BIM-based steel structure prefabricated part pre-assembly method and system

Abstract

The present application relates to the technical field of steel component pre-assembly, in particular to a steel structure prefabricated part pre-assembly method and system based on BIM. The method acquires a scanning point cloud and a BIM model, extracts end normal vectors and hole center features, constructs a component body coordinate system to realize data standardization; through a reference alignment transformation, aligns the anchoring end to the design position, superimposes a gravity pre-camber compensation vector to generate a virtual installation state reflecting the real cantilever state; matches the hole position to obtain manufacturing shape deviation and shear deformation deviation, and if qualified, extracts the overall misalignment vector of the free end; decomposes the misalignment vector to the strong and weak axes of the section, inversely calculates the correction force based on the split-axis cantilever beam mechanical model, and outputs the construction instruction combined with the component edge stress and equipment rated load. The present application realizes real simulation of single-end installation conditions and gravity deformation, can scientifically decouple manufacturing defects and elastic deviation, and provides quantitative auxiliary construction guidance, effectively reduces the factory repair rate and improves the on-site installation efficiency.

Description

Technical Field

[0001] This invention relates to the field of steel component pre-assembly technology, specifically to a BIM-based method and system for pre-assembly of prefabricated steel structure components. Background Technology

[0002] With the development of modern architecture towards large spans, high-rise buildings, and prefabricated construction, the application of prefabricated steel structures in engineering is becoming increasingly widespread. In actual construction, large steel components are usually prefabricated in the factory and transported to the site for high-altitude assembly. Due to the elasticity of steel, long-span and large cantilever components will experience significant deflection and sag under their own weight (i.e., gravity pre-camber problem). In addition, slight manufacturing dimensional errors are inevitable during the welding and drilling of end plates. These factors combined make it difficult to accurately align the connection holes of components during on-site installation, seriously affecting the construction progress and project quality.

[0003] In recent years, the industry has introduced 3D laser scanning technology for virtual pre-assembly, replacing physical trial assembly with digital means. Existing point cloud matching algorithms generally employ a holistic best fit, i.e., finding the minimum average deviation between the measured point cloud and the BIM model across the entire component. However, actual steel structure installation typically follows a single-end constraint sequence of anchoring one end first, then adjusting the other. The holistic fitting algorithm ignores this installation sequence, distributing the small angular error at the anchored end evenly across the entire length, thus masking the real large deviation caused by the cantilever effect at the free end. Secondly, most existing methods only perform rigid comparisons at a purely geometric level, ignoring the elastic sagging deformation of the component under gravity. This makes it impossible to accurately distinguish the nature of the component deviation—whether it is caused by irreversible manufacturing distortion (requiring rework) or by recoverable elastic misalignment (which can be resolved through on-site correction). Furthermore, the lack of mechanical assessment of the feasibility of auxiliary straightening installations leads existing pre-assembly software to often misclassify qualified components that could be straightened by applying external forces on-site (such as jacking or chain hoisting) as unqualified, resulting in an inflated factory rework rate. Simultaneously, existing technology cannot provide specific construction instructions regarding the magnitude and direction of the straightening force, causing on-site workers to operate blindly when faced with deviations, easily leading to plastic damage to components or overloading of construction equipment.

[0004] Therefore, existing three-dimensional laser scanning technology cannot realistically simulate the single-end installation conditions and gravity deformation effects of steel components, making it difficult to scientifically separate manufacturing defects and elastic deviations, resulting in distorted pre-assembly conclusions and a lack of quantitative construction guidance. Summary of the Invention

[0005] To address the technical problems of existing 3D laser scanning technology's inability to accurately simulate the single-end installation conditions and gravity deformation effects of steel components, its difficulty in scientifically separating manufacturing defects and elastic deviations, leading to distorted pre-assembly conclusions and a lack of quantitative construction guidance, this invention aims to provide a BIM-based method and system for pre-assembling precast steel structures. The specific technical solution adopted is as follows: In a first aspect, one embodiment of the present invention provides a BIM-based method for prefabricated steel structure components, the method comprising the following steps: Acquire scanned point cloud data and BIM model data of precast steel structure components; Based on the BIM model data, the end area is located, and the measured end plate plane normal vector, measured anchor end hole center, and measured free end hole center are extracted from the scanned point cloud data. Based on the measured end plate plane normal vector and measured anchor end hole center, a component body coordinate system is constructed, and the extracted measured hole centers are mapped to the component body coordinate system to obtain the standardized anchor end hole center and standardized free end hole center. Obtain the reference alignment transformation matrix that aligns the standardized anchoring end hole center to the designed anchoring end hole center; apply the reference alignment transformation matrix to the standardized free end hole center, and superimpose the gravity precamber compensation vector determined based on the component properties to generate the virtual installed free end hole center; Match the virtual installation state free end hole center with the design free end hole center, obtain the manufacturing shape deviation and shear deformation deviation of the hole group. If the manufacturing shape deviation meets the preset size tolerance threshold and the shear deformation deviation meets the preset ratio threshold, then calculate the overall misalignment vector of the virtual installation state free end hole center relative to the design free end hole center. The overall misalignment vector is decomposed into the strong and weak axes of the cross section, and the vertical and horizontal corrective forces are back-calculated based on the axial cantilever beam mechanical model. Based on the component edge stress corresponding to the corrective force and the rated load of the on-site equipment, construction instructions are output.

[0006] Furthermore, the method for obtaining the component body coordinate system is as follows: The origin is the geometric centroid of the measured anchoring end hole, and the Z-axis is the measured plane normal vector of the end plate. Calculate the line connecting the hole pairs with the furthest distance in the measured anchoring end holes, project the line connecting the hole pairs onto the end plate plane as the initial reference vector, and map the local axial direction of the component in the BIM model data onto the end plate plane to obtain the target reference vector. Calculate the angle between the initial reference vector and the target reference vector in the endplate plane, rotate the initial reference vector by the angle using a two-dimensional rotation matrix to make it parallel to the target reference vector, and generate the X-axis after normalization. The Y-axis is obtained by calculating the cross product of the Z-axis and the X-axis using the right-hand rule. Construct a component body coordinate system based on the origin, X-axis, Y-axis, and Z-axis.

[0007] Furthermore, the method for obtaining the reference alignment transformation matrix is ​​as follows: The geometric centers of the standardized anchoring end hole center and the designed anchoring end hole center are calculated separately. The standardized anchoring end hole center and the designed anchoring end hole center are decentered and the cross-covariance matrix is ​​calculated. The initial rotation matrix is ​​obtained by performing singular value decomposition on the cross-covariance matrix. The determinant of the initial rotation matrix is ​​checked. If the determinant is less than zero, the last column of the right singular matrix obtained by singular value decomposition is inverted to recalculate the physically valid rotation matrix. If the determinant is not less than zero, then the initial rotation matrix is ​​used as the rotation matrix; Multiply the geometric center of the standardized anchoring end hole center by the rotation matrix to obtain the rotated geometric center; Subtract the rotated geometric center from the geometric center of the anchoring end hole to obtain the translation vector; The rotation matrix and translation vector are combined into a homogeneous transformation matrix, which serves as the reference alignment transformation matrix.

