar coordinate origin centering circle, a laser directional mirror and a vertical laser vertical alignment system. The laser radar device and the laser inkjet printer are both fixed on the rotary-wing UAV; the method includes step S1: hovering the rotary-wing UAV above the polar coordinate origin centering circle and centering it, step S2: establishing a layout instruction according to the coordinates to be laid out, the rotary-wing UAV flies to the coordinates to be laid out according to the layout instruction and hovers, the laser radar device informs the rotary-wing UAV of the real-time coordinates of the laser coder through the vertical laser vertical alignment system, the rotary-wing UAV corrects its orientation, and when the remote control obtains the confirmation instruction from the surveyor, controls the laser coder to code.

[0004] Patent document CN118208053A discloses a power tower stakeout system and method based on drone laser guidance. After obtaining the coordinates of the center pile, the system automatically calculates the coordinates of the tower leg piles and tower leg corner piles, controls the drone to fly to the specified position, calibrates the coordinate difference in real time, and then uses the drone laser to guide the layout of the stakeout points and conduct verification. Summary of the invention

[0005] The purpose of the present invention is to provide a construction layout method and device based on UAV RTK. The method is aimed at the construction layout task of a large-span overwater steel tube concrete arch bridge. It can obtain three-dimensional space coordinates in a complex terrain environment without or with less use of ground image control points to realize the construction layout of the arch axis.

[0006] In order to achieve the first object of the present invention, the following technical solution is provided: a construction lofting method based on UAV RTK, comprising the following steps:

[0007] Obtaining an aerial photo of the steel tube concrete arch bridge construction area through a drone, and preprocessing the aerial photo to obtain a corresponding construction area mapping;

[0008] For the steel tube concrete arch bridge in the construction area mapping, an arch axis coordinate system corresponding to the preset arch degree is constructed, and the coordinates of the arch axis control points in the arch axis coordinate system are collected and converted into the geodetic coordinate system to obtain the hovering coordinates of the UAV;

[0009] The drone is controlled by the hovering coordinates to perform layout collection to obtain construction layout data.

[0010] The present invention introduces RTK technology into UAV aerial survey to obtain the spatial position of the corresponding exposure point, thereby realizing the construction layout of the arch axis without or with less use of ground image control points.

[0011] Specifically, the UAV uses oblique photography to obtain aerial photographs of the construction area of ​​the steel tube concrete arch bridge.

[0012] Specifically, the specific process of the pretreatment is as follows:

[0013] The aerial photos are cut into multiple sizes, screened by quick puzzle-solving, and aerial triangulation is performed to obtain the final construction area mapping.

[0014] Specifically, the arch axis coordinate system takes the arch top of the steel tube concrete arch bridge as the origin, and takes the span direction and the sagittal height as the coordinate axes.

[0015] Specifically, the conversion formula of the hovering coordinates is as follows:

[0016] X i '=a ij X j

[0017] a ij = cos(α ij )

[0018] Where i = 1, 2, 3; j = 1, 2, (X1', X2', X3') represents the hovering coordinates in the geodetic coordinate system, (X1, X2) represents the coordinates of the arch axis control point in the arch axis coordinate system, α ij Indicates X in the geodetic coordinate system i 'Direction vector and X in the arch axis coordinate system j The angle between the direction vectors.

[0019] Specifically, during the layout and collection process, the current arch axis position is monitored after each arch axis control point is laid out. When the offset is greater than a threshold, the current arch axis position needs to be corrected.

[0020] Specifically, the process of the correction processing is as follows:

[0021] When the cumulative arch axis elevation error during construction exceeds the threshold, the error is adjusted by using the weld and phased linear adjustment method;

[0022] Based on the adjustment results, the weld width of each segment of the steel tube concrete arch bridge is increased and rotated along the axis direction to minimize the linear error and obtain the optimal adjustment value.

[0023] The remaining arch axis control points are adjusted based on the optimal adjustment value.

[0024] Specifically, the expression for minimizing the linear error is as follows:

[0025]

[0026] Where w is the weld width, α is the rotation angle, k wy They are the axis influence vectors corresponding to the weld width X2, They are the axis influence vectors corresponding to the rotation angle X2, y c is the current segment error, and (ni) represents the number of remaining segments.

[0027] In order to achieve the second purpose of the present invention, the following technical solution is provided: a construction layout device, used to implement the steps of the above-mentioned construction layout method based on UAV RTK.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The fixed solution accuracy of real-time differential data obtained based on RTK technology can reach the centimeter level, which is consistent with the allowable range of measurement errors of the arch rib lateral deviation and arch axis elevation; at the same time, the combination of drone aerial survey and RTK technology can obtain the spatial position of the exposure point in real time, so as to achieve the construction layout of the arch axis without or with less use of ground image control points, and avoid setting control points in the water that are easily affected by water flow, navigation, construction and other factors and have poor stability. Compared with traditional surveying and mapping operations, drone-based RTK has high adaptability to complex terrain. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A flowchart of the construction layout method based on UAV RTK provided in this embodiment;

[0031] Figure 2 A flowchart of construction area mapping provided for this embodiment;

[0032] Figure 3 A schematic diagram of converting the coordinates of the arch axis control points to the geodetic coordinate system provided in this embodiment;

[0033] Figure 4 A schematic diagram of the arch axis position monitoring and deviation correction process provided in this embodiment;

[0034] Figure 5 The UAV RTK layout device provided in this embodiment. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0036] like Figure 1 As shown, a construction layout method based on drone RTK provided in this embodiment includes the following steps:

[0037] Aerial images of the construction area of ​​the steel tube concrete arch bridge are obtained by using a drone, and the aerial images are preprocessed to obtain corresponding construction area mapping.

