Construction method based on movable steel box girder road-crossing construction working platform

Abstract

The invention relates to the technical field of bridge construction, and discloses a construction method based on a movable steel box girder road-crossing construction working platform, which comprises the following steps: building a light modular elevated track system above a bridge site to be built; the intelligent self-driven suspension type transfer crane is used for transporting the steel box girder segments to be spliced along the rail; during butt joint, the adjoint type dynamic stress balance system is started, active balance torque is applied to the installed segments through a stress balance arm so as to counteract cantilever disturbance torque of the segments to be spliced, and meanwhile the main gripper system conducts posture fine adjustment to achieve alignment. The connection operation is carried out by an independent welding work station, and the transfer crane can transport the next section in parallel. The system comprises the track system and a crane. Construction and the ground are decoupled, traffic is not interrupted, the method does not depend on a large site, the splicing precision is guaranteed through dynamic balance butt joint, and the construction efficiency is improved through parallel operation.

Description

Technical Field

[0001] This invention relates to the field of bridge construction technology, specifically a construction method based on a mobile steel box girder cross-road construction platform. Background Technology

[0002] Steel box girders have been widely used in urban infrastructure construction, such as elevated bridges and grade-separated interchanges, due to their advantages of high load-bearing capacity, lightweight structure, and aesthetically pleasing appearance. However, in busy urban environments with limited land, how to efficiently, safely, and with low impact complete the erection of steel box girders remains a major technical challenge in the field of bridge construction.

[0003] Currently, there are various technical methods in the industry for constructing steel box girders across roads. One relatively traditional method is the ground-supported scaffolding method. This method requires erecting full-span or partial load-bearing scaffolding under the bridge to be built, and then assembling the steel box girder segments piece by piece or hoisting them as a whole on the scaffolding. A significant drawback of this method is that the temporary scaffolding system will occupy the existing road below for a long time and over a large area, forcing traffic to be interrupted or complex traffic diversions to be carried out during construction, which will seriously affect the normal operation of urban traffic.

[0004] To minimize disruption to ground traffic, the incremental launching method of bridge construction was developed. This method involves setting up a large rear assembly area at one end of the bridge, where steel box girder segments are assembled one by one. Then, using jacks and other equipment, the connected girder is pushed forward until it reaches the designated bridge position. Although the incremental launching method has minimal impact on traffic below during the launching process, its application is subject to a strict prerequisite: a sufficiently long and flat rear assembly area is required. In densely built-up urban areas where land is scarce and resources are limited, finding a large construction site that meets this condition is often extremely difficult, which greatly restricts the applicability of this method.

[0005] In addition, the large-segment hoisting method is also an option. It uses large-tonnage crawler cranes or truck cranes to directly hoist long beam segments prefabricated in the factory into place. Although this method can shorten the on-site welding and assembly time, the entry, boom extension, and operation of large lifting equipment itself require considerable ground space. Furthermore, some lanes still need to be temporarily closed during hoisting to ensure safety, making it difficult to fundamentally solve the dual dependence of construction on traffic and site conditions.

