Automatic welding production line for l-shaped rib steel bridge deck panel unit connecting plate and welding method thereof

Abstract

This invention discloses an automated welding production line and welding method for L-shaped ribbed steel bridge deck unit joints, relating to the field of bridge welding manufacturing technology. The automated welding production line includes L-shaped ribbed steel bridge deck units; gantry rails spaced at intervals; a multi-functional gantry workstation mounted on the gantry rails; a vision-teaching collaborative robot located inside the L-shaped ribbed steel bridge deck unit; and a tracked welding workstation located outside the L-shaped ribbed steel bridge deck unit. The automated welding method includes the following steps: S1: assembly and positioning; S2: hoisting and fixing; S3: equipment deployment; S4: first teaching welding; S5: second teaching welding; S6: equipment transfer; S7: repeating steps S2-S6 until all U-shaped groove welds of the T-shaped transverse ribs and partition joints of all L-shaped ribbed steel bridge deck units are completed. This invention solves the technical problems of low welding efficiency and unstable welding quality in existing L-shaped rib joints.

Description

Technical Field

[0001] This invention relates to the field of bridge welding manufacturing technology, and in particular to an automated welding production line for L-shaped rib steel bridge deck unit joint plates and its welding method. Background Technology

[0002] Orthotropic steel bridge decks, with their advantages of lightweight, high load-bearing capacity, and high construction efficiency, have become the core bridge deck structure for modern long-span suspension bridges and cable-stayed bridges. They are mainly composed of a top plate, intersecting longitudinal and transverse stiffening ribs, and welded transverse diaphragm joints. The transverse diaphragm joints, as an important component of the transverse stiffening ribs, are key components ensuring the overall structural stability and load-bearing performance of the steel bridge deck. As bridge construction develops towards longer spans and heavier loads, higher requirements are placed on the manufacturing precision, welding quality, and construction efficiency of steel bridge decks. When the new L-shaped longitudinal ribs + apple-hole toothed structure are widely used in the top plate units of steel box girders, the sheer number of steel bridge deck panels and the dense distribution of the L-shaped longitudinal ribs (12-13 L-shaped longitudinal ribs and 9-10 transverse joints per plate unit) significantly increases the welding volume between the top plate joints and the L-shaped longitudinal ribs and the top plate itself—more than three times the welding volume of traditional U-shaped rib steel bridge deck joints.

[0003] If conventional welding methods are used, several insurmountable problems will arise: First, the welding workload is enormous. Each L-rib steel bridge deck unit has several U-shaped groove welds, with a total weld length of approximately 190 meters. Manual or semi-automatic welding would be inefficient and unable to meet the large-scale, high-efficiency construction requirements, easily delaying the construction schedule. Second, the apple-shaped holes at the intersection of the L-shaped longitudinal ribs and the connecting plates require wrap welding. The corners and wrap welding areas experience more severe stress concentration and fatigue effects, and welding defects will further reduce the steel bridge deck's resistance. Fatigue performance threatens the long-term operational safety of bridges. Manual welding is greatly affected by human factors such as the skill level and sense of responsibility of the operators, making it difficult to guarantee the consistency of weld formation and resulting in poor welding quality stability. Thirdly, the U-shaped groove of the L-shaped rib plate is affected by the L-shaped rib head. The robotic arm of a conventional large gantry welding machine is prone to hitting the welding torch in the U-shaped groove. In order to adjust the welding posture, the online programming teaching time is very long, and the production efficiency cannot meet the construction period requirements. In addition, the procurement cost of large gantry welding machines is high and the footprint is large, making it difficult to achieve clustered use on a single component. Summary of the Invention

[0004] The purpose of this invention is to provide an automated welding production line and welding method for L-shaped rib steel bridge deck unit joints, which solves the technical problems of low welding efficiency and unstable welding quality of L-shaped rib joints in the prior art.

[0005] This application discloses an automated welding production line for L-shaped ribbed steel bridge deck unit joints, including: L-shaped ribbed steel bridge deck unit; Gantry rails, wherein the gantry rails are spaced apart; A multi-functional gantry workstation is installed on the gantry guide rail; A visual teaching collaborative robot is located inside the L-shaped ribbed steel bridge panel unit; A tracked welding workstation is located on the outside of the L-shaped ribbed steel bridge deck unit; The visual teaching collaborative robot includes: Aluminum alloy hollow frame; The wire feeder slide is mounted on the aluminum alloy hollow frame; A wire feeder is mounted on the wire feeder slide. Magnetic bases are disposed on both sides of the aluminum alloy hollow frame. The collaborative robot's electrically driven slide is mounted on the aluminum alloy hollow frame; The collaborative robot body is mounted on the electrically driven slide of the collaborative robot.

[0006] This application also discloses an automated welding method for L-shaped ribbed steel bridge deck unit joint plates, which uses an automated welding production line for L-shaped ribbed steel bridge deck unit joint plates and includes the following steps: S1: Assembly and positioning: Insert the T-shaped transverse ribs and partition plates into the L-shaped rib steel bridge deck unit. After insertion, control the assembly gap between the T-shaped transverse ribs, partition plates and L-shaped ribs, and control the assembly gap between the T-shaped transverse ribs, partition plates and top plate. Then perform U-shaped groove positioning welding. S2: Lifting and fixing: After the L-shaped rib steel bridge panel unit is assembled and positioned, it is lifted onto a special welding jig so that the long side of the bridge panel unit is parallel to the walking direction of the multi-functional gantry workstation, and the jig is rigidly fixed around the perimeter using constraint fixtures. S3: Equipment Layout: Using a multi-functional gantry workstation with a special lifting tool, the visual teaching collaborative robot and the transverse electric drive slide rail are hoisted and placed as a whole at the T-shaped transverse rib and the partition plate. The transverse electric drive slide rail is placed parallel to the T-shaped transverse rib and the partition plate. Multiple sets of visual teaching collaborative robots and transverse electric drive slide rails are arranged on each L-shaped rib steel bridge panel unit. Each set is equipped with a tracked welding workstation. S4: One-time teaching welding: A visual teaching collaborative robot equipped with an industrial camera is used to capture real-time images of the L-shaped rib U-shaped slot shape through the camera. Combined with the visual welding system algorithm, the welding path is automatically generated. The weld of a single U-shaped slot is divided into two at the midpoint of the bottom side and welded in two steps from bottom to top. The welding of multiple U-shaped slots on one side is completed in a fully automated manner by cooperating with the transverse electric drive slide rail. S5: Secondary teaching welding: By using the rotating base under the visual teaching collaborative robot, the robot is turned 180° and the S4 step is repeated to automatically complete the welding of multiple U-shaped slots of the L-shaped rib steel bridge panel unit on the other side. S6: Transfer equipment: Using a multi-functional gantry workstation with a special lifting tool, the visual teaching collaborative robot and the transverse electric drive slide rail are hoisted and placed as a whole at the T-shaped transverse rib and partition plate joint in the unwelded area; S7: Repeat steps S2-S6 until all the T-shaped transverse ribs and partition plates of the L-shaped rib steel bridge deck unit are welded. When there is no hoisting or transfer task, the multi-functional gantry workstation uses the onboard laser scanning teaching and collaborative robot to sequentially weld the L-shaped half-groove welds between the left and right ends of the T-shaped transverse ribs and partition plates and the L-shaped ribs and panels, weld the end fillet welds between the L-shaped ribs and panels, and weld the angled fillet welds between the web of the T-shaped transverse ribs and the cover plate, thereby improving the overall utilization rate of the multi-functional gantry workstation.

[0007] This application uses visual teaching collaborative robots and other devices to replace conventional welding, which solves the problems of high manual labor intensity, low efficiency, and poor quality and precision in conventional welding. Through the collaboration of multiple devices, fully automated welding is achieved. The robot can automatically generate welding paths and slide workstations without human intervention. This can improve the automation rate of L-shaped rib plate welding, control the stability of its welding quality, and ensure the precision of plate units after welding.