[0038] More specifically, if Figure 2 As shown in the figure, the mapping process of the construction area is as follows:

[0039] Step 1-1: Based on data collection and site investigation, complete the aerial survey plan design and quality inspection and determine the flight parameters.

[0040] Step 1-2: Complete the layout and measurement of ground image control points and perform image control point data preprocessing.

[0041] Steps 1-3: Conduct drone aerial survey and collect aerial survey data through oblique photography.

[0042] Steps 1-4: Pre-process the collected flight data and aerial survey image data, and conduct a preliminary check on the photo quality through quick puzzle to ensure high-quality photos.

[0043] Steps 1-5: Process the image data, perform aerial triangulation, and obtain the mapping results in the geodetic coordinate system.

[0044] For the steel tube concrete arch bridge in the construction area mapping, an arch axis coordinate system corresponding to the preset arch degree is constructed, and the coordinates of the arch axis control points in the arch axis coordinate system are collected and converted into the geodetic coordinate system to obtain the hovering coordinates of the UAV.

[0045] More specifically, if Figure 3 As shown, the process of obtaining the hovering coordinates is as follows:

[0046] Step 2-1, the origin of the geodetic coordinate system is O', and the three mutually perpendicular coordinate axes are x1', x2' and x3'; the local coordinate axis of the arch axis takes the arch top O as the origin, the span direction is the x1 axis, and the sagittal height direction is the x2 axis. The coordinates of point O in the geodetic coordinate system are (x o1 ',x o2 ',x o3 '), x i 'Axis and x j The angle between the axes is α ij (i=1,2,3,j=1,2).

[0047] Step 2-2, calculate the arch axis coordinates in the local coordinate system after setting the pre-arch degree, and set the arch axis control point.

[0048] Step 2-3: The vector of the coordinates of a point in the geodetic coordinate system is represented by X i ', the vector of the coordinate in the local coordinate system of the arch axis is expressed as X j (i=1,2,3;j=1,2), according to the coordinate transformation formula of the vector component, the transformation formula between the geodetic coordinate system and the local coordinate system of the arch axis is: i '=a ij X j , where a ij = cos(α ij ),Right now

[0049] The drone is controlled by the hovering coordinates to perform layout collection to obtain construction layout data.

[0050] Furthermore, the position is fine-tuned to the precise coordinates and hovered according to the RTK positioning data, and the laser launch device on the drone is turned on to complete the layout guidance flowchart using laser.

[0051] Step 3-1, set the layout hovering point: the x1' and x2' coordinates of one UAV are the same as the converted x1' and x2' coordinates of the layout point, and its laser emitting device makes the laser irradiate vertically; the x2' and x3' coordinates of another UAV are the same as the converted x2' and x3' coordinates of the layout point, and its laser emitting device makes the laser perpendicular to the x2'x3' plane and emits horizontally.

[0052] Step 3-2: Turn on the laser transmitter on the drone at the set hovering point and calibrate it.

[0053] Step 3-3: Fine-tune the position to precise coordinates based on RTK positioning data and hover, using laser for layout guidance.

[0054] like Figure 4 The figure shows the method of monitoring and correcting the position of the arch axis. The hollow circle in the figure represents the coordinates of the design control point of the i-th segment, the black circle represents the coordinates of the actual control point of the i-th segment, the gray circle represents the coordinates of the weld width correction control point of the k-th segment, and the red circle represents the coordinates of the final correction control point of the k-th segment, where k = i+1, i+2...n. After each arch axis control point is staked out, the current arch axis position is monitored. When the elevation offset is greater than ±L / 3000, correction is performed. The specific process is as follows:

[0055] Step 4-1: Monitor the current arch axis position. When the cumulative arch axis elevation error during construction exceeds ±L / 3000, use the weld and phased linear adjustment method to adjust the error.

[0056] Step 4-2: Increase the weld width of each segment along the axis direction and rotate it by a certain angle to minimize the linear error and obtain the optimal adjustment value:

[0057] Among them, the calculation expression of the effect of increasing the weld width on the line shape is: Δx w =wk wx ,Δy w =wk wy , where: Δx w with Δy w are the linear influences of the axes X1 and X2 corresponding to the weld width, w is the weld width, k wx With k wy They are the axis influence vectors corresponding to the weld widths X1 and X2 respectively;

[0058] The calculation expression of the effect of rotation angle on line shape is: Where: Δx α with Δy α are the influence of the X1 and X2 axes of the linear rotation angle, α is the rotation angle, and They are the axis influence vectors corresponding to the rotation angles X1 and X2 respectively;

[0059] When (ni) segments remain, the minimization of the control line elevation error is used as the objective function, and its expression is:

[0060]

[0061] Where: y c is the current segment error.