[0006] Therefore, existing steel box girder construction techniques for road crossings generally face irreconcilable contradictions when applied to complex urban environments with heavy traffic and limited space: either sacrificing traffic flow or requiring a large amount of land. There is an urgent need for a new method that can fundamentally decouple the construction of the bridge superstructure from the ground space, achieving truly "groundless" construction. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a construction method based on a mobile steel box girder cross-road construction platform. This method solves the problems of existing steel box girder cross-road construction methods occupying road traffic for extended periods and relying on large rear assembly sites, making them unsuitable for complex urban environments with heavy traffic and limited space.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a construction method based on a mobile steel box girder cross-road construction platform, comprising: The first aspect of this invention provides a construction method based on a mobile steel box girder cross-road construction platform, the method comprising the following steps: S1: Above the bridge site to be built, a lightweight modular elevated track system will be erected along the non-traffic areas on both sides of the road. This system will serve as a temporary mobile track for subsequent equipment. S2: Using an intelligent self-driven suspended transfer vehicle, the steel box girder segments to be spliced ​​are transported to the cantilever end of the installed steel box girder segments along the light modular elevated track system. S3: Control the intelligent self-driven suspended transfer vehicle to perform docking operations, which include: The stress balance arm on the intelligent self-driven suspended transfer vehicle is anchored to the installed steel box girder segment. The accompanying dynamic stress balancing system integrated in the intelligent self-driven suspended transfer vehicle can sense the cantilever disturbance moment generated by the weight of the steel box girder segment to be spliced ​​in real time, and drive the stress balancing arm to apply an active balancing moment to the installed steel box girder segment to counteract the influence of the cantilever disturbance moment. While applying the active balancing torque, the main gripper system of the intelligent self-driven suspended transfer vehicle is used to perform six-degree-of-freedom attitude fine-tuning on the steel box girder segment to be spliced, so that the docking end face of the steel box girder segment to be spliced ​​and the docking end face of the installed steel box girder segment are geometrically aligned at the preset docking interface. S4: After the docking operation is completed, the steel box girder segment to be spliced ​​is fixedly connected to the installed steel box girder segment through the connection operation.

[0009] As a preferred technical solution, while the connection operation is being carried out in S4, the intelligent self-driven suspended transfer vehicle detaches from the docking interface and returns to grab the next steel box girder segment to be spliced, thereby realizing the parallel execution of the connection operation and the transportation operation.

[0010] As a preferred technical solution, the connection operation in S4 is completed by an independent, unmanned aerial alignment and welding workstation. Before welding, the workstation's built-in 3D laser scanning system scans the docking interface to obtain 3D morphological data of the weld. The welding robot automatically plans its path and performs welding based on this data.

[0011] As a preferred technical solution, before S2, the method further includes: lifting the steel box girder segment to be spliced ​​from the ground to the working height of the lightweight modular elevated track system through a vertical feeding and pre-processing platform set on one side of the bridgehead.

[0012] In the docking operation, the objective of mechanical control is to make the docking interface... The relative displacement vector at the location With relative rotation vector Simultaneously, it approaches zero. To achieve this goal, the system needs to establish dynamic torque balance at the docking interface, with the following equilibrium equation: ; in: The cantilever disturbance moment is caused by the gravity of the steel box girder segments to be spliced. and the force arm vector of its center of mass relative to the main gripper suspension point Generation is the main disturbance of the system, and its expression is: ; The active balancing moment is the active force exerted by the stress balance arm on the installed steel box girder segment. and its point of application lever arm vector Generation is the main control input of the system, used to offset... Its expression is: ; This is the attitude fine-tuning torque, which is applied by the main gripper system during attitude fine-tuning to compensate for unmodeled residual disturbances.

[0013] A second aspect of the present invention provides a construction system for implementing the aforementioned method, the system comprising: The transport module is used to transport steel box girder segments to be assembled to the cantilever ends of already installed steel box girder segments using an intelligent self-driven suspended transfer vehicle that moves along a lightweight modular elevated track system. The torque balancing module is used to sense the cantilever disturbance moment generated by the steel box girder segment to be spliced ​​in real time during the docking process, and to apply an active balancing torque to the installed steel box girder segment to counteract the cantilever disturbance moment. The attitude fine-tuning module is used to fine-tune the attitude of the steel box girder segments to be spliced ​​while the torque balancing module applies the active balancing torque, so as to achieve alignment at the docking interface. The collaborative control module is used to coordinate the operation of the torque balance module and the attitude fine-tuning module based on sensor feedback data.

[0014] In a specific physical implementation, the system includes: A lightweight, modular elevated rail system is designed to provide a temporary aerial rail above the bridge site to be constructed. An intelligent, self-driven, suspended transfer vehicle, configured to move along the aforementioned lightweight modular elevated track system, comprises: The main gripper system is used for gripping, transporting, and fine-tuning the attitude of steel box girder segments; The accompanying dynamic stress balancing system includes a stress balancing arm that can extend and be anchored to an installed steel box girder segment, a sensor array for sensing the cantilever disturbance torque, and an actuation unit for driving the stress balancing arm to apply an active balancing torque. The collaborative control core is used to control the actuation unit to apply the active balancing torque based on the sensing data of the sensor array, and to coordinate with the main gripper system to perform attitude fine-tuning.

