Shield tunnel side box culvert positioning control method based on 3D structured light

Abstract

The invention discloses a shield tunnel side box culvert positioning control method based on 3D structured light, and the method comprises the following steps: S1), determining the feature surfaces of an opening part and the inner arc surface of a duct piece based on the view field range of a 3D structured light sensor, and selecting a proper position for arranging the sensor; s2) scanning the inner cambered surfaces of the opening part and the duct piece to obtain 3D structured light data, and adopting a clustering segmentation method based on a normal vector to complete identification and segmentation of the feature surface of the opening part; s3) comparing the position information of the feature surface with the size of the side box culvert, and calculating the thickness of a gasket required below the side box culvert; and S4) the thickness of the gasket is transmitted to a side box culvert assembling vehicle control system, the gasket with the corresponding thickness is selected and placed at the preset connecting position of the side box culvert and the pipe piece, and the side box culvert is placed at the preset position. According to the shield tunnel side box culvert positioning control method based on the 3D structured light, a manual attempt method can be replaced to position the side box culvert, and the positioning precision of the side box culvert is remarkably improved.

Description

Technical Field

[0001] The present invention relates to a positioning control method for side box culverts in shield tunnels, and in particular to a positioning control method for side box culverts in shield tunnels based on 3D structured light. Background Technique

[0002] The shield tunneling method refers to a method of using a shield machine to advance in the ground, preventing the surrounding rock from collapsing into the tunnel by means of the shield shell and segment support, while excavating the soil body with a cutting device in front of the excavation face, discharging the slag, and assembling segments in the machine to form a lining and implementing post-grouting behind the lining, so as to construct a tunnel without disturbing the surrounding soil.

[0003] During the construction of large-diameter shield tunnels, in order to facilitate the transportation of segments, the middle part of the internal structure is often designed in the form of a box culvert in the internal structure design. At present, the positioning of side box culverts during the construction of shield tunnels relies on multiple attempts by workers, which has the disadvantages of low efficiency and poor accuracy. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a positioning control method for side box culverts in shield tunnels based on 3D structured light, which can replace the method of manual attempt to position the side box culvert and significantly improve the positioning accuracy of the side box culvert.

[0005] The technical solution adopted by the present invention to solve the above technical problem is to provide a positioning control method for side box culverts in shield tunnels based on 3D structured light, including the following steps: S1) Determine the characteristic surfaces of the socket piece and the inner arc surface of the segment based on the field of view of the 3D structured light sensor, and select a suitable position to arrange the sensor; S2) Scan the socket piece and the inner arc surface of the segment to obtain their 3D structured light data, and complete the recognition and segmentation of the characteristic surface of the socket piece by using the clustering segmentation method based on the normal vector; S3) Compare the position information of the characteristic surface with the size of the side box culvert to calculate the thickness of the gasket required under the side box culvert; S4) Transmit the gasket thickness to the control system of the side box culvert assembly vehicle, select the gasket with the corresponding thickness and place it at the preset connection between the side box culvert and the segment, and place the side box culvert at the preset position.

[0006] Further, the characteristic surfaces in the step S1 include: the inner arc surface of the segment lining, the concrete pouring surface, the side surface of the socket piece, and the lower bottom surface of the opening on the side surface of the socket piece.

[0007] Further, the step S2 includes: S21) calculating the normal vector of the point cloud according to the neighboring points of each point in the point cloud; S22) creating a vector cluster, including the point cloud and the feature normal vector, selecting any point in the point cloud, and using its normal vector as the feature normal vector; S23) traversing the point cloud, calculating the angle between the normal vector of the point and the feature normal vector of the existing vector cluster, if the angle is less than the angle threshold, it is classified into the vector cluster, if the angles are all greater than the angle threshold, a new vector cluster is established, and the normal vector of the current point is used as its feature normal vector; S24) traversing the vector clusters, discarding the vector clusters with a point cloud scale smaller than the point cloud scale threshold; S25) performing DB-scan clustering on the point cloud of each vector cluster to generate several position-vector clusters, discarding the position-vector clusters with a point cloud scale smaller than the point cloud scale threshold; S26) through the above steps, the obtained position-vector clusters are the segmentation of the feature surface.