[0008] Based on the above technical solution, the present application can be further improved as follows: Furthermore, in step S1, the assembly gap between the T-shaped transverse rib, the partition plate and the L-shaped rib is controlled within 2mm, and the assembly gap between the T-shaped transverse rib, the partition plate and the top plate is controlled within 1mm. For tack welding, a solid welding wire argon-rich gas shielded welding process is used for tack welding of the U-shaped groove. The tack weld leg size should be less than 3mm, the tack weld length should be 35-40mm, and the tack weld spacing should be 250-300mm. The tack weld should avoid the area within 80mm of the intersection of the L-rib and the panel, as well as the end of the apple-shaped hole at the intersection of the L-rib and the connecting plate. The solid welding wire used is G49A3UC1S6 with a diameter of 1.0mm, and the shielding gas is 80% Ar by volume and 20% Ar by volume. CO2, gas flow rate 20-25L / min, welding current 190-205A, arc voltage 21-23V, welding speed 500-530mm / min, DC reverse polarity power supply, weld extension 12-16mm, heat input 4.5-5.5KJ / cm. The beneficial effect of this step is that because the weld leg size of the U-shaped groove weld is small, in order to avoid bulging of the subsequent formal weld, the use of this process parameter for positioning welding can strictly control the size of the positioning weld and improve the forming quality of the U-shaped groove weld.

[0009] Furthermore, the special welding jig in step S2 includes H-beams and patterned steel plates. Multiple H-beams are connected longitudinally and transversely to form a frame. L-shaped ribbed steel bridge panel units are set on the frame. The patterned steel plates are laid on the frame and located outside the L-shaped ribbed steel bridge panel units. The tracked welding workstation is arranged on the patterned steel plate to ensure that the tracked welding workstation can move along the length of the L-shaped ribbed steel bridge panel units. The beneficial effect of this step is that the patterned steel plate can avoid the situation where various cables such as power cords, wire feed tubes, and PLC control lines are tangled and messy on the plate unit, which would affect the welding quality.

[0010] Furthermore, in step S3: Before hoisting, the vision teaching collaborative robot was returned to a safe point to prevent the center of gravity from shifting and causing it to tip over during the overall hoisting process. During hoisting, when the visual teaching collaborative robot and the horizontal electric drive slide rail are placed as a whole, the center position is specifically located 800mm between the T-shaped horizontal rib and the partition plate. The tracked welding workstation is parked on the side of the slide rail. The power cord, wire feed tube, and PLC control line of the vision teaching collaborative robot extend from the side of the slide rail to the tracked welding workstation. At the same time, the wire feeder is installed on the transverse electric drive slide rail slide block. The advantage of this step is that it is a reasonable arrangement that ensures the machine can work stably in the future.

[0011] Furthermore, the visual teaching collaborative robot uses an extended welding torch to avoid the risk of the L-shaped ribs colliding with the torch, and the industrial camera is mounted on the side of the extended end of the welding torch using a clamp; The specific content of step S4 is as follows: Multiple sets of visual teaching collaborative robots were used to simultaneously weld the U-shaped groove welds of the T-shaped transverse ribs and partition plates of the L-shaped rib steel bridge deck unit on the west side. The visual teaching collaborative robots were equipped with industrial cameras to capture real-time images of the shape of the L-shaped rib U-shaped grooves. Combined with the visual welding system algorithm, the welding path was automatically generated. The weld of a single U-shaped groove was divided into two at the midpoint of the bottom side and welded in two stages from bottom to top. The welding parameters were dynamically adjusted according to the welding position without stopping the arc. The visual teaching collaborative robots were first placed on the northernmost side of the L-shaped rib steel bridge deck unit. After the first U-shaped groove was welded, the robots walked and fine-tuned the parameters. Then, with the help of the transverse electric drive slide rail, they completed the welding of multiple U-shaped grooves on one side in a fully automated manner from north to south. The advantage of this step is that multiple machines are used for automated work, which greatly improves welding efficiency and reduces the intensity of manual labor.

[0012] Furthermore, the specific details of the fully automated sequential welding of multiple U-shaped grooves on one side in step S4 are as follows: The visual teaching collaborative robot is mounted on a horizontal electric drive slide rail via a slide block. The slide block is equipped with a stepper motor and is connected to the visual teaching collaborative robot via a PLC control system. After the welding of a single U-shaped groove is completed, the stepper motor receives a walking command and drives the visual teaching collaborative robot and wire feeder on the horizontal electric drive slide rail to the next U-shaped groove according to the preset walking distance. After reaching the designated position, the visual teaching collaborative robot receives a PLC control signal and begins to take pictures and scan the weld seam of the U-shaped groove, automatically plan the welding path, and then automatically weld the weld seam of the U-shaped groove.

[0013] Furthermore, in step S4, when the visual teaching collaborative robot welds the flat corner welds of the T-shaped transverse ribs and the U-shaped grooves of the L-shaped rib steel bridge deck unit, the robot control program calls the short-circuit transition CO2 gas shielded welding mode. The gas shielded welding material is T492T1-1C1AU flux-cored welding wire (φ1.2mm), the welding current is 270-290A, the arc voltage is 26-27V, the welding speed is 200-210mm / min, the extension length is 14-18mm, the gas flow rate is 15-20L / min, the swing arc is sinusoidal, the swing frequency is 1.8Hz, the swing amplitude is 3.0mm, the left and right swing arc pause times are both 0.1s, and the L-shaped swing arc angle is 90°. When the visual teaching collaborative robot welds the T-shaped transverse ribs and U-shaped grooves of the L-shaped rib steel bridge deck unit, the robot control program calls the short-circuit transition CO2 gas shielded welding mode. The gas shielded welding material is T492T1-1C1AU flux-cored wire (φ1.2mm), the welding current is 195-205A, the arc voltage is 23-24V, the welding speed is 85-95mm / min, the extension length is 14-18mm, the gas flow rate is 15-20L / min, the swing arc is sinusoidal, the swing frequency is 1.5Hz, the swing amplitude is 4.0mm, the left and right swing arc pause time is 0.5s, and the L-shaped swing arc angle is 90°. The beneficial effect of this step is that the welding quality of the U-shaped groove can be improved through precise parameter control.

[0014] Furthermore, the specific process of hoisting and placing the vision teaching collaborative robot and the lateral electric drive slide rail in steps S3 and S6 using the aforementioned multi-functional gantry workstation and special lifting equipment is as follows: The first step is pre-lifting preparation: Move the vision teaching collaborative robot to the preset safety point and lock it to ensure that it is in a non-operational state and will not be displaced during the lifting process, thereby avoiding the safety hazards of imbalance of the center of gravity and tipping over due to the robot's position shift during the overall lifting; at the same time, check the integrity of the special lifting tool, adjust the length of the slings to keep the lifting beam of the lifting tool horizontal, and ensure that the force is evenly distributed during the lifting. The second step is to connect the lifting equipment: precisely align and lock the lower end of the sling of the special lifting equipment with the preset lifting point of the horizontal electric drive slide rail to ensure that the connection between the lifting equipment and the horizontal electric drive slide rail is reliable and there is no risk of loosening or slippage; then connect the iron chain of the gantry frame transfer crane to the lifting lug of the lifting equipment. After the connection is completed, check the firmness of the connection part again. After confirming that there are no errors, proceed to the lifting stage. The third step is overall transfer and hoisting: Start the transfer crane, slowly lift the iron chain, and drive the lifting device, the horizontal electric drive slide rail and the vision teaching collaborative robot to rise steadily together. During the lifting process, observe the overall center of gravity in real time to avoid tilting. After the whole is lifted to the preset height, adjust the hoisting position by using the transfer crane, and transfer the vision teaching collaborative robot and the horizontal electric drive slide rail as a whole to the T-shaped cross rib and the partition plate in the unwelded area, and accurately align the center position at the distance of 800mm between the two components. Step 4, precise placement: Slowly lower the hoisted object until the horizontal electric drive slide rail is stably placed in the designated position, ensuring that the horizontal electric drive slide rail is parallel to the T-shaped cross rib and the partition plate. After placement, first unlock the connection between the lifting device and the horizontal electric drive slide rail, and then disconnect the connection between the transfer crane chain and the lifting device to complete the overall hoisting and placement operation.