[0015] This invention provides a construction method based on a mobile steel box girder cross-road construction platform. It has the following beneficial effects: 1. This invention achieves physical isolation between the construction process and the existing ground traffic by constructing a lightweight modular elevated track system above the bridge site along both sides of the road in non-traffic areas, and transferring all major construction procedures such as the transportation, docking and connection of steel box girder segments to the air. This allows the bridge to be erected without interrupting or occupying the main traffic lanes for an extended period of time.

[0016] 2. This invention utilizes an intelligent self-driven suspended transfer vehicle integrated with an accompanying dynamic stress balancing system. During the docking process, it actively applies an active balancing torque that is equal in magnitude and opposite in direction to the cantilever disturbance torque. In conjunction with the main gripper system, it performs attitude fine-tuning, which can eliminate geometric misalignment and initial internal stress caused by the cantilever effect of the segments to be spliced. This enables high-precision unmanned docking and provides ideal initial conditions for subsequent high-quality connection operations.

[0017] 3. This invention separates the functions of the intelligent self-driven suspended transfer vehicle for transporting steel box girder segments from the unmanned aerial alignment and welding workstation for performing connection operations. This allows the operation of transporting the next segment to be performed in parallel with the operation of connecting the current segment, transforming the traditional serial process into an efficient aerial assembly line operation mode, thereby shortening the total construction cycle. Attached Figure Description

[0018] Figure 1 This is a flowchart of the method of the present invention; Figure 2 This is a system architecture diagram of the present invention. Detailed Implementation

[0019] 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.

[0020] Example: Please see the appendix Figure 1 This invention provides a construction method based on a mobile steel box girder cross-road construction platform, comprising the following steps: S1: Construct a lightweight modular elevated track system above the proposed bridge site; In this embodiment, the lightweight modular elevated track system is a temporary, non-permanent infrastructure constructed to realize the aerial relay assembly construction method proposed in this invention. Its core function is to provide a stable, precise, and independent mobile and operational platform for the subsequent intelligent self-propelled suspended transfer vehicle.

[0021] Specifically, the lightweight modular elevated track system consists of two basic standard units: multiple column modules and multiple truss beam segment modules.

[0022] The column modules are designed to provide vertical support. Each column module has a connecting flange at its bottom for quick bolt connection to a pre-installed temporary foundation on the ground. Preferably, the temporary foundations are located in non-main traffic areas such as non-motorized vehicle lanes, sidewalks, or central green belts on both sides of the road to ensure that normal vehicle traffic is not interfered with throughout the construction period.

[0023] Truss beam segment modules are the skeletal units that form the horizontal track in the air. They are made of lightweight, high-strength materials and designed as a space truss structure to minimize their own weight while meeting load-bearing requirements. This design allows for hoisting using small to medium-sized lifting equipment, reducing the demands on construction machinery. Each truss beam segment module has standardized connection interfaces at both ends for quick and precise bolting to the top of adjacent truss beam segment modules or column modules.

[0024] In this embodiment, the erection steps of the lightweight modular elevated track system are as follows: First, temporary foundations are set up in non-traffic areas along the planned route. Then, during periods of low traffic flow, such as at night, lifting equipment is used to hoist the column modules into place and connect them to the foundations. Finally, truss beam segments are hoisted section by section and connected between the columns, ultimately forming a continuous elevated track that spans the entire span of the bridge under construction and exceeds the clearance requirements of the completed bridge.

[0025] It should be noted that the lightweight modular elevated track system does not bear the final permanent load of the steel box girder, but only serves as a mobile carrier and guide path for the intelligent self-propelled suspended transfer vehicle during transportation and docking operations. Therefore, its structural design and load-bearing capacity only need to meet the vehicle's own weight and the dynamic and static load requirements of the individual steel box girder segments it lifts.

