Welding control system and method for B-type sleeve

Abstract

The invention discloses a B-type sleeve welding control system and method, and belongs to the technical field of welding automation, and the B-type sleeve welding control system comprises a welding trolley, a welding gun, a visual perception unit and a control unit. By constructing a composite sensing system combining laser vision, molten pool recognition and welding gun sounding calibration, continuous and effective positioning in a narrow space in the sleeve under the condition that multiple layers of welding beads cover layer by layer is achieved. A welding gun is used for conducting welding wire penetration detection in a set coordinate system, space point positions are recorded in real time when the end of a welding wire makes contact with a sleeve and a base metal entity, self-adaptive correction of a welding bead starting point and a swing center is achieved, the positioning precision in the welding process of multiple layers of welding beads is greatly improved, and reliable reference is provided for follow-up path planning of the welding beads. A multi-sensor fusion algorithm is adopted, parameters such as the swing amplitude, the swing frequency, the welding height and the walking speed in the welding process are adjusted in real time, and the forming quality consistency of multiple layers of welding seams can be guaranteed.

Description

Technical Field

[0001] This invention relates to the field of welding automation technology, and in particular to a welding control system and method for type B sleeves. Background Technology

[0002] Type B sleeves are widely used in the repair of defects in oil and gas pipelines. They are typically used to reinforce or seal pipeline areas with corrosion, cracks, or mechanical damage, achieving structural fixation and pressure sealing through circumferential welding. This type of welding process demands extremely high precision in weld formation, consistency of interlayer overlap, and control of penetration depth; its welding quality directly affects the reliability and service life of the pipeline repair.

[0003] Currently, while automated solutions using tracked vehicles or robots in conjunction with vision sensors have emerged for welding type B sleeves, aiming to replace manual labor and improve consistency and efficiency, existing automated systems still suffer from the following inherent defects when dealing with the unique multi-layer, multi-pass, all-position circumferential welding of type B sleeves, preventing them from achieving high-quality, fully automated welding: (1) Sensor failure and positioning accuracy bottleneck in multi-layer welding: Existing automated systems generally rely on laser or vision sensors for weld seam identification and tracking. However, in the welding of type B sleeves, a pre-layer is required before multi-layer filling welding. After the pre-layer welding is completed, due to the high temperature and high reflectivity of the covering metal surface and the geometric irregularity of the weld seam surface, the vision sensor cannot effectively identify the weld seam center, which causes the system to lose its automatic positioning capability in the multi-layer filling stage.

[0004] (2) Lack of automatic correction capability to cope with interlayer geometric changes: The welding path of existing solutions is usually generated based on a fixed model of the initial scan. However, thermal deformation during the welding process and the uncertainty of interlayer weld formation will cause deviations between the actual weld geometry and the model. Existing systems lack a mechanism to detect and correct interlayer paths in real time during the welding process, and cannot adaptively compensate for these deviations.

[0005] (3) Fixed welding parameter control: Existing solutions mostly use preset, segmented parameters for welding, or can only make limited adjustments based on a single signal (such as electric arc). For the constantly changing heat dissipation conditions, position (flat welding, vertical welding, overhead welding) and groove filling state in the multi-layer welding of type B sleeves, this fixed or simple feedback control mode is difficult to achieve accurate and adaptive matching between welding heat input and molten pool behavior, which can easily cause defects such as uneven penetration and poor forming.

[0006] (4) Weak process monitoring and quality closed-loop control: Most existing systems focus on initial positioning and trajectory reproduction, but lack effective real-time monitoring and closed-loop feedback control capabilities for the dynamics of the molten pool and the weld bead forming dimensions during the welding process. It is impossible to adjust parameters in real time according to the state of the molten pool, and it is also impossible to detect key dimensions such as layer height and width in a timely manner after welding and make process adjustments. The consistency and reliability of welding quality are still difficult to guarantee. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems of the prior art and provide a welding control system and method for type B sleeves.

[0008] The objective of this invention is achieved through the following technical solution: a welding control system for a type B sleeve, the system comprising: The welding trolley is movable and orbits around the B-type sleeve on a circular track; The welding torch is mounted on the welding carriage and includes a multi-degree-of-freedom adjustment structure. The visual perception unit includes a laser sensor and an image sensor. The laser sensor is used to collect pre-weld groove geometry information, sleeve edge morphology and post-weld bead formation information, while the image sensor is used to collect molten pool morphology information in real time. Control unit, used for: Based on the pre-welding bevel geometry and sleeve edge morphology, a multi-layer, multi-pass planned welding path and welding process parameters are generated. During the filler welding process, the welding torch is moved to make the end of the welding wire contact the side wall of the B-type sleeve and the pipe base material. The actual weld boundary is determined based on the contact signal, and the planned welding path is corrected. During the welding process, the state of the molten pool is analyzed based on the molten pool morphology information, and the welding process parameters of the current weld bead are dynamically adjusted. The welding path and welding process parameters of subsequent welds are dynamically adjusted based on the weld bead formation information after welding.

