A method for measuring the posture of a spatially complex thin-walled carbon steel process pipeline

Abstract

This invention discloses a method for measuring the attitude of a spatially complex thin-walled carbon steel pipeline. The method includes: using a robotic arm carrying a laser measuring instrument to measure the thin-walled carbon steel process pipeline along a parallel line; inputting the measurement data into a computer for data extraction; fitting the extracted data using an ellipse fitting method; performing spatial straight-line fitting on the center coordinates of the cross-sections of each ellipse fitting point for pipeline i using the least squares method to obtain the direction vector of the ideal axis of pipeline i; and obtaining the spatial vector angle α between all adjacent pipelines. i According to the angle α between the spatial vectors i The value determines the angle of the bend; the included angle α is selected. i The method involves obtaining the lengths and bevel angles of each pipeline and bend. This method enables precise docking of thin-walled spatial pipelines, selecting the correct docking bends, thereby improving welding efficiency, ensuring welding quality, enhancing manufacturing efficiency, and reducing welding deformation.

Description

Technical Field

[0001] This invention mainly relates to the field of pipeline structure welding, and specifically to a method for measuring the attitude of spatially complex thin-walled carbon steel process pipelines. Background Technology

[0002] Thin-walled pipelines are a crucial part of pipeline welding, typically used in the welding of spatial pipeline sections. In the welding of thin-walled pipelines in space, measuring the spatial orientation of the pipeline and the angle of bends is critical. Inaccurate measurements of these aspects can lead to misalignment and welding deformation after welding, significantly impacting the accuracy of the connection and compromising precision. Currently, manual measurement is still required for thin-walled pipelines in space, heavily relying on worker experience. This can easily introduce errors during connection, necessitating recutting, re-welding, or recalibration, ultimately degrading the performance of the thin-walled pipeline. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for measuring the attitude of spatially complex thin-walled carbon steel process pipelines. By measuring and solving the docking model of the spatial thin-walled pipeline, the correct selection of elbows for the spatial thin-walled pipeline is achieved, thus realizing the precise docking of the spatial thin-walled pipeline, reducing welding deformation, improving welding efficiency, and ensuring operational safety.

[0004] The technical solution to achieve the objective of this invention is as follows:

[0005] The present invention provides a method for measuring the attitude of a spatially complex thin-walled carbon steel process pipeline, comprising the following steps:

[0006] Step 1: Clamp the complex thin-walled carbon steel process pipeline to be inspected onto the worktable, and process the pipeline into sections, labeled l1, l2…l n Establish a reference space rectangular coordinate system o-xyz on the workbench, with the vertical direction of the workbench as the y-axis, the horizontal rightward direction as the x-axis, and the horizontal forward direction as the z-axis;

[0007] Step 2: Select point o1 of the spatial rectangular coordinate system o-xyz as the zero point coordinate on the workbench and fix the robot arm. Use the robot arm to carry the laser measuring instrument and measure the thin-walled carbon steel process pipeline along the parallel line of the pipeline.

[0008] Step 3: After measuring the thin-walled carbon steel process pipeline, output the measured pipeline coordinate values ​​to the computer and extract the coordinates (x, y, y) of each measurement point of the i-th pipeline. i1 ,yi1 ,z i1 ), (x i2 ,y i2 ,z i2 )…(x in ,y in ,z in );

[0009] Step 4, pass (x) i1 ,y i1 ,z i1 ), (x i2 ,y i2 ,z i2 ), (x i3 ,y i3 ,z i3 ) Create a cutting plane x'o'y' for the pipeline using three measurement points. Project each measurement point of the extracted i-th pipeline onto the x'o'y' plane to obtain the planar coordinates of the measurement points. i1 ',y i1 '), (x i2 ',y i2 ')…(x in ',y in Using an ellipse as the fitting constraint, the coordinate values ​​of each measurement point obtained in step three are fitted.

[0010] Step 5: Convert the plane coordinates (x, y) of pipeline i from Step 4. i1 ',y i1 '), (x i2 ',y i2 ')…(x in ',y in Substitute these values ​​into the ellipse formula in step four to solve for the sum of squares Q of the data for pipeline i;

[0011] Step 6: According to the principle of extreme values, differentiate the parameters {A, B, C, D, E, F} of the sum of squares of data Q for pipeline i and set the differentiated values ​​to zero to obtain the optimal solutions for each parameter. Then, solve for the center coordinates of the cross sections of pipeline i when fitting each ellipse according to the standard form of the ellipse.