[0015] Furthermore, in step S7, when the multi-functional gantry workstation welds the fillet weld between the web plate and the cover plate of the T-shaped transverse rib at an elevation angle, the robot control program calls the short-circuit transition CO2 gas shielded welding mode. The gas shielded welding material is T492T1-1C1AU flux-cored wire (φ1.2mm), the welding current is 210-220A, the arc voltage is 23-24V, the welding speed is 360-380mm / min, the extension length is 12-16mm, the gas flow rate is 15-20L / min, the arc swinging method is triangular, the swinging frequency is 1.8Hz, the swinging amplitude is 3.0mm, the left and right swinging pause times are both 0.3s, and the L-shaped swinging angle is 90°.

[0016] Furthermore, the gantry height of the multi-functional gantry workstation is set to 2.2-2.6 meters; The partition plate is connected to the L-shaped rib and the top plate by a double-sided fillet weld, with U-shaped grooves on both sides. In order to reduce welding deformation and reduce welding residual stress, the U-shaped grooves on both sides of the same partition plate in steps S4 and S7 are welded using a staggered and symmetrical welding process. The fillet weld between the partition plate and the apple-shaped hole on the upper side of the L-shaped rib in the thickness direction is welded using an asymmetric fillet welding process.

[0017] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages: 1. This application discloses an automated welding method for L-shaped ribbed steel bridge deck unit joint plates, effectively solving the pain points of conventional welding of L-shaped ribbed steel bridge deck unit joint plates, which suffers from high manual labor intensity, low efficiency, and poor quality and precision. It achieves fully automated welding through multi-device collaboration. Robots can automatically generate welding paths and slide positions without human intervention. Multiple robots require only one operator for management, freeing welders from harsh environments and reducing reliance on manual labor. Simultaneously, it precisely designs welding process parameters, dynamically adjusts them according to the welding position, and avoids arc interruptions in critical areas, reducing welding defects. The robot calibrates the path in real time to ensure that the weld size and formation meet standards, guaranteeing the strength of the bridge structure. 2. During assembly, this application effectively avoids welding deformation and collision damage by strictly controlling assembly gaps, using a dedicated jig for rigid fixation, and precise hoisting, ensuring the post-weld accuracy of the plate unit and ensuring precise matching with other components to avoid delays and rework in the final assembly.

[0018] 3. The single robot in this application can weld 50 single-sided U-shaped grooves per shift, which is suitable for batch welding needs. The multi-functional workstation improves equipment utilization, and automated operation reduces labor and rework costs, achieving the optimal cost configuration. At the same time, the robot replaces manual operation to avoid safety risks, standardizes the hoisting process, and PLC precise control reduces safety accidents. It practices the concept of "human-machine collaboration", effectively promotes the application of automated welding technology in steel bridge manufacturing, and accelerates the transformation of bridge construction technology towards intelligence and safety. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of the L-shaped ribbed steel bridge deck unit in the automated welding production line for L-shaped ribbed steel bridge deck unit as described in Specific Embodiment 1 of the present invention. Figure 2 This is a schematic diagram of the U-shaped groove structure of the L-shaped ribbed steel bridge deck unit joint plate in the automated welding production line for L-shaped ribbed steel bridge deck unit joint plates according to specific embodiment 1 of the present invention. Figure 3 This is a schematic diagram of the automated welding production line for L-shaped ribbed steel bridge deck unit joints as described in specific embodiment 1 of the present invention; Figure 4 yes Figure 3 Schematic diagram of the structure of the mid-vision teaching collaborative robot, the lateral electric drive slide rail, and the tracked welding workstation; Figure 5 yes Figure 3 Schematic diagram of the structure of the multi-functional gantry workstation and gantry guide rail; Figure 6 yes Figure 3 A schematic diagram of the hoisting of a multi-functional gantry workstation for transporting a vision teaching collaborative robot and a lateral electric drive slide rail; Figure 7 This is a flowchart illustrating an automated welding method for L-shaped ribbed steel bridge deck unit splicing plates according to a specific embodiment 2 of the present invention. Figure 8 This is a schematic diagram of the welding path in step S4 of the automated welding method for L-shaped ribbed steel bridge deck unit splice plates according to specific embodiment 2 of the present invention; Figure 9 This is a schematic diagram of the overall welding sequence of the L-shaped ribbed steel bridge deck unit joint plate in an automated welding method according to a specific embodiment 2 of the present invention. In the schematic diagram, A~G are welded in sequence according to the alphabetical order. The same letter indicates that multiple devices are welding at the same time. In the schematic diagram, (1,12) indicates that the 1st to 12th U-shaped slots are welded in sequence according to the direction indicated by the arrow. Figure 10 This is a perspective view of the automated welding process in the automated welding method for L-shaped ribbed steel bridge deck unit joint plates described in Embodiment 2 of the present invention. Figure 11 This is a photograph of the U-shaped groove weld in an automated welding method for L-shaped ribbed steel bridge deck unit joint plates as described in Embodiment 2 of the present invention. Figure 12 This is a schematic diagram of the automated welding process of L-shaped ribbed steel bridge deck unit joint plate according to a specific embodiment 2 of the present invention, in which the two U-shaped grooves adopt staggered and symmetrical welding paths. In the schematic diagram, ①-④ indicate welding in sequence according to the direction indicated by the arrows, and then welding in sequence according to the direction indicated by the arrows ⑤-⑧. Figure 13 This is a schematic diagram of the asymmetric corner welding process in the thickness direction of the apple-shaped perforated plate in an automated welding method for L-shaped ribbed steel bridge deck unit joint plates according to a specific embodiment 2 of the present invention. Figure 14 This is a schematic diagram of the automated corner weld at the end of the L-shaped rib and the panel in an automated welding method for L-shaped rib steel bridge panel unit as described in Embodiment 2 of the present invention.

[0021] Figure 15 The product schematic diagram was obtained by following the method of Comparative Example 1.

[0022] Figure 16 The product schematic diagram was obtained by following the method of Comparative Example 2.

[0023] The attached figures are labeled as follows: 1-L-shaped ribbed steel bridge panel unit; 2-L-shaped rib; 3-Panel; 4-T-shaped transverse rib; 5-Partition plate; 6-Automated welding production line; 7-Vision teaching collaborative robot; 8-Transverse electric drive slide rail; 9-Crawler welding workstation; 10-Multi-functional gantry workstation; 11-Gantry guide rail; 12-Collaborative robot body; 13-Industrial camera; 14-Collaborative robot electric drive slide; 15-Wire feeder slide; 16-Aluminum alloy hollow frame; 17-Magnetic base; 18-Drive motor; 19-Crawler chassis; 20-Welding power supply; 21-PLC control cabinet; 22-Wire feeder; 23-Gantry frame; 24-Laser scanning teaching collaborative robot; 25-Transfer crane; 26-Special lifting tool. Detailed Implementation

[0024] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention. It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0025] In the description of this application, it should be understood that the terms "upper", "lower", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0026] In this application, unless otherwise expressly specified and limited, the terms "installation," "setup," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0027] To better understand the above technical solutions, the following will provide a detailed description of the technical solutions in conjunction with the accompanying drawings and specific embodiments.