[0008] Further, the step S3 includes: S31) iteratively fitting a plane to the point cloud of the side part of the opening piece and the bottom surface point cloud of the opening on the side of the opening piece using the RANSAC method according to the point cloud of the feature surface of the opening piece obtained in step S2, and calculating the plane equation; S32) extracting the vertical border line from the side point cloud of the opening on the side of the opening piece obtained in step S2; S33) calculating the normal vectors of the two planes according to the plane equations of the side of the opening piece and the bottom surface of the opening on the side of the opening piece in S31, respectively serving as the X-axis direction and the Y-axis direction, and determining the Z-axis direction by cross multiplication, so that the Y-axis direction coincides with the vertical border line of the opening on the side of the opening piece in S32, and the coordinate origin is at the intersection of the vertical border line of the opening on the side of the opening piece and the bottom surface of the opening on the side of the opening piece, to establish a Cartesian coordinate system; S34) obtaining the coordinates of the required gasket position points of the side box culvert according to the geometric relationship of the model and the Cartesian coordinate system in S33; S35) traversing the points in the inner arc surface point cloud of the segment, calculating the distances between the points near the coordinates of the points obtained in step S33, and taking their average value as the gasket thickness.

[0009] Further, the step S4 includes: S41) transmitting the calculated gasket thickness of the side box culvert to the control system of the side box culvert assembling vehicle; S42) using the side box culvert assembling vehicle to place the side box culvert at a position far from the target position, controlling the vertical interval ≤ 300 mm and the horizontal interval ≤ 200 mm; S43) reducing the oil cylinder pressure, slowly moving the side box culvert to near the target position, controlling the vertical interval ≤ 100 mm and the horizontal interval ≤ 100 mm; S44) setting the pump source protection pressure of the oil cylinder, slowly placing the side box culvert on the installed gasket, if the side box culvert contacts the gasket in advance and the pump source pressure rises to the protection pressure value, the action stops.

[0010] The present invention has the following beneficial effects compared with the prior art: The positioning control method for the side box culvert of the shield tunnel based on 3D structured light provided by the present invention adopts a 3D structured light sensor and a point cloud processing method, which can replace the manual attempt method to position the side box culvert, and significantly improve the positioning accuracy of the side box culvert. Description of the Drawings

[0011] Figure 1 It is a flowchart of the positioning control of the side box culvert of the shield tunnel based on 3D structured light of the present invention; Figure 2 It is a schematic diagram of identifying and segmenting the feature surface of the mating part by using the clustering segmentation method based on the normal vector of the present invention; Figure 3 It is a schematic diagram of the specific algorithm implementation of the positioning control method for the side box culvert of the shield tunnel of the present invention. Detailed Embodiments

[0012] The present invention will be further described below in conjunction with the drawings and embodiments.

[0013] Figure 1 It is a flowchart of the positioning control of the side box culvert of the shield tunnel based on 3D structured light of the present invention.

[0014] Please refer to Figure 1 , the positioning control method for the side box culvert of the shield tunnel based on 3D structured light provided by the present invention includes: S1. Determine the feature surfaces of the mating part and the inner arc surface of the segment based on the field of view of the 3D structured light sensor, and select a suitable position to deploy the sensor. The feature surfaces include: the inner arc surface of the segment lining, the concrete pouring surface, the side surface of the mating part, and the lower bottom surface of the opening on the side surface of the mating part. The field of view of the sensor needs to cover the feature surfaces.

[0015] S2. Scan the mating part and the inner arc surface of the segment to obtain their 3D structured light data, and use the clustering segmentation technology based on the normal vector to complete the identification and segmentation of the feature surface of the mating part. Please continue to refer to Figure 2 , the specific steps are as follows: S21) Calculate the normal vector of the point cloud according to the neighboring points of each point in the point cloud.

[0016] S22) Create a vector cluster, including: the point cloud and the feature normal vector, and select any point in the point cloud, and its normal vector is used as the feature normal vector.

[0017] S23) Traverse the point cloud, calculate the angle between the normal vector of the point and the feature normal vector of the existing vector cluster. If the angle is less than the angle threshold, it is classified into the vector cluster. If the angles are all greater than the angle threshold, a new vector cluster is established, and the normal vector of the current point is used as its feature normal vector.

[0018] S24) Traverse the vector clusters and discard the vector clusters with a point cloud scale smaller than the point cloud scale threshold.

[0019] S25) Perform DB-scan clustering on the point cloud of each vector cluster to generate several position-vector clusters, and discard the position-vector clusters with a point cloud scale smaller than the point cloud scale threshold.

[0020] S26) After the above steps, the obtained position-vector clusters are the segmentation of the feature surface.

