Large steel structure segmented in-plant pre-assembly closed loop compensation method

Abstract

This invention discloses a segmented, pre-assembled, closed-loop compensation method for large steel structures, comprising: establishing a unified spatial reference on an assembly platform; deploying multiple supporting fixtures adapted to the main body segments; hoisting multiple main body segments onto the supporting fixtures; performing preliminary positioning and splicing based on the spatial reference to form a preliminary frame of the large steel structure; acquiring actual three-dimensional coordinate data of the docking interfaces of adjacent main body segments on the preliminary frame based on a unified measurement reference; calculating the measured distance between adjacent interfaces based on the actual three-dimensional coordinate data and comparing it with the theoretical distance in the theoretical model; determining the compensation dimension of the transition section based on the difference between the two; processing the transition section in the factory according to the compensation dimension; and assembling the processed transition section with the corresponding main body segment to form the final overall frame. This invention transforms static prevention into dynamic closed-loop compensation, effectively mitigating assembly risks by moving them forward to the factory, thus ensuring the long-term safety of the structure.

Description

Technical Field

[0001] This invention relates to the field of large steel structure manufacturing technology, specifically a segmented, in-plant pre-assembled closed-loop compensation method for large steel structures. Background Technology

[0002] Large steel structures, such as large bridges and stadium trusses, are typically constructed using a segmented manufacturing and on-site assembly method due to their massive dimensions. However, during segmented manufacturing, welding deformation, machining errors, and assembly errors are difficult to completely avoid. This results in unpredictable cumulative errors during on-site assembly, even though each segment may meet tolerance requirements when manufactured individually. These cumulative errors manifest as misaligned interfaces, misaligned bolt holes, and out-of-tolerance overall dimensions, becoming a long-standing technical challenge for on-site assembly in the industry.

[0003] Currently, the industry practice is to improve initial machining accuracy by strictly controlling the manufacturing tolerances of each individual component segment, thereby ensuring smooth on-site assembly. However, when unavoidable cumulative errors lead to interface mismatches, traditional solutions can only passively resort to remedial measures such as on-site trimming, flame straightening, forced hole enlargement, or adding shims. These on-site operation methods have significant drawbacks: First, construction efficiency is low, heavily relying on workers' experience and on-site judgment, and constrained by variable and uncontrollable environmental factors, affecting measurement and assembly accuracy. Second, costs are high, including high labor costs, machinery rental fees, site rental fees, and huge economic losses due to project delays. More seriously, forced assembly introduces additional assembly stress, directly damaging the long-term fatigue performance and safety durability of the structure.

[0004] In summary, existing technologies are essentially preventative open-loop control strategies, unable to provide dynamic feedback and compensation for errors already generated during the manufacturing process. Therefore, there is an urgent need in this field for an innovative method capable of achieving closed-loop precision control. This method would systematically predict, quantify, and compensate for accumulated errors within a well-designed factory environment, thereby transforming uncontrollable on-site assembly risks into controllable in-plant manufacturing problems. Summary of the Invention

[0005] The purpose of this invention is to provide a segmented, prefabricated closed-loop compensation method for large steel structures to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for prefabricated closed-loop compensation of segmented steel structures in a factory, the method comprising:

[0007] S1: Establish a unified spatial benchmark on the assembly platform, deploy multiple supporting fixtures adapted to the main body segments, hoist multiple main body segments onto the supporting fixtures, and perform preliminary positioning and splicing based on the spatial benchmark to form the preliminary frame of the large steel structure; S2: Based on the unified measurement benchmark, obtain the actual three-dimensional coordinate data of the docking interfaces of adjacent main body segments on the preliminary frame; calculate the measured distance between adjacent interfaces based on the actual three-dimensional coordinate data, compare it with the theoretical distance in the theoretical model, and determine the compensation size of the transition section used to connect adjacent main body segments based on the difference between the two; S3: Process the transition section in the factory according to the compensation size, and assemble the processed transition section with the corresponding main body segment to form the final overall frame.

[0008] Furthermore, in step S1, after establishing a unified spatial reference on the assembly platform and setting up multiple support fixtures, all support fixtures are leveled as a whole.

[0009] Furthermore, the spatial reference is established by drawing mutually perpendicular cross reference lines and component positioning lines.

[0010] Furthermore, the supporting fixture is a height-adjustable rigid support.

[0011] Furthermore, in step S2, a total station or laser tracker is used to acquire the actual three-dimensional coordinate data.

