An automatic welding method and device for axle housing and c-beam attachment welding

Abstract

The application provides an automatic welding method and device for axle housing and C-shaped beam accessory welding, and relates to the technical field of welding automation. The automatic welding method comprises the following steps: S1, a clamping step; S2, a calibration step; S3, a location searching step; S4, a trajectory generation step; S5, a parameter adjustment step; S6, a welding execution step: the welding torch is ignited when reaching the welding starting point, the robot drives the welding torch to move along the welding seam according to the target coordinates and angle of the welding torch, the laser head continuously scans in the welding process, the control unit continuously updates the target coordinates and angle of the welding torch, when the laser head detects the welding seam endpoint, the control unit marks the target coordinates and posture angle corresponding to the welding seam endpoint in the target sequence, and the welding torch performs arc extinguishing after reaching the endpoint; and S7, a recording step. The problems of unstable welding parameters, poor welding seam quality consistency and low welding efficiency caused by the dependence on manual operation in the prior art axle housing and C-shaped beam accessory welding are solved.

Description

Technical Field

[0001] This invention relates to the field of welding automation technology, and more specifically, to an automatic welding method and apparatus for welding bridge shells and C-beam accessories. Background Technology

[0002] Currently, welding of the C-beam accessories in the bridge shell relies primarily on manual operation. Operators hold welding torches and control the torch angle, the height between the torch and the weld, and the speed of movement along the weld seam based on visual observation and personal experience. Because the weld seam is a spatial curve and the welding space is relatively confined, it is difficult for operators to maintain a consistently stable torch angle, height, and movement speed throughout the welding process. This leads to the following problems: insufficient or excessive weld bead height, weld trajectory deviating from the weld center, localized weld bead accumulation or undercut, and poor consistency in the appearance of each weld bead. Furthermore, under manual operation conditions, the adjustment of welding parameters depends entirely on the operator's experience and judgment. Welding quality varies significantly between different operators and even among the same operator at different times, resulting in high rework and scrap rates. Summary of the Invention

[0003] The present invention aims to solve the problems of unstable welding parameters, poor weld quality consistency, low welding efficiency and lack of traceability of welding process caused by the reliance on manual operation in the welding of bridge shells and C-beam accessories in the prior art.

[0004] To address the above problems, this invention provides an automated welding method for welding bridge shells and C-beam accessories, comprising the following steps: S1. Clamping steps: Install and fix the axle housing on the base, making the axis of the axle housing parallel to the X-axis. Fit the C-beam accessory into the designated position on the journal of the axle housing and tighten it. S2. Calibration steps: Establish the transformation relationship between the laser coordinate system of the laser head and the robot coordinate system through the control unit, and record the front distance of the laser scanning line of the laser head relative to the contact tip TCP of the welding gun. S3. Positioning Step: The robot moves the welding torch along a preset safety trajectory to approach the welding starting point. The laser head scans the edges of the bridge shell and C-beam accessories to be welded. The control unit identifies the welding starting point position and determines whether the deviation of the weld center and height is within the preset threshold range. If the deviation exceeds the preset threshold, a clamping abnormality prompt is issued. S4. Trajectory generation step: The laser head scans along the weld direction at a preset sampling interval, and the control unit converts the weld width B, lateral deviation ΔY and height deviation ΔZ obtained from each sampling into the target coordinates and angle of the welding gun. S5. Parameter adjustment steps: The control unit adjusts the welding current, welding voltage, wire feed speed or welding speed of the welding torch in stages according to the weld width B and height deviation ΔZ. S6. Welding execution steps: When the welding torch reaches the welding starting point, it initiates an arc. The robot drives the welding torch to move along the weld seam according to the target coordinates and angle of the welding torch. During the welding process, the laser head continuously scans, and the control unit continuously updates the target coordinates and angle of the welding torch. When the laser head detects the end point of the weld seam, the control unit marks the target coordinates and attitude angle corresponding to the end point of the weld seam in the target sequence, and uses the target coordinates and attitude angle as the arc termination trigger position. After the welding torch reaches the end point, it terminates the arc. S7. Recording Steps: The control unit records the lateral deviation ΔY, height deviation ΔZ, welding torch target coordinates and angle, welding current, welding voltage, wire feed speed, welding speed, arc start time, arc end time and abnormal shutdown information of each weld seam during this welding process as welding records corresponding to the workpiece number.