[0012] Step 7: Using the least squares method, perform spatial straight-line fitting on the center coordinates of the cross-sections of pipe i when fitting each ellipse to obtain the direction vector P of the ideal axis of pipe i. i ;

[0013] Step 8: Install pipelines separately. i+1 l i+2 For the cutting surfaces x'o'z' and y'o'z', repeat steps three through seven to obtain the direction vectors P1, P2…P of the ideal axes of all pipelines. n ;

[0014] Step 9: Based on the direction vector P of adjacent pipelines i (a i b i c i ),P i+1 (a i+1 b i+1 c i+1 Find the spatial vector angle α between all adjacent pipelines. i ;

[0015] Step 10: Based on the angle α between the spatial vectors i The value determines the angle of the bend; the included angle α is selected. i For the bend, place the center point of the selected bend's corner on the direction vector P. i ,P i+1 With P i ,P i+1 The center point of the common perpendicular vector m or the direction vector P i ,P i+1 The intersection of the extended lines;

[0016] Step 11: Using the center point of the bend as the center, adjust the deflection angle θ. i When the extension of the center line on both sides of the elbow intersects with pipeline P i ,P i+1 When the center line or its extension intersects, stop adjusting the deflection angle θ. i Extract the overall centerline obtained by the intersection of the pipeline centerlines;

[0017] Step 12: Based on the overall centerline obtained in Step 11, obtain the three-dimensional model of the pipeline and the three-dimensional model of the elbow using the design radius R0 of the pipeline as a constraint.

[0018] Step 13: Using the intersection point of the center lines of the 3D model of the pipeline and the elbow as the dividing point, divide the 3D model to obtain the length and oblique angle of each pipeline and elbow.

[0019] The beneficial effects of this invention are: this method enables precise docking of thin-walled spatial pipelines, selects the correct docking elbow, thereby improving welding efficiency, ensuring the welding quality of thin-walled spatial pipelines, improving the manufacturing efficiency of thin-walled pipelines, and reducing welding deformation. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the process for measuring the attitude of a spatially complex thin-walled carbon steel pipeline according to the present invention;

[0021] Figure 2This is a schematic diagram of a spatially complex thin-walled carbon steel process pipeline attitude measurement method according to the present invention;

[0022] Figure 3 This is a schematic diagram of the cutting plane x'o'y' of the present invention;

[0023] Figure 4 This is a schematic diagram of the measurement data fitting for pipeline li of the present invention;

[0024] Figure 5 This is a schematic diagram of the measurement data fitting for pipeline li+1 of the present invention;

[0025] Figure 6 This is a schematic diagram illustrating the principle of spatial pipeline bend arrangement in this invention. Detailed Implementation

[0026] The present invention will be further described below with reference to specific embodiments.

[0027] The present invention provides a method for measuring the attitude of a spatially complex thin-walled carbon steel pipeline, comprising the following steps:

[0028] Step 1: Clamp the complex thin-walled carbon steel process pipeline to be inspected onto the worktable, and process the pipeline into sections, labeled l1, l2…l n Establish a reference space rectangular coordinate system o-xyz on the workbench, with the vertical direction of the workbench as the y-axis, the horizontal rightward direction as the x-axis, and the horizontal forward direction as the z-axis;

[0029] Step 2: Select point o1 of the spatial rectangular coordinate system o-xyz as the zero point coordinate on the workbench and fix the robot arm. Use the robot arm to carry the laser measuring instrument and measure the thin-walled carbon steel process pipeline along the parallel line of the pipeline.