[0008] Furthermore, the method for obtaining the virtual installation state free end hole center is as follows: Obtain the initial gravity vector in the global coordinate system of the BIM model data, and extract the theoretical rotation matrix of the local coordinate system of the precast steel structure component in the BIM model data relative to the global coordinate system. Multiply the initial gravity vector by the inverse of the theoretical rotation matrix to obtain the projection vector of the initial gravity vector in the local coordinate system. The direction of the projection vector is used as the direction of the compensation vector; Read the preset camber value from the BIM model data as the compensation amount; If no preset camber value is specified, the section moment of inertia, elastic modulus, linear density, and cantilever length of the precast steel structure are obtained; where the section moment of inertia is the principal axis moment of inertia of the component perpendicular to the direction of gravity in the virtual installation state. Multiply the linear density, gravitational acceleration, and the fourth power of the cantilever length to obtain the first product; multiply the constant 8, elastic modulus, and moment of inertia of the section to obtain the second product; divide the first product by the second product to obtain the quotient, which is used as the compensation amount; The direction of the compensation vector is normalized to a unit direction vector, and the unit direction vector is multiplied by the compensation amount to obtain the gravity precamber compensation vector. After multiplying the reference alignment transformation matrix with the standardized free end hole center, and then adding it with the gravity pre-camber compensation vector, the virtual installation state free end hole center is obtained.

[0009] Furthermore, the method for obtaining the manufacturing shape deviation and shear deformation deviation is as follows: A one-to-one correspondence between the virtual installed free end hole center and the designed free end hole center is established by using a bipartite graph matching algorithm. The geometric centers of the virtual installed free end hole center and the designed free end hole center are calculated respectively, and the corresponding homogeneous transformation matrix is ​​obtained as the best matching transformation matrix. Apply the best matching transformation matrix to the virtual installed free end hole center, calculate the root mean square error between the transformed virtual installed free end hole center and the corresponding design free end hole center, and use it as the manufacturing shape deviation. Singular value decomposition is performed on the virtual installation state free end hole center set and the design free end hole center set after decentralization and projection onto the end plate plane, respectively. The singular values ​​of each set in the two principal axis directions in the end plate plane are extracted. The larger value of the singular values ​​in the two principal axis directions of each set is divided by the smaller value to obtain the singular value ratio of each set. The absolute value of the difference between the singular value ratio of the virtual installed free end hole set and the design free end hole set is taken as the shear deformation deviation.

[0010] Furthermore, the method for obtaining the overall misalignment vector is as follows: Based on the one-to-one correspondence, calculate the coordinate difference vector between each virtual installation state free end hole center and the corresponding design free end hole center; The average of the coordinate difference vectors of all matching hole pairs is used to obtain the overall misalignment vector of the virtual installed free end hole center relative to the designed free end hole center.

[0011] Furthermore, the method for obtaining the vertical corrective force and the horizontal corrective force is as follows: The overall misalignment vector is projected onto the strong and weak axes of the local coordinate system of the precast steel structure to obtain the vertical displacement component and the horizontal displacement component. Extract the elastic modulus, moment of inertia of the strong axis section, moment of inertia of the weak axis section, and cantilever length from the BIM model data; The vertical corrective force is calculated by substituting the moment of inertia and vertical displacement components of the strong axial section into the stress-deformation formula at the end of the cantilever beam. The horizontal corrective force is calculated by substituting the moment of inertia and horizontal displacement components of the weak axis section into the stress-deformation formula at the end of the cantilever beam.

[0012] Furthermore, the method for outputting construction instructions is as follows: The vertical stress calculation numerator is obtained by multiplying the vertical correction force, cantilever length, and the maximum distance from the center to the edge of the cross-section of the precast steel structure in the vertical direction. Divide the calculated vertical stress numerator by the moment of inertia of the strong axis section to obtain the vertical component edge stress corresponding to the vertical correction force; Multiply the horizontal correction force, cantilever length, and the maximum distance from the center to the edge of the cross-section of the precast steel structure in the horizontal direction to obtain the numerator for calculating the horizontal stress. Divide the horizontal stress calculation numerator by the moment of inertia of the weak axis section to obtain the horizontal component edge stress corresponding to the horizontal correction force; The vertical and horizontal correction forces are converted to the same dimension and unified to the dimension unit corresponding to the rated load of the field equipment. If the edge stress of the vertical or horizontal component is greater than the allowable stress of the precast steel structure material, or if the correction force after unification is greater than the rated load threshold of the field equipment, then forced correction is deemed infeasible and a hole enlargement correction command is generated. If the edge stress of both the vertical and horizontal components is less than or equal to the allowable stress, and the corrective force after unification of dimensions is less than or equal to the corresponding rated load threshold of the field equipment, then forced correction is deemed feasible, and an auxiliary correction instruction is generated.

[0013] Furthermore, the method for obtaining the measured end plate plane normal vector is as follows: extract the theoretical center coordinates based on the connection markers in the BIM model data, and establish an oriented bounding box in the scanned point cloud data to cut out the end point cloud subset; Principal component analysis is performed on the scanned point cloud data to extract the principal inertial axis, which is then aligned with the major axis of the component in the BIM model data to obtain a coarse alignment matrix. The theoretical normal vectors in the BIM model data are mapped to the coordinate system of the current point cloud using the coarse alignment matrix. Random sampling consistency plane fitting with normal constraints is performed on the end point cloud subset to obtain the measured end plate plane normal vectors. The normal constraint is that the angle between the fitted plane normal vector and the mapped theoretical normal vector is less than a preset angle threshold. The method for obtaining the measured anchor end hole center is as follows: In the end point cloud subset corresponding to the anchor end, noise points exceeding the distance limit are removed based on the fitted optimal end plate plane, and Euclidean clustering and cylindrical surface fitting are performed on the remaining point cloud to extract the cylindrical surface center to obtain the measured anchor end hole center. The method for obtaining the measured center of the free end hole is as follows: Euclidean clustering and cylindrical surface fitting are performed on the end point cloud subset corresponding to the free end to extract the center of the cylindrical surface and obtain the measured center of the free end hole.

[0014] Secondly, another embodiment of the present invention provides a BIM-based prefabricated steel structure component pre-assembly system, the system comprising: a memory, a processor, and a computer program stored in the memory and running on the processor, wherein when the processor executes the computer program, it implements the steps of any of the above methods.

[0015] The present invention has the following beneficial effects: This invention first locates the end region based on BIM model data, which facilitates rapid identification of key connection interfaces to be inspected and filters out irrelevant environmental noise. Then, it extracts the measured end plate plane normal vector, the measured anchor end hole center, and the measured free end hole center from the scanned point cloud data, achieving semantic decoupling between the measured geometric features and the original point cloud. To eliminate the interference of component yard posture on spatial analysis, a component body coordinate system is constructed based on the measured end plate plane normal vector and the measured anchor end hole center, establishing a stable and unique mathematical analysis benchmark. Then, the extracted measured hole centers are mapped to the component body coordinate system to obtain the standardized anchor end hole center and... Standardized free-end holes enable complete decoupling of measurement data from the scanning equipment's posture. To simulate the actual installation sequence of fixing one end and then aligning the other, a reference alignment transformation matrix is ​​obtained to align the standardized anchoring end holes to the designed anchoring end holes, allowing for precise calculation of the anchoring end's installation and docking pose matrix. To correct cantilever displacement distortion caused by the self-weight deflection of long-span components, the reference alignment transformation matrix is ​​applied to the standardized free-end holes, and a gravity pre-camber compensation vector determined based on component properties is superimposed to generate a virtual installed free-end hole, thereby reconstructing the true state of the component under gravity in digital space. The actual assembly posture is determined; to mathematically separate manufacturing defects and installation deviations of components, and then match the virtual installation state free end hole center with the designed free end hole center, the manufacturing shape deviation and shear deformation deviation of the hole group are obtained, accurately reflecting the degree of pure manufacturing distortion of the end plate hole group after excluding displacement interference, which is beneficial for timely interception of unqualified components with out-of-tolerance shapes; if the manufacturing shape deviation meets the preset dimensional tolerance threshold and the shear deformation deviation meets the preset proportional threshold, then the overall misalignment vector of the virtual installation state free end hole center relative to the designed free end hole center is calculated to quantify the macroscopic spatial offset of the component's free end relative to the design position; in order to By accurately addressing the differences in axial mechanical resistance of steel components with varying stiffness, the overall misalignment vector is decomposed into the strong and weak axes of the cross-section. Based on the axial cantilever beam mechanical model, the vertical and horizontal corrective forces are calculated, accurately reflecting the theoretical mechanical thrust required to eliminate deviations in each direction, providing a quantitative basis for on-site equipment selection. To prevent material damage or equipment overload accidents during the correction process, construction instructions are output based on the component edge stress corresponding to the corrective force and the rated load of on-site equipment. This directly guides the on-site team to complete precise alignment and installation through mechanical means, achieving a technological leap from pre-assembly testing to construction support decision-making. Attached Figure Description

