A measurement accuracy evaluation method and system for pipeline online detection equipment

Abstract

The present invention provides a method and system for evaluating the measurement accuracy of pipeline online detection equipment, which belongs to the field of equipment calibration technology, and includes: obtaining characteristic parameters of a three-dimensional optical measuring instrument in the pipeline online detection equipment to be evaluated; determining the measurement size range of the three-dimensional optical measuring instrument's measurement space according to the characteristic parameters, and determining the test pieces whose spatial diagonal sizes are within the measurement size range among multiple test pieces to be selected as target test pieces; wherein the target test pieces are continuous pipe-shaped pieces; obtaining a first data set measured by the pipeline online detection equipment to be evaluated and a second data set measured by a three-dimensional metrology device; and evaluating the measurement accuracy of the pipeline online detection equipment to be evaluated according to the first data set and the second data set. The method can accurately evaluate the measurement accuracy of the pipeline online detection equipment whose measurement object is a pipeline.

Description

Technical Field

[0001] The invention belongs to the technical field of equipment calibration, and in particular relates to a measurement accuracy evaluation method and system for pipeline online detection equipment. Background Art

[0002] In the field of modern high-end equipment manufacturing, especially in automobile engines, aerospace engines, hydraulic actuation and other systems, there are a large number of industrial pipelines. These industrial pipelines have different shapes and diameters, various curvatures, free changes in three-dimensional space, and complex arrangements. With the increasing demand for pipeline morphology and defect measurement in the manufacturing field, as well as the increasing demand for correction of pipe bending machines, dedicated pipeline online detection equipment has emerged in the industry. At the same time, higher requirements are also placed on the detection accuracy of pipeline online detection equipment, so it is necessary to evaluate the detection accuracy to reflect the detection accuracy of pipeline online detection equipment.

[0003] At present, the measurement accuracy of pipeline online detection equipment is mainly measured by a ball-bar standard set, that is, the ball diameter, ball center distance and other parameters of the ball-bar standard are measured by the pipeline online equipment, and the measurement accuracy of the pipeline online equipment is evaluated based on the measurement results. However, when the measurement subject of the pipeline online detection equipment is a pipeline, the parameters obtained by the above method are disconnected from the relevant parameters of the pipeline (for example, the distance of the intersection of the central axis, the angle, etc.), and therefore, the measurement accuracy of the pipeline online detection equipment cannot be accurately evaluated.

[0004] Therefore, there is an urgent need for an evaluation method suitable for measuring pipelines to evaluate the measurement accuracy of pipeline online detection equipment. Summary of the invention

[0005] In order to solve the problem in the prior art that when the measurement object is a pipeline, the measurement accuracy of a pipeline online detection device cannot be accurately evaluated, the present invention provides a measurement accuracy evaluation method for a pipeline online detection device.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A method for evaluating the measurement accuracy of a pipeline online detection device, comprising:

[0008] Obtain characteristic parameters of a three-dimensional optical measuring instrument in an online detection device for the pipeline to be evaluated;

[0009] Determine the measurement size range of the measurement space of the three-dimensional optical measuring instrument according to the characteristic parameters, and determine the test piece whose spatial diagonal size is within the measurement size range among the multiple test pieces to be selected as the target test piece; wherein the target test piece is a continuous tubular piece;

[0010] Acquire a first data set measured by the pipeline online detection device to be evaluated and a second data set measured by a three-dimensional metrology device; wherein the first data set is a set of geometric characteristic dimension values ​​of the spatial center axis of the target test piece measured by the pipeline online detection device to be evaluated, and the second data set is a set of geometric characteristic dimension values ​​of the spatial center axis of the target test piece measured by the three-dimensional metrology device;

[0011] The measurement accuracy of the pipeline online detection device to be evaluated is evaluated according to the first data set and the second data set.

[0012] Preferably, the characteristic parameters include the surface length D, surface width W and depth of field H of the three-dimensional optical measuring instrument, wherein the surface length D is greater than the surface width W, and the spatial diagonal size L of the target test piece is less than or equal to And it is greater than or equal to 2 / 3 of the minimum value of the width W and the depth of field H, and satisfies the formula:

[0013]

[0014] Among them, x is the length of the minimum envelope rectangle of the projection of the target test piece on the xy plane of the rectangular coordinate system, y is the width of the minimum envelope rectangle of the projection of the target test piece on the xy plane of the rectangular coordinate system, and z is the height of the projection of the target test piece on the xz plane.

[0015] Preferably, it also includes:

[0016] When it is detected that there is a preset measurement space size, the length X, width Y and height Z of the preset measurement space are obtained;

[0017] The target test piece is determined according to the length X, width Y and height Z of the preset measurement space; wherein the spatial diagonal size L of the target test piece is less than or equal to and is greater than or equal to 2 / 3 of the minimum value among the length X, the width Y, and the height Z.

[0018] Preferably, the target test piece includes n straight cylindrical segments and n-1 curved cylindrical segments, where 4≤n≤6; when the spatial diagonal size is less than 500mm, the number of straight cylindrical segments of the target test piece is 4; when the spatial diagonal size is greater than or equal to 500mm and less than or equal to 700mm, the number of straight cylindrical segments of the target test piece is 5; when the spatial diagonal size is greater than 700mm, the number of straight cylindrical segments of the target test piece is 6.

[0019] Preferably, the starting end and the ending end of the target test piece are planes, and the geometric characteristic dimension values ​​include a length characteristic dimension, a first angle characteristic dimension and a second angle characteristic dimension; wherein the length characteristic dimension is the distance between two adjacent intersection points, and the intersection points include the intersection point of the central axis of two adjacent straight cylindrical segments, the intersection point of the central axis of the straight cylindrical segment and the starting end plane of the target test piece, and the intersection point of the central axis of the straight cylindrical segment and the ending end plane of the target test piece; the first angle characteristic dimension is the angle between the central axes of two adjacent straight cylindrical segments; and the second angle characteristic dimension is the angle between the planes formed by three adjacent intersection points.

[0020] Preferably, obtaining a second data set measured by a three-dimensional metrology device includes:

[0021] Performing cleaning and temperature balancing pretreatment on the target test piece;

[0022] An initial workpiece coordinate system is established, and a three-dimensional coordinate measuring machine is used to perform contact measurement on each linear cylindrical segment of the target test piece one by one to obtain a spatial point data set containing three-dimensional coordinates;

[0023] The coordinates of the intersection points between the central axis of the target test piece and the central axis are calculated according to the spatial point data set to obtain the set of geometric feature size values.