[0005] The present invention provides an automatic welding method for welding bridge shells and C-beam accessories, which, compared with the prior art, has the following beneficial effects, but is not limited to: This automated welding method for bridge shell and C-beam attachments establishes a positioning reference parallel to the X-axis of the bridge shell through a clamping step and applies pressure to the C-beam attachments, providing a definite spatial reference for subsequent laser scanning and welding, eliminating the problem of unstable workpiece position during manual support. Secondly, a calibration step establishes the transformation relationship between the laser coordinate system and the robot coordinate system and records the forward distance, enabling the control unit to accurately map the weld contour data collected by the laser head in front of the welding torch to the robot's working coordinate system. Furthermore, a trajectory generation step converts the weld width, lateral deviation, and height deviation acquired in each sampling into the target coordinates and angle of the welding torch in real time. This allows the robot to drive the welding torch to follow the actual weld center in real time, rather than moving along a fixed preset trajectory, effectively compensating for weld position offsets caused by workpiece clamping deviations and workpiece dimensional tolerances. The target coordinates and angles simultaneously contain the spatial position and attitude angle information of the welding torch's TCP, ensuring that the welding torch performs welding at the optimal attitude angle at each sampling point of the three-dimensional curved weld. The parameter adjustment steps adjust the welding current, welding voltage, wire feed speed or welding speed in stages according to the deviation of weld width and height, so that the welding parameters can automatically adapt to the actual weld conditions, avoiding defects such as incomplete penetration, burn-through or weld beads that may occur when the weld conditions change in constant parameter welding.

[0006] This method records the welding process data by binding it to the workpiece number, so that each weld of each workpiece has a complete welding process data record. This provides a data foundation for subsequent quality traceability, process optimization and defect analysis, and solves the problem of untraceability of manual welding process.

[0007] Furthermore, at least one intermediate frame is installed on the base, and the upper part of the intermediate frame is provided as a V-shaped support surface for supporting the axle housing. The intermediate frame is also connected to a pressure plate for pressing the C-beam attachment. The clamping step in S1 is specifically as follows: the axle housing is placed on the V-shaped support surface of the intermediate frame, so that the axis of the axle housing is parallel to the X-axis, the C-beam attachment is fitted into the designated position of the journal of the axle housing, and the pressure plate is operated to press the upper surface of the C-beam attachment.

[0008] Furthermore, the laser head, robot, and welding torch are all connected to a control unit. The control unit is used to receive weld contour data collected by the laser head, determine the weld center position, weld width, and height deviation based on the weld contour data, convert the weld center position and height deviation into target coordinates and angles of the welding torch, and adjust the welding parameters of the welding torch based on the weld width and height deviation.

[0009] Furthermore, the control unit includes a robot controller, a welding power interface, a high-speed data acquisition module, a data cache module, and a parameter recording module. The high-speed data acquisition module is used to receive the weld contour data of the laser head. The data cache module stores the weld contour data and the processed welding torch target coordinates and angles. The parameter recording module is used to bind and record the weld deviation, target coordinates and angles, welding parameters, and abnormal shutdown information of each welding process with the workpiece number.

[0010] Furthermore, in S4, the preset sampling interval is 1mm, the control unit converts the lateral deviation ΔY and height deviation ΔZ into the target pose of the robot with a sampling period of 10ms to 20ms, and writes the target coordinates and angles into the target sequence in a first-in-first-out order.

[0011] Further, in step S5, when the weld width B is within the range of 90% to 110% of the reference weld width, a reference welding current, a reference welding voltage, and a reference welding speed are used; when the weld width B is greater than 110% but not greater than 125% of the reference weld width and the absolute value of the height deviation ΔZ is greater than 0.8 mm, the wire feeding speed is increased by 5% to 12%, while the welding speed is decreased by 5% to 10%; when the weld width B is less than 90% of the reference weld width, the welding current is decreased by 5% to 8%.

[0012] Furthermore, in S7, the welding record also includes the weld width B of each weld, the number of sampling points, and the robot coordinates of the welding start and end points.

[0013] Furthermore, the robot is slidably mounted on the base, and the positions of the robot and welding torch are adjusted according to the position of the weld.