[0012] Furthermore, step S4 involves precisely adjusting the overall frame and creating matching marks at the segmented connection interfaces where the adjustments are in place.

[0013] Furthermore, before creating the matching marks, at least some of the connecting flanges of the overall frame are spot-welded together for fixation.

[0014] Furthermore, the pairing mark is a stamp.

[0015] Furthermore, ambient temperature data is monitored and recorded simultaneously throughout the entire pre-installation process.

[0016] Furthermore, in step S3, the overall frame formed meets the following accuracy requirements: the overall length deviation is ±5mm, the diagonal deviation is ±10mm, and the flatness and straightness are no more than 10mm.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: By collecting the actual data of the preliminary framework and directly comparing it with the theoretical model, the present invention dynamically calculates the precise compensation amount, processes the transition section based on this, actively eliminates the cumulative errors generated during the manufacturing and pre-assembly processes, transforms static prevention into dynamic closed-loop compensation, moves the assembly risk forward to be effectively resolved within the factory, ensures the matching of each segmented interface, thus eliminating the additional assembly stress introduced by forced assembly at the source, ensuring the long-term safety of the structure, and forming a general solution that can be widely applied to various large steel structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the overall process flow chart of the in-factory pre-assembly closed-loop compensation method for large steel structures in the present invention;

[0019] Figure 2 It is a schematic diagram of lofting on the in-factory pre-assembly platform in the in-factory pre-assembly closed-loop compensation method for large steel structures in the present invention;

[0020] Figure 3 It is the main view structural schematic diagram of the tooling layout on the in-factory pre-assembly platform in the in-factory pre-assembly closed-loop compensation method for large steel structures in the present invention;

[0021] Figure 4 It is the top view structural schematic diagram of the tooling layout on the in-factory pre-assembly platform in the in-factory pre-assembly closed-loop compensation method for large steel structures in the present invention;

[0022] Figure 5 It is a schematic diagram of the assembly of the "mouth" - shaped preliminary framework in the in-factory pre-assembly closed-loop compensation method for large steel structures in the present invention;

[0023] Figure 6 It is the schematic diagram of the closed-loop control principle in the in-factory pre-assembly closed-loop compensation method for large steel structures in the present invention;

[0024] Figure 7 It is a schematic diagram of the reset reference line of the main view structure in the in-factory pre-assembly closed-loop compensation method for large steel structures in the present invention;

[0025] Figure 8 It is a schematic diagram of the reset reference line of the top view structure in the in-factory pre-assembly closed-loop compensation method for large steel structures in the present invention;

[0026] Figure 9 It is a schematic diagram of the steel stamp matching mark of the flange in the in-factory pre-assembly closed-loop compensation method for large steel structures in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] like Figure 1 As shown, this embodiment provides a method for prefabricated closed-loop compensation of large steel structures in a segmented factory, including the following steps:

[0029] S1. Establishing a reference and setting up tooling: Establish a unified spatial reference on the assembly platform and set up multiple supporting toolings that are compatible with the main body segments. Through this step, output a unified spatial reference and a leveled tooling platform.

[0030] S2. Preliminary Frame Assembly: Multiple main body sections are hoisted onto supporting fixtures, and preliminary positioning and splicing are carried out based on spatial references to form the preliminary frame of the large steel structure. Through this step, the cumulative error of the exposed interfaces can be obtained.

[0031] S3. Data Acquisition and Closed-Loop Compensation: Based on a unified measurement benchmark, acquire the actual three-dimensional coordinate data of the docking interfaces of adjacent main body segments on the preliminary frame; calculate the measured distance between adjacent interfaces based on the actual three-dimensional coordinate data, and compare it with the theoretical distance in the theoretical model. Determine the compensation size of the transition section used to connect adjacent main body segments based on the difference between the two. Output the optimal compensation amount through this step. If the requirements are not met, use a total station to measure and calculate the precise size of the transition section. S4. Overall Frame Assembly, Fine Adjustment and Marking: Process the transition section in the factory according to the compensation size, and assemble the processed transition section with the corresponding main body segment to form the final overall frame. Make precise adjustments to the overall frame, and make matching marks at the segment connection interfaces where the adjustment is in place. Output permanent marks through this step, and adaptability processing and on-site cutting can be performed.

[0032] S5. Environmental monitoring: During the entire pre-installation process, the ambient temperature data is monitored and recorded synchronously, and the temperature record is output through this step.