[0024] Preferably, establishing an initial workpiece coordinate system includes:

[0025] The starting end plane is measured to generate a first plane PLA1, and the ending end plane of the target test piece is measured to generate a second plane PLA2, wherein the number of measurement points on each plane is greater than 8;

[0026] The linear cylindrical segment where the starting end plane is located is measured to generate a cylinder MCYL1, and the linear cylindrical segment where the ending end plane is located is measured to generate a cylinder MCYLn;

[0027] Constructing the three-dimensional coordinates of the theoretical point according to the three-dimensional coordinates of the first intersection point, and constructing the theoretical plane according to the central axis of the cylinder MCYL1 and the three-dimensional coordinates of the theoretical point; wherein the first intersection point is the intersection point of the central axis of the cylinder MCYL1 and the first plane PLA1;

[0028] The Y axis is established through the central axis of the cylinder MCYL1, the Z axis is established through the theoretical plane, the coordinate origin is established through the coordinates of the first intersection point, and the initial workpiece coordinate system is established.

[0029] Preferably, a three-dimensional coordinate measuring machine is used to perform contact measurement on each linear cylindrical segment of the target test piece one by one to obtain a spatial point data set of three-dimensional coordinates, including:

[0030] Each linear cylindrical segment of the target test piece is automatically measured by a measurement program to generate a cylinder MCYLi, where 1≤i≤n;

[0031] Among them, on each straight cylindrical segment, the measuring points are distributed in at least 4 layers along the length direction of the cylinder, with at least 8 measuring points in each layer, and each layer of measuring points should cover at least 180° of the cylindrical surface in the radial direction of the cylinder.

[0032] Preferably, calculating the intersection point between the central axis and the central axis of the target test piece according to the spatial point data set to obtain the set of geometric feature dimension values ​​includes:

[0033] Calculate the intersection point D0 according to the first plane PLA1 and the central axis of the cylinder MCYL1, and calculate the intersection point Dn according to the second plane PLA2 and the central axis of the cylinder MCYLn;

[0034] Calculating direction parameters and coordinate parameters of the central axis of the target test piece;

[0035] Calculate the coordinates of the intersection point between the central axes of two adjacent straight cylindrical segments according to the direction parameter and the coordinate parameter;

[0036] The formula for calculating the direction parameter is:

[0037]

[0038] Among them, (u i , v i , w i ) is the direction of the central axis of the cylinder MCYLi, (u i+1 , v i+1 , w i+1 ) is the direction of the median axis of the cylinder MCYLi+1;

[0039] The formula for calculating the coordinate parameters is:

[0040]

[0041] Among them, (x i ,y i , z i ) is the coordinate of the center of mass of the central axis of the cylinder MCYLi, (x i+1 ,y i+1 , z i+1 ) are the coordinates of the centroid of the median axis of the cylinder MCYLi+1;

[0042] The formula for calculating the coordinates of the intersection points between the central axes is:

[0043]

[0044] The length characteristic dimension is obtained by calculating the distance between two adjacent intersection points through the coordinates of the intersection points of each central axis from D0 to Dn, and the first angle characteristic dimension is obtained by calculating the angle between the central axes of two adjacent straight cylindrical segments through the central axis direction of the cylinder MCYLi and the coordinates of the center of mass point; the second angle characteristic dimension is obtained by the angle between the planes formed by the three adjacent intersection points from D0 to Dn.

[0045] The present invention also provides a measurement accuracy evaluation system for pipeline online detection equipment, comprising:

[0046] A first acquisition module is used to acquire characteristic parameters of a three-dimensional optical measuring instrument in an online detection device for a pipeline to be evaluated;

[0047] A determination module is used to determine the measurement size range of the measurement space of the three-dimensional optical measuring instrument according to the characteristic parameters, and determine the test piece whose space diagonal size is within the measurement size range among the multiple test pieces to be selected as the target test piece; wherein the target test piece is a continuous tubular piece;

[0048] A second acquisition module is used to acquire a first data set measured by the online detection device for the pipeline to be evaluated and a second data set measured by a three-dimensional metrology device; wherein the first data set is a set of geometric characteristic dimension values ​​of the spatial center axis of the target test piece measured by the online detection device for the pipeline to be evaluated, and the second data set is a set of geometric characteristic dimension values ​​of the spatial center axis of the target test piece measured by the three-dimensional metrology device;

[0049] A processing module is used to evaluate the measurement accuracy of the pipeline online detection equipment to be evaluated based on the first data set and the second data set.

[0050] The present invention also provides a computer device, comprising a memory, a processor and a computer program stored in the memory, wherein the processor executes the computer program to implement any one of the steps in the measurement accuracy evaluation method for pipeline online detection equipment.

[0051] The present invention also provides a computer-readable storage medium, on which a computer program is stored, characterized in that when the computer program is loaded by a processor, it can execute any step of the measurement accuracy evaluation method of the pipeline online detection equipment.

[0052] The measurement accuracy evaluation method of the pipeline online detection equipment provided by the present invention has the following beneficial effects:

[0053] According to the characteristic parameters of the three-dimensional optical measuring instrument, a target test piece that meets the measurement size range of the measurement space is determined from multiple test pieces, which can ensure that the three-dimensional optical measuring instrument in the pipeline online detection equipment can measure the relevant parameters of the target test piece to the greatest extent. Since the target test piece is a pipe-shaped piece, the pipeline-related parameters can be obtained, and then the measurement accuracy of the pipeline online equipment can be accurately evaluated based on the pipeline-related parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the embodiment of the present invention and its design scheme, the following briefly introduces the drawings required for this embodiment. The drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0055] Figure 1 A schematic flow chart of a method for evaluating the measurement accuracy of a pipeline online detection device provided in an embodiment of the present application;

[0056] Figure 2 A schematic flow chart of another method for evaluating the measurement accuracy of an online pipeline detection device provided in an embodiment of the present application;

[0057] Figure 3 A schematic diagram of the structure of a test piece provided in an embodiment of the present application;

[0058] Figure 4 A schematic diagram of the structure of a measurement accuracy evaluation system for pipeline online detection equipment provided in an embodiment of the present application. DETAILED DESCRIPTION

[0059] In order to enable those skilled in the art to better understand the technical solution of the present invention and implement it, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the scope of protection of the present invention.