[0009] In one example, the laser sensor includes a front laser sensor and a rear laser sensor. The front laser sensor collects pre-weld bevel geometry information and sleeve edge morphology, while the rear laser sensor collects post-weld bead forming information.

[0010] In one example, the multi-degree-of-freedom adjustment structure includes a rod extension mechanism, a horizontal pendulum mechanism, and an angular pendulum mechanism.

[0011] It should be further noted that the technical features corresponding to the above system examples can be combined or replaced to form new technical solutions.

[0012] The present invention also includes a welding method for a type B sleeve, implemented based on the control system formed by any or a combination of the above examples, the method comprising the following steps: Laser sensors are used to scan the bevel and sleeve edge to collect pre-welding geometric information of the bevel and the morphology of the sleeve edge. The control unit generates multi-layer, multi-pass planned welding paths and welding process parameters based on the pre-welding bevel geometry and sleeve edge morphology. The control unit controls the welding torch to perform pre-layer welding according to the planned welding path and welding process parameters; After the pre-layering is completed, the control unit controls the movement of the welding torch so that the end of the welding wire contacts the side wall of the B-type sleeve and the pipe base material. The actual weld boundary is determined according to the contact signal, the planned welding path is corrected, and the welding torch is controlled to weld along the corrected path. The image sensor collects information on the molten pool morphology in real time, the control unit analyzes the state of the molten pool, and dynamically adjusts the welding process parameters of the current weld bead. A laser sensor measures the weld bead formation information after welding. The control unit dynamically adjusts the welding path and welding process parameters of subsequent weld beads based on the weld bead formation information until the filling weld and capping weld are completed.

[0013] In one example, the welding torch is initially installed with the angle between its axis and the tangential direction of the pipe set at 40°-50°.

[0014] In one example, the pre-layer welding process further includes: The last two weld passes of the pre-layer are arranged flush with each other, with a narrow gap reserved between them for subsequent tempering weld passes. After all the pre-layer welding is completed, control the welding torch to raise it by one weld bead height, move it radially towards the sleeve side by half the weld bead width to reach the center position of the preset tempering weld bead, and perform tempering welding.

[0015] In one example, determining the actual weld boundary based on the contact signal and correcting the planned welding path specifically includes: Record the first coordinate when the welding wire contacts the sleeve sidewall and the second coordinate when the welding wire contacts the pipe base material or the surface of the previous weld bead. Based on the first and second coordinates, and combined with the known standard width and height of a single weld bead, the actual weld center position is calculated. The actual weld center position is compared with the planned theoretical center position. If the deviation exceeds the allowable error, coordinate compensation is performed on the subsequent welding path.

[0016] In one example, during filler welding, the angle of the welding torch gradually increases as the current filler layer increases, until it reaches 90°; The control unit calculates and compensates for the horizontal and height deviations at the tip of the welding torch in real time based on the change in the welding torch tilt angle.

[0017] In one example, the method further includes an interrupt annealing step: When the filling height reaches 40% to 60% of the expected total filling height, the current filling welding is automatically interrupted, and the welding torch is controlled to move to the upper edge of the sleeve to perform at least two annealing welds and manual grinding. After the annealing welding is completed, control the welding torch to return to the interrupted position and continue to perform fill or cover welding.

[0018] In one example, after the cap welding is completed, the following is also included: A laser sensor is used to scan the surface of the cover layer to obtain the contour data of the outer surface of the weld. Fit the slope of the straight line at the upper edge of the weld and compare it with the target slope range; If the comparison results do not meet the preset target, plan and execute the repair welding path.

[0019] It should be further noted that the technical features corresponding to the above examples can be combined or replaced to form new technical solutions.

[0020] Compared with the prior art, the beneficial effects of the present invention are: 1. In one example, this invention introduces a physical contact positioning and calibration method—where the welding wire touches the sidewall of the B-type sleeve and the base material of the pipe—to achieve adaptive correction of the weld start point and the center of oscillation. This fundamentally solves the problem of failure of existing vision technology after multiple weld passes, significantly improving the positioning accuracy during multi-layer weld welding and providing a reliable reference for subsequent weld path planning. Simultaneously, by integrating pre-weld scanning planning, real-time monitoring of the weld pool during welding, and post-weld dimensional inspection, a fully closed-loop control system of planning-execution-monitoring-correction is constructed. This systematically overcomes the problems of low positioning accuracy, rigid parameter adjustment, lack of adaptive correction capability, and weak quality control in existing technologies, achieving high-quality, fully automated multi-layer, multi-pass welding of the B-type sleeve.

[0021] 2. In one example, by limiting the initial working angle of the welding torch, the direction of the electric arc is ensured to simultaneously point towards the heated areas of the outer wall of the sleeve and the base material of the pipe, thereby improving the fusion depth and joint strength.

[0022] 3. In one example, after the pre-layer welding is completed, tempering welding can reduce the surface tensile stress of the pre-welded layer by performing tempering welding, making the subsequent filling more stable.