[0016] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic flowchart illustrating a BIM-based prefabrication method for steel structure components according to an embodiment of the present invention. Figure 2 The diagram shows a BIM-based prefabrication system for steel prefabricated components, provided in one embodiment of the present invention. Figure 3 This is a schematic diagram of a computer device provided according to an embodiment of the present invention. Detailed Implementation

[0018] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of the BIM-based prefabrication method and system for steel structure precast components proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0020] The following description, in conjunction with the accompanying drawings, details the specific scheme of the BIM-based prefabrication method and system for steel structure prefabrication provided by this invention.

[0021] Example 1: This invention proposes a BIM-based method for the prefabrication of steel structure components. Please refer to [link / reference]. Figure 1 The diagram illustrates a schematic flowchart of a BIM-based prefabrication method for steel structure precast components according to an embodiment of the present invention. The method includes the following steps: Step S1: Obtain scanned point cloud data and BIM model data of precast steel structure components.

[0022] Specifically, this embodiment uses a precast steel structure component to be inspected as an example for analysis. All subsequent references to precast steel structures refer to this component. Considering that the precast steel structures to be inspected in actual factories or storage yards may have random placement and the scanning environment may contain interference noise such as ground surfaces or support frames, this embodiment uses a 3D laser scanner to scan the point cloud data of the precast steel structure component defined in the scanning equipment coordinate system. The corresponding BIM model data is imported from the engineering database. The BIM model data is defined in the global design coordinate system and includes the component's design geometric dimensions, connection identification information, and material properties. The material properties include at least the precast steel structure's elastic modulus, linear density, strong axis section moment of inertia, and weak axis section moment of inertia.

[0023] Step S2: Locate the end area based on BIM model data, extract the measured end plate plane normal vector, measured anchor end hole center and measured free end hole center from the scanned point cloud data; construct the component body coordinate system based on the measured end plate plane normal vector and measured anchor end hole center, map the extracted measured hole center to the component body coordinate system to obtain the standardized anchor end hole center and standardized free end hole center.

[0024] Specifically, to narrow the point cloud processing range and avoid interference from irrelevant background environments, thereby improving the computational efficiency and accuracy of feature extraction, the end region is located based on BIM model data. This involves using topological information from BIM design semantics as prior constraints. This facilitates the accurate and efficient extraction of the measured end plate plane normal vector (i.e., the actual orientation of the anchored end plate), the measured anchored end hole center (i.e., the actual set of center points of the anchored end bolt holes), and the measured free end hole center (i.e., the actual set of center points of the free end bolt holes) from the scanned point cloud data, providing key geometric features for subsequent pose analysis. To eliminate the influence of components on... The influence of the arbitrary placement posture on the spatial coordinates in the site or storage yard is investigated. Based on the measured plane normal vector of the end plate and the measured anchoring end hole center, a component body coordinate system is constructed. This achieves complete decoupling between the measurement data and the scanning equipment posture, which helps eliminate directional ambiguity caused by the symmetry of the hole group and ensures that the coordinate system is unique. To unify the mathematical analysis benchmark, the extracted measured hole centers (i.e., the measured anchoring end hole center and the measured free end hole center) are further mapped to the component body coordinate system, resulting in standardized anchoring end hole centers and standardized free end hole centers. This provides standard data input without posture interference for subsequent virtual installation simulation. It should be noted that the anchoring end is determined by the assembly constraint relationship in the BIM model data (such as the end that is preferentially connected to the fixed structure, or the end with greater node stiffness), and the free end is determined by the cantilever end of the component or the end to be adjusted that has not yet been locked with other components. If not explicitly labeled in the BIM model, the end with more connecting holes or larger connecting flange size will be selected by default as the anchoring end to ensure the stability of the virtual reference conversion. Implementers can manually intervene to specify the anchoring end according to the actual construction and hoisting sequence on site, but no restrictions are imposed here.

[0025] The method for obtaining the measured plane normal vector of the end plate is as follows: The theoretical center coordinates are extracted based on the connection markers in the BIM model data. Using these theoretical center coordinates as the center, an oriented bounding box is established in the scanned point cloud data to cut out the end point cloud subsets (including the end point cloud subsets corresponding to the anchored end and the end point cloud subsets corresponding to the free end), thereby achieving accurate selection of the area to be measured and significantly filtering out external noise. It should be noted that in this embodiment, the size of the oriented bounding box is set to be slightly larger than the geometric envelope size of the end plate (e.g., ...). The orientation of the bounding box is consistent with the orientation of the BIM local coordinate system, ensuring complete coverage of the end plate and bolt hole area while eliminating interference from irrelevant components. The implementer can set the size and orientation of the bounding box according to the actual cross-sectional dimensions of the component end or the ranging accuracy of the scanner, without limitation here. To prevent interference from weld reinforcement or flange plates in the point cloud that could lead to plane fitting errors, principal component analysis is performed on the scanned point cloud data to extract the principal inertial axes (i.e., the three orthogonal direction vectors that best represent the extensibility of the point cloud distribution). To eliminate the initial rotational deviation between the scanning equipment coordinate system and the BIM design coordinate system, the aforementioned principal inertial axes are aligned with the major axes of the components in the BIM model data to obtain a coarse alignment matrix. This coarse alignment matrix is ​​used to establish the initial rotational mapping relationship between the scanning coordinate system and the design coordinate system. Finally, the theoretical normal vectors in the BIM model data are mapped to the coordinate system where the current point cloud resides using the coarse alignment matrix. A random sampling consistency plane fitting with normal constraints is performed on the end point cloud subset (i.e., consistency screening is performed by iteratively selecting plane parameters and combining them with a preset normal vector) to obtain the measured end plate plane normal vector, ensuring the physical uniqueness and correctness of the extracted plane. The normal constraint is that the angle between the fitted plane normal vector and the mapped theoretical normal vector is less than a preset angle threshold. In this embodiment, the preset angle threshold is set to 15° to ensure that the algorithm can robustly ignore interference from mutually perpendicular web plates. Implementers can set the preset angle threshold according to the complexity of the actual component or the expected maximum processing distortion error; this is not limited here. Principal component analysis is a well-known technique and will not be elaborated further.

[0026] The method for obtaining the measured anchor end hole center is as follows: To eliminate the interference of surface burrs or rust on the hole wall boundary, noise points exceeding the distance limit (i.e., point clouds whose vertical distance from the fitted plane is greater than a preset threshold, which is set to 2mm in this embodiment) are removed from the point cloud subset corresponding to the anchor end based on the fitted optimal end plate plane. This ensures that weld spatter and outlier noise on the end plate surface can be effectively filtered out, while retaining the complete hole edge and internal hole wall geometric features. The implementer can set the preset threshold according to the ranging accuracy of the 3D laser scanner or the actual processing roughness of the component surface, which is not limited here. This is to purify the point cloud data around the hole. Then, Euclidean clustering and cylindrical surface fitting are performed on the remaining point cloud (specifically, each independent hole candidate region is first identified by point cloud clustering, and then least squares cylindrical surface parameter fitting is performed on the point cloud of each candidate region). The center of the cylindrical surface is extracted to obtain the measured anchor end hole center, which effectively improves the extraction accuracy of the hole center coordinates. The least squares algorithm is well known and will not be described in detail.