[0014] The present invention also provides an automatic welding device for welding bridge shells and C-beam accessories, including a base, a central frame, a pressure plate, a laser head, and a control unit. The base is fixedly installed, the central frame is installed on the base to support the bridge shell, the pressure plate is provided on the central frame to press the C-beam accessories, and the laser head is installed on the base to collect weld contour data. The automatic welding device also includes a robot and a welding torch. The welding torch is connected to the arm end of the robot, and the robot, welding torch, and laser head are all communicatively connected to the control unit.

[0015] Furthermore, the base is provided with a guide rail and a slider slidably connected to the guide rail. The laser head is mounted on the slider, and the horizontal position of the laser head is adjusted according to the position of the weld. The laser head is mounted on the slider through an L-shaped bracket, which has a height adjustment elongated hole for adjusting the height of the laser head relative to the weld.

[0016] Since the technical improvements and beneficial effects of the automatic welding device are at least the same as those of the automatic welding method used for welding bridge shells and C-beam accessories, the automatic welding device will not be described in detail here. Attached Figure Description

[0017] Figure 1 This is a process flow diagram of an automatic welding method for welding bridge shells and C-beam accessories according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the automatic welding device for welding bridge shells and C-beam accessories according to an embodiment of the present invention.

[0018] Explanation of reference numerals in the attached figures: 1. Base; 2. Middle frame; 3. Pressure plate; 4. Robot; 5. Welding torch; 6. Guide rail; 7. Slider; 8. Laser head; 9. Control unit. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, specific embodiments of this application are described clearly and completely below with reference to the accompanying drawings. It should be understood that the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments described in this application without creative effort will fall within the scope of protection of this application.

[0020] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the specification of this application is for the purpose of describing specific embodiments only and is not intended to limit this application; the terms "comprising," "including," "having," "containing," "comprise," etc., in the specification, claims, and accompanying drawings of this application are open-ended terms, indicating that a method comprises one or more steps, or an apparatus comprises one or more elements, but do not exclude the inclusion of other steps or elements. The terms "first," "second," etc., in the specification, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or primary / secondary relationship. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0021] In the description of this application, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application 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. Therefore, they should not be construed as limitations on this application.

[0022] Furthermore, in the attached diagram, the X-axis represents the vertical direction, that is, the front-to-back position, and the positive direction of the X-axis (that is, the direction the arrow points to) represents the front, and the negative direction of the X-axis (that is, the direction opposite to the positive direction of the X-axis) represents the back; in the attached diagram, the Y-axis represents the horizontal direction, that is, the left-to-right position, and the positive direction of the Y-axis (that is, the direction the arrow points to) represents the left, and the negative direction of the Y-axis (that is, the direction opposite to the positive direction of the Y-axis) represents the right; in the attached diagram, the Z-axis represents the vertical direction, that is, the up-to-down position, and the positive direction of the Z-axis (that is, the direction the arrow points to) represents the up, and the negative direction of the Z-axis (that is, the direction opposite to the positive direction of the Z-axis) represents the down.

[0023] It should also be noted that the aforementioned X-axis, Y-axis and Z-axis are only for the purpose of facilitating the description of this application and simplifying the description, and are not intended to 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 this application.

[0024] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0025] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0026] See Figures 1-2 An automatic welding method for welding bridge shells and C-beam accessories according to an embodiment of the present invention includes the following steps: S1. Clamping steps: Install and fix the axle housing on the base 1, so that the axis of the axle housing is parallel to the X-axis. Fit the C-beam accessory into the designated position of the journal of the axle housing and tighten it. S2. Calibration steps: Establish the transformation relationship between the laser coordinate system of the laser head 8 and the robot coordinate system of the robot 4 through the control unit 9, and record the front distance of the laser scanning line of the laser head 8 relative to the conductive tip TCP of the welding torch 5. S3. Positioning Step: Robot 4 drives welding torch 5 to approach the welding starting point along a preset safety trajectory. Laser head 8 scans the edges to be welded on the bridge shell and C-beam accessories. Control unit 9 identifies the welding starting point position and determines whether the weld center and height deviation are within the preset threshold range. If the deviation exceeds the preset threshold, a clamping abnormality prompt is issued. S4. Trajectory generation step: The laser head 8 scans along the weld direction at a preset sampling interval, and the control unit 9 converts the weld width B, lateral deviation ΔY and height deviation ΔZ obtained from each sampling into the target coordinates and angle of the welding gun 5. S5. Parameter adjustment steps: The control unit 9 adjusts the welding current, welding voltage, wire feed speed or welding speed of the welding torch 5 in stages according to the weld width B and height deviation ΔZ. S6. Welding execution steps: When the welding torch 5 reaches the welding starting point, it starts an arc. The robot 4 drives the welding torch 5 to move along the weld seam according to the target coordinates and angle of the welding torch. During the welding process, the laser head 8 continuously scans, and the control unit 9 continuously updates the target coordinates and angle of the welding torch. When the laser head 8 detects the end point of the weld seam, the control unit 9 marks the target coordinates and attitude angle corresponding to the end point of the weld seam in the target sequence, and uses the target coordinates and attitude angle as the arc termination trigger position. After the welding torch 5 reaches the end point, it terminates the arc. S7. Recording Steps: The control unit 9 records the lateral deviation ΔY, height deviation ΔZ, welding torch target coordinates and angle, welding current, welding voltage, wire feed speed, welding speed, arc start time, arc end time and abnormal shutdown information of each weld seam during this welding process as welding records corresponding to the workpiece number.