[0023] 4. In one example, by increasing the welding torch angle during the filler welding process, it is ensured that the change in welding torch posture does not affect the coordinate accuracy after the weld layer height increases; at the same time, by compensating for horizontal / height deviations, it is possible to ensure that no cumulative offset occurs during the planning process, thereby improving welding accuracy.

[0024] 5. In one example, by performing annealing welding, the intermediate layer structure can be stabilized, ensuring the stability and reliability of the weld.

[0025] 6. In one example, after the cover welding is completed, the final formed profile is further evaluated, and automatic repair welding is performed if the requirements are not met, so that the appearance and size of the weld meet the welding standards, thereby ensuring the welding quality. Attached Figure Description

[0026] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. The accompanying drawings are provided to provide a further understanding of the present application and constitute a part of the present application. The same reference numerals are used in these drawings to denote the same or similar parts. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation of the present application.

[0027] Figure 1 This is a partial system structure diagram provided as an example of the present invention; Figure 2 A system structure diagram provided as an example of the present invention; Figure 3 A flowchart illustrating a method provided as an example of the present invention; Figure 4 This is a schematic diagram of the welding torch angle provided as an example of the present invention; Figure 5 This is a schematic diagram of the weld bead pre-overlay forming process provided in an example of the present invention; Figure 6 This is a schematic diagram of the cross-section of a type B sleeve fillet weld provided in an example of the present invention; Figure 7 A flowchart illustrating a preferred method provided as an example of the present invention.

[0028] In the diagram: 11-Main controller; 12-Control controller 12; 2-Welding torch; 21-Wire feeding hose; 22-Welding wire spool; 23-Wire drawing motor; 24-Rod extension motor; 25-Angle pendulum motor; 31-Front laser sensor; 32-Rear laser sensor; 33-Molten pool camera sensor; 4-Walking motor. Detailed Implementation

[0029] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0031] In one example, a welding control system for a type B sleeve is suitable for welding applications where the reinforcing sleeve is installed on the outer wall of a pipeline. The welding object is typically a pressurized pipeline or an industrial energy medium pipeline. The system includes a welding carriage, a highly flexible welding torch, a vision sensing unit, and a control unit. These units work collaboratively to achieve automated, intelligent, and high-precision control of the multi-layer, multi-pass welding process of the type B sleeve. Preferably, in this example, the control unit includes a central controller and an execution controller, which are communicatively connected. The central controller generates the planned multi-layer, multi-pass welding path and welding process parameters. The execution controller controls the welding carriage and welding torch, and performs real-time calculations based on visual information collected by the vision sensing unit. It extracts pre-weld bevel size information, molten pool state information during welding, and post-weld bead formation information to correct the welding path. By setting up a two-layer collaborative architecture between the central controller and the execution controller, centralized decision-making and separation of motion control throughout the welding process are achieved. Optionally, some functions of the central controller and the execution controller can be interchanged; for example, the central controller can also perform real-time calculations based on visual information collected by the vision sensing unit.

[0032] The welding trolley is movable and orbits around the B-type sleeve on a circular track. Specifically, as shown... Figures 1-2 As shown, the welding carriage integrates an automatic walking subsystem (track walking mechanism) connected to a track. This subsystem includes a walking motor 4, which, in conjunction with a corresponding walking actuator, enables linear drive of the carriage. The welding carriage moves stably along a circular track arranged on the outside of the sleeve. The walking subsystem provides servo drive for the welding carriage, controlling its speed and stability in real time. The actuator dynamically adjusts the welding carriage speed based on feedback from laser vision and the molten pool state, ensuring the welding torch mounted on the carriage maintains a stable posture and uniform movement throughout the circumferential welding process. This achieves continuous, smooth, and high-precision control of the circumferential weld, providing a reliable motion foundation for fully automated multi-layer, multi-pass welding.

[0033] like Figures 1-2As shown, the welding torch 3 is mounted on a welding carriage and includes a multi-degree-of-freedom adjustment structure. Specifically, the welding torch is equipped with welding wire, a wire feeding hose 21, a welding wire spool 22, and a wire drawing motor 23. The welding wire on the wire spool enters the wire feeder via a guide mechanism. The wire drawing motor inside the wire feeder drives the wire feeding wheel assembly to push the welding wire into the wire feeding hose with precisely controlled thrust. The wire feeding hose acts as a flexible channel, transporting the welding wire into the torch body of the high-flexibility welding torch and finally extending it from the conductive nozzle at the front end of the welding torch. Preferably, the multi-degree-of-freedom adjustment structure includes a rod extension mechanism, a horizontal swing mechanism, and an angular swing mechanism. The rod extension mechanism includes a rod extension motor 24, the horizontal swing mechanism includes a horizontal swing motor (not shown in the figure), and the angular swing mechanism includes an angular swing motor 25. Through the cooperation of the three motors with the corresponding multi-degree-of-freedom adjustment components, the welding torch can achieve precise extension, swing, and angle adjustment in space. Under the command of the controller, the welding torch can be dynamically adjusted in real time based on laser vision, molten pool image and calibration feedback. It is used to correct weld seam offset, maintain the best incident angle, control the swing width and swing frequency, and automatically perform layer and pass attitude switching in the multi-layer and multi-pass welding process. It is the core execution device for the whole system to realize precise welding path and multi-pass welding sequence planning.