[0062] Step 4-3, calculate the coordinates of the arch axis control points of the remaining (ni) segments after correction. The coordinates of the kth control point before correction are (x 1k ,x 2k ), the correction amount is Δx k =Δx wk +Δx αk ,Δy k =Δy yk +Δy αk , after correction, (x 1k ±Δx k ,x 2k ±Δy k ).

[0063] Step 4-4: Complete the subsequent layout task based on the corrected control point coordinates.

[0064] This embodiment also provides a construction layout device, such as Figure 5 As shown, the steps for implementing the construction layout method based on UAV RTK mentioned in the above embodiment.

[0065] More specifically, it includes a drone, a ground operating station, a staking device and matching staking detection.

[0066] The UAV is equipped with RTK positioning and laser devices. The ground control station mainly performs flight control and measurement control of the UAV. The layout device is used to obtain the corresponding arch axis control points through the images collected by the UAV, and calibrate the current arch axis position through layout monitoring. If there is a deviation, the ground control station controls the UAV to re-collect and layout according to the calibration results.

[0067] In addition, the terms "upper", "lower", "inner", "outer", "front", "rear" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. Unless otherwise specifically stated, the relative steps, numerical expressions and values ​​of the components and steps described in these embodiments do not limit the scope of the present invention.

[0068] Of course, the above description is only a specific embodiment of the present invention and is not intended to limit the scope of implementation of the present invention. All equivalent changes or modifications made according to the structure, characteristics and principles described in the patent application scope of the present invention should be included in the patent application scope of the present invention.

[0069] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A construction layout method based on UAV RTK, characterized in that: The following steps are involved: Obtaining an aerial photo of the steel tube concrete arch bridge construction area through a drone, and preprocessing the aerial photo to obtain a corresponding construction area mapping; For the steel tube concrete arch bridge in the construction area mapping, an arch axis coordinate system corresponding to the preset arch degree is constructed, and the coordinates of the arch axis control points in the arch axis coordinate system are collected and converted into the geodetic coordinate system to obtain the hovering coordinates of the UAV; The drone is controlled by the hovering coordinates to perform layout collection to obtain construction layout data.

2. The construction layout method based on UAV RTK according to claim 1 is characterized in that: The UAV uses oblique photography to obtain aerial photographs of the steel tube concrete arch bridge construction area.

3. The construction layout method based on UAV RTK according to claim 1 is characterized in that: The specific process of the pretreatment is as follows: The aerial photos are cut into multiple sizes, screened by quick puzzle-solving, and aerial triangulation is performed to obtain the final construction area mapping.

4. The construction layout method based on UAV RTK according to claim 1, characterized in that: The arch axis coordinate system takes the arch top of the steel tube concrete arch bridge as the origin, and takes the span direction and the sagittal height as the coordinate axes.

5. The construction layout method based on UAV RTK according to claim 1, characterized in that: The conversion formula of the hovering coordinates is as follows: X i ’=a ij X j a ij =cos(α ij ) Where i = 1, 2, 3; j = 1, 2, (X1', X2', X3') represents the hovering coordinates in the geodetic coordinate system, (X1, X2) represents the coordinates of the arch axis control point in the arch axis coordinate system, α ij Indicates X in the geodetic coordinate system i 'Direction vector and X in the arch axis coordinate system j The angle between the direction vectors.

6. The construction layout method based on UAV RTK according to claim 1, characterized in that: During the layout and collection process, the current arch axis position is monitored after each arch axis control point is laid out. When the offset is greater than the threshold, the current arch axis position needs to be corrected.

7. The construction layout method based on UAV RTK according to claim 6 is characterized in that: The process of the correction process is as follows: When the cumulative arch axis elevation error during construction exceeds the threshold, the error is adjusted by using the weld and phased linear adjustment method; Based on the adjustment results, the weld width of each segment of the steel tube concrete arch bridge is increased and rotated along the axis direction to minimize the linear error and obtain the optimal adjustment value. The remaining arch axis control points are adjusted based on the optimal adjustment value.

8. The construction layout method based on UAV RTK according to claim 7 is characterized in that: The expression for minimizing the linear error is as follows: minf(w,α)=∑(wk wy +αk αy -y c / (n-i)) 2 Where w is the weld width, α is the rotation angle, k wy are the axis influence vectors corresponding to the weld width X2, k αy They are the axis influence vectors corresponding to the rotation angle X2, y c is the current segment error, and (ni) represents the number of remaining segments.

9. A construction layout device, characterized in that: The method is used to implement the steps of the construction layout method based on UAV RTK as described in any one of claims 1 to 9.

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