[0027] In this embodiment, the automated welding method for welding bridge shells and C-beam attachments establishes a positioning reference parallel to the X-axis of the bridge shell axis and applies pressure to the C-beam attachments through a clamping step. This provides a definite spatial reference for subsequent laser scanning and welding, eliminating the problem of unstable workpiece position during manual support. Secondly, a calibration step establishes the transformation relationship between the laser coordinate system and the robot coordinate system and records the forward distance, enabling the control unit to accurately map the weld contour data collected by the laser head in front of the welding torch to the robot's working coordinate system. Furthermore, a trajectory generation step converts the weld width, lateral deviation, and height deviation obtained from each sampling into the target coordinates and angle of the welding torch in real time. This allows the robot to drive the welding torch to follow the actual weld center in real time, rather than moving along a fixed preset trajectory, effectively compensating for weld position offsets caused by workpiece clamping deviations and workpiece dimensional tolerances. The target coordinates and angles simultaneously contain the spatial position and attitude angle information of the welding torch's TCP, ensuring that the welding torch performs welding at the optimal attitude angle at each sampling point of the three-dimensional curved weld. The parameter adjustment steps adjust the welding current, welding voltage, wire feed speed or welding speed in stages according to the deviation of weld width and height, so that the welding parameters can automatically adapt to the actual weld conditions, avoiding defects such as incomplete penetration, burn-through or weld beads that may occur when the weld conditions change in constant parameter welding.

[0028] This method records the welding process data by binding it to the workpiece number, so that each weld of each workpiece has a complete welding process data record. This provides a data foundation for subsequent quality traceability, process optimization and defect analysis, and solves the problem of untraceability of manual welding process.

[0029] It should be noted that base 1 is a rectangular frame structure arranged along the X-axis. Its upper surface has crisscrossing bolt mounting holes and T-shaped mounting slots. Adjustable feet are provided at both the front and rear ends of base 1. Base 1 is fixed to the ground foundation of the welding station and serves as the assembly and load-bearing benchmark for all components of the entire system.

[0030] In this embodiment, at least one intermediate frame 2 is installed on the base 1. Preferably, two intermediate frames are provided, located at opposite ends of the base 1. The upper part of the intermediate frame 2 is provided as a V-shaped support surface for supporting the bridge shell. The center line connecting the support surfaces of the pairs of intermediate frames 2 coincides with the X-axis, so that the axis of the bridge shell placed on the intermediate frame 2 is automatically parallel to the X-axis. A pressure plate 3 for pressing the C-beam attachment is also connected to the intermediate frame 2. The main body of the pressure plate 3 is a long strip pressure plate, and the front end is provided with a pressing block that contacts the upper surface of the C-beam attachment. It is connected to the intermediate frame 2 by a hinge and is used to press the upper surface of the C-beam attachment to prevent the C-beam attachment from moving or floating in the height direction during welding. The clamping step in S1 is specifically as follows: the bridge shell is placed on the V-shaped support surface of the intermediate frame 2, so that the axis of the bridge shell is parallel to the X-axis; the C-beam attachment is fitted into the designated position of the journal of the bridge shell; and the pressure plate 3 is operated to press the upper surface of the C-beam attachment.