[0034] The visual sensing unit includes a laser sensor and an image sensor. Preferably, such as Figures 1-2 As shown, the system is equipped with two laser vision sensors, one at the front and one at the rear. The front laser sensor 31 is installed at the front end of the welding torch and scans the pre-weld bevel with a laser line. The bevel width, depth, gap position, and sleeve edge shape are extracted by a deep learning semantic segmentation model integrated into the execution controller, thus obtaining the initial geometric data of the weld and providing a basis for layer planning. The rear laser vision sensor 32 is located behind the welding torch and scans the weld bead in real time. It compares the data with the pre-weld data from the front laser sensor to calculate the forming thickness, filling amount, and weld bead offset. This information is then fed back to the execution controller for dynamic adjustment of welding current, voltage, wire feed speed, and welding torch oscillation parameters, achieving closed-loop control of the forming quality. Furthermore, the image sensor is specifically a molten pool camera sensor 33, which performs real-time imaging of the welding area. Through a deep learning model integrated into the execution controller, key features such as the molten pool contour, molten depth variation, weld bead offset, and heat input status are extracted. Based on the changes in the molten pool morphology, the execution controller can adjust the walking speed, welding energy input, and welding torch oscillation rhythm in real time to keep the molten pool in a stable state, ensure uniform weld bead formation, and avoid defects such as undercut, porosity, and lack of fusion. This constitutes the core of heat input and molten pool stability control during the welding process.

[0035] like Figures 1-2As shown, the main controller 11 is the core decision-making module of the entire intelligent welding system, responsible for system operation management, sensor data fusion and analysis, weld layering and pass planning, welding parameter calculation, and logical control of the entire welding process. The main controller integrates a high-performance industrial processor, which performs high-speed calculations based on information such as the front laser, rear laser, and molten pool images fed back by sensors. It generates multi-layer, multi-pass welding path planning and welding process parameters at the microsecond level, and issues real-time execution commands to the execution controller via the communication bus, achieving coordinated operation of the entire system. Simultaneously, the main controller dynamically adjusts the welding path and welding process parameters of subsequent weld passes based on the post-weld bead formation information.

[0036] like Figures 1-2 As shown, the execution controller 12 is arranged on the welding carriage and is an edge intelligent unit responsible for local real-time motion execution. It has a built-in embedded AI acceleration chip, enabling it to perform deep learning inference on laser vision and molten pool images locally to identify bevel information and molten pool features. Based on the identification results, the execution controller rapidly controls the extension, horizontal swing, and angular swing mechanisms of the welding torch, achieving actions such as fine-tuning of the welding torch behavior, weld seam tracking, and swing correction, while simultaneously controlling the track travel speed, forming a complete execution layer closed loop. Specifically, the execution controller is used to: 1) control the movement of the welding torch during the filler welding process, ensuring the welding wire tip contacts the sidewall of the B-type sleeve and the pipe base material, determining the actual weld seam boundary based on the contact signal, and correcting the planned welding path. Specifically, after the base layer welding is completed, the filler welding and capping welding stages begin. Since B-type sleeve welding typically requires dozens of weld passes layer by layer, the surface geometry of the weld seam changes after each layer of welding. To achieve stable weld seam superposition, this invention uses laser vision, molten pool recognition, and welding wire contact in a coordinated manner to perceive the weld seam state. Before each pass of the filler weld, the welding torch automatically moves to the planned starting point, allowing the welding wire to slowly probe towards the sleeve and pipe directions. When the end of the welding wire touches the solid material, the contact coordinates are recorded. The system compares the measured position with the theoretically planned position, correcting the centerline, starting point coordinates, and oscillation amplitude of the current weld pass to ensure precise alignment between multiple layers and passes, avoiding cumulative weld offset. 2) During welding, the molten pool state is analyzed based on the molten pool morphology information, and the welding process parameters for the current weld pass are dynamically adjusted. Optionally, the main controller can also analyze the molten pool state based on the molten pool morphology information, dynamically adjust the welding process parameters for the current weld pass, and send the optimized welding process parameters to the execution controller.

[0037] This invention provides an automated welding control system for multi-layer, multi-pass circumferential welding of type B sleeves. This system integrates a track-walking mechanism, a highly flexible welding torch mechanism, a laser vision sensor, and a molten pool camera sensor, and constructs a two-layer collaborative architecture of a central controller and an execution controller. This achieves intelligent control throughout the entire process, including weld data acquisition, welding path planning, automatic positioning control, and adaptive adjustment of welding parameters. Before welding, the system uses a front-mounted laser vision sensor to perform bevel scanning and geometric analysis, acquiring the sleeve thickness, bevel width, and boundary position to generate the initial welding path for the base layer welding and the first layer of filler welding. During welding, the molten pool camera sensor identifies the molten pool size, contour, and weld bead offset in real time. Combined with a rear-mounted laser vision sensor, the system scans the welded area and dynamically adjusts the welding current, voltage, wire feed speed, oscillation width, oscillation frequency, and walking speed based on changes in weld bead thickness and shape, achieving closed-loop control of energy input and weld bead formation.