[0028] Example 1: like Figure 1-6 As shown in the embodiment of this application, an automated welding production line for L-shaped ribbed steel bridge deck unit plates is disclosed, including: L-shaped ribbed steel bridge deck unit 1; Gantry rails 11 are spaced apart; A multi-functional gantry workstation 10 is mounted on the gantry guide rail 11; The visual teaching collaborative robot 7 is located inside the L-shaped ribbed steel bridge panel unit 1; A tracked welding workstation 9 is located on the outside of the L-shaped ribbed steel bridge deck unit 1; The visual teaching collaborative robot 7 includes: 16mm aluminum alloy hollow frame; The wire feeder slide 15 is mounted on the aluminum alloy hollow frame 16; The wire feeder 22 is mounted on the wire feeder slide 15; Magnetic bases 17 are disposed on both sides of the aluminum alloy hollow frame 16. The collaborative robot's electrically driven slide 14 is mounted on the aluminum alloy hollow frame 16; The collaborative robot body 12 is mounted on the collaborative robot electric drive slide 14.

[0029] The automated welding production line also includes other components, as shown in the attached diagram, which will not be described in detail here.

[0030] Further explanation of the L-rib steel bridge deck unit: The L-rib steel bridge deck unit includes L-ribs, a deck panel, T-shaped transverse ribs, and partition plates. There are 12-13 L-ribs spaced equidistantly at 300mm intervals laterally. There are 9-10 T-shaped transverse ribs and partition plates spaced equidistantly at 1600mm intervals, alternating between them. The T-shaped transverse ribs are welded to the L-ribs and the deck panel using double-sided K7 fillet welds. The arc must not be stopped within 80mm of the junction between the L-ribs and the deck panel. The partition plates are welded to the L-ribs and the deck panel using double-sided K8 fillet welds. The arc must not be stopped within 80mm of the junction between the L-ribs and the deck panel. The length of the U-shaped groove weld between a single T-shaped transverse rib or partition plate and the L-rib or deck panel is 791mm. The L-rib steel bridge deck unit has at least 240 U-shaped groove welds. After the L-rib steel bridge deck unit is welded, it needs to participate in the overall assembly of the steel bridge segments. During the overall assembly of the segments, the deck and partition plates will be matched and connected with other components. The accuracy of the plate unit after welding is crucial. At the same time, the L-rib steel bridge deck unit can exceed 2,000 pieces / bridge on long-span bridges. Its welding efficiency and welding quality are not only directly related to the smooth progress of the overall assembly of the steel bridge segments, but also the core prerequisite for ensuring the overall structural strength, durability and traffic safety of the steel bridge.

[0031] Example 2: In the field of bridge engineering, as bridge construction develops towards longer spans and heavier loads, higher requirements are placed on the manufacturing precision, welding quality, and construction efficiency of steel bridge decks. For example, a new type of L-shaped longitudinal rib with apple-hole toothed structure is widely used on the top plate unit of steel box girders. If gantry welding machines are used in the conventional way, the robotic arm of a conventional large gantry welding machine is prone to hitting the welding torch in the U-shaped groove. To adjust the welding posture, the online programming teaching time is very long, and the production efficiency cannot meet the schedule requirements. In addition, the purchase cost of large gantry welding machines is high, the footprint is large, and it is difficult to achieve clustered use on a single component.

[0032] Therefore, such as Figure 7-14 This application provides an automated welding method for L-shaped ribbed steel bridge deck unit joint plates, using the welding production line described in Example 1. The specific steps are as follows: S1: Assembly and Positioning: Using a partition assembly device, the T-shaped transverse ribs and partition plates are inserted into the L-shaped rib steel bridge deck unit. After insertion, the assembly gap between the T-shaped transverse ribs / partition plates and the L-shaped ribs is controlled within 2mm, and the assembly gap between the T-shaped transverse ribs / partition plates and the top plate is controlled within 1mm. Subsequently, argon-rich gas shielded welding with solid welding wire is used for U-shaped groove positioning welding. The positioning welds avoid the area within 80mm of the intersection between the L-shaped rib and the deck, as well as the apple-shaped hole ends at the intersection of the L-shaped rib and the connecting plate. G49A solid welding wire is selected. 3UC1S6, diameter 1.0mm, shielding gas 80% Ar and 20% CO2 by volume, gas flow 20L / min, welding current 190A, arc voltage 21V, welding speed 500mm / min, DC reverse polarity, weld extension 12mm, heat input 4.5KJ / cm. Because the weld leg size of the U-shaped groove weld is small, in order to avoid bulging of the subsequent formal weld, this process parameter is used for positioning welding to strictly control the size of the positioning weld and improve the forming quality of the U-shaped groove weld. S2: Hoisting and Fixing: The assembled and positioned L-shaped ribbed steel bridge panel unit is hoisted onto a special welding jig, ensuring that the long side of the bridge panel unit is parallel to the walking direction of the multi-functional gantry workstation. A constraint fixture is used to rigidly fix the jig around its perimeter. The special welding jig is constructed from H-beams connected longitudinally and transversely. To ensure the tracked welding workstation can move smoothly along the length of the plate unit, a continuous patterned steel plate is laid on the side of the plate unit on the H-beams. This allows the vision teaching collaborative robot, the transverse electric drive slide rail, and the tracked welding workstation to dynamically move according to the welding area, always maintaining adjacent positional relationships and preventing various cables such as power lines, wire feed tubes, and PLC control lines from becoming tangled and messy on the plate unit, thus affecting welding quality. S3: Equipment Layout: Using a multi-functional gantry workstation with a special lifting tool, the visual teaching collaborative robot and the transverse electric drive slide rail are hoisted and placed in the center position 800mm between the T-shaped cross rib and the partition plate. The transverse electric drive slide rail is placed parallel to the T-shaped cross rib and the partition plate. Before hoisting, the visual teaching collaborative robot is returned to the safe point to avoid the center of gravity shifting and tipping over during the overall hoisting. Three sets of visual teaching collaborative robots and transverse electric drive slide rails are arranged on each L-shaped rib steel bridge panel unit. Each set is equipped with a tracked welding workstation, which is parked on the side of the slide rail. The power cord, wire feed tube, and PLC control line of the visual teaching collaborative robot extend from the side of the slide rail to the tracked welding workstation. At the same time, the wire feeder is installed on the slide rail slide base. S4: Single-stage teaching welding: Multiple sets of visual teaching collaborative robots are used to simultaneously weld the U-shaped groove welds of the T-shaped transverse ribs and partition plates of the L-shaped rib steel bridge deck unit on the west side. The visual teaching collaborative robots are equipped with Tracer P2 industrial cameras from Zhixiang Optoelectronics. The cameras capture real-time images of the shape of the L-shaped rib U-shaped grooves. Combined with the Tracer Studio visual welding system algorithm, the welding path is automatically generated. The weld of a single U-shaped groove is divided into two at the midpoint of the bottom side and welded in two stages from bottom to top. The welding parameters are dynamically adjusted according to the welding position without stopping the arc. The visual teaching collaborative robot is first placed on the northernmost side of the L-shaped rib steel bridge deck unit. After the first U-shaped groove welding is performed and the parameters are finely adjusted, it completes the welding of 12 U-shaped grooves on one side in a fully automated manner from north to south by cooperating with the transverse electric drive slide rail. S5: Secondary teaching welding: After the welding of the T-shaped transverse ribs and partition plates of the west L-shaped rib steel bridge deck unit is completed, the robot is rotated 180° by the rotating base under the vision teaching collaborative robot, and the S4 step is repeated. The welding of 12 T-shaped slots on one side of the T-shaped transverse ribs and partition plates of the east L-shaped rib steel bridge deck unit is completed in a fully automated manner. S6: Transfer Equipment: Using a multi-functional gantry workstation with a special lifting tool, the visual teaching collaborative robot and the transverse electric drive slide rail are hoisted and placed in the center position 800mm between the T-shaped transverse rib and the partition plate in the unwelded area. The transverse electric drive slide rail is placed parallel to the T-shaped transverse rib and the partition plate. Before hoisting, the visual teaching collaborative robot is returned to the safe point to avoid the center of gravity shifting and tipping over during the overall hoisting. Multiple sets of visual teaching collaborative robots and transverse electric drive slide rails are arranged on each L-shaped rib steel bridge panel unit. Each set is equipped with a tracked welding workstation, which is parked on the side of the slide rail. The power cord, wire feed tube and PLC control line of the visual teaching collaborative robot extend from the side of the slide rail to the tracked welding workstation. At the same time, the wire feeder is installed on the slide rail slide base. S7: Repeat steps S2-S6 until all the U-shaped groove welds of the T-shaped transverse ribs and partition plates of the L-shaped rib steel bridge deck unit are completed. When there is no hoisting or transfer task, the multi-functional gantry workstation uses the onboard laser scanning teaching collaborative robot to sequentially weld the L-shaped half-groove welds between the left and right ends of the T-shaped transverse ribs and partition plates and the L-shaped ribs and the deck, weld the end fillet welds of the L-shaped ribs and the deck, and weld the angled fillet welds between the web of the T-shaped transverse ribs and the cover plate, thereby improving the overall utilization rate of the multi-functional gantry workstation.

