An electronic sanding method and device based on three-dimensional scanning and discrete element simulation

Abstract

The present invention relates to an electronic sand-laying method and device based on three-dimensional scanning and discrete element simulation, and the method comprises the following steps: three-dimensional scanning of the road surface to obtain three-dimensional road surface data; preprocessing the three-dimensional road surface data; using the discrete element simulation method to establish a road surface model and a cylinder of fine sand model according to the three-dimensional road surface data; using the established road surface model and fine sand model to spread the fine sand on the road surface model; judging whether the fine sand is spread flat, if it is spread flat, outputting the structural depth, if it is not spread flat, continuing to spread the fine sand. Compared with the traditional manual sand-laying method, the present invention can eliminate the influence of the operator's technical level and the like, and has high accuracy; compared with the existing road surface structural depth scanning technology, the output result of the present invention is intuitive, has a clear physical meaning, is suitable for the current road surface structural depth detection, and can effectively improve the detection accuracy.

Description

Technical Field

[0001] The invention relates to the technical field of road surface structure depth detection and road surface anti-skid performance evaluation, and in particular to an electronic sand spreading method and device based on three-dimensional scanning and discrete element simulation. Background Art

[0002] Pavement structural depth refers to the average depth of the open gaps on the uneven road surface of a certain area. It is one of the important indicators that reflects the roughness of the road surface and characterizes the anti-skid performance of the road surface, and is directly related to the driving safety of the road. Therefore, how to scientifically, accurately and vividly detect the pavement structural depth is of great significance. The "Highway Roadbed and Pavement Field Test Procedure" (JTG 3450-2019) provides three detection methods for how to detect the pavement structural depth: manual sand laying method, electric sand laying method and vehicle-mounted laser structural depth meter method.

[0003] The manual sand spreading method is based on the principle of volume displacement. A certain volume of standard sand is spread on the road surface and the construction depth is determined according to the size of the spreading area. The manual sand spreading method is simple in principle and easy to operate. It is a commonly used method in engineering, but it lacks actual operating standards, has low accuracy, is greatly affected by the operator's technical level, and is not suitable for testing in wet weather.

[0004] The principle of electric sand spreading is basically the same as that of manual sand spreading, but in operation, the electric sand spreading method spreads fine sand through automatic mechanical movement, and the pavement structure depth is obtained by comparing it with the spreading situation on the glass plate. The electric sand spreading method can avoid the shortcomings of inaccurate test results due to differences in human operation, but the electric sand spreading method is more complicated to operate and the level of mechanical standardization is not high, so it is not widely used in my country at present.

[0005] The detection principle of the vehicle-mounted laser structural depth meter is the laser ranging principle. It measures the surface of the road aggregate particles and the depth changes between the aggregate particles by emitting lasers, and calculates the road structural depth through a calculation model (my country uses the SMTD algorithm). This detection method has high test efficiency and good reproducibility, and is also suitable for wet weather. However, the algorithm used in this detection method is based on a statistical algorithm and has weak physical significance. Therefore, it is generally necessary to establish a relationship with the structural depth value of the sand paving method and convert it into the structural depth of the sand paving method.

[0006] Therefore, the existing pavement structure depth detection methods have defects. The traditional manual sand-laying method has low detection accuracy and is greatly affected by the environment. The electronic sand-laying method is complicated to operate and the level of mechanical standardization is not high. The algorithm output results of the existing pavement structure depth scanning technology are not intuitive and clear, which increases the difficulty of pavement structure depth detection. Therefore, it is necessary to propose a pavement structure depth detection solution that effectively solves the above problems. Summary of the invention

[0007] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide an electronic sand-laying method and device based on three-dimensional scanning and discrete element simulation, which can eliminate the influence of the operator's technical level, has high accuracy, and the output results are intuitive and have clear physical meaning. It is suitable for current pavement structure depth detection and can effectively improve the accuracy of detection.