[0026] Furthermore, the lightweight modular elevated track system also provides a physical carrier for other subsystems of the present invention. For example, in a preferred embodiment, the signal base station for high-precision navigation of the gantry crane and the temporary cables for powering various devices can be laid along the truss beam module. This provides the necessary support for subsequent high-precision transportation by the intelligent self-driven suspended transfer gantry crane and for unmanned aerial alignment and welding workstations to perform operations.

[0027] By setting up such a temporary aerial rail system, this invention has creatively expanded the construction work space, transferring the transportation, hoisting, and assembly processes that traditionally had to be completed on the ground to an aerial level that does not conflict with ground traffic.

[0028] This system forms the physical foundation for subsequent core technological steps such as aerial relay transportation of steel box girder segments and dynamic stress balance docking. The intelligent self-driven suspended transfer trolley moves along this track system to perform its transportation function. When the trolley performs docking operations, the track system provides it with a stable reference coordinate system, enabling the trolley to precisely perform torque balance and attitude fine-tuning.

[0029] Torque balance equation The realization of this depends on the stable support provided by the orbital system. Among these, the cantilever disturbance moment... The generation and transmission of the active balancing torque. All adjustments are made with reference to this orbital system. Without the independent operating platform provided by this orbital system, the vehicle cannot stably perform the aforementioned balancing and adjustment maneuvers in the air.

[0030] Therefore, the installation of this lightweight modular elevated track system is not simply a matter of laying tracks, but rather the creation of a complete, ground-independent aerial construction environment. Its lightweight and modular characteristics ensure rapid deployment and dismantling, minimizing the impact of the entire construction process on the urban environment. This system enables a series of subsequent automated and parallel construction steps, which is one of the key prerequisites for this invention to solve the problems of existing technologies.

[0031] S2: Using an intelligent self-driven suspended transfer vehicle, the steel box girder segments to be spliced ​​are transported to the cantilever end of the installed steel box girder segments along a lightweight modular elevated track system. In this embodiment, the use of an intelligent self-driven suspended transfer vehicle to transport the steel box girder segments to be assembled to the cantilever ends of the already installed steel box girder segments along a lightweight modular elevated track system is a key transfer step in realizing the unmanned aerial construction process. This step begins with the aerial grabbing of the steel box girder segments and ends with their arrival at the predetermined docking position, laying the foundation for subsequent dynamic stress balance docking.

[0032] Specifically, the intelligent self-driving suspended transfer vehicle is the core execution device of the method of this invention. Its main structure is equipped with a drive wheel system that meshes with the aforementioned lightweight modular elevated track system, enabling it to move autonomously along the track. The vehicle has a built-in independent power supply unit, preferably a high-capacity lithium battery pack, to support its long-term autonomous operation.

[0033] The initial step of this process involves the intelligent, self-driven, suspended transfer trolley moving to a position directly above the onshore vertical feeding and pre-processing platform. At this location, the trolley's main gripping system is activated. This system, possessing multi-degree-of-freedom adjustment capabilities, descends and grips the steel box girder segment to be assembled (hereinafter referred to as...) which has been raised to the working height. To achieve a firm grip and lock.

[0034] After completing the steel box girder segments After the object is captured, the transportation operation officially begins. One of the core features of the intelligent self-driven suspended transfer vehicle lies in its autonomous navigation and transportation capabilities. This capability is ensured by an integrated, multi-sensor fusion positioning and navigation system.

[0035] In a preferred embodiment, the positioning and navigation system includes a real-time dynamic differential positioning unit for acquiring global absolute coordinates, a lidar for sensing the surrounding environment and performing local path planning, and an inertial measurement unit for providing continuous attitude and position estimation during sensor signal update intervals.