[0031] Preferably, the surface of the pressure plate 3 that contacts the C-beam accessory is covered with a heat-resistant pad to prevent scratching the workpiece surface.

[0032] In this embodiment, the laser head 8, the robot 4, and the welding torch 5 are all connected to the control unit 9. The control unit 9 is used to receive the weld contour data collected by the laser head 8, determine the weld center position, weld width, and height deviation based on the weld contour data, convert the weld center position and height deviation into the target coordinates and angle of the welding torch 5, and adjust the welding parameters of the welding torch 5 based on the weld width and height deviation.

[0033] Specifically, robot 4 is a multi-axis industrial robot. The workspace of robot 4 covers all weld seams to be welded on both ends of the bridge shell and the C-beam attachments on the central frame 2. The scanning surface of laser head 8 covers the width of the lap weld seam between the bridge shell and the C-beam attachments. Robot 4 can be fixed to one side of base 1 or slidably connected to base 1 for easy position adjustment. Preferably, robot 4 is slidably mounted on base 1, and the positions of robot 4 and welding torch 5 are adjusted according to the position of the weld seam.

[0034] Furthermore, the end of robot 4 has a flange interface for mounting welding torch 5. The front end of welding torch 5 has a conductive nozzle and a protective gas nozzle, and the rear end has a torch clip that connects to the flange at the end of robot 4. The wire feed tube, protective gas tube, and cooling water tube of welding torch 5 are fixed along the arm of robot 4.

[0035] In this embodiment, the control unit 9 includes a robot controller, a welding power interface, a high-speed data acquisition module, a data cache module, and a parameter recording module. The high-speed data acquisition module is used to receive the weld contour data of the laser head 8. The data cache module stores the weld contour data and the processed welding torch target coordinates and angles. The parameter recording module is used to bind and record the weld deviation, target coordinates and angles, welding parameters, and abnormal shutdown information of each welding process with the workpiece number.

[0036] Specifically, the control unit 9 is located on one side of the base 1, maintaining a safe distance from the welding spatter area. The robot controller is connected to the control interface of the robot 4 via a communication cable, the welding power interface is connected to the welding torch 5 and the welding power supply via a power cable, and the high-speed data acquisition module receives the weld contour data output by the laser head 8 via a signal cable.

[0037] In this embodiment, in step S4, the preset sampling interval is 1mm, and the control unit 9 converts the lateral deviation ΔY and height deviation ΔZ into the target pose of the robot 4 with a sampling period of 10ms to 20ms, and writes the target coordinates and angles into the target sequence in a first-in-first-out order.

[0038] Specifically, the lateral deviation ΔY is the offset of the actual weld center relative to the preset welding trajectory in the Y-axis direction obtained by laser detection; the height deviation ΔZ is the offset of the actual weld center or weld surface relative to the preset welding trajectory in the Z-axis direction.

[0039] In this embodiment, in step S5, when the weld width B is within the range of 90% to 110% of the reference weld width, a reference welding current, a reference welding voltage, and a reference welding speed are used; when the weld width B is greater than 110% but not greater than 125% of the reference weld width and the absolute value of the height deviation ΔZ is greater than 0.8 mm, the wire feeding speed is increased by 5% to 12%, while the welding speed is decreased by 5% to 10%; when the weld width B is less than 90% of the reference weld width, the welding current is decreased by 5% to 8%.

[0040] In step S7, the welding record also includes the weld width B of each weld, the number of sampling points, and the robot coordinates of the welding start and end points.

[0041] The automatic welding method for welding bridge shells and C-beam accessories provided in this embodiment of the invention operates as follows: Before welding begins, base 1 serves as a fixed reference surface, providing a unified geometric reference for the entire system. The bridge housing is hoisted and placed on a pair of intermediate supports 2, with the bridge housing axis constrained to be parallel to the X-axis. After the C-beam attachment is fitted into the designated position on the journal of the bridge housing, the operator presses the handle of the pressure plate 3 to press the clamping block against the upper surface of the C-beam attachment, preventing the C-beam attachment from moving or drifting during welding. Thus, base 1, intermediate supports 2, and pressure plate 3 constitute a stable workpiece clamping system, providing a definite spatial reference for subsequent laser scanning and welding, and solving the problem of unstable workpiece position during manual support.