[0033] In step S1 of this application, when the L-shaped rib steel bridge deck unit is positioned and welded, the size of the positioning weld leg is required to be less than 3mm, the positioning weld length is 35mm, and the positioning weld spacing is 250mm.

[0034] Further explanation of step S4 of this application: the vision teaching collaborative robot uses an extended welding torch to avoid the risk of L-shaped ribs colliding with the torch. An industrial camera is mounted on the side of the extended end of the welding torch via a clamp. The industrial camera is connected to the tracked welding workstation via a data cable. The work camera transmits the real-time image of the L-shaped rib groove to the vision welding system (Tracer Studio), thereby automatically planning the welding path to achieve no manual programming and greatly improve welding efficiency. The partition plate, L-rib, and top plate are joined by double-sided fillet welds, with U-shaped grooves on both sides. To reduce welding deformation and residual stress, the U-shaped grooves on both sides are welded using a staggered and symmetrical welding process. The fillet welds in the thickness direction between the partition plate and the apple-shaped hole on the upper side of the L-rib are welded using an asymmetrical fillet weld process. One side has a full arc termination and a large weld bead area, while the other side has a compact arc termination and a smaller weld bead area, thus improving the fatigue resistance of the L-rib steel bridge deck.

[0035] Step S4 of this application describes the need for fully automated sequential welding of 12 U-shaped grooves on one side. The specific steps are as follows: The visual teaching collaborative robot is mounted on a horizontal electric drive slide rail via a slide block. The slide block is equipped with a stepper motor and is connected to the visual teaching collaborative robot through a PLC control system. After the welding of a single U-shaped slot is completed, the stepper motor receives a walking command and drives the visual teaching collaborative robot and wire feeder on the horizontal electric drive slide rail to the next U-shaped slot according to the preset walking distance. After reaching the designated position, the visual teaching collaborative robot receives a PLC control signal, begins to take pictures and scan the weld seam of the U-shaped slot, automatically plans the welding path, and then automatically welds the weld seam of the U-shaped slot. The 12 U-shaped slot weld seams on one side are welded sequentially by a single visual teaching collaborative robot without human intervention, which greatly improves welding efficiency and reduces the intensity of manual labor.

[0036] For welding U-shaped slots, when the vision teaching collaborative robot welds the flat corner welds of the T-shaped transverse ribs and partition plate U-shaped slots of the L-shaped rib steel bridge deck unit, the robot control program calls the short-circuit transition CO2 gas shielded welding mode. The gas shielded welding material is T492T1-1C1AU flux-cored welding wire (φ1.2mm), the welding current is 270A, the arc voltage is 26V, the welding speed is 200mm / min, the extension length is 14mm, the gas flow rate is 15L / min, the swing arc mode is sinusoidal, the swing frequency is 1.8Hz, the swing amplitude is 3.0mm, the left and right swing arc pause times are both 0.1s, and the L-shaped swing arc angle is 90°. When the visual teaching collaborative robot welds the T-shaped transverse ribs and U-shaped slots of the L-shaped rib steel bridge deck unit, the robot control program calls the short-circuit transition CO2 gas shielded welding mode. The gas shielded welding material is T492T1-1C1AU flux-cored wire (φ1.2mm), the welding current is 195A, the arc voltage is 23V, the welding speed is 85mm / min, the extension length is 14mm, the gas flow rate is 15L / min, the swing arc is sinusoidal, the swing frequency is 1.5Hz, the swing amplitude is 4.0mm, the left and right swing arc pause times are both 0.5s, and the L-shaped swing arc angle is 90°.

[0037] The gantry height of the multi-functional gantry workstation described in this application is set to 2.2-2.6 meters. This height range can effectively avoid collisions between equipment and components during hoisting and transportation, while ensuring that the robot welding arm can fully cover the L-shaped semi-groove weld seam and end corner welding operation area. Under the premise of meeting operational safety and welding accessibility, it achieves the optimal configuration of structural materials, equipment selection and manufacturing costs, resulting in the best overall economic efficiency.

[0038] Further explanation regarding the use of specialized lifting equipment with the multi-functional gantry workstation: The multi-functional gantry workstation includes a gantry frame, a laser scanning teaching collaborative robot, and a transfer crane. The special lifting device used with it is an adjustable balancing lifting device adapted to the transverse electric drive slide rail. The lifting device includes a lifting beam, lifting lugs symmetrically arranged at both ends of the lifting beam, and adjustable length slings. The lower end of the slings is equipped with a snap-fit ​​structure that matches the preset lifting points of the transverse electric drive slide rail, ensuring that the lifting device is firmly connected to the transverse electric drive slide rail and that the force is evenly distributed during lifting, thus avoiding slippage or center of gravity shift during the lifting process.

[0039] The specific process for hoisting and placing the visual teaching collaborative robot and the transverse electric drive slide rail using the aforementioned multi-functional gantry workstation and specialized lifting equipment is as follows: Step 1, Pre-hoisting preparation: Move the visual teaching collaborative robot to the preset safety point and lock it, ensuring it is in a non-operating state and will not shift during hoisting. This avoids potential safety hazards such as imbalance and tipping due to robot position deviation during overall hoisting. Simultaneously, check the integrity of the specialized lifting equipment and adjust the sling length to keep the lifting beam horizontal, ensuring even force distribution during hoisting. Step 2, Lifting equipment connection: Precisely align and lock the lower end of the specialized lifting equipment's sling with the preset lifting points on the transverse electric drive slide rail, ensuring a reliable connection between the lifting equipment and the transverse electric drive slide rail without any risk of loosening or slippage. Then, connect the chain of the gantry frame's transfer crane to the corresponding lifting lugs of the lifting equipment. After connection, check the firmness of the connection points again. Once confirmed, proceed to the hoisting stage. Step 3, Overall Transfer and Lifting: Start the transfer crane, slowly lift the chain, and smoothly raise the lifting device, horizontal electric drive slide rail, and vision teaching collaborative robot together. During the lifting process, observe the overall center of gravity in real time to avoid tilting. After the whole thing is lifted to the preset height, adjust the lifting position using the transfer crane, and transfer the vision teaching collaborative robot and horizontal electric drive slide rail as a whole between the T-shaped cross rib and the partition plate in the unwelded area, accurately aligning them with the center position at the 800mm distance between the two components. Step 4, Precise Placement: Slowly lower the lifted object until the horizontal electric drive slide rail is stably placed in the designated position, ensuring that the horizontal electric drive slide rail is parallel to the T-shaped cross rib and the partition plate. After placement, first unlock the connection between the lifting device and the horizontal electric drive slide rail, then disconnect the transfer crane chain from the lifting device, completing the overall lifting and placement operation.