[0008] The purpose of the present invention can be achieved by the following technical solutions:

[0009] According to a first aspect of the present invention, there is provided an electronic sanding method based on three-dimensional scanning and discrete element simulation, comprising the following steps:

[0010] S1. Scan the road surface in three dimensions to obtain three-dimensional road surface data, including x-coordinates, y-coordinates, z-coordinates of road surface points and scanned reflection intensity;

[0011] S2, preprocessing the three-dimensional road surface data, finding outliers and using linear interpolation processing, fitting the road surface plane position based on the three-dimensional road surface data to obtain a fitting plane, determining the inclination, and using the fitting plane to correct the inclination of the three-dimensional road surface data;

[0012] S3, using discrete element simulation method, establish a road surface model according to the three-dimensional road surface data, establish a cylinder of fine sand model with a total volume of V, and establish a constrained cylindrical surface L1;

[0013] S4, using the established pavement model and fine sand model, using a rotating plane L2 to spread the fine sand, using a translation plane L3 to assist in spreading, and spreading the fine sand on the pavement model;

[0014] S5. Determine whether the fine sand is flattened. If it is flattened, the diameter of the constrained cylindrical surface L1 is the diameter D of the flattened fine sand, and the output structural depth TD = V / (πD 2 / 4), if it is not flattened, the diameter of the constraining cylindrical surface L1 is enlarged and step S4 is repeated.

[0015] Further, the step of finding the outlier is as follows:

[0016] Find outliers based on reflection intensity: set the reflection intensity range, and road points with reflection intensity greater than or less than the reflection intensity range are outliers;

[0017] Find outliers based on z-coordinates: Set the z-coordinate value range, and road points with z-coordinate values ​​greater than or less than the z-coordinate value range are outliers.

[0018] Furthermore, the least square method is used to fit all road surface points to obtain a fitting plane, as follows:

[0019] Assume that the fitted plane equation is, and substitute the coordinates of all road points into it:

[0020] z1=ax1+by1+c

[0021] z2=ax2+by2+c

[0022] …

[0023] z n =ax n +by n +c

[0024] Represented as a matrix: That is to say Therefore, the parameters of the plane fitted by the least squares method are:

[0025]

[0026] Where n represents the number of road points.

[0027] Furthermore, the method of using the fitting plane to correct the slope of the three-dimensional road surface data is specifically as follows:

[0028] According to the fitted plane, for any point (x, y, z), the corresponding point on the fitted plane is (x, y, ax+by+c), and the center of the scanned area is (x c ,y c ,z c ), the point on the fitting plane corresponding to the center of the scanned area is (x c ,y c ,ax c +by c +c), then any road point after slope correction becomes: (x,y,z-(ax+by+c)+(ax c +by c +c)).

[0029] Further, the determination of whether the fine sand is spread out is specifically as follows:

[0030] If the height of the center of all fine sand is less than the road surface height h + the maximum diameter of the fine sand d max , it means it has been flattened.

[0031] Furthermore, the road surface height h is the maximum value of the z coordinate values ​​of all road surface points.

[0032] According to a second aspect of the present invention, there is provided an electronic sanding device based on three-dimensional scanning and discrete element simulation, comprising:

[0033] A three-dimensional scanning module is used to perform three-dimensional scanning on the road surface to obtain three-dimensional road surface data, including the x-coordinate, y-coordinate, z-coordinate of the road surface point and the scanned reflection intensity;

[0034] The data preprocessing module is used to preprocess the three-dimensional road surface data, find out the abnormal values ​​and use linear interpolation processing, fit the road surface plane position based on the three-dimensional road surface data to obtain a fitting plane, determine the inclination, and use the fitting plane to correct the inclination of the three-dimensional road surface data;

[0035] A discrete element simulation module is used to establish a road surface model according to the three-dimensional road surface data by using a discrete element simulation method, establish a cylinder of fine sand model with a total volume of V, establish a constrained cylindrical surface L1, use the established road surface model and fine sand model, use a rotating plane L2 to spread the fine sand, and use a translation plane L3 to assist in spreading the fine sand, so as to spread the fine sand on the road surface model;

[0036] The control module is used to determine whether the fine sand is flattened. If it is flattened, the diameter of the constrained cylindrical surface L1 is the diameter D of the flattened fine sand, and the output structural depth TD = V / (πD 2 / 4), if it is not flattened, the diameter of the constrained cylindrical surface L1 is enlarged and the paving operation is repeated in the discrete element simulation module.

[0037] Further, the step of finding the outlier is as follows:

[0038] Find outliers based on reflection intensity: set the reflection intensity range, and road points with reflection intensity greater than or less than the reflection intensity range are outliers;

[0039] Find outliers based on z-coordinates: Set the z-coordinate value range, and road points with z-coordinate values ​​greater than or less than the z-coordinate value range are outliers.