[0038] To address the problem of visually obscuring interlayer boundaries during multi-layer, multi-pass welding of type B sleeves, which involves layer-by-layer weld overlap, this invention proposes an automatic calibration mechanism based on welding wire contact. After pre-layer welding is completed, the system moves the welding torch to the planned theoretical starting point before each weld pass. Then, it controls the welding wire to explore along both the sleeve and pipe directions. When the wire tip touches the solid material, the contact position is recorded to correct the weld centerline, weld start coordinates, and the swing range of the next pass, thereby ensuring precise positioning of each layer and strict adherence to the multi-pass stacking rule. Through the combined control of laser vision, molten pool recognition, and contact calibration, this invention achieves the most critical multi-layer, multi-pass automatic positioning in sleeve welding, enabling the welding torch to maintain a stable and accurate welding path even under complex weld geometry variations.

[0039] The control system of this invention adopts a master controller-execution controller architecture. The master controller is responsible for global data fusion, welding process planning, hierarchical planning, pass strategy generation, and parameter optimization decisions; the execution controller is responsible for welding torch posture adjustment, local motion control, and visual reasoning execution. The two achieve real-time information interaction and control command synchronization through high-speed communication. Combined with the trolley mechanism of the track-walking system, it can achieve stable circumferential movement along the outer wall of the sleeve, and the walking speed is dynamically adjusted under the coordinated action of the master controller and the execution controller, so that the welding process remains continuous, stable, and highly precise. The control system of this invention, through the comprehensive application of sensor fusion, deep learning recognition, multi-degree-of-freedom actuators, and touch-based calibration technology, realizes the full automation of the B-type sleeve welding process, providing a stable, reliable, and industrially applicable intelligent control solution for complex multi-layer and multi-pass welding.

[0040] This invention also includes a welding method for a type B sleeve, implemented based on the aforementioned welding control system. This method addresses the characteristics of sleeve welds—multi-layered, multi-pass, all-position circumferential welds, high forming requirements, and the difficulty in ensuring precision using traditional manual welding. Through pre-welding scanning, intelligent planning, real-time control, and touch-based automatic calibration, it achieves fully automated and highly consistent welding throughout the sleeve welding process. Specifically, as... Figure 3 As shown, the welding method includes the following steps: S1: Use a laser sensor to scan the bevel and sleeve edge to collect pre-welding bevel geometry and sleeve edge morphology.

[0041] During the pre-welding preparation stage, the welding trolley is installed on the outer track of the sleeve. Before the system starts, the laser vision sensor performs a 360° circumferential scan of the bevel area, collecting geometric information such as bevel width, bevel depth, edge position of the outer wall of the sleeve, outer contour of the pipe, and welding gap. The deep learning model integrated by the execution controller performs semantic segmentation and structural recognition on the laser image to obtain complete three-dimensional structural parameters of the bevel and transmits them to the main controller.

[0042] S2: The control unit generates multi-layer, multi-pass planned welding paths and welding process parameters based on the pre-welding bevel geometry and sleeve edge morphology.

[0043] Specifically, based on the geometric information such as the bevel width, bevel depth, sleeve outer wall edge position, pipe outer contour, and welding gap, the main controller automatically generates multi-layer, multi-pass planned welding paths and welding process parameters. The welding process parameters include the starting position, welding torch angle, travel speed, and initial oscillation parameters, thereby realizing automatic planning of multi-layer, multi-pass welding.

[0044] S3: The control unit controls the welding torch to perform pre-layer welding according to the planned welding path and welding process parameters, and controls the welding carriage and welding torch to perform pre-layer welding.

[0045] S4: After the pre-layering is completed, the control unit controls the movement of the welding torch so that the end of the welding wire contacts the side wall of the B-type sleeve and the main body of the pipe. The actual weld boundary is determined according to the contact signal, the planned welding path is corrected, and the welding torch is controlled to weld along the corrected path.

[0046] After the base layer welding is completed, the system enters the filler welding stage. Since the welding of type B sleeves usually requires dozens of weld passes to fill the gaps layer by layer, the surface geometry of the weld changes after each layer is welded. In order to achieve stable weld pass stacking, this invention uses three methods in combination to sense the weld state, namely laser vision, molten pool recognition and welding wire touch, and corrects the planned welding path.

[0047] S5: The image sensor collects molten pool morphology information in real time, the control unit analyzes the molten pool status, and dynamically adjusts the welding process parameters of the current weld bead.

[0048] During the welding process, this invention uses a molten pool camera to image the welding area in real time. By using a deep learning model integrated into the controller, information such as the molten pool contour, weld depth, weld trajectory, and forming deviation is extracted. Then, the current welding process parameters, including welding current, voltage, wire feed speed, welding torch oscillation width, oscillation frequency, and welding carriage travel speed, are adjusted according to the deviation information.