[0036] The vehicle's onboard collaborative control core receives the target command, which includes the endpoint coordinates of the cantilever end of the installed steel box girder segment. Based on its own real-time position and the target position, the collaborative control core autonomously plans an optimal travel path and speed curve along the lightweight modular elevated track system and controls the drive wheel system to execute it precisely.

[0037] To further improve the docking accuracy in the final stage of transportation, this embodiment also introduces a digital beacon-based guidance mechanism. Specifically, each steel box girder segment is implanted with a unique digital beacon during the pre-processing stage. When the intelligent self-driving suspended transfer vehicle carries the steel box girder segment... Travel along the track and approach the target segment At this time, its navigation mode can be switched from RTK-based global absolute coordinate navigation to read-based navigation. Local relative coordinate navigation using digital beacon signals. This switching enables the vehicle to navigate using... Using a reference point, more precise relative position adjustments are made to achieve accurate docking at the docking position.

[0038] Throughout the transportation process, the load-bearing gravity of the intelligent self-driven suspended transfer vehicle is steel box girder segments When it arrives When the cantilever end is suspended, a key physical state is formed: the steel box girder segment to be spliced... It is completely suspended in a cantilevered state by the main gripper system.

[0039] In this state, its gravity The lever arm vector relative to the main gripper suspension point This will inevitably generate a significant cantilever disturbance moment. Its mathematical expression is: ; The cantilever disturbance moment is the core issue to be addressed in the subsequent dynamic stress balancing step. Therefore, the direct technical effect of this transportation step is not merely to complete a displacement, but to accurately and controllably establish a mechanical initial condition that needs to be actively balanced at a predetermined location.

[0040] In summary, this step, through the autonomous navigation and precise transport of an intelligent self-propelled suspended transfer vehicle, safely and accurately delivers independent steel box girder segments from the supply point to the assembly point. It is not only a physical bridge connecting the ground and the air, and linking different construction sites, but also a crucial step for the next stage of high-precision dynamic stress balance docking, i.e., achieving moment balance equations. The necessary and precise initial mechanical and geometric environment was created. The completion of this step marks the transition of the system from the macroscopic transportation stage to the microscopic, precision docking preparation stage based on force and displacement closed-loop control.

[0041] S3: Initiate the docking using the intelligent self-driving suspended transfer vehicle's integrated dynamic stress balancing system. The docking includes: The stress balance arm on the intelligent self-driven suspended transfer vehicle is anchored to the installed steel box girder segment. The accompanying dynamic stress balance system can sense the cantilever disturbance moment generated by the steel box girder segment to be spliced ​​in real time, and drive the stress balance arm to apply an active balancing moment to the installed steel box girder segment to counteract the cantilever disturbance moment. Meanwhile, the main gripper system of the intelligent self-driven suspended transfer vehicle is used to finely adjust the attitude of the steel box girder segments to be spliced ​​in order to achieve alignment with the docking interface of the already installed steel box girder segments. In this embodiment, the step of activating the accompanying dynamic stress balancing system integrated with the intelligent self-driven suspended transfer vehicle for docking is the core technical link in achieving high-precision unmanned assembly in the method of this invention. This step follows the transportation step, and its purpose is to actively and accurately transform the passive suspension state with large initial errors into an ideal docking state without internal stress and geometric misalignment, thereby providing a foundation for subsequent permanent connection operations.

[0042] Specifically, the execution of this docking step relies on a unique and highly coordinated subsystem integrated into the intelligent self-driven suspended transfer vehicle, namely the accompanying dynamic stress balance system and the main gripper system.

[0043] The process begins with the deployment and anchoring of the stress-balancing arm on the intelligent self-driven suspended transfer gantry crane. The gantry crane then places the steel box girder segments to be assembled... Transported to the installed steel box girder segments After the cantilever end is roughly aligned, the stress balance arm extends from the main structure of the vehicle and spans the docking interface to be formed. And an anchoring device at its end is connected to the installed steel box girder segment. Mechanical locking is performed at the pre-set anchor points on the bridge. This establishes a temporary, rigid mechanical transmission path between the vehicle and the existing bridge structure, which is the physical prerequisite for achieving active torque balance.