[0060] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the technical solutions of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0061] In addition, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance. In the description of the present invention, it should be noted that, unless otherwise clearly specified or limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. In the description of the present invention, unless otherwise specified, "plurality" means two or more, which will not be described in detail here.

[0062] Example 1

[0063] Figure 1 A schematic flowchart of a method for evaluating the measurement accuracy of a pipeline online detection device provided in an embodiment of the present application. The executor of the method may be a module / unit in the device having a computing or processing function.

[0064] Exemplarily, the method is performed as follows:

[0065] S110, obtaining characteristic parameters of a three-dimensional optical measuring instrument in an online detection device for the pipeline to be evaluated.

[0066] The pipeline online detection equipment to be evaluated may be a pipeline online detection equipment that needs to be evaluated for measurement accuracy, including a three-dimensional optical measuring instrument.

[0067] The characteristic parameters include the surface length D, the surface width W and the depth of field H of the three-dimensional optical measuring instrument, wherein the surface length D is greater than the surface width W.

[0068] S120, determining a measurement size range of a measurement space of the three-dimensional optical measuring instrument according to the characteristic parameters, and determining a test piece whose space diagonal size is within the measurement size range among the multiple test pieces to be selected as a target test piece.

[0069] The test piece to be selected and the target test piece are both free-bending pipe pieces and continuous pipe pieces, and include a straight cylindrical segment and a curved cylindrical segment.

[0070] Optionally, the target test piece includes n straight cylindrical segments and n-1 curved cylindrical segments, where 4≤n≤6.

[0071] In a possible implementation, the implementation process of S120 may be: determining the measurement size range of the measurement space of the three-dimensional optical measuring instrument according to the surface length D, the surface width W and the depth of field value H; and determining the test piece whose space diagonal size is within the measurement size range as the target test piece.

[0072] Among them, the spatial diagonal size L of the target test piece is less than or equal to And it is greater than or equal to 2 / 3 of the minimum value between the field width W and the depth of field value H.

[0073] Among them, the spatial diagonal L size of the target test piece should also meet the following conditions:

[0074]

[0075] Wherein, x is the length of the minimum enveloping rectangle of the projection of the target test piece on the xy plane of the rectangular coordinate system, y is the width of the minimum enveloping rectangle of the projection of the target test piece on the xy plane of the rectangular coordinate system, and z is the height of the projection of the target test piece on the xz plane.

[0076] Exemplarily, D is defined as the length of the three-dimensional optical measuring instrument of the online detection equipment of the pipeline to be evaluated, W is the width of the surface, and D>W, H is the depth of field, then the spatial diagonal size L of the target test piece should meet the following conditions:

[0077]

[0078] Among them, MIN(·) means finding the minimum value.

[0079] Define an ideal rectangular coordinate system. The length of the minimum enveloping rectangle of the projection of the target test piece on the xy plane of the coordinate system is x, the width is y, and the height of the projection of the target test piece on the xz plane is z. Then the calculation method of the spatial diagonal size L of the target test piece should meet the following conditions:

[0080]

[0081] A possible implementation method is that if the size of the measurement space is customized in advance, the following steps can also be performed: when a preset measurement space size is detected, the length X, width Y and height Z of the preset measurement space are obtained; and the spatial diagonal size L of the target test piece is determined according to the length X, width Y and height Z of the preset measurement space.

[0082] Among them, the spatial diagonal size L of the target test piece should meet the following conditions:

[0083]

[0084] Optionally, after the value of the spatial diagonal L is determined, the number of straight cylindrical segments in the target test piece can be determined according to the spatial diagonal L. Exemplarily, the implementation process of the above S120 can be: when the spatial diagonal dimension L is less than 500mm, the number of straight cylindrical segments is determined to be 4; when the spatial diagonal dimension L is less than or equal to 700mm and greater than or equal to 500mm, the number of straight cylindrical segments is determined to be 5; when the spatial diagonal dimension L is greater than 500mm, the number of straight cylindrical segments is determined to be 6.

[0085] For example, the first preset value is defined as 500 mm, and the second preset value is defined as 700 mm. When selecting the test piece, the number of its straight cylindrical segments should meet the following conditions:

[0086] When L<500mm, the number of straight cylindrical segments of the test piece is 4; when 500mm≤L≤700mm, the number of straight cylindrical segments of the test piece is 5; when L>700mm, the number of straight cylindrical segments of the test piece is 6.

[0087] S130, obtaining a first data set measured by an online detection device for the pipeline to be evaluated and a second data set measured by a three-dimensional metrology device.

[0088] The first data set is a set of geometric characteristic dimension values ​​of the spatial center axis of the target test piece measured by the online detection device for the pipeline to be evaluated, and the second data set is a set of geometric characteristic dimension values ​​of the spatial center axis of the target test piece measured by the three-dimensional metrology device. It should be understood that the three-dimensional metrology device is a standard measurement device.

[0089] Furthermore, the geometric characteristic dimension value includes a length characteristic dimension, a first angle characteristic dimension and a second angle characteristic dimension.

[0090] Among them, the length characteristic dimension is the distance between two adjacent intersections, and the intersections include the intersection of the middle axes of two adjacent straight cylindrical segments, the intersection of the middle axis of the straight cylindrical segment and the starting end plane of the target test piece, and the intersection of the middle axis of the straight cylindrical segment and the ending end plane of the target test piece. It can be understood that the intersection includes the intersection of the middle axis of the first straight cylindrical segment from left to right and the starting end plane, the intersection of the middle axes of two adjacent straight cylindrical segments, and the intersection of the middle axis of the last straight cylindrical segment and the ending end plane.

[0091] The first angle characteristic dimension is the angle between the central axes of two adjacent straight cylindrical segments; the second angle characteristic dimension is the angle between the planes formed by three adjacent intersection points.

[0092] Specifically, the definition of the geometric characteristic dimensions of the axis in space includes:

[0093] The straight cylindrical segments of the target test piece are denoted as MCYL1, MCYL2, ..., MCYLn, the intersection points between the fitted central axes of two adjacent straight cylindrical segments are D1, D2, ...Dn, and the intersection points between the fitted central axis of the straight cylindrical segment and the first and tail end surfaces of the target test piece are D0 and Dn+1, respectively.

[0094] The length characteristic dimension of the target test piece's spatial mid-axis geometric characteristic dimension is defined as the distance L between two adjacent intersection points. i , that is, the distance between D1 and D0 is L1, the distance between D2 and D1 is L2, ..., the distance between Dn+1 and Dn is L n .