[0049] S6: The laser sensor measures the weld bead formation information after welding. The control unit dynamically adjusts the welding path and welding process parameters of subsequent weld beads based on the weld bead formation information until the filling welding and capping welding are completed.

[0050] The laser vision sensor scans the newly welded weld bead, and the controller compares the formed weld bead data with the pre-weld data to obtain key parameters such as weld bead height, width, and filler volume. It then dynamically adjusts the welding current, voltage, wire feed speed, welding torch oscillation width and frequency, and welding carriage travel speed to achieve closed-loop control of welding heat input and weld formation. Through real-time identification and dynamic parameter adjustment, the system can automatically compensate for localized thermal deformation of the sleeve, changes in the bevel structure, or unstable weld formation, ensuring uniform weld formation and smooth interlayer transitions.

[0051] The process of this invention combines bevel scanning, molten pool identification, wire contact calibration, and dynamic parameter adjustment to achieve accurate identification and continuous correction of the welding path throughout the welding process. This ensures that multi-layer and multi-pass welding is always superimposed along the expected position, avoiding interlayer misalignment and weld bead offset. Especially in scenarios such as sleeve welding where space is limited, welds are deep, and there are many weld beads, it can significantly improve stability and weld quality, achieving automated welding effects that are difficult to achieve manually in the traditional way.

[0052] In one example, the system location deployment and initial sensor calibration for steps S1-S2 include: Before welding begins, the detachable track is positioned along the pipe's axial direction on the outer surface of the pipe near the area to be reinforced by the sleeve. The welding trolley is then mounted on the track, ensuring that the trolley can move smoothly along the circumference of the sleeve. Figure 4 As shown, the welding torch is installed at an angle relative to the pipe axis. The initial angle between the welding torch axis and the tangential direction of the pipe is set to 40°-50°, preferably 45°, to ensure that the arc direction simultaneously points to the heated areas of both the outer wall of the sleeve and the pipe base material, thereby improving the fusion depth and joint strength. The angle gradually increases until it is perpendicular to the pipe.

[0053] The laser vision sensor is positioned at approximately a 10° angle to the direction of the sleeve, allowing the laser line to cover the inner end face of the sleeve and the outer wall of the pipe, thereby obtaining the profile features of the gap between the sleeve and the pipe. After the system starts, the main controller performs depth segmentation analysis on the laser vision image, extracts the geometric parameters of the bevel region, including the pipe wall thickness T, the sleeve-pipe gap G, the bevel width distribution, curvature variation characteristics, etc., and establishes a three-dimensional geometric reference benchmark for the sleeve welding area.

[0054] Calculate the total weld width required for the pre-layer based on the measurement data. The pre-stacking design width is estimated according to the following relationship: This width is used to compensate for the geometric step difference between the inner side of the sleeve and the pipe base material, forming a transition weld pad. Based on the pre-welding process qualification, the single-pass weld width W and weld height H are determined, and the system automatically estimates the number of pre-layer weld passes. This allows for precise advance planning for multi-layer, multi-pass welding.

[0055] In one example, the pre-stacking process in step S3 includes: The welding carriage moves at a constant speed along the track around the sleeve, and the welding torch performs welding pass by pass from the sleeve side to the pipe side according to the planned path. The pre-clad weld passes are arranged in parallel. After each weld pass is completed, the welding torch moves outward to the welding reference position of the next weld layer, and the moving distance is approximately the weld pass width W. The overlap between weld passes maintains an appropriate coverage according to process requirements to ensure that the pre-clad weld layer has good density and uniform height.

[0056] To form the subsequent tempering groove structure, such as Figure 5 As shown, the last two weld passes of the pre-layer are not stacked or overlapped, but are arranged flat and adjacent to each other, with a narrow gap between the two weld passes for subsequent tempering weld passes, thus reducing stress concentration in the heat-affected zone.

[0057] During the initial stage of pre-cladding welding, a molten pool camera sensor acquires real-time images of the molten pool during the welding process, identifies the molten pool contour and subsequent weld bead width, and performs online evaluation of welding parameters based on the identification results. If welding parameters deviate from process requirements, dynamic adjustments are made promptly to ensure weld bead formation quality and welding stability. After pre-cladding welding is completed, as follows... Figure 5 As shown, the welding torch is raised by one weld bead height H and moved radially towards the sleeve side by half a weld bead width W / 2 to reach the center position of the preset tempering weld bead, and a tempering stabilization weld is performed to reduce the surface tensile stress of the pre-welded layer and make the subsequent filling more stable.

[0058] In one example, step S4, filling welding and wire touch calibration, includes: Record the first coordinate when the welding wire contacts the sleeve sidewall and the second coordinate when the welding wire contacts the pipe base material or the surface of the previous weld bead. Based on the first and second coordinates, and combined with the known standard width and height of a single weld bead, the actual weld center position is calculated. The actual weld center position is compared with the planned theoretical center position. If the deviation exceeds the allowable error, coordinate compensation is performed on the subsequent welding path.