[0040] Furthermore, the least square method is used to fit all road surface points to obtain a fitting plane, as follows:

[0041] Assume that the fitted plane equation is, and substitute the coordinates of all road points into it:

[0042] z1=ax1+by1+c

[0043] z2=ax2+by2+c

[0044] …

[0045] z n =ax n +by n +c

[0046] Represented as a matrix: That is to say Therefore, the parameters of the plane fitted by the least squares method are:

[0047]

[0048] Where n represents the number of road points.

[0049] Further, the determination of whether the fine sand is spread out is specifically as follows:

[0050] If the height of the center of all fine sand is less than the road surface height h + the maximum diameter of the fine sand d max , it means it has been flattened.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] It can effectively solve the problems of low detection accuracy and great environmental influence of traditional manual sand spreading methods. It can also solve the problems of unintuitive and unclear meaning of the algorithm output results of existing pavement structure depth scanning technology, so as to intuitively and accurately detect the pavement structure depth, reflect the roughness of the pavement, and characterize the anti-skid performance of the pavement. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is the algorithm flow chart of the present invention;

[0054] Figure 2 is the frequency distribution histogram of reflection intensity and z-coordinate of road surface points;

[0055] Figure 3 This is a flowchart of three-dimensional data preprocessing;

[0056] Figure 4 This is a modeling example diagram;

[0057] Figure 5 This is a schematic diagram for spreading fine sand;

[0058] Figure 6 This is a schematic diagram of the flattening results. DETAILED DESCRIPTION

[0059] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given. Obviously, the described embodiment is only an embodiment of a part of the present invention, not all embodiments, and the protection scope of the present invention is not limited to the following embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

[0060] "One embodiment" or "embodiment" referred to herein refers to a specific feature, structure or characteristic that may be included in at least one implementation of the present invention. In the description of the present invention, it should be understood that the terms "first", "second" and "third" in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units that are inherent to these processes, methods, products or devices.

[0061] This specification provides method operation steps such as embodiments or flowcharts, but more or fewer operation steps may be included based on conventional or non-creative labor. The order of steps listed in the embodiments is only one way of executing the order of many steps and does not represent the only execution order. When the actual system or server product is executed, it can be executed in sequence or in parallel (for example, in a parallel processor or multi-threaded processing environment) according to the method shown in the embodiments or the drawings, or the execution order of steps without timing restrictions can be adjusted.

[0062] Embodiment 1:

[0063] An electronic sanding method based on 3D scanning and discrete element simulation, the specific process is as follows Figure 1 This method mainly uses three-dimensional scanning, linear interpolation processing, slope correction, three-dimensional modeling, discrete element simulation and other methods to achieve accurate detection of road surface structure depth, which mainly includes the following steps:

[0064] S1. Scan the road surface in three dimensions to obtain three-dimensional road surface data, including x-coordinates, y-coordinates, z-coordinates of road surface points and scanned reflection intensity;

[0065] 3D scanning refers to the technology of digitally collecting the geometric shape and surface features of objects with the help of sound, light, machinery, electricity and computer technology. 3D scanning technology can collect information such as the spatial shape of an object with high precision and fully automatic; and the road surface structural depth refers to the average depth of the open gaps in the uneven road surface of a certain area. It is one of the important indicators reflecting the roughness of the road surface and characterizing the anti-skid performance of the road surface. The texture information of the road surface can be obtained through 3D scanning technology, and then the texture information is used to analyze and calculate the structural depth of the road surface, reflecting the roughness of the road surface and the anti-skid performance.

[0066] When using 3D scanning equipment to scan the road surface, according to the "Highway Roadbed and Pavement Field Test Procedure" (JTG3450-2019), it is recommended that the scanning area be no less than 30cm×30cm. Of course, the specific scanning area size can also be adjusted according to actual conditions.

[0067] S2, preprocessing the three-dimensional road surface data, finding outliers and using linear interpolation processing, fitting the road surface plane position based on the three-dimensional road surface data to obtain a fitting plane, determining the inclination, and using the fitting plane to correct the inclination of the three-dimensional road surface data;

[0068] Find outliers and use linear interpolation to process them as follows:

[0069] Find outliers based on reflection intensity: set the reflection intensity range, and road points with reflection intensity greater than or less than the reflection intensity range are outliers. Use linear interpolation to replace outliers. Specifically, the frequency distribution histogram of the reflection intensity of all road points can be counted and drawn, such as Figure 2 As shown in the left figure, the appropriate reflection intensity range is determined according to the frequency distribution histogram to find out the abnormal values ​​caused by excessive or insufficient reflection intensity. Any data with reflection intensity outside this range is considered to be abnormal data, and the abnormal values ​​are replaced by interpolation processing. Of course, the reflection intensity range can also be preset based on experience and actual engineering conditions to find out the abnormal values.