[0095] The first angular characteristic dimension of the spatial central axis geometric characteristic dimension of the target test piece includes the angle α between the central axes of two adjacent straight cylindrical segments. i , that is, the angle α1 between MCYL1 and MCYL2, the angle α2 between MCYL2 and MCYL3, ..., the angle α between MCYLn-1 and MCYLn n-1 .

[0096] The second angular characteristic dimension of the target test piece's spatial mid-axis geometric characteristic dimension includes the angle β between the planes formed by three adjacent intersection points. j , that is, the angle β1 between plane 1 composed of D0, D1 and D2 and plane 2 composed of D1, D2 and D3, the angle β2 between plane 2 and plane 3 composed of D2, D3 and D4, ..., the angle β between plane n-2 and plane n-1 n-2 .

[0097] In one possible implementation, the process of obtaining the second data set measured by the three-dimensional metrology equipment can be: cleaning and temperature balancing the target test piece; establishing an initial workpiece coordinate system, using a three-dimensional coordinate measuring machine to perform contact measurement on each linear cylindrical segment of the target test piece one by one to obtain a spatial point data set of three-dimensional coordinates; calculating the central axis and intersection of the target test piece based on the spatial point data set to obtain a set of geometric feature dimension values.

[0098] Optionally, the pretreatment process may include: cleaning impurities on the surface of the target test piece; and performing temperature balancing on the target test piece for a preset time.

[0099] Exemplarily, the surface of the target test piece is cleaned to remove residual material powder, dust, and grease on the surface; the target test piece is placed on a workbench in a metrology room and temperature equilibrated for at least 4 hours; the target test piece is mounted on a workbench of a high-precision three-dimensional coordinate measuring machine, and deformation caused by clamping is avoided as much as possible.

[0100] Optionally, the target test piece is a rigid body, and the starting end and the ending end are planes, and the process of establishing the workpiece coordinate system can be: measuring the starting end plane of the target test piece to generate a first plane PLA1, and measuring the ending end plane of the target test piece to generate a second plane PLA2; measuring the straight cylindrical segment where the starting end plane is located to generate cylinder MCYL1, and measuring the straight cylindrical segment where the ending end plane is located to generate a second cylinder MCYLn; constructing the three-dimensional coordinates of the theoretical point according to the three-dimensional coordinates of the first intersection, and constructing the theoretical plane according to the center axis of the cylinder MCYL1 and the three-dimensional coordinates of the theoretical point; wherein the first intersection is the intersection of the center axis of the cylinder MCYL1 and the first plane PLA1; establishing the Y axis through the center axis of the cylinder MCYL1, establishing the Z axis through the theoretical plane, establishing the coordinate origin through the coordinates of the first intersection, and establishing the initial workpiece coordinate system.

[0101] Specifically, the starting end plane of the target test piece is measured to generate plane PLA1, and the ending end plane of the target test piece is measured to generate plane PLA2. The number of measurement points on each plane should be greater than 8.

[0102] The linear cylindrical segment where the starting end plane is located is measured to generate cylinder MCYL1, and the linear cylindrical segment where the ending end plane is located is measured to generate cylinder MCYLn. The intersection point of the calculated axis of MCYL1 and plane PLA1 is recorded as MD0, and the intersection point of the calculated axis of MCYLn and plane PLA2 is recorded as MDn.

[0103] Let the three-dimensional coordinates of MD0 be (x0, y0, z0), the three-dimensional coordinates of the constructed theoretical point MD0' be (x0+10, y0, z0), and the theoretical plane MPLA1 be constructed using the central axis of MCYL1 and MD0'.

[0104] Use the axis of MCYL1 to locate the +Y axis, use MPLA1 to locate the +Z axis, use the coordinates of the MD0 point to locate the positive coordinate origin, and establish the initial workpiece coordinate system.

[0105] In a possible implementation, the above process of using a three-dimensional coordinate measuring machine to perform contact measurement on each linear cylindrical segment of the target test piece one by one to obtain a spatial point data set of three-dimensional coordinates can be: each linear cylindrical segment of the target test piece is measured through a measurement program to automatically measure and generate a cylinder MCYLi, where 1≤i≤n.

[0106] The measuring points on each straight cylindrical segment are distributed in at least 4 layers along the length direction of the cylinder, each layer has at least 8 measuring points, and each layer of measuring points covers at least 180° of the cylindrical surface in the radial direction of the straight cylinder.

[0107] Specifically, a measurement program is written to automatically measure the linear cylindrical segment where the starting end plane of the test piece is located to generate cylinder MCYL1. All subsequent linear cylindrical segments are automatically measured to generate cylinders MCYL2, MCYL3, ..., MCYLn.

[0108] On each straight cylindrical segment, the measuring points are distributed in at least 4 layers along the length direction of the cylinder, with at least 8 measuring points in each layer.

[0109] Optionally, the above process of calculating the central axis and intersection of the target test piece according to the spatial point data set to obtain a set of geometric characteristic dimension values ​​can be: calculating the intersection D0 according to the central axis of the first plane PLA1 and the cylinder MCYL1, and calculating the intersection Dn according to the central axis of the second plane PLA2 and the cylinder MCYLn; calculating the direction parameters and coordinate parameters of the central axis of the target test piece; calculating the intersection coordinates between the central axes of two adjacent straight cylindrical segments according to the direction parameters and coordinate parameters; calculating the distance between two adjacent intersections through each central axis intersection from D0 to Dn to obtain the length characteristic dimension, and calculating the angle between the central axes of two adjacent straight cylindrical segments through the central axis direction of the cylinder MCYLi and the coordinates of the center of mass point to obtain the first angle characteristic dimension; obtaining the second angle characteristic dimension through the angle between the planes formed by the three adjacent intersections from D0 to Dn.

[0110] The formula for calculating the direction parameter is:

[0111]

[0112] Among them, (u i , v i , w i ) is the direction of the central axis of the cylinder MCYLi, (u i+1 , v i+1 , w i+1 ) is the direction of the central axis of the cylinder MCYLi+1.

[0113] The formula for calculating the coordinate parameters is:

[0114]

[0115] Among them, (x i ,y i ,z i ) is the coordinate of the center of mass of the central axis of the cylinder MCYLi, (x i+1 ,y i+1 ,z i+1 ) are the coordinates of the center of mass of the central axis of the cylinder MCYLi+1.