[0042] The control unit 9 first executes a calibration program to establish a transformation matrix between the laser coordinate system of the laser head 8 and the robot coordinate system of the robot 4, and records the forward distance L of the laser scanning line of the laser head 8 relative to the conductive tip TCP of the welding torch 5. By making the laser scanning line and the welding torch TCP reach the same spatial reference point and recording the corresponding robot positions, a precise transformation between the two coordinate systems can be achieved.

[0043] During the welding process, robot 4 first moves welding torch 5 along a preset safe trajectory from a safe position to the welding start area. Simultaneously, laser head 8 scans the edges of the bridge shell and C-beam attachments to be welded, and the high-speed data acquisition module of control unit 9 receives weld contour data at 1mm intervals and 10ms to 20ms cycles. Control unit 9 extracts the weld center position, weld width B, and the height deviation ΔZ of the welding torch TCP relative to the weld center from the weld contour data. When the detected lateral deviation ΔY exceeds ±3mm or the height deviation ΔZ exceeds ±2mm, control unit 9 determines that the workpiece clamping is abnormal and issues a warning, preventing welding from being performed under excessive deviation conditions and causing product scrap. This positioning mechanism filters out abnormally clamped workpieces before welding begins, reducing the welding scrap rate.

[0044] After successful positioning, the laser head 8 continues to scan forward along the weld seam direction. The control unit 9 converts the lateral deviation ΔY and height deviation ΔZ obtained at each sampling point into the target coordinates and angles of the welding torch 5. Specifically, the control unit 9 superimposes the nominal coordinates and attitude angles of each point on the preset welding trajectory with the deviation values ​​of the corresponding sampling points to generate corrected target coordinates and angles, and writes the target coordinates and angles into the target sequence in a first-in-first-out order. The robot 4 drives the welding torch 5 to move according to the target sequence, ensuring that the TCP of the welding torch 5 always follows the actual weld seam center and that the welding torch attitude angle remains consistent with the weld seam normal.

[0045] Simultaneously, the control unit 9 adaptively adjusts the welding parameters based on the weld width B and height deviation ΔZ obtained from the laser head 8. When the weld width B is within 90% to 110% of the reference weld width, it indicates that the weld gap is normal, and the reference welding current, reference welding voltage, and reference welding speed are used. When the weld width B is greater than 110% but not greater than 125% of the reference weld width, and the absolute value of the height deviation ΔZ is greater than 0.8 mm, it indicates that the weld gap is too large and the distance between the welding torch and the weld is too large. The control unit 9 increases the wire feed speed by 5% to 12% to increase the amount of filler metal, while decreasing the welding speed by 5% to 10% to increase the heat input per unit length of weld, ensuring full penetration and filling of the weld. When the weld width B is less than 90% of the reference weld width, it indicates that the weld gap is too small. The control unit 9 decreases the welding current by 5% to 8% to reduce heat input and prevent burn-through. The above-mentioned graded adjustment strategy adopts different adjustment ranges for different degrees of deviation, avoiding welding defects such as incomplete penetration, burn-through, or weld beads that may occur when welding with single fixed parameters changes the weld conditions.

[0046] When the welding torch 5 reaches the welding start point, the control unit 9 controls the welding torch 5 to ignite the arc, and the robot 4 drives the welding torch 5 to move along the weld seam according to the target coordinates and angle sequence. During the welding process, the laser head 8 continuously scans forward, and the control unit 9 continuously updates the target coordinates, angle sequence, and welding parameters. When the laser head 8 detects the weld seam endpoint feature, i.e., the weld seam edge disappears, the control unit 9 marks the endpoint position in the target coordinates and angle sequence, and the robot 4 drives the welding torch 5 to the endpoint and executes the arc termination procedure. The combination of welding endpoint recognition and arc termination control effectively prevents missed welding or over-welding at the weld seam end.

[0047] After each weld is completed, the parameter recording module of control unit 9 stores all data from the welding process—including the lateral deviation ΔY, height deviation ΔZ, weld width B, target coordinates and angle, welding current, welding voltage, wire feed speed, welding speed, arc initiation time, arc termination time, and abnormal shutdown information at each sampling point—as a welding record bound to the workpiece number. Each weld on each workpiece corresponds to an independent welding record. When weld quality issues arise subsequently, the corresponding welding record can be quickly retrieved using the workpiece number to trace abnormal weld deviation points, abnormal parameter periods, and abnormal shutdown events, achieving full traceability of welding quality.