[0070] Find outliers based on z coordinates: set the z coordinate value range, and road points with z coordinate values ​​greater than or less than the z coordinate value range are outliers; specifically, the frequency distribution histogram of the z coordinates can be counted and plotted, such as Figure 2 As shown in the figure on the right, the appropriate z-coordinate range is determined based on the frequency distribution histogram to find out the z-coordinate values ​​that are too large or too small and obviously abnormal. Any data with z-coordinates outside this range is considered to be abnormal data, and interpolation processing is used to replace the abnormal values. Of course, the z-coordinate value range can also be preset based on experience and actual engineering conditions to find abnormal values.

[0071] After finding the outliers and using linear interpolation, the processed data needs to be corrected for slope. The reason for the need for slope correction is that it is impossible to ensure that the 3D scanning to obtain the road surface texture information is a completely flat scan, and it is also impossible to ensure that the road surface itself is horizontal. Therefore, it is necessary to correct the slope of the scanned data. Specifically:

[0072] (1) Use the least squares method to fit all points to obtain the fitting plane: Assume that the equation of the fitting plane is z = ax + by + c, and substitute the coordinates of all points to obtain:

[0073] z1=ax1+by1+c

[0074] z2=ax2+by2+c

[0075] …

[0076] z n =ax n +by n +c

[0077] Represented as a matrix: That is to say Therefore, the parameters of the plane fitted by the least squares method are:

[0078]

[0079] Where n represents the number of road points. The fitted plane is Figure 3 As shown in the middle picture.

[0080] (2) According to the fitted plane, for any point (x, y, z), the corresponding point on the fitted plane is (x, y, ax+by+c), and the center of the scanned area is (x c ,y c ,z c ), the point on the fitting plane corresponding to the center is (x c ,y c ,ax c +by c +c), then after the slope correction for any point becomes: (x,y,z-(ax+by+c)+(ax c +by c +c)), the inclination correction is completed.

[0081] The data preprocessing process is as follows Figure 3 As shown, the left figure is the model built using unprocessed data, in which there are a large number of outliers and a certain tilt. The right figure is the preprocessed data, in which the data outliers are replaced by interpolation and the tilt is corrected.

[0082] In this embodiment, a road surface texture laser scanner is used to scan the road surface, and histogram statistics are performed based on the scanned data. The range of the reflection intensity intensity is set to (100, 1500), and the range of the road surface point z coordinate is set to (-5, 5). Data outside this range is regarded as abnormal data and is processed by linear interpolation. The road surface plane equation obtained by fitting with the least squares method is: , and the slope of the road surface points is corrected based on the fitted road surface plane equation.

[0083] S3, using discrete element simulation method, establish a road surface model according to the three-dimensional road surface data, establish a cylinder of fine sand model with a total volume of V, and establish a constrained cylindrical surface L1;

[0084] Discrete element method is a numerical calculation method, which is mainly used to calculate how a large number of particles move under given conditions. Through the discrete element simulation method, we can simulate how fine sand moves during the paving process and what the results of the movement are.

[0085] First, a pavement model was established based on the preprocessed data. Combined with the provisions of the "Highway Roadbed and Pavement Field Test Regulations" (JTG3450-2019), a cylinder with a total volume of 25cm 3 , a fine sand model with a particle size distribution of (0.15-0.30) mm; establish a constrained cylindrical surface L1 with a bottom circle diameter of D to ensure that the fine sand can be spread into a circle and prevent the fine sand from flying and causing excessive errors, such as Figure 4 Of course, the fine sand volume and particle size distribution can be adjusted as needed according to the actual road surface conditions.

[0086] The bottom circle diameter of the constrained cylindrical surface L1 is D=15 cm. The initial value D is 15 cm because a large number of actual experiments have shown that the average diameter of flattened fine sand is between 15 and 25 cm.

[0087] S4, using the established pavement model and fine sand model, using a rotating plane L2 to spread the fine sand, using a translation plane L3 to assist in spreading, and spreading the fine sand on the pavement model;

[0088] The established model is used to set the linear contact model, the gravity acceleration is 9.8N / kg, and the density of fine sand is 2700g / mm 3 , using a rotating plane L2 to spread fine sand, such as Figure 5 As shown in the left figure, the function of the rotating plane L2 is to drive the fine sand to move through the rotation of the plane, thereby achieving the effect of paving; and the fine sand may not be spread flat by relying solely on the rotating plane L2, so a translation plane L3 is used to assist in paving, as shown in Figure 5 As shown in the middle figure, the function of the translation plane L3 is to assist the paving of the rotating plane L2 to prevent some fine sand from being unable to be flattened under the action of the rotating plane L2, thereby ensuring uniform paving of the fine sand.