[0030] Step 3: After measuring the thin-walled carbon steel process pipeline, output the measured pipeline coordinate values ​​to the computer and extract the coordinates (x, y, y) of each measurement point of the i-th pipeline. i1 ,y i1 ,z i1 ), (x i2 ,y i2 ,z i2 )…(x in ,y in ,z in );

[0031] Step 4, pass (x) i1 ,y i1 ,z i1 ), (x i2 ,y i2 ,z i2 ), (x i3 ,yi3 ,z i3 ) Create a cutting plane x'o'y' for the pipeline using three measurement points. Project each measurement point of the extracted i-th pipeline onto the x'o'y' plane to obtain the planar coordinates of the measurement points. i1 ',y i1 '), (x i2 ',y i2 ')…(x in ',y in Using an ellipse as the fitting constraint, the coordinate values ​​of each measurement point obtained in step three are fitted. The parametric equation of the ellipse can be expressed as:

[0032] F(x, y) = Ax 2 +Bxy+Cy 2 +Dx+Ey+F

[0033] In the formula: {A, B, C, D, E, F} are the parameter values ​​to be determined for the ellipse; (x, y) are the elliptical coordinates in the x'o'y' plane.

[0034] Step 5: Convert the plane coordinates (x, y) of pipeline i from Step 4. i1 ',y i1 '), (x i2 ',y i2 ')…(x in ',y in Substituting the values ​​into the ellipse formula in step four, we can solve for the sum of squares of the data for pipeline i, Q. The calculation formula is as follows:

[0035]

[0036] In the formula: Q is the sum of squares of data for pipeline i, n is the number of data collected, and i is the pipeline number.

[0037] Step 6: According to the principle of extreme values, differentiate the parameters {A, B, C, D, E, F} of the sum of squares of data Q for pipeline i and set the differentiated values ​​to zero to obtain the optimal solutions for each parameter. Then, solve the cross-sectional center coordinates of each ellipse fitting section of pipeline i according to the standard form of the ellipse.

[0038]

[0039] In the formula: a and b are the values ​​of the major and minor axes of the ellipse.

[0040] Step 7: Using the least squares method, perform spatial straight-line fitting on the center coordinates of the cross-sections of pipe i when fitting each ellipse to obtain the direction vector of the ideal axis of pipe i. The specific steps are as follows:

[0041] Step 1: Let the spatial line l i The equation is:

[0042]

[0043] In the formula: {G, M, N} are spatial lines l i Parameter values; (x i y i , z i (spatial straight line l) i Spatial measurement point coordinates; (x0, y0, z0) spatial line l i The initial spatial coordinates are set to (1,1,1).

[0044] The second step is to obtain the spatial line l using the least squares method. i Parametric equations, formulas as follows:

[0045]

[0046] In the formula: (x i y i , z i ) is a straight line in space l i The coordinates of the i-th measurement point; n is the number of measurement points; {G, M, N} is the spatial line l. i The parameter value.

[0047] The third step is to differentiate the parameters {G, M, N} using the principle of extrema, and then set the differentiated values ​​to zero to obtain the values ​​of the parameters {G, M, N}, thus obtaining the spatial linear equation l of pipe i. i Direction vector P i .

[0048] Step 8: Install pipelines separately. i+1 l i+2 For the cutting surfaces x'o'z' and y'o'z', repeat steps three through seven to obtain the direction vectors P1, P2…P of the ideal axes of all pipelines. n ;

[0049] Step 9: Based on the direction vector P of adjacent pipelines i (a i b i c i ),P i+1 (a i+1 b i+1 c i+1 Find the spatial vector angle α between all adjacent pipelines. i The calculation formula is as follows:

[0050]

[0051] In the formula: α iThe angle between adjacent vectors; (a i b i c i (a) is the direction vector of pipeline i; i+1 b i+1 c i+1 ) is the direction vector of pipeline i+1.

[0052] Step 10: Based on the angle α between the spatial vectors i The value determines the angle of the bend; the included angle α is selected. i For the bend, place the center point of the selected bend's corner on the direction vector P. i ,P i+1 With P i ,P i+1 The center point of the common perpendicular vector m or the direction vector P i ,P i+1 The intersection of the extended lines;

[0053] Step 11: Using the center point of the bend as the center, adjust the deflection angle θ. i When the extension of the center line on both sides of the elbow intersects with pipeline P i ,P i+1 When the center line or its extension intersects, stop adjusting the deflection angle θ. i Extract the overall centerline obtained by the intersection of the pipeline centerlines;

[0054] Step 12: Based on the overall centerline obtained in Step 11, obtain the three-dimensional model of the pipeline and the three-dimensional model of the elbow using the design radius R0 of the pipeline as a constraint.

[0055] Step 13: Using the intersection point of the center lines of the 3D model of the pipeline and the elbow as the dividing point, divide the 3D model to obtain the length and oblique angle of each pipeline and elbow.