[0027] The method for obtaining the measured center of the free end hole is as follows: In the point cloud subset corresponding to the free end, Euclidean clustering and cylindrical surface fitting are performed (using the same feature extraction process as the anchoring end, clustering is performed based on the preset point cloud distance threshold and the hole wall region is locked, and the least squares algorithm is used to solve the cylindrical geometric parameters), and the center of the cylindrical surface is extracted to obtain the measured center of the free end hole, so as to obtain the real three-dimensional spatial distribution features of the free end connection hole.

[0028] Preferably, in one feasible embodiment of this invention, the method for obtaining the component body coordinate system is as follows: Using the geometric centroid of the measured anchoring end hole center as the origin and the measured end plate plane normal vector as the Z-axis, the spatial foundation position and main normal orientation of the component are established. Considering that symmetrical hole groups (such as square distributed holes or circular flange holes) are prone to directional ambiguity during coordinate system establishment, leading to random jumps in the coordinate system, the line connecting the farthest hole pairs in the measured anchoring end hole center is calculated. This line is projected onto the end plate plane as the initial reference vector. The local axial mapping of the component in the BIM model data is then projected onto the end plate plane to obtain the target reference vector. The coordinate system is designed to eliminate the inherent geometric deflection between the natural connecting lines (such as the diagonals of the hole group) and the principal axes of the actual cross-section of the component, ensuring that the constructed coordinate axes are accurately aligned with the true force direction of the steel component. This involves calculating the angle between the initial reference vector and the target reference vector in the end plate plane, rotating the initial reference vector by this angle using a two-dimensional rotation matrix to make it parallel to the target reference vector, and then normalizing it to generate the X-axis, ensuring the physical uniqueness of the X-axis direction. To complete the three-dimensional orthogonal coordinate system, the Y-axis is obtained by calculating the cross product of the Z-axis and the X-axis using the right-hand rule. Finally, a component body coordinate system is constructed based on the origin, X-axis, Y-axis, and Z-axis. The right-hand rule is a well-known principle and will not be elaborated further.

[0029] Step S3: Obtain the reference alignment transformation matrix to align the standardized anchoring end hole center to the designed anchoring end hole center; apply the reference alignment transformation matrix to the standardized free end hole center, and superimpose the gravity precamber compensation vector determined based on the component properties to generate the virtual installed free end hole center.

[0030] Specifically, to recreate the actual physical condition of fixing one end of the component during on-site installation in the digital space, and to obtain the benchmark alignment transformation matrix that aligns the standardized anchoring end hole center to the designed anchoring end hole center, a rigid mapping relationship between the measured data and the design model is established. This helps to eliminate macroscopic deviations caused by the overall rigid displacement of the component and provides a reliable benchmark for extracting the actual microscopic deviations caused by manufacturing and installation. In addition, considering that long-span steel structures will produce significant cantilever sagging deformation under their own weight, purely geometric rigid alignment will lead to a distorted calculation of the free end position. To correct the defect of traditional pre-assembly algorithms that ignore the elastic deformation of materials, the benchmark alignment transformation matrix is ​​applied to the standardized free end hole center, and a gravity pre-camber compensation vector (characterizing the theoretical deflection correction amount generated by the component under its own weight) determined based on the component properties is superimposed to generate a virtual installed free end hole center. This allows for the accurate reproduction of the actual spatial pose of the component under real gravity and single-end constraints in the digital space.

[0031] Preferably, in one feasible embodiment, the method for obtaining the reference alignment transformation matrix is ​​as follows: To eliminate the influence of the scattered distribution of the hole group on the overall position determination, the geometric centers of the standardized anchoring end hole center and the designed anchoring end hole center are calculated respectively using a coordinate mean solution algorithm to determine the spatial position reference of the two sets of hole groups, which facilitates the subsequent separation of translation and rotation components in rigid body transformation; To construct a mathematical model reflecting the correlation between the shapes of the two sets of point groups, the standardized anchoring end hole center and the designed anchoring end hole center are decentered by subtracting the corresponding geometric center coordinates from the coordinates of each hole center and the cross-covariance matrix is ​​calculated. Specifically, the matrix formed by the two sets of point sets after decentering (i.e., the transpose of the measured point set matrix and the designed point set matrix) is multiplied to eliminate the interference of translation deviation on the rotation attitude calculation; To calculate the optimal matching attitude in the least squares sense, the classic SVD (Singular Value Decomposition) is used. The Value Decomposition (VFD) algorithm performs singular value decomposition on the cross-covariance matrix to obtain the initial rotation matrix. Since mathematical algorithms are prone to generating erroneous reflection transformation matrices when dealing with near-planar hole groups, this embodiment verifies the determinant of the initial rotation matrix by calculating whether its algebraic determinant value is -1. This ensures the rotation transformation has physical validity. If the determinant is less than zero, it indicates that the initial rotation matrix represents a spatial mirror flip, violating the reality that steel structures cannot be physically flipped during assembly. To ensure that the calculated posture conforms to the rigid body rotation motion of the real world, and that subsequent error analysis is based on the correct physical topology, the last column of the right singular matrix obtained from the VFD is inverted to recalculate a physically valid rotation matrix, accurately reflecting the spatial rotation posture during the actual installation and docking of the anchoring end. If the determinant is not less than zero, it indicates that the initial rotation matrix is ​​a valid pure rotation matrix without mirror flipping, and the initial rotation matrix is ​​used as the rotation matrix. To separate and solve the relative translational deviation between the two sets of holes, the geometric center of the standardized anchoring end hole is multiplied by a rotation matrix to obtain the rotated geometric center, thus unifying the geometric positions. Based on this, the rotated geometric center is subtracted from the designed anchoring end hole's geometric center to obtain a translation vector, accurately quantifying the spatial distance difference between the two ends. To facilitate subsequent unified affine transformation operations on other feature points, the rotation matrix and translation vector are combined into a homogeneous transformation matrix, i.e., a fourth-order square matrix containing rotation and translation information is constructed as the reference alignment transformation matrix. This facilitates efficient pose mapping calculations of all point clouds and coordinates at the free end using single matrix multiplication. The cross-covariance matrix, decentralization, and SVD decomposition algorithm are all well-known and will not be elaborated further.