[0044] After the stress balance arm is anchored, the accompanying dynamic stress balance system enters the real-time sensing and active balancing phase. At this moment, the steel box girder segment to be assembled, suspended by the main gripper system... Its own gravity The lever arm vector relative to the main gripper suspension point This will inevitably generate a cantilever disturbance moment that causes the free end of the segment to deflect downwards. This torque is the root cause of docking difficulties and the generation of initial stress. Its mathematical expression is: ; To actively counteract this disturbing torque, the accompanying dynamic stress balancing system incorporates a sensor array, preferably a multi-axis force / torque sensor mounted on the stress balancing arm, which measures the force / torque in real time due to the stress. The force exists and is transmitted to the anchor point. The vehicle's collaborative control core receives this sensor data and, through its built-in control algorithm, instantly calculates the required reverse balancing torque.

[0045] Subsequently, the collaborative control core outputs commands to the precision hydraulic actuation unit on the stress balancing arm. This actuation unit drives the balancing arm towards the installed steel box girder segment. Apply a precisely calculated active force The force acts through the vector of its moment of application. Generate an active balancing torque Its mathematical expression is: ; Under closed-loop control, the system continuously adjusts. , making Size and Equal in magnitude but opposite in direction. The function of this active balancing torque is to pre-load the entire cantilever effect of the segment to be spliced, thereby ensuring the stability of the installed segment. The mating end faces can be restored to their theoretical ideal posture, undisturbed by external forces.

[0046] Simultaneously, while the aforementioned torque balancing process continues, the main gripper system of the intelligent self-driven suspended transfer vehicle performs attitude fine-tuning. Due to non-ideal factors such as wind load, sensor measurement errors, and structural manufacturing tolerances, even after torque balancing, the docking interface... There may still be minor geometric deviations at that point.

[0047] To eliminate these deviations, a vision system, preferably a high-precision 3D laser scanning system, is configured on the gantry crane or a standalone unmanned aerial alignment and welding workstation to monitor the interface. A continuous, non-contact scanning process is performed on the gap at the interface. This scan acquires a 3D point cloud of the docking interface in real time. Through data processing, the relative displacement vector between the end faces of the two segments can be accurately obtained. and relative rotation vector .

[0048] These geometric deviation data, as feedback signals, are sent to the collaborative control core. Based on this feedback, the control core drives the six-degree-of-freedom main gripper system to perform a series of fine adjustments, including translation, lifting, and rotation. These adjustments generate an attitude fine-tuning torque. This is used to compensate for residual disturbances.

[0049] The essence of this step lies in the fact that torque balancing and attitude fine-tuning are not two isolated or sequential steps, but rather a parallel closed-loop control process with multiple variable inputs and outputs, uniformly scheduled by the collaborative control core. The ultimate control objective of the system is to simultaneously satisfy both mechanical equilibrium and geometric alignment conditions, that is, at the docking interface... At this point, the torque balance equation must be satisfied: ; It must also meet the requirements of geometric alignment with the target: and ; The docking process is complete when the collaborative control core determines that all mechanical and geometric deviations have converged within the preset tolerance range. At this point, the steel box girder segments to be spliced ​​and the installed steel box girder segments form an ideal connection state at the docking interface that is geometrically precisely aligned and mechanically stress-free. Achieving this state eliminates potential welding defects and structural deformations caused by misalignment and internal stress release in subsequent high-quality automated welding operations, and is a key step in ensuring the final bridge alignment accuracy and structural safety.

[0050] S4: After the docking is completed, connect the steel box girder segment to be spliced ​​with the installed steel box girder segment.

[0051] In this embodiment, the step of connecting the steel box girder segments to be spliced ​​with the already installed steel box girder segments after the initial docking is a crucial step in achieving the continuity and permanent load-bearing capacity of the bridge structure. This step is based on the idealized docking state achieved in the previous stage, aiming to transform this precise temporary state into a stable and reliable permanent structural connection.