[0048] like Figure 2As shown, another embodiment of the present invention also provides an automatic welding device for welding bridge shells and C-beam accessories, including a base 1, a central frame 2, a pressure plate 3, a laser head 8, and a control unit 9. The base 1 is fixedly installed, the central frame 2 is installed on the base 1 to support the bridge shell, the pressure plate 3 is provided on the central frame 2 to press the C-beam accessories, and the laser head 8 is installed on the base 1 to collect weld contour data. The automatic welding device also includes a robot 4 and a welding torch 5. The arm end of the robot 4 is connected to the welding torch 5, and the robot 4, the welding torch 5, and the laser head 8 are all communicatively connected to the control unit 9.

[0049] In this embodiment, the base 1 is provided with a guide rail 6 and a slider 7 slidably connected to the guide rail 6. The laser head 8 is mounted on the slider 7. The horizontal position of the laser head 8 is adjusted according to the position of the weld. The laser head 8 is mounted on the slider 7 through an L-shaped bracket. The L-shaped bracket has a height adjustment elongated hole for adjusting the height of the laser head 8 relative to the weld.

[0050] Preferably, the guide rail 6 is a linear guide rail, mounted on the upper surface of the base 1 along the X-axis. The effective stroke of the guide rail 6 covers the entire length range of the welding positions at both ends of the bridge housing, with a certain allowance reserved at both ends. The upper surface of the guide rail 6 has a precision-machined positioning surface and a mounting surface for mounting the slider 7. The guide rail 6 is fixed to the base 1 by bolts, and its degrees of freedom in the Y and Z directions are restricted by positioning pins.

[0051] The slider 7 is slidably mounted on the guide rail 6 and can slide along the X-axis to accommodate the welding positions of bridge housings of different specifications. The bottom of the slider 7 has a groove that mates with the guide rail 6, and the upper part has an annular adjustment groove and a mounting surface. The slider 7 is provided with bolt holes and a positioning surface for mounting the laser head 8.

[0052] Since the technical improvements and beneficial effects of the automatic welding device are at least the same as those of the automatic welding method used for welding bridge shells and C-beam accessories, the automatic welding device will not be described in detail here.

[0053] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. An automatic welding method for welding bridge shells and C-beam accessories, characterized in that, Includes the following steps: S1. Clamping steps: Install and fix the bridge housing on the base (1), so that the axis of the bridge housing is parallel to the X-axis, and put the C-beam accessory into the designated position of the journal of the bridge housing and press it tight; S2, Calibration steps: Establish the transformation relationship between the laser coordinate system of the laser head (8) and the robot coordinate system of the robot (4) through the control unit (9), and record the front distance of the laser scanning line of the laser head (8) relative to the conductive tip TCP of the welding gun (5); S3, Positioning Step: The robot (4) drives the welding torch (5) to approach the welding starting point along the preset safety trajectory. The laser head (8) scans the edge to be welded of the bridge shell and C-beam accessories. The control unit (9) identifies the welding starting point position and determines whether the weld center and height deviation are within the preset threshold range. If the deviation exceeds the preset threshold, a clamping abnormality prompt is issued. S4. Trajectory generation step: The laser head (8) scans along the weld direction at a preset sampling interval, and the control unit (9) converts the weld width B, lateral deviation ΔY and height deviation ΔZ obtained from each sampling into the target coordinates and angle of the welding gun (5). S5. Parameter adjustment steps: The control unit (9) adjusts the welding current, welding voltage, wire feeding speed or welding speed of the welding gun (5) in stages according to the weld width B and height deviation ΔZ. S6. Welding execution steps: When the welding torch (5) reaches the welding starting point, it starts an arc. The robot (4) drives the welding torch (5) to move along the weld seam according to the target coordinates and angle of the welding torch. During the welding process, the laser head (8) continuously scans and the control unit (9) continuously updates the target coordinates and angle of the welding torch. When the laser head (8) detects the end point of the weld seam, the control unit (9) marks the target coordinates and attitude angle corresponding to the end point of the weld seam in the target sequence and uses the target coordinates and attitude angle as the arc termination trigger position. The welding torch (5) terminates the arc after reaching the end point. S7. Recording steps: The control unit (9) records the transverse deviation ΔY, height deviation ΔZ, welding gun target coordinates and angle, welding current, welding voltage, wire feeding speed, welding speed, arc starting time, arc ending time and abnormal shutdown information of each weld seam during this welding process as welding records corresponding to the workpiece number.