[0021] S3. Compare the position information of the feature surface with the side box culvert dimensions to calculate the required gasket thickness of the side box culvert. The specific steps are as follows: S31) According to the feature point cloud obtained in step S2, use the RANSAC (Random Sample Consensus) method to iteratively fit the plane for the side surface of the orifice part and the bottom surface points of the opening on the side surface of the orifice part, and calculate the plane equation.

[0022] S32) Extract the vertical border lines from the side surface point cloud of the opening on the side surface of the orifice part obtained in step S2.

[0023] S33) According to the plane equations of the side surface of the orifice part and the bottom surface of the opening on the side surface of the orifice part in S31, calculate the normal vectors of the two planes, which are used as the X-axis direction and the Y-axis direction respectively, and determine the Z-axis direction by cross product, so that the Y-axis direction coincides with the vertical border line of the opening on the side surface of the orifice part in S32, and the coordinate origin is at the intersection of the vertical border line of the opening on the side surface of the orifice part and the bottom surface of the opening on the side surface of the orifice part, and establish a Cartesian coordinate system.

[0024] S34) According to the geometric relationship of the model and the Cartesian coordinate system in S33, obtain the coordinates of the required gasket position points of the side box culvert.

[0025] S35) Traverse the points in the inner arc point cloud of the segment near the coordinates of the points obtained in step S33, calculate the distances between the points, and take their average value as the gasket thickness.

[0026] S4. Transmit the gasket thickness to the control system of the side box culvert assembly vehicle, select the gasket with the corresponding thickness and place it at the preset connection position between the side box culvert and the segment, and place the side box culvert at the preset position. The specific steps are as follows: S41) Perform steps S1 to S3, calculate the gasket thickness of the side box culvert, and transmit it to the control system of the side box culvert assembly vehicle; S42) The side box culvert assembly vehicle places the side box culvert at a position far from the target position, and controls the vertical interval ≤ 300 mm and the horizontal interval ≤ 200 mm; S43) Reduce the oil cylinder pressure, slowly move the side box culvert to near the target position, and control the vertical interval ≤ 100 mm and the horizontal interval ≤ 100 mm; S44) Set the pump source protection pressure of the hydraulic cylinder, and slowly place the side box culvert at the installed gasket. If the side box culvert touches the gasket in advance and the pump source pressure rises to the protection pressure value, the operation stops.

[0027] Please continue to refer to Figure 3 , Figure 3 In [reference], 1 is the cross-section of the gasket on the inner arc surface of the segment, 2 is the cross-section of the gasket in the pouring layer, and 3 is the grouting cross-section; the vision system will first establish a Cartesian coordinate system at the opening on the side of the orifice part. Since the side box culvert and the orifice part are closely attached, that is, the sides completely coincide. Then when the Cartesian coordinate system is determined, the position and attitude of the side box culvert are also determined. The outer arc surface of the side box culvert is a cylindrical surface with R = 6800. Then, a cylindrical coordinate system is established with the cylindrical surface of the outer arc surface of the side box culvert. The direction perpendicular to the paper surface and inward is the Z direction, the radius pointing to the lower edge of the grouting area is the R direction, and the right-handed helix around the Z axis is θ direction. The angle between the straight line at the position of the lower gasket of the side box culvert and the polar axis is β .

[0028] Then the circular arc equation of the outer arc surface of the side box culvert is: ; The circular arc equation of the arc surface at the position of the upper required gasket is: ; The plane equation at the position of the lower required gasket is: ; There is a transformation matrix , c represents the Cartesian coordinate system, p represents the polar coordinate system, such that the point in the Cartesian coordinate system can be mutually transformed with the point in the polar coordinate system: Then, the points on the inner arc surface of the tunnel and the points in the concrete pouring layer in the Cartesian coordinate system segmented by the vision system can be transformed into the polar coordinate system, and their coordinates are: .

[0029] Calculation of the height of the upper gasket: Traverse the points on the inner arc surface of the gasket position of the segment ( i = 1 to m ), and the height of the gasket can be calculated by the average value of the distances from the points to the outer arc surface at the position of the upper gasket of the side box culvert: ; Among them is the height of the upper gasket.

[0030] Calculation of the height of the lower gasket: The height of the lower gasket is the same as that of the upper one, except that the plane equation is used to replace the arc surface: ; Among them is the height of the lower gasket.

[0031] In summary, the present invention uses a 3D structured light sensor and a point cloud processing method for the positioning control of the side box culvert in a shield tunnel, which can replace the manual attempt method to position the side box culvert and significantly improve the positioning accuracy of the side box culvert.