[0040] Further explanation of S7 in this application: When the multi-functional gantry workstation is not performing hoisting and transfer tasks, and when using the onboard laser scanning teaching collaborative robot to weld the L-shaped semi-groove welds between the left and right ends of the T-shaped transverse ribs and partition plates and the L-shaped ribs and panels, the welding process selected is the same as that for the U-shaped groove welds. When welding the end fillet welds between the L-shaped ribs and the panels, the robot control program calls the short-circuit transition CO2 gas shielded welding mode. The gas shielded welding material selected is flux-cored wire T492T1-1C1AU (φ1.2mm), the welding current is 250A, the arc voltage is 26V, the welding speed is 280mm / min, the extension length is 12mm, the gas flow rate is 15L / min, the arc swinging method is crescent-shaped, the swinging frequency is 1.6Hz, the swinging amplitude is 4.0mm, the left and right swinging pause times are both 0.2s, and the L-shaped swinging angle is 90°. The cover plate of the T-shaped transverse rib can only be assembled after the partition assembly equipment inserts the T-shaped transverse rib into the L-shaped rib steel bridge panel unit. When the multi-functional gantry workstation welds the fillet weld between the web plate and the cover plate of the T-shaped transverse rib at the elevation angle, the robot control program calls the short-circuit transition CO2 gas shielded welding mode. The gas shielded welding material is T492T1-1C1AU flux-cored welding wire (φ1.2mm), the welding current is 210A, the arc voltage is 23V, the welding speed is 360mm / min, the extension length is 12mm, the gas flow rate is 15L / min, the arc swinging method is triangular, the swinging frequency is 1.8Hz, the swinging amplitude is 3.0mm, the left and right arc stop times are both 0.3s, and the L-shaped arc swinging angle is 90°.

[0041] Taking an eight-hour shift as an example, each vision-teaching collaborative robot, in conjunction with a transverse electric drive slide rail and working in collaboration with a multi-functional gantry workstation, can weld 50 single-sided U-shaped slots per shift. Three vision-teaching collaborative robots can be managed by a single operator, achieving precise welding and high-quality weld formation for dissimilar steel bridge components. The method described in this application not only significantly reduces the incidence of common defects such as porosity, lack of fusion, and undercut, ensuring the appearance quality and mechanical properties of the weld, but also liberates welders from harsh working environments, thus protecting their physical and mental health, and achieving human-machine collaboration and complementary advantages.

[0042] Example 3: This application embodiment adjusts the relevant parameters of embodiment 2, while the other steps remain the same, as follows: In step S1: gas flow rate 25L / min, welding current 205A, arc voltage 23V, welding speed 530mm / min, DC reverse power supply, dry extension 16mm, heat input 5.5KJ / cm; When positioning and welding the L-shaped ribbed steel bridge deck unit's U-shaped groove, the size of the positioning weld leg should be less than 3mm, the positioning weld length should be 40mm, and the positioning weld spacing should be 300mm.

[0043] The welding of the U-shaped groove in step S4: When the visual teaching collaborative robot welds the flat corner weld of the T-shaped transverse rib and partition plate U-shaped groove of the L-shaped rib steel bridge deck unit, the robot control program calls the short-circuit transition CO2 gas shielded welding mode. The gas shielded welding material is T492T1-1C1AU flux-cored welding wire (φ1.2mm), the welding current is 290A, the arc voltage is 27V, the welding speed is 210mm / min, the extension length is 18mm, the gas flow rate is 20L / min, the swing arc mode is sinusoidal, the swing frequency is 1.8Hz, the swing amplitude is 3.0mm, the left and right swing arc pause time is 0.1s, and the L-shaped swing arc angle is 90°. When the visual teaching collaborative robot welds the T-shaped transverse ribs and U-shaped grooves of the L-shaped rib steel bridge deck unit, the robot control program calls the short-circuit transition CO2 gas shielded welding mode. The gas shielded welding material is T492T1-1C1AU flux-cored wire (φ1.2mm), the welding current is 205A, the arc voltage is 24V, the welding speed is 95mm / min, the extension length is 18mm, the gas flow rate is 20L / min, the swing arc is sinusoidal, the swing frequency is 1.5Hz, the swing amplitude is 4.0mm, the left and right swing arc pause times are both 0.5s, and the L-shaped swing arc angle is 90°.

[0044] Step S7: When the multi-functional gantry workstation is not performing hoisting and transfer tasks, and is using the onboard laser scanning teaching collaborative robot to weld the L-shaped semi-groove welds between the left and right ends of the T-shaped transverse ribs and partition plates and the L-shaped ribs and panels, the welding process selected is the same as that for the U-shaped groove welds. When welding the end fillet welds between the L-shaped ribs and the panels, the robot control program calls the short-circuit transition CO2 gas shielded welding mode. The gas shielded welding material selected is flux-cored wire T492T1-1C1AU (φ1.2mm), the welding current is 260A, the arc voltage is 27V, the welding speed is 300mm / min, the extension length is 18mm, the gas flow rate is 20L / min, the swing arc is crescent-shaped, the swing frequency is 1.6Hz, the swing amplitude is 4.0mm, the left and right swing arc pause times are both 0.2s, and the L-shaped swing arc angle is 90°. The cover plate of the T-shaped transverse rib can only be assembled after the partition assembly equipment inserts the T-shaped transverse rib into the L-shaped rib steel bridge panel unit. When the multi-functional gantry workstation welds the fillet weld between the web plate and the cover plate of the T-shaped transverse rib at the elevation angle, the robot control program calls the short-circuit transition CO2 gas shielded welding mode. The gas shielded welding material is T492T1-1C1AU flux-cored welding wire (φ1.2mm), the welding current is 220A, the arc voltage is 24V, the welding speed is 380mm / min, the extension length is 16mm, the gas flow rate is 20L / min, the arc swinging method is triangular, the swinging frequency is 1.8Hz, the swinging amplitude is 3.0mm, the left and right arc stop times are both 0.3s, and the L-shaped arc swinging angle is 90°.

[0045] Example 4: This application embodiment adjusts the relevant parameters of embodiment 2, while the other steps remain the same, as follows: In step S1: gas flow rate 22L / min, welding current 200A, arc voltage 22V, welding speed 510mm / min, DC reverse power supply, dry extension 14mm, heat input 5KJ / cm; When positioning and welding the L-shaped ribbed steel bridge deck unit's U-shaped groove, the size of the positioning weld leg should be less than 3mm, the positioning weld length should be 38mm, and the positioning weld spacing should be 280mm.

[0046] The welding of the U-shaped groove in step S4: When the visual teaching collaborative robot welds the flat corner weld of the T-shaped transverse rib and partition plate U-shaped groove of the L-shaped rib steel bridge deck unit, the robot control program calls the short-circuit transition CO2 gas shielded welding mode. The gas shielded welding material is T492T1-1C1AU flux-cored welding wire (φ1.2mm), the welding current is 280A, the arc voltage is 26V, the welding speed is 205mm / min, the extension length is 16mm, the gas flow rate is 18L / min, the swing arc mode is sinusoidal, the swing frequency is 1.8Hz, the swing amplitude is 3.0mm, the left and right swing arc stop time is 0.1s, and the L-shaped swing arc angle is 90°. When the visual teaching collaborative robot welds the T-shaped transverse ribs and U-shaped grooves of the L-shaped rib steel bridge deck unit, the robot control program calls the short-circuit transition CO2 gas shielded welding mode. The gas shielded welding material is T492T1-1C1AU flux-cored wire (φ1.2mm), the welding current is 200A, the arc voltage is 23V, the welding speed is 90mm / min, the extension length is 16mm, the gas flow rate is 18L / min, the swing arc is sinusoidal, the swing frequency is 1.5Hz, the swing amplitude is 4.0mm, the left and right swing arc pause times are both 0.5s, and the L-shaped swing arc angle is 90°.