[0052] It should be noted first that the initial state of this connection step is an excellent initial condition created by the aforementioned dynamic stress balance butt welding step. In this state, the steel box girder segments to be spliced... With the installed steel box girder segments On the interface At that location, its relative displacement vector With relative rotation vector All have converged to near the preset zero value, and due to the active balancing torque Due to the effect of the cantilever effect, there is no initial internal stress at the docking interface.

[0053] Once the collaborative control core confirms that the ideal docking state has been achieved, a temporary locking device can be activated to temporarily fix the relative positions of the two segments. The direct technical effect of this is that the intelligent self-driven suspended transfer vehicle, having completed its transportation and docking tasks, has finished its mission and can detach from the docking interface.

[0054] At this point, one of the core advantages of this invention, namely parallel operation, becomes apparent. After detachment, the intelligent self-driven suspended transfer trolley does not need to wait for the connection operation to be completed; instead, it is immediately dispatched and returns along the lightweight modular elevated track system to the vertical feeding and pre-processing platform on the shore side to grab and transport the next steel box girder segment to be assembled. This allows for the overlap and parallel operation of the connection work of the previous interface and the transportation preparation work of the next segment in terms of time.

[0055] After the intelligent self-propelled suspended transfer vehicle departs, the aerial unmanned alignment and welding workstation, specifically responsible for the connection operation, enters the workflow. In a preferred embodiment, this workstation is an automated device independent of the transfer vehicle, which can move along the same track system or be suspended under the existing bridge section.

[0056] The unmanned aerial alignment and welding workstation moves to the docking interface. Directly below or to the side. Its primary action is to use its built-in high-precision 3D laser scanning system to perform a final, detailed scan of the aligned weld bevel. This step is not a simple repetition; its purpose is twofold: first, as a final quality verification, to confirm that the butt joint geometry meets the welding process requirements; second, to obtain accurate 3D morphological data of the weld bevel after butt joint completion. Due to potential minor manufacturing tolerances in actual construction, the actual weld cross-section is not the ideal theoretical shape.

[0057] The acquired 3D point cloud data of the weld is transmitted to the welding control system of the workstation. Based on this precise digital model, the system automatically plans the welding path. This planning process includes, but is not limited to: generating spatial trajectories for each pass of multi-layer, multi-pass welding, dynamically adjusting the posture and angle of the welding torch, and setting welding process parameters such as current, voltage, and wire feed speed in real time according to the width and depth of the weld.

[0058] After path and parameter planning is completed, multiple multi-degree-of-freedom industrial welding robots in the aerial unmanned alignment and welding workstation are activated. These robotic arms are equipped with welding tools at their ends, and they begin automated welding of the entire docking interface according to a preset program. Multiple robots can work collaboratively, each responsible for welding different sections, to balance heat input and improve work efficiency.

[0059] As a further preferred embodiment, the aerial unmanned alignment and welding workstation can also integrate non-destructive testing equipment, such as a phased array ultrasonic testing unit. When the welding operation is completed or reaches a specific stage, the testing equipment can immediately test the weld quality to ensure that there are no defects such as incomplete penetration, slag inclusion, or porosity inside the connection, thereby ensuring the reliability of the structural connection.

[0060] In summary, this connection step, by utilizing a dedicated, automated welding workstation with its high-precision 3D sensing and path planning capabilities, achieved a high-quality permanent connection under ideal docking conditions. More importantly, by separating the connection and transportation functions on the physical equipment, this invention successfully transforms the two most time-consuming sequential processes in traditional construction—transportation and welding—into parallel processes, thereby constructing an efficient aerial assembly line operation mode without compromising construction quality.

[0061] Please see the appendix Figure 2 The construction system based on the mobile steel box girder cross-road construction platform includes the following modules: The transport module is used to transport steel box girder segments to be assembled to the cantilever ends of already installed steel box girder segments using an intelligent self-driven suspended transfer vehicle that moves along a lightweight modular elevated track system. The torque balancing module is used to sense the cantilever disturbance moment generated by the steel box girder segment to be spliced ​​in real time during the docking process, and to apply an active balancing torque to the installed steel box girder segment to counteract the cantilever disturbance moment. The attitude fine-tuning module is used to fine-tune the attitude of the steel box girder segments to be spliced ​​while the torque balancing module applies the active balancing torque, so as to achieve alignment at the docking interface. The collaborative control module is used to coordinate the operation of the torque balance module and the attitude fine-tuning module.