[0059] Specifically, after the pre-layering is completed, due to the high temperature and high reflectivity of the covered metal surface and the irregular geometry of the weld surface, laser vision has difficulty in effectively distinguishing the center of the weld. Therefore, the system adopts a two-stage positioning method of "weld geometric calculation + welding wire touch positioning calibration".

[0060] First, the welding torch moves to the left until the welding wire contacts the sleeve, at which point the torch is positioned near the root sealing weld. Then, the root sealing weld begins. After the root sealing weld is completed, the initial position for subsequent welds is determined by the system based on the center coordinates of the previous weld. Calculate the estimated center coordinates of the next weld pass. : After the welding torch is moved to the vicinity of the estimated position, a low-speed touch detection is performed. The welding wire is slowly moved towards the inside and below the weld seam, and when an arc short circuit or metal contact signal is detected, the first coordinate is recorded. Second coordinate Then calculate the precise position of the weld center. : If the deviation does not exceed the system's allowable error ε, welding of that weld bead is initiated; if the deviation exceeds the limit, coordinate compensation is performed. : This allows for stable positioning throughout the entire filler welding process without the need for laser measurement.

[0061] In one example, during the filler welding process, to ensure that the change in the welding torch posture does not affect the coordinate accuracy as the weld layer height increases, the welding torch tilt angle is gradually increased during the layer-by-layer outward movement of the weld until it approaches 90°.

[0062] Preferably, the controller calculates and compensates for the horizontal and height deviations at the tip of the welding torch in real time based on the change in the welding torch tilt angle and using trigonometric relationships. in, To change the angle of the welding torch, and These are the horizontal and vertical changes caused by variations in the welding torch tilt angle, respectively, to ensure that no cumulative offset occurs during the planning process.

[0063] In one example, the method also includes an interrupt annealing step: When the fill height reaches 40% to 60% of the expected total fill height, the current fill welding is automatically interrupted, and the welding torch is moved to the upper edge of the sleeve to perform at least two annealing welds to stabilize the middle layer structure.

[0064] After the annealing welding is completed, control the welding torch to return to the interrupted position and continue to perform fill or cover welding.

[0065] After annealing, grinding and finishing are required to reduce stress concentration. It should be noted that when the welding torch reaches the annealed weld bead position, it indicates that the capping welding stage has begun.

[0066] In one example, after the cap welding is completed, the following is also included: A laser sensor is used to scan the surface of the cover layer to obtain the contour data of the outer surface of the weld. Fit the slope of the straight line at the upper edge of the weld and compare it with the target slope range; If the comparison results do not meet the preset target, plan and execute the repair welding path.

[0067] Specifically, after the cover weld is completed, the welding carriage is reset to its initial position, and the height profile of the outer surface of the weld is obtained through a laser vision sensor, and the slope of the straight line at the upper edge of the weld is fitted. : When the slope |K| If the slope is insufficient or excessive, the system will automatically initiate a repair weld to meet the design requirements for the bevel transition morphology. Finally, the system applies two final tempering welds to the top layer of the capping layer, completing the entire welding process.

[0068] This multi-layer, multi-pass automated welding process achieves fully automated B-type sleeve welding without manual intervention through laser vision modeling, pre-weld geometry reconstruction, wire-touch self-calibration positioning, and welding torch posture compensation mechanism. In particular, the wire-touch positioning scheme effectively solves the problem of lasers being unable to identify the forming characteristics of high-temperature deposited metal, achieving millimeter-level positioning accuracy for the filler layer weld bead and ensuring uniform and reliable weld formation. Layer-by-layer adjustment of the welding torch angle, combined with a triangular compensation algorithm, ensures the fusion and metallurgical reliability of the sleeve and base material. Staged tempering welding further reduces residual stress and improves the fatigue life of the reinforced structure under long-term pressure conditions.

[0069] By combining the above-described welding methods, a preferred welding method of the present invention is obtained, the implementation process of which is as follows: Figure 7 As shown in the diagram, this invention achieves continuous and effective positioning in the narrow space within the sleeve and in situations where multiple weld beads are covered layer by layer by layer, by constructing a composite sensing system that combines laser vision, molten pool recognition, and welding torch probing calibration. Traditional systems, after the first weld bead, cannot continue effective trajectory extraction due to changes in the weld surface morphology, chaotic laser reflection, and unrecognizable images, leading to interruptions in automated welding or requiring manual recalibration. This invention utilizes the welding torch to perform "wire probing" within a set coordinate system, recording the spatial position in real time when the welding wire tip contacts the sleeve and the base material. This enables adaptive correction of the weld bead starting point and oscillation center, significantly improving the positioning accuracy during multi-layer weld bead welding and providing a reliable reference for subsequent weld bead path planning.

[0070] This invention employs a multi-sensor fusion algorithm to adjust parameters such as oscillation amplitude, oscillation frequency, welding height, and travel speed in real time during the welding process, enabling the welding process to automatically maintain stable formation according to changes in heat input. Compared to traditional methods relying on manual observation and parameter adjustment, this invention's control strategy can significantly reduce the risk of defects such as spatter, porosity, and incomplete fusion during the welding process, ensuring consistent quality of multi-layer, multi-pass welds. It is particularly suitable for pressure pipelines and safety components with stringent weld quality requirements.