[0032] Preferably, in one feasible method of this embodiment, the method for obtaining the center of the free end hole in the virtual installation state is as follows: Considering that the installation orientation of the precast steel structure components in the BIM model is different and the axis of gravity is not constant, in order to accurately calculate the influence of gravity on the current posture of a specific component, the initial gravity vector (usually set to the negative Z-axis) in the global coordinate system of the BIM model data is obtained by analyzing the engineering design reference environment parameters. The theoretical rotation matrix of the local coordinate system of the precast steel structure component in the BIM model data relative to the global coordinate system is extracted by reading the spatial transformation attribute matrix of the component instance in the BIM model. The initial gravity vector is multiplied by the inverse of the theoretical rotation matrix to obtain the projection vector of the initial gravity vector in the local coordinate system, so as to achieve the alignment of the gravity direction with the axis of the component's geometric features. In order to clarify the absolute direction of the bending displacement of the component end due to its own weight, the direction of the projection vector is used as the direction of the compensation vector to ensure the physical correctness of the sagging deformation logic. To obtain the specific deformation value of the drooping end of the component, and then read the preset camber value in the BIM model data as the compensation amount, the reverse preset deflection parameter given in the original design is given priority. In this embodiment, the preset camber value is set by parsing the component prefabrication compensation attribute label in the design drawings of the BIM model, so as to ensure that the deflection compensation of the component fully meets the initial mechanical expectations of the design institute. The implementer can set the preset camber value according to the construction specifications of the specific project or the extended attribute fields reserved by the design software, which is not limited here. If there is no preset camber value, in order to adaptively calculate the self-weight deflection of the component of arbitrary span through mechanical means, the section moment of inertia, elastic modulus, linear density and cantilever length of the steel structure prefabricated component are obtained. Among them, the section moment of inertia is the section principal axis moment of inertia of the component perpendicular to the gravity direction in the virtual installation state (for example, if the gravity acts along the strong axis direction, the weak axis moment of inertia is taken; if the gravity acts along the weak axis direction, the strong axis moment of inertia is taken) to ensure the accuracy of the bending stiffness selection. Considering that the cantilever structure behaves as a typical uniformly distributed load cantilever beam under its own weight, in order to obtain the maximum sag deflection at the free end, the theoretical deflection is accurately calculated using the classic elastic deformation formula for a uniformly distributed load cantilever beam. This involves multiplying the linear density, gravitational acceleration, and the fourth power of the cantilever length to obtain the first product, which accurately reflects the combined effect of the structure's self-weight load and the amplification effect of its cantilever span. Further, the constant 8, the elastic modulus, and the moment of inertia of the section are multiplied to obtain the second product, which accurately reflects the basic stiffness of the structure's material against bending deformation. To obtain the final deflection displacement value, the first product is divided by the second product to obtain the quotient, which serves as a compensation amount, accurately reflecting the theoretical maximum sag distance of the structure when the bottom support is completely lost. Here, the gravitational acceleration is... It is stored in the system's local basic parameter configuration library and is used to convert the linear density in the mass dimension into a uniformly distributed load in the force dimension. In order to convert the scalar displacement value into a vector expression in three-dimensional space, the direction of the compensation vector is normalized to a unit direction vector by dividing the vector by its own magnitude, eliminating the interference of the length dimension. Then, the unit direction vector is multiplied by the compensation amount to obtain the gravity precamber compensation vector, forming a complete geometric component characterizing the bending phenomenon under force. To obtain the final theoretical form of the component during on-site assembly, the reference alignment transformation matrix is ​​first multiplied with the standardized free end hole center to simulate the spatial pose of the component after rigid body rotation and translation with the anchor end as the fulcrum. Then, the above multiplication result is added with the gravity precamber compensation vector to introduce the elastic sag displacement correction under the action of gravity of the cantilever, thereby obtaining the virtual installation state free end hole center.

[0033] Step S4: Match the virtual installed free end hole center with the designed free end hole center, obtain the manufacturing shape deviation and shear deformation deviation of the hole group. If the manufacturing shape deviation meets the preset size tolerance threshold and the shear deformation deviation meets the preset ratio threshold, then calculate the overall misalignment vector of the virtual installed free end hole center relative to the designed free end hole center.

[0034] Specifically, in order to scientifically decouple the manufacturing distortion and elastic deformation of the component from a mathematical perspective, and then match the virtual installed free end hole center with the designed free end hole center, the manufacturing shape deviation and shear deformation deviation of the hole group are obtained to determine whether the component end plate itself has suffered irreversible physical structural damage; considering that there are inevitably slight errors in the processing of steel components in actual engineering, in order to avoid the overly strict theoretical judgment causing qualified components to be falsely reported and rejected, this embodiment sets a preset dimensional tolerance threshold and a preset proportional threshold according to the relevant national steel structure acceptance specifications to ensure the engineering rationality of error judgment. Implementers can set the preset dimensional tolerance threshold and preset proportional threshold according to the specific engineering level requirements or design specifications, which is not limited here. If the manufacturing shape deviation meets the preset dimensional tolerance threshold and the shear deformation deviation meets the preset proportional threshold, it indicates that the geometry of the hole group on the end plate of the component is qualified (i.e., it is made accurately). There is only recoverable displacement caused by the long span cantilever effect or assembly stress. In order to quantify this recoverable displacement to guide on-site mechanical correction, the overall misalignment vector of the free end hole center in the virtual installation state relative to the design free end hole center is calculated. This accurately reflects the sum of the macroscopic spatial translation and rotation deviation of the free end of the component relative to the BIM design position, thus completing the accurate assessment of the soft defects of the component.

[0035] Preferably, in one feasible embodiment, the method for obtaining the manufacturing shape deviation and shear deformation deviation is as follows: To prevent cross-locking between adjacent holes due to large deflection deformation of the component, and with the goal of minimizing the Euclidean distance of the hole center space, a one-to-one correspondence between the virtual installed free end hole center and the designed free end hole center is established using a bipartite graph matching algorithm. This minimizes the global distance cost to ensure the correctness of the topological association. Then, the geometric centers of the virtual installed free end hole center and the designed free end hole center are calculated respectively using coordinate mean calculation. The homogeneity is obtained in step S3. The method of transformation matrix is ​​used to obtain the corresponding homogeneous transformation matrix as the best matching transformation matrix to eliminate the interference of the overall component offset on the local hole group shape comparison. In order to quantify the pure morphological difference of the hole group after excluding rigid displacement, the best matching transformation matrix is ​​applied to the virtual installation state free end hole center, and the root mean square error between the transformed virtual installation state free end hole center and the corresponding design free end hole center is calculated as the manufacturing shape deviation, which intuitively reflects hard processing defects such as hole spacing deviation. Among them, the bipartite graph matching algorithm and the root mean square error acquisition method are well known and will not be described in detail. To further capture potential non-uniform deformations (such as rhomboid shear deformation) of the end plate, the classic SVD algorithm is used to perform singular value decomposition on the virtual installed free end hole center set and the designed free end hole center set after decentering and projecting onto the end plate plane. The singular values ​​of each set in the two principal axis directions (i.e., the mutually orthogonal maximum variance direction and the second largest variance direction) are extracted to characterize the discrete span characteristics of the hole group in the plane. In order to quantitatively evaluate the geometric distribution ratio of the hole group in the two principal axis directions, the larger value of the singular values ​​in the two principal axis directions of each set is divided by the smaller value to obtain the singular value ratio of each set, which accurately measures the change in the overall length-width ratio of the hole group corresponding to each set. It should be noted that, in order to avoid the smaller value being 0, which would render the calculation meaningless, this embodiment uses the sum of the smaller value and a preset minimum positive number as the denominator. The preset minimum positive number is set to 0.001 to completely avoid the risk of computational crash (divided by zero) caused by extreme degenerate states such as single-row collinearity of the hole group. The implementer can set the size of the preset minimum positive number according to the floating-point precision standard of the computer used, which is not limited here. The SVD algorithm is well known and will not be described in detail here. To effectively eliminate errors caused by isotropic deformation such as normal thermal expansion and contraction, the absolute value of the difference between the singular value ratio of the virtual installed free end hole set and the designed free end hole set is used as the shear deformation deviation, which accurately reflects the degree of pure shear distortion caused by residual stress during the processing and welding of the component end plate. In order to establish a sound and rigorous manufacturing defect interception mechanism, any deviation in either the manufacturing shape deviation or the shear deformation deviation must be reworked in the factory if either exceeds the limit, thereby cutting off the possibility of inferior components entering the on-site construction process.