[0047] Step S7: When the multi-functional gantry workstation is not performing hoisting and transfer tasks, and is using the onboard laser scanning teaching collaborative robot to weld the L-shaped half-groove welds between the left and right ends of the T-shaped transverse ribs and partition plates and the L-shaped ribs and panels, the welding process selected is the same as that for the U-shaped groove welds. When welding the end fillet welds between the L-shaped ribs and the panels, the robot control program calls the short-circuit transition CO2 gas shielded welding mode. The gas shielded welding material selected is flux-cored wire T492T1-1C1AU (φ1.2mm), the welding current is 255A, the arc voltage is 26V, the welding speed is 290mm / min, the extension length is 16mm, the gas flow rate is 18L / min, the swing arc is crescent-shaped, the swing frequency is 1.6Hz, the swing amplitude is 4.0mm, the left and right swing arc pause times are both 0.2s, and the L-shaped swing arc angle is 90°. The cover plate of the T-shaped transverse rib can only be assembled after the partition assembly equipment inserts the T-shaped transverse rib into the L-shaped rib steel bridge panel unit. When the multi-functional gantry workstation welds the fillet weld between the web plate and the cover plate of the T-shaped transverse rib at the elevation angle, the robot control program calls the short-circuit transition CO2 gas shielded welding mode. The gas shielded welding material is T492T1-1C1AU flux-cored welding wire (φ1.2mm), the welding current is 215A, the arc voltage is 23V, the welding speed is 370mm / min, the extension length is 14mm, the gas flow rate is 17L / min, the arc swinging method is triangular, the swinging frequency is 1.8Hz, the swinging amplitude is 3.0mm, the left and right arc stop times are both 0.3s, and the L-shaped arc swinging angle is 90°.

[0048] Comparative Example 1: When a visual teaching collaborative robot welds the T-shaped transverse ribs and U-shaped grooves of the L-shaped rib steel bridge deck unit, and the robot control program calls the commonly used short-circuit transition CO2 gas shielded welding mode or automatic pulse argon-rich gas shielded welding mode for U-rib grooves, the space of the U-shaped groove in the L-shaped rib joint is much smaller than that of the U-rib groove due to the obstruction of the L-shaped rib head structure. This prevents the welding torch from being adjusted to the optimal welding posture, resulting in poor welding accessibility and limited torch swivel space. Consequently, the weld formation is poor, and the appearance and internal quality fail to meet standards. See details... Figure 15 .

[0049] Comparative Example 2: When manually welding the fillet welds at the ends of L-shaped ribs and panels, the numerous fillet welds at the L-shaped rib ends and the dispersed work points result in high labor intensity for manual welding. Furthermore, continuous, uninterrupted arc welding of the entire fillet weld is difficult to achieve, leading to numerous weld joints, uneven transitions, and poor overall weld formation, which is detrimental to the structure's fatigue resistance. See details... Figure 16 .

[0050] Combination Figure 11 , Figure 15 , Figure 16 A comparison shows that the products processed by the automated welding method for L-shaped ribbed steel bridge deck unit joints disclosed in this application are of better quality than existing welded products.

[0051] Numerous specific details are set forth in this specification. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0052] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. An automated welding production line for L-shaped ribbed steel bridge deck unit joint plates, characterized in that, include: L-shaped ribbed steel bridge deck unit; Gantry rails, wherein the gantry rails are spaced apart; A multi-functional gantry workstation is installed on the gantry guide rail; A visual teaching collaborative robot is located inside the L-shaped ribbed steel bridge panel unit; A tracked welding workstation is located on the outside of the L-shaped ribbed steel bridge deck unit; The visual teaching collaborative robot includes: Aluminum alloy hollow frame; The wire feeder slide is mounted on the aluminum alloy hollow frame; A wire feeder is mounted on the wire feeder slide. Magnetic bases are disposed on both sides of the aluminum alloy hollow frame. The collaborative robot's electrically driven slide is mounted on the aluminum alloy hollow frame; The collaborative robot body is mounted on the electrically driven slide of the collaborative robot.

2. An automated welding method for L-shaped ribbed steel bridge deck unit joint plates, characterized in that, The process using the automated welding production line for L-shaped ribbed steel bridge deck unit joints as described in claim 1 includes the following steps: S1: Assembly and positioning: Insert the T-shaped transverse ribs and partition plates into the L-shaped rib steel bridge deck unit. After insertion, control the assembly gap between the T-shaped transverse ribs, partition plates and L-shaped ribs, and control the assembly gap between the T-shaped transverse ribs, partition plates and top plate. Then perform U-shaped groove positioning welding. S2: Lifting and fixing: After the L-shaped rib steel bridge panel unit is assembled and positioned, it is lifted onto a special welding jig so that the long side of the bridge panel unit is parallel to the walking direction of the multi-functional gantry workstation, and the jig is rigidly fixed around the perimeter using constraint fixtures. S3: Equipment Layout: Using a multi-functional gantry workstation with a special lifting tool, the visual teaching collaborative robot and the transverse electric drive slide rail are hoisted and placed as a whole at the T-shaped transverse rib and the partition plate. The transverse electric drive slide rail is placed parallel to the T-shaped transverse rib and the partition plate. Multiple sets of visual teaching collaborative robots and transverse electric drive slide rails are arranged on each L-shaped rib steel bridge panel unit. Each set is equipped with a tracked welding workstation. S4: One-time teaching welding: A visual teaching collaborative robot equipped with an industrial camera is used to capture real-time images of the L-shaped rib U-shaped slot shape through the camera. Combined with the visual welding system algorithm, the welding path is automatically generated. The weld of a single U-shaped slot is divided into two at the midpoint of the bottom side and welded in two steps from bottom to top. The welding of multiple U-shaped slots on one side is completed in a fully automated manner by cooperating with the transverse electric drive slide rail. S5: Secondary teaching welding: By using the rotating base under the visual teaching collaborative robot, the robot is turned 180° and the S4 step is repeated to automatically complete the welding of multiple U-shaped slots of the L-shaped rib steel bridge panel unit on the other side. S6: Transfer equipment: Using a multi-functional gantry workstation with a special lifting tool, the visual teaching collaborative robot and the transverse electric drive slide rail are hoisted and placed as a whole at the T-shaped transverse rib and partition plate joint in the unwelded area; S7: Repeat steps S2-S6 until all the T-shaped transverse ribs and partition plates of the L-shaped rib steel bridge deck unit are welded. When there is no hoisting or transfer task, the multi-functional gantry workstation uses the onboard laser scanning teaching and collaborative robot to sequentially weld the L-shaped half-groove welds between the left and right ends of the T-shaped transverse ribs and partition plates and the L-shaped ribs and panels, weld the end fillet welds between the L-shaped ribs and panels, and weld the angled fillet welds between the web of the T-shaped transverse ribs and the cover plate, thereby improving the overall utilization rate of the multi-functional gantry workstation.

3. The automated welding method for L-shaped ribbed steel bridge deck unit joints according to claim 2, characterized in that, In step S1, the assembly gap between the T-shaped transverse rib, the partition plate and the L-shaped rib is controlled within 2mm, and the assembly gap between the T-shaped transverse rib, the partition plate and the top plate is controlled within 1mm. For tack welding, a solid welding wire argon-rich gas shielded welding process is used for tack welding of the U-shaped groove. The tack weld leg size should be less than 3mm, the tack weld length should be 35-40mm, and the tack weld spacing should be 250-300mm. The tack weld should avoid the area within 80mm of the intersection of the L-shaped rib and the panel, as well as the end of the apple-shaped hole at the intersection of the L-shaped rib and the connecting plate. The solid welding wire used is G49A3UC1S6 with a diameter of 1.0mm. The shielding gas is 80% Ar and 20% CO2 by volume, with a gas flow rate of 20-25L / min, a welding current of 190-205A, an arc voltage of 21-23V, a welding speed of 500-530mm / min, DC reverse polarity power supply, a dry extension of 12-16mm, and a heat input of 4.5-5.5KJ / cm.

4. The automated welding method for L-shaped ribbed steel bridge deck unit joints according to claim 3, characterized in that, The special welding jig in step S2 includes H-beams and patterned steel plates. Multiple H-beams are connected longitudinally and transversely to form a frame. L-shaped ribbed steel bridge deck units are set on the frame. The patterned steel plates are laid on the frame and located outside the L-shaped ribbed steel bridge deck units. Tracked welding workstations are arranged on the patterned steel plates to ensure that the tracked welding workstations can move along the length of the L-shaped ribbed steel bridge deck units.