[0089] S5. Determine whether the fine sand is flattened. If it is flattened, the diameter of the constrained cylindrical surface L1 is the diameter D of the flattened fine sand, and the output structural depth TD = V / (πD 2 / 4), if it is not flattened, the diameter of the constraining cylindrical surface L1 is enlarged and step S4 is repeated.

[0090] After one paving is completed, the diameter of the circle formed by the fine sand is the diameter D of the constrained cylindrical surface L1. However, since the fine sand may not have been flattened at this time, the diameter D is not the final diameter of the flattened circle. First, it is necessary to determine whether the fine sand is flattened.

[0091] The z coordinate of the center of the fine sand is used to determine whether the fine sand is flat. If the height z of the center of all fine sand is less than the road surface height h + the maximum diameter d of the fine sand max , it means it has been flattened. At this time, the diameter D of the constrained cylindrical surface is the diameter D of the flattened fine sand. Output the structural depth If the height z of the center of the fine sand i Not less than the road surface height h + the maximum diameter of fine sand d max , it means that it is not flattened. At this time, the diameter of the constrained cylindrical surface is enlarged. It is recommended to increase it by 1mm each time and repeat the paving process until it is flattened. Among them, the road surface height h is the maximum value of the z coordinate value of all road surface points. Of course, in other implementation methods, the z coordinate value of the road surface point with the largest proportion can also be selected through statistical analysis, and so on.

[0092] The average result is as follows Figure 6 In this embodiment, the diameter of the constrained cylindrical surface obtained after the fine sand is finally flattened is 221 mm, so the construction depth is:

[0093]

[0094] The present invention also provides an electronic sand-laying device based on three-dimensional scanning and discrete element simulation, comprising:

[0095] A three-dimensional scanning module is used to perform three-dimensional scanning on the road surface to obtain three-dimensional road surface data, including the x-coordinate, y-coordinate, z-coordinate of the road surface point and the scanned reflection intensity;

[0096] The data preprocessing module is used to preprocess the three-dimensional road surface data, find out the abnormal values ​​and use linear interpolation processing, fit the road surface plane position based on the three-dimensional road surface data to obtain a fitting plane, determine the inclination, and use the fitting plane to correct the inclination of the three-dimensional road surface data;

[0097] A discrete element simulation module is used to establish a road surface model according to the three-dimensional road surface data by using a discrete element simulation method, establish a cylinder of fine sand model with a total volume of V, establish a constrained cylindrical surface L1, use the established road surface model and fine sand model, use a rotating plane L2 to spread the fine sand, and use a translation plane L3 to assist in spreading the fine sand, so as to spread the fine sand on the road surface model;

[0098] The control module is used to determine whether the fine sand is flattened. If it is flattened, the diameter of the constrained cylindrical surface L1 is the diameter D of the flattened fine sand, and the output structural depth TD = V / (πD 2 / 4), if it is not flattened, the diameter of the constrained cylindrical surface L1 is enlarged and the paving operation is repeated in the discrete element simulation module.

[0099] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the described module can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0100] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. An electronic sanding method based on three-dimensional scanning and discrete element simulation, characterized in that: The following steps are involved: S1. Scan the road surface in three dimensions to obtain three-dimensional road surface data, including x-coordinates, y-coordinates, z-coordinates of road surface points and scanned reflection intensity; S2, preprocessing the three-dimensional road surface data, finding outliers and using linear interpolation processing, fitting the road surface plane position based on the three-dimensional road surface data to obtain a fitting plane, determining the inclination, and using the fitting plane to correct the inclination of the three-dimensional road surface data; S3, using discrete element simulation method, establish a road surface model according to the three-dimensional road surface data, establish a cylinder of fine sand model with a total volume of V, and establish a constrained cylindrical surface L1; S4, using the established pavement model and fine sand model, using a rotating plane L2 to spread the fine sand, using a translation plane L3 to assist in spreading, and spreading the fine sand on the pavement model; S5. Determine whether the fine sand is flattened. If it is flattened, the diameter of the constrained cylindrical surface L1 is the diameter D of the flattened fine sand, and the output structural depth TD = V / (πD 2 / 4), if it is not flattened, the diameter of the constraining cylindrical surface L1 is enlarged and step S4 is repeated; The specific method of judging whether the fine sand is spread out is as follows: If the height of all the fine sand centers is less than the road surface height + the maximum diameter of the fine sand, it means that it has been leveled; The road surface height is the maximum value of the z coordinate values ​​of all road surface points.