2. The automatic welding method for welding bridge shells and C-beam accessories according to claim 1, characterized in that, At least one intermediate frame (2) is installed on the base (1). The upper part of the intermediate frame (2) is set as a V-shaped support surface for supporting the bridge shell. The intermediate frame (2) is also connected to a pressure plate (3) for pressing the C-beam accessory. The clamping step in S1 is as follows: place the bridge shell on the V-shaped support surface of the intermediate frame (2) so that the axis of the bridge shell is parallel to the X-axis. Fit the C-beam accessory into the designated position of the journal of the bridge shell. Operate the pressure plate (3) to press the upper surface of the C-beam accessory.

3. The automatic welding method for welding bridge shells and C-beam accessories according to claim 1, characterized in that, The laser head (8), robot (4) and welding torch (5) are all connected to the control unit (9). The control unit (9) is used to receive the weld contour data collected by the laser head (8), determine the weld center position, weld width and height deviation according to the weld contour data, convert the weld center position and height deviation into the target coordinates and angle of the welding torch (5), and adjust the welding parameters of the welding torch (5) according to the weld width and height deviation.

4. The automatic welding method for welding bridge shells and C-beam accessories according to claim 3, characterized in that, The control unit (9) includes a robot controller, a welding power interface, a high-speed data acquisition module, a data cache module, and a parameter recording module. The high-speed data acquisition module is used to receive the weld contour data of the laser head (8). The data cache module stores the weld contour data and the processed welding gun target coordinates and angles. The parameter recording module is used to bind and record the weld deviation, target coordinates and angles, welding parameters, and abnormal shutdown information of each welding process with the workpiece number.

5. The automatic welding method for welding bridge shells and C-beam accessories according to claim 3, characterized in that, In S4, the preset sampling interval is 1mm. The control unit (9) converts the lateral deviation ΔY and height deviation ΔZ into the target pose of the robot (4) with a sampling period of 10ms to 20ms, and writes the target coordinates and angles into the target sequence in a first-in-first-out order.

6. The automatic welding method for welding bridge shells and C-beam accessories according to claim 1, characterized in that, In step S5, when the weld width B is within 90% to 110% of the reference weld width, a reference welding current, a reference welding voltage, and a reference welding speed are used; when the weld width B is greater than 110% but not greater than 125% of the reference weld width and the absolute value of the height deviation ΔZ is greater than 0.8 mm, the wire feeding speed is increased by 5% to 12%, while the welding speed is decreased by 5% to 10%; when the weld width B is less than 90% of the reference weld width, the welding current is decreased by 5% to 8%.

7. The automatic welding method for welding bridge shells and C-beam accessories according to claim 6, characterized in that, In step S7, the welding record also includes the weld width B of each weld, the number of sampling points, and the robot coordinates of the welding start and end points.

8. The automatic welding method for welding bridge shells and C-beam accessories according to claim 7, characterized in that, The robot (4) is slidably mounted on the base (1), and the positions of the robot (4) and the welding gun (5) are adjusted according to the position of the weld.

9. An automatic welding device for welding bridge shells and C-beam accessories, characterized in that, The automatic welding device includes a base (1), a middle frame (2), a pressure plate (3), a laser head (8), and a control unit (9). The base (1) is fixedly installed, and the middle frame (2) is installed on the base (1) to support the bridge shell. The middle frame (2) is provided with a pressure plate (3) to press the C-beam attachment. The laser head (8) is installed on the base (1) to collect weld contour data. The automatic welding device also includes a robot (4) and a welding torch (5). The arm end of the robot (4) is connected to the welding torch (5). The robot (4), the welding torch (5), and the laser head (8) are all connected to the control unit (9) in communication.

10. The automatic welding device for welding bridge shells and C-beam accessories according to claim 9, characterized in that, The base (1) is provided with a guide rail (6) and a slider (7) slidably connected to the guide rail (6). The laser head (8) is mounted on the slider (7). The horizontal position of the laser head (8) is adjusted according to the position of the weld. The laser head (8) is mounted on the slider (7) through an L-shaped bracket. The L-shaped bracket has a height adjustment elongated hole for adjusting the height of the laser head relative to the weld.

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