[0116] The formula for calculating the intersection point of the central axis Di is:

[0117]

[0118] Specifically, using the measurement software of a high-precision coordinate measuring machine, the intersection point calculated by the plane PLA1 and the central axis of the cylinder MCYL1 is recorded as D0, and the intersection point calculated by the plane PLA2 and the central axis of the cylinder MCYLn is recorded as Dn.

[0119] The intersection point between the mid-axis lines of two adjacent straight cylindrical segments is calculated as follows:

[0120] The coordinates of the center of mass of the central axis of the cylinder MCYLi are defined as (x i ,y i , z i ), the direction of the central axis is (u i , v i , w i ); the coordinates of the center of mass of the adjacent cylinder MCYLi+1 are (x i+1 ,y i+1 , z i+1 ), the direction of the central axis is (u i+1 , v i+1 , w i+1 ).

[0121] Calculate the direction parameter (u v , v v , w v ), calculated as follows:

[0122]

[0123] Calculate the coordinate parameters r1, r2, and λ according to the following formula:

[0124]

[0125] The coordinates of the central axis intersection point Di are calculated according to the following formula:

[0126]

[0127] Using the measurement software of the high-precision three-dimensional coordinate measuring machine, the distance Li between two adjacent intersection points is calculated using the central axis intersection points D0, D1, ..., Dn; the angle α between the central axes of two adjacent linear cylindrical segments is calculated using the central axes of MCYL1, MCYL2, ..., MCYLn. i . Use D0, D1, and D2 to calculate plane 1, use D1, D2, and D3 to calculate plane 2, ..., use Dn-2, Dn-1, and Dn to calculate plane n-1; use plane 1, plane 2, ..., and plane n-1 to calculate the angle β between the planes formed by the three adjacent intersection points i .

[0128] S140: Evaluate the measurement accuracy of the pipeline online detection device to be evaluated based on the first data set and the second data set.

[0129] In a possible implementation, the measurement accuracy of the pipeline online detection device to be evaluated can be evaluated in the following manner: calculating a first error value E of the length characteristic dimension in the first data set and the length characteristic dimension in the second data set. L , and the root mean square E of the angular feature size in the first data set and the angular feature size in the second data set A ; According to the first error value E L Calculate the first standard deviation STD, based on the second error value E A Calculate the root mean square value RMS; evaluate the length measurement accuracy of the online detection device for the pipeline to be evaluated according to the first standard deviation STD, and evaluate the angle measurement accuracy of the online detection device for the pipeline to be evaluated according to the root mean square value RMS.

[0130] Among them, calculate the first error value E L The formula is:

[0131] E L =L m -L s

[0132] Among them, L m L is the characteristic length dimension of the target test piece measured by the online detection equipment of the pipeline to be evaluated. s The length characteristic dimension of the target test piece measured by the 3D metrology equipment; E L =(e L1 e L2 … e LN ) T , e L1 、e L2 ,…e Ln They are the indication errors of n length dimensions respectively;

[0133] Calculate the second error value E A The formula is:

[0134] E A =A m -A s

[0135] Among them, A m A is the angular characteristic dimension of the target test piece measured by the online detection equipment of the pipeline to be evaluated. s The angular feature size of the target test piece measured by the 3D metrology equipment; E A =(e A1 e A2 … eAm ) T , e A1 、e A2 ,…e Am They are the indication errors of m angular dimensions respectively.

[0136] The formula for calculating the first standard deviation STD is:

[0137]

[0138] Among them, e Li represents the indication error of the i-th length dimension, It represents the average value of the indication error of n length dimensions;

[0139] Calculate the RMS value RMS The formula is:

[0140]

[0141] Among them, e An is the indication error of the nth angular dimension.

[0142] It should be understood that the smaller the first standard deviation STD is, the better the length dimension measurement of the pipeline online detection equipment to be evaluated is, and the smaller the root mean square value RMS is, the higher the angular dimension measurement accuracy of the pipeline online detection equipment to be evaluated is.

[0143] Specifically, define L m =(L m1 L m2 … L mn ) T ,L m1 , L m2 ,…L mn are the length characteristic dimensions of the geometric characteristic dimensions of the spatial center axis obtained by measuring the target test piece using the online detection equipment of the pipeline to be evaluated; L s =(L s1 L s2 … L sn ) T , L S1 , L S2 ,...L Sn are the length characteristic dimensions obtained by measuring the target test piece using a three-dimensional metrology device. m With L S The length dimension measurement indication error is calculated using the following formula:

[0144] E L =L m -L s

[0145] Among them, E L =(e L1 e L2 … e Ln )T,e L1 、e L2 ,…e Ln They are the indication errors of n length dimensions respectively; the smaller the indication error E is, the higher the accuracy of the length dimension measurement of the pipeline online detection equipment is; the standard deviation is calculated based on the indication error: Among them, the smaller the STD value is, the better the length dimension measurement repeatability of the pipeline online detection equipment is.

[0146] Definition A s =(A s1 A s2 … A sn ) T , A s1 , A s2 , …A sn A is the angular characteristic size of the geometric characteristic size of the spatial center axis obtained by measuring the target test piece using the online detection equipment of the pipeline to be evaluated; A m =(A m1 A m2 … A mn ) T , A m1 , A m2 , …A mn They are the angular characteristic dimensions measured by a high-precision three-dimensional coordinate measuring machine on the target test piece. m With A s Calculate the angle dimension measurement indication error: E A =A m -A s , where E A =(e A1 e A2 … e Am ) T , e A1 、e A2 ,…e Am are the indication errors of m angular dimensions respectively; the smaller the indication error E is, the higher the angular dimension measurement accuracy of the pipeline online detection equipment is; according to the indication error E, calculate the RMS value:

[0147]

[0148] The smaller the RMS value, the higher the angular dimension measurement accuracy of the pipeline online detection equipment.

[0149] The present invention determines the spatial diagonal size of the target test piece for testing according to the surface length, width and depth of field of the optical measuring instrument of the pipeline online detection equipment to be evaluated, or the required three-dimensional size of the measurement space, and then determines the number of straight cylindrical segments of the target test piece. It is not limited to the specific style of the target test piece, and any tubular workpiece that meets the spatial diagonal size requirements can be used, and it is easy to obtain in the use occasion of the pipeline online detection equipment.