5. The automated welding method for L-shaped ribbed steel bridge deck unit joints according to claim 4, characterized in that, In step S3: Before hoisting, the vision teaching collaborative robot was returned to a safe point to prevent the center of gravity from shifting and causing it to tip over during the overall hoisting process. During hoisting, when the visual teaching collaborative robot and the horizontal electric drive slide rail are placed as a whole, the center position is specifically located 800mm between the T-shaped horizontal rib and the partition plate. The tracked welding workstation is parked on the side of the slide rail. The power cord, wire feed tube, and PLC control line of the vision teaching collaborative robot extend from the side of the slide rail to the tracked welding workstation. At the same time, the wire feeder is installed on the transverse electric drive slide rail slide block.

6. The automated welding method for L-shaped ribbed steel bridge deck unit joints according to claim 5, characterized in that, The visual teaching collaborative robot uses an extended welding torch to avoid the risk of L-shaped ribs colliding with the torch. An industrial camera is mounted on the side of the extended end of the welding torch using a clamp. The specific content of step S4 is as follows: Multiple sets of visual teaching collaborative robots are used to simultaneously weld the U-shaped groove welds of the T-shaped transverse ribs and partition plates of the L-shaped rib steel bridge deck unit on the west side. The visual teaching collaborative robots are equipped with industrial cameras to capture real-time images of the shape of the L-shaped rib U-shaped grooves. Combined with the visual welding system algorithm, the welding path is automatically generated. The weld of a single U-shaped groove is divided into two at the midpoint of the bottom side and welded in two stages from bottom to top. The welding parameters are dynamically adjusted according to the welding position without the need to stop the arc. The visual teaching collaborative robot is first placed on the northernmost side of the L-shaped rib steel bridge deck unit. After the first U-shaped groove is welded, it walks around to fine-tune the parameters. Then, with the help of the transverse electric drive slide rail, it automatically completes the welding of multiple U-shaped grooves on one side from north to south.

7. The automated welding method for L-shaped ribbed steel bridge deck unit joints according to claim 6, characterized in that, The specific details of the fully automated welding of multiple U-shaped grooves on one side in step S4 are as follows: The visual teaching collaborative robot is mounted on a horizontal electric drive slide rail via a slide block. The slide block is equipped with a stepper motor and is connected to the visual teaching collaborative robot via a PLC control system. After the welding of a single U-shaped groove is completed, the stepper motor receives a walking command and drives the visual teaching collaborative robot and wire feeder on the horizontal electric drive slide rail to the next U-shaped groove according to the preset walking distance. After reaching the designated position, the visual teaching collaborative robot receives a PLC control signal and begins to take pictures and scan the weld seam of the U-shaped groove, automatically plan the welding path, and then automatically weld the weld seam of the U-shaped groove.

8. The automated welding method for L-shaped ribbed steel bridge deck unit joints according to claim 7, characterized in that, In step S4, when the visual teaching collaborative robot welds the flat corner weld of the T-shaped transverse rib and the U-shaped groove of the partition plate of the L-shaped rib steel bridge deck unit, the robot control program calls the short-circuit transition CO2 gas shielded welding mode. The gas shielded welding material is T492T1-1C1AU flux-cored welding wire (φ1.2mm), the welding current is 270-290A, the arc voltage is 26-27V, the welding speed is 200-210mm / min, the extension length is 14-18mm, the gas flow rate is 15-20L / min, the swing arc mode is sinusoidal, the swing frequency is 1.8Hz, the swing amplitude is 3.0mm, the left and right swing arc pause time is 0.1s, and the L-shaped swing arc angle is 90°. When the visual teaching collaborative robot welds the T-shaped transverse ribs and U-shaped grooves of the L-shaped rib steel bridge deck unit, the robot control program calls the short-circuit transition CO2 gas shielded welding mode. The gas shielded welding material is T492T1-1C1AU flux-cored welding wire with a diameter of 1.2mm. The welding current is 195-205A, the arc voltage is 23-24V, the welding speed is 85-95mm / min, the extension length is 14-18mm, the gas flow rate is 15-20L / min, the swing arc is sinusoidal, the swing frequency is 1.5Hz, the swing amplitude is 4.0mm, the left and right swing arc pause time is 0.5s, and the L-shaped swing arc angle is 90°.

9. The automated welding method for L-shaped ribbed steel bridge deck unit joints according to claim 8, characterized in that, The specific process of hoisting and placing the vision teaching collaborative robot and the lateral electric drive slide rail using the aforementioned multi-functional gantry workstation and special lifting equipment in steps S3 and S6 is as follows: The first step is pre-lifting preparation: Move the vision teaching collaborative robot to the preset safety point and lock it to ensure that it is in a non-operational state and will not be displaced during the lifting process, thereby avoiding the safety hazards of imbalance of the center of gravity and tipping over due to the robot's position shift during the overall lifting; at the same time, check the integrity of the special lifting tool, adjust the length of the slings to keep the lifting beam of the lifting tool horizontal, and ensure that the force is evenly distributed during the lifting. The second step is to connect the lifting equipment: precisely align and lock the lower end of the sling of the special lifting equipment with the preset lifting point of the horizontal electric drive slide rail to ensure that the connection between the lifting equipment and the horizontal electric drive slide rail is reliable and there is no risk of loosening or slippage; then connect the iron chain of the gantry frame transfer crane to the lifting lug of the lifting equipment. After the connection is completed, check the firmness of the connection part again. After confirming that there are no errors, proceed to the lifting stage. The third step is overall transfer and hoisting: Start the transfer crane, slowly lift the iron chain, and drive the lifting device, the horizontal electric drive slide rail and the vision teaching collaborative robot to rise steadily together. During the lifting process, observe the overall center of gravity in real time to avoid tilting. After the whole is lifted to the preset height, adjust the hoisting position by using the transfer crane, and transfer the vision teaching collaborative robot and the horizontal electric drive slide rail as a whole to the T-shaped cross rib and the partition plate in the unwelded area, and accurately align the center position at the distance of 800mm between the two components. Step 4, precise placement: Slowly lower the hoisted object until the horizontal electric drive slide rail is stably placed in the designated position, ensuring that the horizontal electric drive slide rail is parallel to the T-shaped cross rib and the partition plate. After placement, first unlock the connection between the lifting device and the horizontal electric drive slide rail, and then disconnect the connection between the transfer crane chain and the lifting device to complete the overall hoisting and placement operation.

10. The automated welding method for L-shaped ribbed steel bridge deck unit joints according to claim 9, characterized in that, In step S7, when the multi-functional gantry workstation welds the fillet weld between the web plate and cover plate of the T-shaped transverse rib at an upward angle, the robot control program calls the short-circuit transition CO2 gas shielded welding mode. The gas shielded welding material is T492T1-1C1AU flux-cored wire (φ1.2mm), the welding current is 210-220A, the arc voltage is 23-24V, the welding speed is 360-380mm / min, the extension length is 12-16mm, the gas flow rate is 15-20L / min, the arc swinging method is triangular, the swinging frequency is 1.8Hz, the swinging amplitude is 3.0mm, the left and right swinging pause times are both 0.3s, and the L-shaped swinging angle is 90°. The gantry height of the multi-functional gantry workstation is set to 2.2-2.6 meters; The partition plate is connected to the L-shaped rib and the top plate by a double-sided fillet weld, with U-shaped grooves on both sides. In order to reduce welding deformation and reduce welding residual stress, the U-shaped grooves on both sides of the same partition plate in steps S4 and S7 are welded using a staggered and symmetrical welding process. The fillet weld between the partition plate and the apple-shaped hole on the upper side of the L-shaped rib in the thickness direction is welded using an asymmetric fillet welding process.

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