[0062] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A construction method based on a mobile steel box girder cross-road construction platform, characterized in that, Includes the following steps: S1: Construct a lightweight modular elevated track system above the proposed bridge site; S2: Using an intelligent self-driven suspended transfer vehicle, the steel box girder segments to be spliced ​​are transported to the cantilever end of the installed steel box girder segments along the light modular elevated track system. S3: Activate the accompanying dynamic stress balancing system integrated in the intelligent self-driven suspended transfer vehicle for docking, the docking including: The stress balance arm on the intelligent self-driven suspended transfer vehicle is anchored to the installed steel box girder segment. The accompanying dynamic stress balance system can sense the cantilever disturbance moment generated by the steel box girder segment to be spliced ​​in real time, and drive the stress balance arm to apply an active balancing moment to the installed steel box girder segment to counteract the cantilever disturbance moment. Meanwhile, the main gripper system of the intelligent self-driven suspended transfer vehicle is used to finely adjust the attitude of the steel box girder segment to be spliced, so as to achieve alignment with the docking interface of the installed steel box girder segment. S4: After the docking is completed, connect the steel box girder segment to be spliced ​​with the installed steel box girder segment.

2. The method according to claim 1, characterized in that, While the docking interface is connected in S4, the intelligent self-driven suspended transfer vehicle returns to grab the next steel box girder segment to be spliced, so as to realize the parallel operation of connection and transportation.

3. The method according to claim 1, characterized in that, The connection in S4 is accomplished through automated welding using an aerial unmanned alignment and welding workstation.

4. The method according to claim 3, characterized in that, The automated welding process also includes: using the three-dimensional laser scanning system built into the aerial unmanned alignment and welding workstation to scan the docking interface, so as to obtain three-dimensional morphological data of the weld and guide the welding robot to operate.

5. The method according to claim 1, characterized in that, S2 also includes: lifting the steel box girder segments to be spliced ​​from the ground to the height of the lightweight modular elevated track system by means of a vertical feeding and pre-processing platform set on one side of the bridgehead.

6. The method according to claim 1, characterized in that, The active balancing torque is applied and the attitude fine-tuning is performed in S3 to bring the relative displacement vector and relative rotation angle vector at the docking interface close to zero.

7. The method according to claim 1, characterized in that, In S3, the magnitude of the active balancing torque is equal to the magnitude of the cantilever disturbance torque, but the direction is opposite.

8. The method according to claim 1, characterized in that, The attitude fine-tuning described in S3 involves using a vision system to provide real-time feedback on the geometric deviations of the docking interface, guiding the main gripper system to make adjustments in a closed-loop control manner.

9. The method according to claim 8, characterized in that, The vision system is a three-dimensional laser scanning system.

10. A construction system based on a mobile steel box girder cross-road construction platform, and a construction method based on a mobile steel box girder cross-road construction platform according to any one of claims 1-9, characterized in that, Includes the following modules: The transport module is used to transport steel box girder segments to be assembled to the cantilever ends of already installed steel box girder segments using an intelligent self-driven suspended transfer vehicle that moves along a lightweight modular elevated track system. The torque balancing module is used to sense the cantilever disturbance moment generated by the steel box girder segment to be spliced ​​in real time during the docking process, and to apply an active balancing torque to the installed steel box girder segment to counteract the cantilever disturbance moment. The attitude fine-tuning module is used to fine-tune the attitude of the steel box girder segments to be spliced ​​while the torque balancing module applies the active balancing torque, so as to achieve alignment at the docking interface. The collaborative control module is used to collaboratively control the operation of the torque balancing module and the attitude fine-tuning module.

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