[0150] Using three-dimensional metrology equipment to establish a workpiece coordinate system can achieve higher-precision measurement. The cylindrical segment measurement data obtained during the measurement process is in a functional relationship with the coordinates of the intersection of the center axis of the target test piece. The corresponding functional relationship ensures a comprehensive inspection of the measurement accuracy of the length characteristic dimensions and angle characteristic dimensions of the pipeline online detection equipment.

[0151] The measurement data of the target test piece by the online detection equipment of the pipeline to be evaluated and the measurement data of the target test piece by the three-dimensional metrology equipment are used to evaluate the measurement accuracy of the equipment by calculating the indication error E, the root mean square value RMS and the standard deviation value STD. The smaller the values ​​of the indication error E, the root mean square value RMS and the standard deviation value STD, the higher the measurement accuracy of the online detection equipment of the pipeline to be evaluated.

[0152] Example 2

[0153] Figure 2 Another method for evaluating the measurement accuracy of pipeline online detection equipment provided in an embodiment of the present application.

[0154] Exemplarily, the method includes:

[0155] S201, obtaining the surface length, surface width and depth of field of the optical probe of the pipeline online detection equipment to be evaluated; or obtaining a predefined measurement space size.

[0156] S202, calculating the spatial diagonal size of the target test piece according to the surface length, surface width and depth of field or the defined measurement space size.

[0157] S203, determine the range of the diagonal size of the space, if the size is greater than 700 mm, execute S206; if the size is less than 500 mm, execute S204; otherwise, execute S205.

[0158] S204, determining that the number of straight cylindrical segments is 4.

[0159] S205, determining that the number of straight cylindrical segments is 5.

[0160] S206, determining that the number of straight cylindrical segments is 6.

[0161] S207, selecting a target test piece that meets the requirements.

[0162] S208, measuring the target test piece using the pipeline online detection equipment to be evaluated.

[0163] S209, measuring the target test piece using a three-dimensional metrology device.

[0164] S210, accuracy evaluation.

[0165] The present application is described below with reference to a specific embodiment.

[0166] The method comprises the following steps:

[0167] A1: Determine the spatial diagonal size of the target test piece according to the surface length, surface width and depth of field of the three-dimensional optical measuring instrument of the online detection equipment of the pipeline to be evaluated; wherein, the target test piece is a spatially continuous tubular piece, including n straight cylindrical segments and n-1 curved cylindrical segments, 4≤n≤6.

[0168] A2: Select the target test piece that meets the requirements, measure the target test piece through the online detection equipment of the pipeline to be evaluated, and obtain the geometric characteristic dimensions of the spatial center axis;

[0169] A3: Use 3D metrology equipment to establish a workpiece coordinate system according to the rules of the online inspection equipment for the pipeline to be evaluated in measuring the target test piece, measure the geometric characteristic dimensions of the spatial center axis of the target test piece, and obtain measurement data;

[0170] A4: Based on the two data sets obtained, calculate the indication error E, root mean square value RMS, and standard deviation value STD to evaluate the measurement accuracy of the pipeline online detection equipment to be evaluated.

[0171] For example, to measure a scanning pipeline inspection device with a measuring range of 1000mm×500mm×300mm, the required measuring space is 1000mm×500mm×300mm.

[0172] According to the required three-dimensional dimensions of the measurement space, determine that the spatial diagonal dimensions of the selected target test piece should meet the following requirements:

[0173] 300mm≤L≤868.9mm

[0174] A target test piece is selected, the spatial dimensions of which are 700 mm×300 mm×200 mm, the spatial diagonal of which is L=787.4 mm, and which has 6 straight cylindrical segments. The target test piece is used to measure the pipeline detection equipment.

[0175] The target test piece is measured using the calibrated pipeline detection equipment to obtain measurement data of the geometric dimension characteristics of the center axis of the target test piece.

[0176] The target test piece was measured using a high-precision coordinate measuring machine as the measurement standard. The measurement range of the measurement standard is 1200mm×1000mm×700mm, and the maximum allowable error is: ±(0.3+L / 1000)μm, L:mm. A probe with a diameter of 3mm and a length of 100mm was used to measure the target test piece. Before measurement, the target test piece had been surface cleaned and placed in the measurement chamber for 12 hours of temperature equilibrium.

[0177] The target test piece is properly clamped on the workbench of the coordinate measuring machine. In the manual operation mode, the starting end plane and the ending end plane of the target test piece are measured in the machine coordinate system. The number of measuring points on each end face is 6, and the spatial planes PLA1 and PLA2 are generated. The flatness of the two planes is less than 0.020μm. According to the surface roughness of the end face of the target test piece, it is judged that there is no gross error measurement point. The first straight cylindrical segment where the starting end plane is located is measured to generate cylinder MCYL1, and the sixth straight cylindrical segment where the ending end plane is located is measured to generate cylinder MCYL6. The intersection point of the calculated MCYL1 central axis and plane PLA1 is recorded as MD0, and the intersection point of the calculated MCYL6 central axis and plane PLA2 is recorded as MDn. The fitting method of the central axis is the least squares. Let the three-dimensional coordinates of MD0 be (x0, y0, z0), the three-dimensional coordinates of the constructed theoretical point MD0' be (x0+10, y0, z0), and the theoretical plane MPLA1 be constructed using the central axis of MCYL1 and MD0'.

[0178] Use the axis of MCYL1 to locate the +Y axis, use MPLA1 to locate the +Z axis, use the coordinates of the MD0 point to locate the positive coordinate origin, and establish the initial workpiece coordinate system.

[0179] In the initial workpiece coordinate system, a measurement program is written to automatically measure the six linear cylindrical segments. The theoretical measurement points are distributed in four layers, with 12 measurement points in each layer. The least squares method is used to fit the central axis of the cylinder to generate six cylinders and their central axes. The central axis directions and centroid coordinates of the six cylinders obtained by the high-precision coordinate measuring machine measurement software are substituted into the above formula to calculate the spatial coordinate values ​​of the first central axis intersection, the second central axis intersection, ..., and the fifth central axis intersection.

[0180] Table 1

[0181]

[0182] The corresponding geometric characteristic dimension data of the center axis are calculated using the measurement software of the high-precision coordinate measuring machine. The results are shown in Table 1 above.