[0033] Specifically, this embodiment uses the pre-assembly of the lower crossbeam of a large steel structure as an example for illustration:

[0034] like Figure 2 As shown, on a solid and flat assembly platform in the factory, a total station is used for precise layout to establish a unified spatial reference network. First, mutually perpendicular cross center reference lines are established, namely the horizontal center line and the vertical center line. Figure 2In the diagram, the horizontal dashed lines represent the horizontal center lines, and the vertical dashed lines represent the vertical center lines. Their orthogonality is controlled to ensure that the deviation of each positioning axis from its theoretical position is no greater than 3.0 mm. Next, the positioning axes of all lower crossbeams, such as those numbered 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, and 16, and the layout center lines of each supporting fixture 100 are precisely marked. In this embodiment, the supporting fixture 100 is a height-adjustable rigid support.

[0035] like Figure 3 and Figure 4 As shown, the support fixtures 100 are laid out and leveled. Multiple support fixtures 100 are precisely positioned according to the layout location. An electronic level is used to level the upper surface of all support fixtures 100 as a whole, ensuring that their flatness is better than 0.1 mm / m. After leveling, the support fixtures 100 are pressed and fixed on the assembly platform, thereby forming a highly stable reference system.

[0036] like Figure 5 As shown, the lower crossbeam to be pre-installed is divided into four main sections: A, B, C, and D. These four main sections are then hoisted onto the leveled support fixture 100 in sequence. Using the cross center baseline laid out on the ground as a reference, each main section is initially positioned using tools such as a plumb bob and a steel ruler, controlling the distance deviation between it and the cross center baseline within ±3mm.

[0037] After initial positioning, the geometric position of the preliminary frame is controlled: through measurement and adjustment, the corresponding steel plate walls of main body segment A and main body segment C are ensured to be parallel to each other, with a parallelism of 0.05mm / m. Simultaneously, the theoretical distance L1 between main body segment A and main body segment C is controlled to be equal to the theoretical distance L2 between main body segment B and main body segment D, with a deviation not exceeding ±3mm, thus forming a stable "U"-shaped preliminary frame. To prevent deformation of the preliminary frame during subsequent operations, guy ropes are used to reinforce it.

[0038] After the initial framework stabilizes, data acquisition and closed-loop compensation processing are performed, involving closed-loop accuracy control, the principle of which is as follows: Figure 6 As shown, a total station or laser tracker was used to perform precise measurements on the preliminary frame. The measurements are as follows:

[0039] (1) Use a total station or laser tracker to measure the actual three-dimensional coordinate data of the docking interface of adjacent main body segments on the preliminary frame, and calculate the measured distance between adjacent interfaces based on the actual three-dimensional coordinate data, such as the measured distance L1' between the flange faces of main body segment A and main body segment C, and the measured distance L2' between main body segment B and main body segment D.

[0040] (2) Perform plane fitting on the measuring points on the connecting flanges of each main body segment to detect the flatness of the flange surface and its spatial angle with the horizontal plane.

[0041] Subsequently, closed-loop feedback and dynamic compensation calculations are performed:

[0042] (1) Closed-loop feedback: The measured distance is compared with the theoretical distance in the theoretical model. Based on the difference between the two, the compensation size of the transition section used to connect adjacent main body segments is determined. Taking the transition section of main body segment B as an example, the nodes are compared, and the assembly error of adjacent main body segments, i.e., △L=L1'-L1, is defined as the closed-loop compensation amount. Based on this, the optimal compensation amount of the transition section is calculated through the closed-loop feedback calculation module to obtain the compensation processing size: L 加工 = L2 + △L.

[0043] (2) Dynamic compensation: based on the determined compensation size L 加工 High-precision CNC cutting equipment is used in the factory to cut the raw materials and transition sections of the main body section B on-site, and to complete the beveling at both ends.

[0044] Following the above process, the transition segments of main body segment A, main body segment C, and main body segment D are determined and processed sequentially. The method of determining the compensation dimension based on the difference between the measured distance and the theoretical distance is also applicable to all connection parts that require precision compensation.