[0032] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be defined by the claims.

Claims

1. A shield tunnel side box culvert positioning control method based on 3D structured light, characterized in that: The steps include: S1) Determine the characteristic surfaces of the port member and the inner arc surface of the pipe segment based on the field of view of the 3D structured light sensor, and select a suitable position to deploy the sensor; S2) Scan the inner arc surface of the sub-assembly and the segment to obtain its 3D structured light data, and use the clustering segmentation method based on the normal vector to complete the recognition and segmentation of the characteristic surface of the sub-assembly; S3) Calculate the required gasket thickness under the side box culvert by comparing the position information of the characteristic surface with the size of the side box culvert; S4) The thickness of the gasket is transmitted to the control system of the side box culvert assembly vehicle, a gasket of corresponding thickness is selected and placed at the preset connection between the side box culvert and the pipe segment, and the side box culvert is placed at the preset position.

2. The shield tunnel side box culvert positioning control method based on 3D structured light according to claim 1, characterized in that: The characteristic surfaces in step S1 include: the inner arc surface of the segment lining, the concrete casting surface, the side surface of the port piece, and the lower bottom surface of the side opening of the port piece.

3. The shield tunnel side box culvert positioning control method based on 3D structured light according to claim 1, characterized in that: The step S2 comprises: S21) calculating a normal vector of the point cloud according to the neighborhood points of each point in the point cloud; S22) creating a vector cluster, including a point cloud and a characteristic normal vector, selecting any point in the point cloud and using its normal vector as the characteristic normal vector; S23) traversing the point cloud, calculating the angle between the normal vector of the point and the characteristic normal vector of the existing vector cluster, if the angle is less than the angle threshold, the point is included in the vector cluster, if the angles are all greater than the angle threshold, a new vector cluster is established, and the normal vector of the current point is used as its characteristic normal vector; S24) traversing the vector clusters, and discarding the vector clusters whose point cloud scale is smaller than the point cloud scale threshold; S25) performing DB-scan clustering on the point cloud of each vector cluster to generate a number of position-vector clusters, and discarding the position-vector clusters whose point cloud scale is smaller than the point cloud scale threshold; S26) After the above steps, the position-vector cluster obtained is the segmentation of the feature surface.

4. The shield tunnel side box culvert positioning control method based on 3D structured light according to claim 1, characterized in that: The step S3 comprises: S31) According to the point cloud of the characteristic surface of the mouth part obtained in step S2, the RANSAC method is used to iteratively fit the plane to the point cloud of the side surface of the mouth part and the bottom surface of the side opening of the mouth part, and the plane equation is calculated; S32) extracting the vertical border line of the side opening of the opening member according to the side point cloud obtained in step S2; S33) According to the plane equations of the side surface of the opening member and the lower bottom surface of the side surface of the opening member in S31, calculate the normal vectors of the two planes, use them as the X-axis direction and the Y-axis direction respectively, and determine the Z-axis direction by cross product, so that the Y-axis direction coincides with the vertical frame edge line of the side surface of the opening member in S32, and the coordinate origin is at the intersection of the vertical frame edge line of the side surface of the opening member and the lower bottom surface of the side surface of the opening member, and a Cartesian coordinate system is established; S34) obtaining coordinates of the gasket position points required for the side box culvert according to the geometric relationship of the model and the Cartesian coordinate system in S33; S35) Traversing the point cloud of the inner arc surface of the pipe segment, obtaining points near the coordinates of the point in step S33, calculating the distance between the points, and taking the average value as the gasket thickness.

5. The method for positioning and controlling the side box culvert of a shield tunnel based on 3D structured light according to claim 1, characterized in that: The step S4 comprises: S41) transmitting the calculated side box culvert gasket thickness to the side box culvert assembly vehicle control system; S42) Use a side box culvert assembly vehicle to place the side box culvert at a location far from the target location, and control the vertical spacing to be ≤300mm and the horizontal spacing to be ≤200mm; S43) reducing the oil cylinder pressure, slowly moving the side box culvert to the vicinity of the target position, controlling the vertical interval to be ≤100 mm and the horizontal interval to be ≤100 mm; S44) Set the pump source protection pressure of the oil cylinder, and slowly place the side box culvert onto the installed gasket. If the side box culvert contacts the gasket in advance, the pump source pressure rises to the protection pressure value, and the action stops.

Images