[0183] According to the data in Table 1, the STD value of the length characteristic dimension is calculated to be 0.2397 mm, and the RMS value of the angle characteristic dimension is 0.1416°. The smaller the indication error E and the standard deviation value STD, the higher the length dimension measurement accuracy of the pipeline online detection equipment; the smaller the indication error E and the root mean square value RMS, the higher the angle measurement accuracy of the pipeline online detection equipment.

[0184] Figure 3 A schematic diagram of the structure of a test piece provided in an embodiment of the present application.

[0185] Among them, 1 is the starting end plane; 2 is the first straight cylindrical segment; 3 is the first central axis intersection; 4 is the second straight cylindrical segment; 5 is the second central axis intersection; 6 is the third straight cylindrical segment; 7 is the third central axis intersection; 8 is the fourth straight cylindrical segment; 9 is the fourth central axis intersection; 10 is the fifth straight cylindrical segment; 11 is the fifth central axis intersection; 12 is the sixth straight cylindrical segment; 13 is the ending end plane.

[0186] Figure 4 A schematic diagram of the structure of a measurement accuracy evaluation system for pipeline online detection equipment provided in an embodiment of the present application.

[0187] Exemplarily, the system 400 includes:

[0188] The first acquisition module 410 is used to acquire characteristic parameters of a three-dimensional optical measuring instrument in an online pipeline detection device to be evaluated.

[0189] The determination module 420 is used to determine the measurement size range of the measurement space according to the characteristic parameters, and determine the test piece whose space diagonal size is within the measurement size range among the multiple test pieces to be selected as the target test piece; wherein the target test piece is a continuous tubular piece.

[0190] The second acquisition module 430 is used to acquire a first data set measured by the online detection equipment for the pipeline to be evaluated and a second data set measured by the three-dimensional metrology equipment; wherein the first data set is a set of geometric characteristic dimension values ​​of the spatial center axis of the target test piece measured by the online detection equipment for the pipeline to be evaluated, and the second data set is a set of geometric characteristic dimension values ​​of the spatial center axis of the target test piece measured by the three-dimensional metrology equipment.

[0191] The processing module 440 is used to evaluate the measurement accuracy of the pipeline online detection device to be evaluated based on the first data set and the second data set.

[0192] Each module in the measurement accuracy evaluation system of the above-mentioned pipeline online detection equipment can be implemented in whole or in part by software, hardware and their combination. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the corresponding operations of each of the above modules.

[0193] The present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps in the embodiment of the method for evaluating the measurement accuracy of a pipeline online detection device. The specific implementation method can be found in the method embodiment, which will not be repeated here.

[0194] Furthermore, the present invention also provides a non-temporary computer-readable storage medium containing instructions, and a computer program is stored on the storage medium. For example, a memory containing instructions, the above instructions can be executed by a processor of a computer device to complete the above method. For example, a non-temporary computer-readable storage medium can be a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, and an optical data storage device. When the computer program is executed by the processor, the steps in the embodiment of the method for evaluating the measurement accuracy of the pipeline online detection equipment can be implemented. The specific implementation method can be found in the method embodiment, which will not be repeated here.

[0195] It will be appreciated by those skilled in the art that embodiments of the present invention may provide methods, systems or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0196] The present invention is described with reference to flowcharts and / or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as a combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0197] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0198] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0199] It should be pointed out that the above specific implementation methods can enable those skilled in the art to understand the invention more comprehensively, but do not limit the invention in any way. Therefore, although the present specification and embodiments have described the invention in detail, those skilled in the art should understand that the invention can still be modified or replaced by equivalents; and all technical solutions and improvements that do not deviate from the spirit and scope of the invention are included in the protection scope of the patent for the invention. Any figure mark in the claims should not be regarded as limiting the claims involved. Any simple change or equivalent replacement of the technical solution that can be obviously obtained by any technician familiar with the field within the technical scope disclosed in the present invention belongs to the protection scope of the present invention.

Claims

1. A method for evaluating the measurement accuracy of pipeline online detection equipment, characterized in that: include: Obtain characteristic parameters of a three-dimensional optical measuring instrument in an online detection device for the pipeline to be evaluated; Determine the measurement size range of the measurement space of the three-dimensional optical measuring instrument according to the characteristic parameters, and determine the test piece whose spatial diagonal size is within the measurement size range among the multiple test pieces to be selected as the target test piece; wherein the target test piece is a continuous tubular piece; Acquire a first data set measured by the pipeline online detection device to be evaluated and a second data set measured by a three-dimensional metrology device; wherein the first data set is a set of geometric characteristic dimension values ​​of the spatial center axis of the target test piece measured by the pipeline online detection device to be evaluated, and the second data set is a set of geometric characteristic dimension values ​​of the spatial center axis of the target test piece measured by the three-dimensional metrology device; Evaluate the measurement accuracy of the pipeline online detection device to be evaluated according to the first data set and the second data set; Determine the measurement size range of the measurement space of the three-dimensional optical measuring instrument according to the surface length D, the surface width W and the depth of field value H; determine the test piece whose space diagonal size is within the measurement size range as the target test piece; Among them, the spatial diagonal size L of the target test piece is less than or equal to and is greater than or equal to 2 / 3 of the minimum value of the width W and the depth of field H; Among them, the spatial diagonal L size of the target test piece should also meet the following conditions: Wherein, x is the length of the minimum enveloping rectangle of the projection of the target test piece on the xy plane of the rectangular coordinate system, y is the width of the minimum enveloping rectangle of the projection of the target test piece on the xy plane of the rectangular coordinate system, and z is the height of the projection of the target test piece on the xz plane.

2. The measurement accuracy evaluation method of pipeline online detection equipment according to claim 1 is characterized in that: Also includes: When it is detected that there is a preset measurement space size, the length X, width Y and height Z of the preset measurement space are obtained; The target test piece is determined according to the length X, width Y and height Z of the preset measurement space; wherein the spatial diagonal size L of the target test piece is less than or equal to and is greater than or equal to 2 / 3 of the minimum value among the length X, the width Y, and the height Z.

3. The method for evaluating the measurement accuracy of pipeline online detection equipment according to claim 1 or 2, characterized in that: The target test piece includes n straight cylindrical segments and n-1 curved cylindrical segments, where 4≤n≤6; when the spatial diagonal size is less than 500mm, the number of straight cylindrical segments of the target test piece is 4; when the spatial diagonal size is greater than or equal to 500mm and less than or equal to 700mm, the number of straight cylindrical segments of the target test piece is 5; when the spatial diagonal size is greater than 700mm, the number of straight cylindrical segments of the target test piece is 6.