[0045] All the completed transition sections are hoisted into place and assembled with main body sections A, B, C, and D to form a complete lower crossbeam frame, which is the actual steel structure frame. Subsequently, the overall frame undergoes final fine-tuning. Key dimensions of the overall frame are re-measured using a data acquisition module, such as a total station or laser tracker, including: overall length and diagonal dimensions. Figure 4 The measured geometrical data, such as L1~L6, straightness, and flatness, are used to adjust all dimensions to the preset accuracy range by fine-tuning the height of the support fixture 100. For example, the overall frame length deviation is ±5mm; the diagonal deviation is ±10mm; and the flatness and straightness are no more than 10mm. If the requirements are not met, the nodes are re-compared and the difference △L is recalculated.

[0046] After all dimensions have passed inspection, systematic labeling should be carried out, such as... Figures 7-9 As shown.

[0047] (1) Make clear reset baseline markings at key locations such as the center line of the steel plate wall of the large steel structure support, such as Figure 6 The dashed line in the middle.

[0048] (2) At the connecting flanges of all main body sections, perform matching spot welding, and make a steel stamp matching mark 20 based on this, which is a permanent mark.

[0049] At key points and after the completion of the pre-assembly process, the ambient temperature was monitored and recorded simultaneously. The recorded temperature data provided a benchmark for the thermal deformation analysis and compensation of the structure, enabling precision control and data traceability throughout the entire process from factory pre-assembly to on-site final assembly.

[0050] This invention collects actual data from the preliminary framework and compares it directly with the theoretical model to dynamically calculate the precise compensation amount. Based on this, the transition section is processed, proactively eliminating the cumulative errors generated during manufacturing and pre-assembly. It transforms static prevention into dynamic closed-loop compensation, effectively mitigating assembly risks in the factory and ensuring the compatibility of interfaces between each segment. This eliminates additional assembly stress introduced by forced assembly at the source, ensuring the long-term safety of the structure and forming a universal solution that can be widely applied to various large steel structures.

[0051] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for closed-loop compensation of segmented prefabricated large steel structures in the factory, characterized in that, The method includes: S1: Establish a unified spatial benchmark on the assembly platform, deploy multiple supporting fixtures adapted to the main body segments, hoist the main body segments onto the supporting fixtures, and perform preliminary positioning and splicing based on the spatial benchmark to form the preliminary frame of the large steel structure; S2: Based on the unified measurement benchmark, obtain the actual three-dimensional coordinate data of the docking interfaces of adjacent main body segments on the preliminary frame; calculate the measured distance between adjacent interfaces based on the actual three-dimensional coordinate data, compare it with the theoretical distance in the theoretical model, and determine the compensation size of the transition section used to connect adjacent main body segments based on the difference between the two; S3: Process the transition section in the factory according to the compensation size, and assemble the processed transition section with the corresponding main body segment to form the final overall frame.

2. The segmented prefabricated closed-loop compensation method for large steel structures according to claim 1, characterized in that: In step S1, a unified spatial reference is established on the assembly platform, and after multiple support fixtures are set up, all support fixtures are leveled as a whole.

3. The segmented prefabricated closed-loop compensation method for large steel structures according to claim 1 or 2, characterized in that: The spatial reference is established by drawing mutually perpendicular cross reference lines and component positioning lines.

4. The segmented prefabricated closed-loop compensation method for large steel structures according to claim 1, characterized in that: The supporting fixture is a height-adjustable rigid support.

5. The segmented prefabricated closed-loop compensation method for large steel structures according to claim 1, characterized in that: In step S2, a total station or laser tracker is used to obtain the actual three-dimensional coordinate data.

6. The segmented prefabricated closed-loop compensation method for large steel structures according to claim 1, characterized in that: It also includes step S4, which involves making precise adjustments to the overall frame and creating matching marks at the segmented connection interfaces where the adjustments are in place.

7. The segmented prefabricated closed-loop compensation method for large steel structures according to claim 6, characterized in that: Before creating the matching marks, at least some of the connecting flanges of the overall frame are spot-welded together for fixation.

8. The segmented prefabricated closed-loop compensation method for large steel structures according to claim 1 or 6, characterized in that: The matching mark is a steel stamp.

9. The segmented prefabricated closed-loop compensation method for large steel structures according to claim 1, characterized in that: Throughout the pre-installation process, ambient temperature data is monitored and recorded simultaneously.

10. The segmented prefabricated closed-loop compensation method for large steel structures according to claim 1, characterized in that, In step S3, the overall frame formed meets the following accuracy requirements: the overall length deviation is ±5mm, the diagonal deviation is ±10mm, and the flatness and straightness are no more than 10mm.

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