Claims

1. A method for measuring the attitude of a spatially complex thin-walled carbon steel process pipeline, characterized in that... Includes the following steps: Step 1: Clamp the complex thin-walled carbon steel process pipeline to be inspected onto the worktable, and process the pipeline into sections, labeled l1, l2…l n Establish a reference space rectangular coordinate system o-xyz on the workbench, with the vertical direction of the workbench as the y-axis, the horizontal rightward direction as the x-axis, and the horizontal forward direction as the z-axis; Step 2: Select point o1 of the spatial rectangular coordinate system o-xyz as the zero point coordinate on the workbench and fix the robot arm. Use the robot arm to carry the laser measuring instrument and measure the thin-walled carbon steel process pipeline along the parallel line of the pipeline. Step 3: After measuring the thin-walled carbon steel process pipeline, output the measured pipeline coordinate values ​​to the computer and extract the coordinates (x, y, y) of each measurement point of the i-th pipeline. i1 ,y i1 ,z i1 ), (x i2 ,y i2 ,z i2 )...(x in ,y in ,z in ); Step 4, pass (x) i1 ,y i1 ,z i1 ), (x i2 ,y i2 ,z i2 ), (x i3 ,y i3 ,z i3 ) Create a cutting plane x'o'y' for the pipeline using three measurement points. Project each measurement point of the extracted i-th pipeline onto the x'o'y' plane to obtain the planar coordinates of the measurement points. i1 ',y i1 '), (x i2 ',y i2 ')…(x in ',y in Using an ellipse as the fitting constraint, the coordinate values ​​of each measurement point obtained in step three are fitted. Step 5: Convert the plane coordinates (x, y) of pipeline i from Step 4. i1 ',y i1 '), (x i2 ',y i2 ')…(x in ',y in Substitute these values ​​into the ellipse formula in step four to solve for the sum of squares Q of the data for pipeline i; The parametric equation of the ellipse can be expressed as: ， In the formula: {A, B, C, D, E, F} are the parameter values ​​to be determined for the ellipse; (x, y) are the elliptical coordinates in the x'o'y' plane; The sum of squares of the data for pipeline i, Q, is calculated using the following formula: ， In the formula: Q is the sum of squares of data for pipeline i, n is the number of data collected, and i is the pipeline number; Step 6: According to the principle of extreme values, differentiate the parameters {A, B, C, D, E, F} of the sum of squares of data Q for pipeline i and set the differentiated values ​​to zero to obtain the optimal solutions for each parameter. Then, solve for the center coordinates of the cross sections of pipeline i when fitting each ellipse according to the standard form of the ellipse. Step 7: Using the least squares method, perform spatial straight-line fitting on the center coordinates of the cross-sections of pipe i when fitting each ellipse to obtain the direction vector P of the ideal axis of pipe i. i ; Step 8: Install pipelines separately. i+1 l i+2 Determine the cutting surfaces x'o'z' and y'o'z', and repeat steps three through seven to obtain the direction vectors P1, P2…P of the ideal axes of all pipelines. n ; Step 9: Based on the direction vector P of adjacent pipelines i ( , , ), P i+1 ( , , Find the spatial vector angle α between all adjacent pipelines. i ; Step 10: Based on the angle α between the spatial vectors i The value determines the angle of the bend; the included angle α is selected. i For the bend, place the center point of the selected bend's corner on the direction vector P. i ,P i+1 With P i ,P i+1 The center point of the common perpendicular vector m or the direction vector P i ,P i+1 The intersection of the extended lines; Step 11: Using the center point of the bend as the center, adjust the deflection angle θ. i When the extension of the center line on both sides of the elbow intersects with pipeline P i ,P i+1 When the center line or its extension intersects, stop adjusting the deflection angle θ. i Extract the overall centerline obtained by the intersection of the pipeline centerlines; Step 12: Based on the overall centerline obtained in Step 11, obtain the three-dimensional model of the pipeline and the three-dimensional model of the elbow using the design radius R0 of the pipeline as a constraint. Step 13: Using the intersection point of the center lines of the 3D model of the pipeline and the elbow as the dividing point, divide the 3D model to obtain the length and oblique angle of each pipeline and elbow.

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