4. The measurement accuracy evaluation method of pipeline online detection equipment according to claim 3 is characterized in that: The starting end and the ending end of the target test piece are planes, and the geometric characteristic dimension values ​​include a length characteristic dimension, a first angle characteristic dimension and a second angle characteristic dimension; wherein the length characteristic dimension is the distance between two adjacent intersection points, and the intersection points include the intersection point of the central axis of two adjacent straight cylindrical segments, the intersection point of the central axis of the straight cylindrical segment and the starting end plane of the target test piece, and the intersection point of the central axis of the straight cylindrical segment and the ending end plane of the target test piece; the first angle characteristic dimension is the angle between the central axes of two adjacent straight cylindrical segments; and the second angle characteristic dimension is the angle between the planes formed by three adjacent intersection points.

5. The measurement accuracy evaluation method of pipeline online detection equipment according to claim 4 is characterized in that: Acquiring a second data set measured by a three-dimensional metrology device, including: Performing cleaning and temperature balancing pretreatment on the target test piece; An initial workpiece coordinate system is established, and a three-dimensional coordinate measuring machine is used to perform contact measurement on each linear cylindrical segment of the target test piece one by one to obtain a spatial point data set containing three-dimensional coordinates; The coordinates of the intersection points between the central axis of the target test piece and the central axis are calculated according to the spatial point data set to obtain the set of geometric feature size values.

6. The measurement accuracy evaluation method of pipeline online detection equipment according to claim 5, characterized in that: Establish the initial workpiece coordinate system, including: The starting end plane is measured to generate a first plane PLA1, and the ending end plane of the target test piece is measured to generate a second plane PLA2, wherein the number of measurement points on each plane is greater than 8; The linear cylindrical segment where the starting end plane is located is measured to generate a cylinder MCYL1, and the linear cylindrical segment where the ending end plane is located is measured to generate a cylinder MCYLn; Constructing the three-dimensional coordinates of the theoretical point according to the three-dimensional coordinates of the first intersection point, and constructing the theoretical plane according to the central axis of the cylinder MCYL1 and the three-dimensional coordinates of the theoretical point; wherein the first intersection point is the intersection point of the central axis of the cylinder MCYL1 and the first plane PLA1; The Y axis is established through the central axis of the cylinder MCYL1, the Z axis is established through the theoretical plane, the coordinate origin is established through the coordinates of the first intersection point, and the initial workpiece coordinate system is established.

7. The method according to claim 6, characterized in that A three-dimensional coordinate measuring machine is used to perform contact measurement on each linear cylindrical segment of the target test piece one by one to obtain a spatial point data set of three-dimensional coordinates, including: Each linear cylindrical segment of the target test piece is automatically measured by a measurement program to generate a cylinder MCYLi, where 1≤i≤n; Among them, on each straight cylindrical segment, the measuring points are distributed in at least 4 layers along the length direction of the cylinder, with at least 8 measuring points in each layer, and each layer of measuring points should cover at least 180° of the cylindrical surface in the radial direction of the cylinder.

8. The method according to claim 7, characterized in that Calculating the intersection point between the central axis and the central axis of the target test piece according to the spatial point data set to obtain the set of geometric feature size values ​​includes: Calculate the intersection point D0 according to the first plane PLA1 and the central axis of the cylinder MCYL1, and calculate the intersection point Dn according to the second plane PLA2 and the central axis of the cylinder MCYLn; Calculating direction parameters and coordinate parameters of the central axis of the target test piece; Calculate the coordinates of the intersection point between the central axes of two adjacent straight cylindrical segments according to the direction parameter and the coordinate parameter; The formula for calculating the direction parameter is: Among them, (u i , v i , w i ) is the direction of the central axis of the cylinder MCYLi, (u i+1 , v i+1 , w i+1 ) is the direction of the median axis of the cylinder MCYLi+1; The formula for calculating the coordinate parameters is: Among them, (x i ,y i , z i ) is the coordinate of the center of mass of the central axis of the cylinder MCYLi, (x i+1 ,y i+1 , z i+1 ) are the coordinates of the centroid of the median axis of the cylinder MCYLi+1; The formula for calculating the coordinates of the intersection points between the central axes is: The length characteristic dimension is obtained by calculating the distance between two adjacent intersection points through the coordinates of the intersection points of each central axis from D0 to Dn, and the first angle characteristic dimension is obtained by calculating the angle between the central axes of two adjacent straight cylindrical segments through the central axis direction of the cylinder MCYLi and the coordinates of the center of mass point; the second angle characteristic dimension is obtained by the angle between the planes formed by the three adjacent intersection points from D0 to Dn.

9. A measurement accuracy evaluation system for pipeline online detection equipment, characterized in that: The system comprises: A first acquisition module is used to acquire characteristic parameters of a three-dimensional optical measuring instrument in an online detection device for a pipeline to be evaluated; A determination module is used to determine the measurement size range of the measurement space of the three-dimensional optical measuring instrument according to the characteristic parameters, and determine the test piece whose space diagonal size is within the measurement size range among the multiple test pieces to be selected as the target test piece; wherein the target test piece is a continuous tubular piece; A second acquisition module is used to acquire a first data set measured by the pipeline online detection device to be evaluated and a second data set measured by a three-dimensional metrology device; wherein the first data set is a set of geometric characteristic dimension values ​​of the spatial center axis of the target test piece measured by the pipeline online detection device to be evaluated, and the second data set is a set of geometric characteristic dimension values ​​of the spatial center axis of the target test piece measured by the three-dimensional metrology device; A processing module, configured to evaluate the measurement accuracy of the pipeline online detection device to be evaluated according to the first data set and the second data set; The first acquisition module is specifically used to: Determine the measurement size range of the measurement space of the three-dimensional optical measuring instrument according to the surface length D, the surface width W and the depth of field value H; determine the test piece whose space diagonal size is within the measurement size range as the target test piece; Among them, the spatial diagonal size L of the target test piece is less than or equal to and is greater than or equal to 2 / 3 of the minimum value of the width W and the depth of field H; Among them, the spatial diagonal L size of the target test piece should also meet the following conditions: Wherein, x is the length of the minimum enveloping rectangle of the projection of the target test piece on the xy plane of the rectangular coordinate system, y is the width of the minimum enveloping rectangle of the projection of the target test piece on the xy plane of the rectangular coordinate system, and z is the height of the projection of the target test piece on the xz plane.

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