[0036] Preferably, in one feasible manner of this embodiment, the method for obtaining the overall misalignment vector is as follows: In order to obtain the accurate spatial vector of the component end deviating from the theoretical position, based on the one-to-one correspondence between the virtual installed free end hole center and the designed free end hole center, the coordinate difference vector between each virtual installed free end hole center and the corresponding designed free end hole center is calculated by subtracting the end coordinates, thereby capturing the local offset characteristics of each connection node; in order to eliminate the single hole position extraction error and reflect the overall macroscopic displacement trend of the component, the coordinate difference vectors of all matching hole position pairs are averaged to obtain the overall misalignment vector of the virtual installed free end hole center relative to the designed free end hole center.

[0037] Step S5: Decompose the overall misalignment vector to the strong axis and weak axis of the section, and back-calculate the vertical and horizontal correction forces based on the axial cantilever beam mechanical model; output construction instructions based on the component edge stress corresponding to the correction force and the rated load of the on-site equipment.

[0038] Specifically, to accurately assess the mechanical response characteristics of steel components in different stiffness axes and ensure that the subsequently applied corrective force can precisely offset the displacement deviation in the corresponding direction, the overall misalignment vector is decomposed into the strong axis and weak axis of the cross section (i.e., projected onto the height and width directions of the cross section, respectively), thereby obtaining mutually orthogonal vertical and horizontal displacement components. To transform the abstract geometric deviation into actionable mechanical parameters on site, the vertical and horizontal corrective forces are back-calculated based on the axial cantilever beam mechanical model, that is, a quantitative mapping relationship between displacement and load is established using material mechanics formulas. To ensure that the corrective installation process neither damages the component itself nor exceeds the safe load of the construction equipment, construction instructions are output based on the component edge stress corresponding to the corrective force and the rated load of the on-site equipment, clearly informing on-site personnel of specific operational suggestions for strong pulling, mechanical jacking, or hole enlargement and cutting, thus realizing a technical closed loop from virtual pre-assembly to precise physical installation. This embodiment sets the rated load of on-site equipment by reading the factory parameters on the nameplates of the actual lifting or traction equipment (such as hydraulic jacks, hand chain hoists, etc.) equipped at the construction site. This ensures that the evaluation standard is fully matched with the actual physical construction capabilities on site, and avoids generating theoretical correction instructions that cannot be executed. The implementer can set the rated load of on-site equipment according to the specific equipment ledger of the project or the maximum safe working limit of the equipment actually dispatched on site. No limitation is made here.

[0039] Preferably, in one feasible embodiment of this method, the vertical and horizontal correction forces are obtained as follows: To fully consider the anisotropic influence of the cross-sectional shape of the steel member on the displacement resistance in different dimensions, a spatial vector dot product projection algorithm is used to project the overall misalignment vector onto the strong axis (usually the direction parallel to the web) and weak axis (usually the direction perpendicular to the web) of the local coordinate system of the precast steel structure, thereby obtaining the vertical and horizontal displacement components, which accurately reflect the absolute positional deviation of the free end of the member in the gravity plane and the horizontal lateral plane; in order to establish an engineering conversion mechanism from geometric displacement to actual construction thrust. This method enables pre-assembly inspection to provide quantitative guidance for on-site correction construction. It extracts the elastic modulus, moment of inertia of the strong axis section, moment of inertia of the weak axis section, and cantilever length from the BIM model data. Substituting the moment of inertia of the strong axis section and the vertical displacement component into the force-deformation formula at the end of the cantilever beam, the vertical correction force is calculated, accurately reflecting the lifting or downward pressure required to overcome the strong axis stiffness of the component and eliminate vertical sagging. Similarly, substituting the moment of inertia of the weak axis section and the horizontal displacement component into the force-deformation formula at the end of the cantilever beam, the horizontal correction force is calculated, accurately reflecting the traction or pushing force required to overcome the weak axis stiffness of the component and eliminate horizontal lateral sway. It should be noted that the force-deformation formula at the end of the cantilever beam is... (That is, the corrective force is equal to the product of three times the elastic modulus and the moment of inertia of the section divided by the cube of the cantilever length, and then multiplied by the corresponding displacement component), where F is the corrective force; E is the elastic modulus; I is the moment of inertia of the section; and L is the cantilever length. The displacement component is defined using classical structural mechanics material deformation theory to ensure that the inverse calculation of the corrective force is based on rigorous physical elastic deformation laws, enabling accurate prediction of the mechanical energy level required for component repositioning. The spatial vector dot product projection algorithm is well-known and will not be elaborated further.

[0040] Preferably, in one feasible embodiment, the method for outputting construction instructions is as follows: Considering that the forced correction process essentially generates forced displacement stress within the component, in order to quantitatively assess whether this forced displacement stress will cause irreversible plastic deformation of the component, the vertical correction force, cantilever length, and the maximum distance from the center to the edge of the steel precast section in the vertical direction are multiplied to obtain the vertical stress calculation numerator, which accurately reflects the maximum external bending moment load effect generated when the vertical correction force acts at the end; in order to obtain the exact stress value of the outermost layer of the section under tension or compression, the vertical stress calculation numerator is divided by the moment of inertia of the strong axis section to obtain the vertical correction force corresponding to the moment of inertia. The edge stress of the vertical member accurately reflects the highest mechanical strength challenge the member bears during vertical repositioning, which is helpful in predicting the yield risk of the material. Similarly, multiplying the horizontal correction force, cantilever length, and the maximum distance from the center to the edge of the cross-section of the precast steel structure in the horizontal direction yields the horizontal stress calculation numerator, which accurately reflects the contribution of the horizontal bending moment generated by the lateral correction force at the root of the member. In order to obtain the actual stress distribution in the weak axis direction, the horizontal stress calculation numerator is divided by the moment of inertia of the weak axis section to obtain the horizontal member edge stress corresponding to the horizontal correction force, which accurately reflects the stress state of the member at the edge of the cross-section during horizontal correction, which is helpful in ensuring the overall safety of bidirectional correction. To eliminate the comparison discrepancies between different calculation systems and physical dimensions, the vertical and horizontal correction forces are converted to the same dimension unit as the rated load of the equipment on site (for example, when the calculated force unit is N and the rated load unit is ton (t), N is converted to t based on gravitational acceleration g before numerical comparison), so as to achieve direct comparison between calculated data and equipment capacity. Considering that construction safety is the primary red line for pre-assembly guidance, in order to strictly prevent component damage or equipment overload accidents, the matching relationship between correction requirements and bearing capacity is analyzed. If the edge stress of the vertical or horizontal component is greater than the allowable stress of the precast steel structure material, or if any correction force after unification of dimensions is greater than the rated load threshold of the equipment on site, it is said that... The required correction energy exceeds the physical limits of the material or the rated load of the construction equipment. To prevent safety hazards caused by forced installation, forced correction is deemed infeasible. In order to eliminate residual geometric interference through physical modification, the overlap envelope of the measured hole center and the theoretical hole center is calculated to generate a hole enlargement correction instruction, which clearly indicates the hole enlargement amount and orientation for the specific hole position. The specific method for obtaining the hole enlargement correction instruction is as follows: for the specific hole position where interference occurs, the maximum intrusion depth from the edge of the measured hole wall to the envelope of the designed hole diameter is calculated as the cutting amount, and the unit direction vector from the measured hole center to the designed hole center is used as the hole enlargement orientation, forming a digital processing list containing the hole number, cutting depth and cutting orientation. If the edge stress of both the vertical and horizontal components is less than or equal to the allowable stress, and the corrective force after unification of dimensions is less than or equal to the corresponding rated load threshold of the on-site equipment, it indicates that the component is within the safe range of elastic deformation and the on-site equipment has sufficient capacity. In order to maximize the use of the material's elastic recovery characteristics to complete precise docking, forced correction is deemed feasible. To provide on-site workers with quantitative construction basis, specific force value suggestions for each axial direction are output to generate auxiliary correction instructions, guiding the on-site equipment to apply precise correction thrust. The specific method for obtaining the auxiliary correction instructions is as follows: the calculated vertical and horizontal correction forces are mapped to the control parameters of the on-site hydraulic jacking equipment and lateral traction equipment, respectively, and a construction operation manual containing the coordinates of the force application point (i.e., the center of mass of the free end), the magnitude of the force, and the direction of the force vector is output to guide workers to achieve forced centering installation of the components with mechanical assistance.