2. The electronic sanding method based on three-dimensional scanning and discrete element simulation according to claim 1 is characterized in that: The specific method of finding the outlier is as follows: Find outliers based on reflection intensity: set the reflection intensity range, and road surface points with reflection intensity greater than or less than the reflection intensity range are outliers; Find outliers based on z-coordinates: Set the z-coordinate value range, and road points with z-coordinate values ​​greater than or less than the z-coordinate value range are outliers.

3. The electronic sanding method based on three-dimensional scanning and discrete element simulation according to claim 1 is characterized in that: The least squares method is used to fit all road surface points to obtain the fitting plane, as follows: Assume the fitted plane equation is z=ax+by+c, and substitute the coordinates of all road points to get: z1=ax1+by1+c z2=ax2+by2+c …… z n =ax n +by n +c Represented as a matrix: That is to say Therefore, the parameters of the plane fitted by the least squares method are: Where n represents the number of road points.

4. The electronic sanding method based on three-dimensional scanning and discrete element simulation according to claim 3 is characterized in that: The method of using the fitting plane to correct the slope of the three-dimensional road surface data is specifically as follows: According to the fitted plane z=ax+by+c, for any point (x, y, z), the corresponding point on the fitted plane is (x, y, ax+by+c), and the center of the scanned area is (x c ,y c ,Z c ), the point on the fitting plane corresponding to the center of the scanned area is (x c ,y c ,ax c +by c +c), then any road point after slope correction becomes: (x,y,z-(ax+by+c)+(ax c +by c +c)).

5. An electronic sanding device based on three-dimensional scanning and discrete element simulation, characterized in that: include: A three-dimensional scanning module is used to perform three-dimensional scanning on the road surface to obtain three-dimensional road surface data, including the x-coordinate, y-coordinate, and z-coordinate of the road surface point and the reflection intensity of the scan; The data preprocessing module is used to preprocess the three-dimensional road surface data, find out the abnormal values ​​and use linear interpolation processing, fit the road surface plane position based on the three-dimensional road surface data to obtain a fitting plane, determine the inclination, and use the fitting plane to correct the inclination of the three-dimensional road surface data; A discrete element simulation module is used to establish a road surface model according to the three-dimensional road surface data by using a discrete element simulation method, establish a cylinder of fine sand model with a total volume of V, establish a constrained cylindrical surface L1, use the established road surface model and fine sand model, use a rotating plane L2 to spread the fine sand, and use a translation plane L3 to assist in spreading the fine sand, so as to spread the fine sand on the road surface model; The control module is used to determine whether the fine sand is flattened. If it is flattened, the diameter of the constrained cylindrical surface L1 is the diameter D of the flattened fine sand, and the output structural depth TD = V / (πD 2 / 4), if it is not flattened, the diameter of the constrained cylindrical surface L1 is enlarged and the paving operation is repeated in the discrete element simulation module; The specific method of judging whether the fine sand is spread out is as follows: If the height of the center of all fine sand is less than the road surface height + the maximum diameter of the fine sand, it means that it has been leveled.

6. The electronic sand-laying device based on three-dimensional scanning and discrete element simulation according to claim 5 is characterized in that: The specific method of finding the outlier is as follows: Find outliers based on reflection intensity: set the reflection intensity range, and road surface points with reflection intensity greater than or less than the reflection intensity range are outliers; Find outliers based on z-coordinates: Set the z-coordinate value range, and road points with z-coordinate values ​​greater than or less than the z-coordinate value range are outliers.

7. The electronic sand-laying device based on three-dimensional scanning and discrete element simulation according to claim 5 is characterized in that: The least squares method is used to fit all road surface points to obtain the fitting plane, as follows: Assume the fitted plane equation is z=ax+by+c, and substitute the coordinates of all road points to get: z1=ax1+by1+c z2=ax2+by2+c …… z n =ax n +by n +c Represented as a matrix: That is to say Therefore, the parameters of the plane fitted by the least squares method are: Where n represents the number of road points.

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