[0041] In summary, this embodiment acquires scanned point clouds and BIM models, extracts end normal vectors and hole center features, and constructs a component body coordinate system to achieve data standardization. Through datum alignment transformation, the anchoring end is aligned to the design position, and a gravity pre-camber compensation vector is superimposed to generate a virtual installation state reflecting the actual cantilever condition. Hole positions are matched to obtain manufacturing shape deviations and shear deformation deviations; if qualified, the overall misalignment vector of the free end is extracted. The misalignment vector is decomposed to the strong and weak axes of the section, and the corrective force is calculated based on the axial cantilever beam mechanical model. Construction commands are then output by combining the component edge stress and the equipment's rated load. This invention achieves realistic simulation of single-end installation conditions and gravity deformation, scientifically decouples manufacturing defects and elastic deviations, and provides quantitative auxiliary construction guidance, effectively reducing factory rework rates and improving on-site installation efficiency.

[0042] Example 2: This invention also proposes a BIM-based prefabrication system for steel structure components. Please refer to [link / reference]. Figure 2 The diagram shows a structural diagram of a BIM-based prefabrication system for steel structures provided in an embodiment of the present invention. The system includes: a data acquisition module 10, a standardized hole acquisition module 20, a virtual installation state free end hole acquisition module 30, an overall misalignment vector acquisition module 40, and a construction instruction acquisition module 50.

[0043] The data acquisition module 10 is used to acquire scanned point cloud data of precast steel structures and BIM model data.

[0044] The standardized hole center acquisition module 20 is used to locate the end area based on BIM model data, extract the measured end plate plane normal vector, the measured anchor end hole center, and the measured free end hole center from the scanned point cloud data; construct the component body coordinate system based on the measured end plate plane normal vector and the measured anchor end hole center, and map the extracted measured hole center to the component body coordinate system to obtain the standardized anchor end hole center and the standardized free end hole center.

[0045] The virtual installation state free end hole center acquisition module 30 is used to acquire the reference alignment transformation matrix that aligns the standardized anchoring end hole center to the design anchoring end hole center; apply the reference alignment transformation matrix to the standardized free end hole center, and superimpose the gravity precamber compensation vector determined based on the component properties to generate the virtual installation state free end hole center.

[0046] The overall misalignment vector acquisition module 40 is used to match the virtual installation state free end hole center with the design free end hole center, and obtain the manufacturing shape deviation and shear deformation deviation of the hole group. If the manufacturing shape deviation meets the preset size tolerance threshold and the shear deformation deviation meets the preset ratio threshold, then the overall misalignment vector of the virtual installation state free end hole center relative to the design free end hole center is calculated.

[0047] The construction instruction acquisition module 50 is used to decompose the overall misalignment vector to the strong axis and weak axis of the section, and back-calculate the vertical and horizontal correction forces based on the axial cantilever beam mechanical model; based on the component edge stress corresponding to the correction force and the rated load of the on-site equipment, it outputs construction instructions.

[0048] It should be noted that the system provided in the above embodiments is only an example of the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the computer equipment can be divided into different functional modules to complete all or part of the functions described above. In addition, the BIM-based prefabricated steel structure component pre-assembly system and the BIM-based prefabricated steel structure component pre-assembly method embodiments provided in the above embodiments belong to the same concept, and their specific implementation process is detailed in the method embodiments, which will not be repeated here.

[0049] Example 3: This invention also proposes a BIM-based prefabrication device for steel structure precast components. This device includes a memory and a processor. The memory stores executable program code, and the processor calls and executes the executable program code to perform the BIM-based prefabrication method for steel structure precast components provided in the embodiments of this application. Specifically, the device may be a chip, component, or module. The chip may include a connected processor and memory; the memory stores instructions, and when the processor calls and executes the instructions, the chip can perform the BIM-based prefabrication method for steel structure precast components provided in the above embodiments.

[0050] In addition, this embodiment also protects a computer device; please refer to [link to relevant documentation]. Figure 3 The computer device includes a memory 401, a processor 402, and a computer program 403 stored in the memory 401 and running on the processor 402. When the processor 402 executes the computer program 403, the computer device can execute any of the BIM-based prefabrication methods for steel structure components described above.

[0051] Example 4: The present invention also provides a computer-readable storage medium storing computer program code, which, when executed on a computer, causes the computer to perform the aforementioned method steps to implement the BIM-based prefabrication method for steel structure precast components provided in the above embodiments.

[0052] Example 5: The present invention also provides a computer program product that, when run on a computer, causes the computer to perform the aforementioned related steps to realize the BIM-based prefabrication method for steel structure prefabrication provided in the above embodiments.

[0053] In this embodiment, the device, computer-readable storage medium, computer program product, or chip are all used to execute the corresponding methods provided above. Therefore, the beneficial effects they can achieve can be referred to the beneficial effects in the corresponding methods provided above, and will not be repeated here.

[0054] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0055] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A BIM-based method for prefabricated steel structure components, characterized in that, The method includes the following steps: Acquire scanned point cloud data and BIM model data of precast steel structure components; Based on the BIM model data, the end area is located, and the measured end plate plane normal vector, measured anchor end hole center, and measured free end hole center are extracted from the scanned point cloud data. Based on the measured end plate plane normal vector and measured anchor end hole center, a component body coordinate system is constructed, and the extracted measured hole centers are mapped to the component body coordinate system to obtain the standardized anchor end hole center and standardized free end hole center. Obtain the reference alignment transformation matrix that aligns the standardized anchoring end hole center to the designed anchoring end hole center; apply the reference alignment transformation matrix to the standardized free end hole center, and superimpose the gravity precamber compensation vector determined based on the component properties to generate the virtual installed free end hole center; Match the virtual installation state free end hole center with the design free end hole center, obtain the manufacturing shape deviation and shear deformation deviation of the hole group. If the manufacturing shape deviation meets the preset size tolerance threshold and the shear deformation deviation meets the preset ratio threshold, then calculate the overall misalignment vector of the virtual installation state free end hole center relative to the design free end hole center. The overall misalignment vector is decomposed into the strong and weak axes of the cross section, and the vertical and horizontal corrective forces are back-calculated based on the axial cantilever beam mechanical model. Based on the component edge stress corresponding to the corrective force and the rated load of the on-site equipment, construction instructions are output.

2. The BIM-based prefabrication method for steel structure components as described in claim 1, characterized in that, The method for obtaining the component body coordinate system is as follows: The origin is the geometric centroid of the measured anchoring end hole, and the Z-axis is the measured plane normal vector of the end plate. Calculate the line connecting the hole pairs with the farthest distance in the measured anchoring end holes, project the line connecting the hole pairs onto the end plate plane as the initial reference vector, and map the local axial direction of the component in the BIM model data onto the end plate plane to obtain the target reference vector. Calculate the angle between the initial reference vector and the target reference vector in the endplate plane, rotate the initial reference vector by the angle using a two-dimensional rotation matrix to make it parallel to the target reference vector, and generate the X-axis after normalization. The Y-axis is obtained by calculating the cross product of the Z-axis and the X-axis using the right-hand rule. Construct a component body coordinate system based on the origin, X-axis, Y-axis, and Z-axis.

3. The BIM-based prefabrication method for steel structure components as described in claim 1, characterized in that, The method for obtaining the reference alignment transformation matrix is ​​as follows: The geometric centers of the standardized anchoring end hole center and the designed anchoring end hole center are calculated separately. The standardized anchoring end hole center and the designed anchoring end hole center are decentered and the cross-covariance matrix is ​​calculated. The initial rotation matrix is ​​obtained by performing singular value decomposition on the cross-covariance matrix. The determinant of the initial rotation matrix is ​​checked. If the determinant is less than zero, the last column of the right singular matrix obtained by singular value decomposition is inverted to recalculate the physically valid rotation matrix. If the determinant is not less than zero, then the initial rotation matrix is ​​used as the rotation matrix; Multiply the geometric center of the standardized anchoring end hole center by the rotation matrix to obtain the rotated geometric center; Subtract the rotated geometric center from the geometric center of the anchoring end hole to obtain the translation vector; The rotation matrix and translation vector are combined into a homogeneous transformation matrix, which serves as the reference alignment transformation matrix.

4. The BIM-based prefabrication method for steel structure components as described in claim 1, characterized in that, The method for obtaining the virtual installation state free end hole center is as follows: Obtain the initial gravity vector in the global coordinate system of the BIM model data, and extract the theoretical rotation matrix of the local coordinate system of the precast steel structure component in the BIM model data relative to the global coordinate system. Multiply the initial gravity vector by the inverse of the theoretical rotation matrix to obtain the projection vector of the initial gravity vector in the local coordinate system. The direction of the projection vector is used as the direction of the compensation vector; Read the preset camber value from the BIM model data as the compensation amount; If no preset camber value is specified, the section moment of inertia, elastic modulus, linear density, and cantilever length of the precast steel structure are obtained; where the section moment of inertia is the principal axis moment of inertia of the component perpendicular to the direction of gravity in the virtual installation state. Multiply the linear density, gravitational acceleration, and the fourth power of the cantilever length to obtain the first product; multiply the constant 8, elastic modulus, and moment of inertia of the section to obtain the second product; divide the first product by the second product to obtain the quotient, which is used as the compensation amount; The direction of the compensation vector is normalized to a unit direction vector, and the unit direction vector is multiplied by the compensation amount to obtain the gravity precamber compensation vector. After multiplying the reference alignment transformation matrix with the standardized free end hole center, and then adding it with the gravity pre-camber compensation vector, the virtual installation state free end hole center is obtained.

5. The BIM-based prefabrication method for steel structure components as described in claim 3, characterized in that, The method for obtaining the manufacturing shape deviation and shear deformation deviation is as follows: A one-to-one correspondence between the center of the virtual installed free end hole and the center of the designed free end hole is established by using a bipartite graph matching algorithm. The geometric centers of the virtual installed free end hole and the designed free end hole are calculated respectively, and the corresponding homogeneous transformation matrix is ​​obtained as the best matching transformation matrix. Apply the best matching transformation matrix to the virtual installed free end hole center, calculate the root mean square error between the transformed virtual installed free end hole center and the corresponding design free end hole center, and use it as the manufacturing shape deviation. Singular value decomposition is performed on the virtual installation state free end hole center set and the design free end hole center set after decentralization and projection onto the end plate plane, respectively. The singular values ​​of each set in the two principal axis directions in the end plate plane are extracted. The larger value of the singular values ​​in the two principal axis directions of each set is divided by the smaller value to obtain the singular value ratio of each set. The absolute value of the difference between the singular value ratio of the virtual installed free end hole set and the design free end hole set is taken as the shear deformation deviation.

6. The BIM-based prefabrication method for steel structure components as described in claim 5, characterized in that, The method for obtaining the overall misalignment vector is as follows: Based on the one-to-one correspondence, calculate the coordinate difference vector between each virtual installation state free end hole center and the corresponding design free end hole center; The average of the coordinate difference vectors of all matching hole pairs is used to obtain the overall misalignment vector of the virtual installed free end hole center relative to the designed free end hole center.

7. The BIM-based prefabrication method for steel structure components as described in claim 4, characterized in that, The method for obtaining the vertical and horizontal corrective forces is as follows: The overall misalignment vector is projected onto the strong and weak axes of the local coordinate system of the precast steel structure to obtain the vertical displacement component and the horizontal displacement component. Extract the elastic modulus, moment of inertia of the strong axis section, moment of inertia of the weak axis section, and cantilever length from the BIM model data; The vertical corrective force is calculated by substituting the moment of inertia and vertical displacement components of the strong axial section into the stress-deformation formula at the end of the cantilever beam. The horizontal corrective force is calculated by substituting the moment of inertia and horizontal displacement components of the weak axis section into the stress-deformation formula at the end of the cantilever beam.

8. The BIM-based prefabrication method for steel structure components as described in claim 7, characterized in that, The method for outputting construction instructions is as follows: The vertical stress calculation numerator is obtained by multiplying the vertical correction force, cantilever length, and the maximum distance from the center to the edge of the cross-section of the precast steel structure in the vertical direction. Divide the calculated vertical stress numerator by the moment of inertia of the strong axis section to obtain the vertical component edge stress corresponding to the vertical correction force; Multiply the horizontal correction force, cantilever length, and the maximum distance from the center to the edge of the cross-section of the precast steel structure in the horizontal direction to obtain the numerator for calculating the horizontal stress. Divide the horizontal stress calculation numerator by the moment of inertia of the weak axis section to obtain the horizontal component edge stress corresponding to the horizontal correction force; The vertical and horizontal correction forces are converted to the same units as the rated load of the equipment on site. If the edge stress of a vertical member or the edge stress of a horizontal member is greater than the allowable stress of the precast steel structure material, or if any uniform dimension correction force is greater than the rated load threshold of the field equipment, then forced correction is deemed infeasible, and a hole enlargement correction command is generated. If the edge stress of both the vertical and horizontal components is less than or equal to the allowable stress, and the corrective force after unification of dimensions is less than or equal to the corresponding rated load threshold of the field equipment, then forced correction is deemed feasible, and an auxiliary correction instruction is generated.

9. The BIM-based prefabrication method for steel structure components as described in claim 1, characterized in that, The method for obtaining the measured end plate plane normal vector is as follows: extract the theoretical center coordinates based on the connection markers in the BIM model data, and establish an oriented bounding box in the scanned point cloud data to cut out the end point cloud subset; Principal component analysis is performed on the scanned point cloud data to extract the principal inertial axis, which is then aligned with the major axis of the component in the BIM model data to obtain a coarse alignment matrix. The theoretical normal vectors in the BIM model data are mapped to the coordinate system of the current point cloud using the coarse alignment matrix. Random sampling consistency plane fitting with normal constraints is performed on the end point cloud subset to obtain the measured end plate plane normal vectors. The normal constraint is that the angle between the fitted plane normal vector and the mapped theoretical normal vector is less than a preset angle threshold. The method for obtaining the measured anchor end hole center is as follows: In the end point cloud subset corresponding to the anchor end, noise points exceeding the distance limit are removed based on the fitted optimal end plate plane, and Euclidean clustering and cylindrical surface fitting are performed on the remaining point cloud to extract the cylindrical surface center to obtain the measured anchor end hole center. The method for obtaining the measured center of the free end hole is as follows: Euclidean clustering and cylindrical surface fitting are performed on the end point cloud subset corresponding to the free end to extract the center of the cylindrical surface and obtain the measured center of the free end hole.

10. A BIM-based prefabrication system for steel structure components, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the BIM-based prefabrication method for steel structure prefabrication as described in any one of claims 1-9.

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