[0071] Furthermore, the welding process of this invention, through strategies such as setting up backing welds, interlayer planning, and adaptive weld bead allocation, enables a high degree of controllability and repeatability in multi-layer, multi-pass welding processes. The system, through precise control of weld bead positions, interlayer gaps, and thermal cycling, allows the entire welding process to be completed smoothly without manual intervention, significantly improving welding efficiency. Based on the matching design of the track-type trolley and the sleeve structure, the system possesses stable operating characteristics and can quickly adapt to welding tasks with sleeves of different specifications, improving the versatility of industrial production.

[0072] This invention reduces the degree of human intervention, enabling the automated completion of complex, delicate, and labor-intensive multi-layer, multi-pass welding tasks for sleeves. It significantly lowers the operating threshold, improves welding quality stability and production efficiency, and has significant promotional value for realizing intelligent welding equipment.

[0073] The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

Claims

1. A welding control system for a type B sleeve, characterized in that, include: The welding trolley is movable and orbits around the B-type sleeve on a circular track; The welding torch is mounted on the welding carriage and includes a multi-degree-of-freedom adjustment structure. The visual perception unit includes a laser sensor and an image sensor. The laser sensor is used to collect pre-weld groove geometry information, sleeve edge morphology and post-weld bead formation information, while the image sensor is used to collect molten pool morphology information in real time. Control unit, used for: Based on the pre-welding bevel geometry and sleeve edge morphology, a multi-layer, multi-pass planned welding path and welding process parameters are generated. During the filler welding process, the welding torch is moved to make the end of the welding wire contact the side wall of the B-type sleeve and the pipe base material. The actual weld boundary is determined based on the contact signal, and the planned welding path is corrected. During the welding process, the state of the molten pool is analyzed based on the molten pool morphology information, and the welding process parameters of the current weld bead are dynamically adjusted. The welding path and welding process parameters of subsequent welds are dynamically adjusted based on the weld bead formation information after welding.

2. The welding control system for the type B sleeve according to claim 1, characterized in that, The laser sensor includes a front laser sensor and a rear laser sensor. The front laser sensor collects the geometric information of the bevel and the shape of the sleeve edge before welding, while the rear laser sensor collects the weld bead formation information after welding.

3. The welding control system for the type B sleeve according to claim 1, characterized in that, The multi-degree-of-freedom adjustment structure includes a rod extension mechanism, a horizontal pendulum mechanism, and an angular pendulum mechanism.

4. A welding method for a type B sleeve, implemented based on the control system described in any one of claims 1-3, characterized in that, Includes the following steps: Laser sensors are used to scan the bevel and sleeve edge to collect pre-welding geometric information of the bevel and the morphology of the sleeve edge. The control unit generates multi-layer, multi-pass planned welding paths and welding process parameters based on the pre-welding bevel geometry and sleeve edge morphology. The control unit controls the welding torch to perform pre-layer welding according to the planned welding path and welding process parameters; After the pre-layering is completed, the control unit controls the movement of the welding torch so that the end of the welding wire contacts the side wall of the B-type sleeve and the pipe base material. The actual weld boundary is determined according to the contact signal, the planned welding path is corrected, and the welding torch is controlled to weld along the corrected path. The image sensor collects information on the molten pool morphology in real time, the control unit analyzes the state of the molten pool, and dynamically adjusts the welding process parameters of the current weld bead. A laser sensor measures the weld bead formation information after welding. The control unit dynamically adjusts the welding path and welding process parameters of subsequent weld beads based on the weld bead formation information until the filling weld and capping weld are completed.

5. The welding method for the type B sleeve according to claim 4, characterized in that, When the welding torch is initially installed, the angle between the welding torch axis and the tangential direction of the pipe is set to 40°-50°.

6. The welding method for the type B sleeve according to claim 4, characterized in that, The pre-layer welding process also includes: The last two weld passes of the pre-layer are arranged flush with each other, with a gap left between them for subsequent tempering weld passes. After all the pre-layer welding is completed, control the welding torch to raise it by one weld bead height, move it radially towards the sleeve side by half the weld bead width to reach the center position of the preset tempering weld bead, and perform tempering welding.

7. The welding method for the type B sleeve according to claim 4, characterized in that, The step of determining the actual weld boundary based on the contact signal and correcting the planned welding path specifically includes: Record the first coordinate when the welding wire contacts the sleeve sidewall and the second coordinate when the welding wire contacts the pipe base material or the surface of the previous weld bead. Based on the first and second coordinates, and combined with the known standard width and height of a single weld bead, the actual weld center position is calculated. The actual weld center position is compared with the planned theoretical center position. If the deviation exceeds the allowable error, coordinate compensation is performed on the subsequent welding path.

8. The welding method for the type B sleeve according to claim 4, characterized in that, During the filler welding process, the tilt angle of the welding torch gradually increases as the number of filler layers increases, until it reaches 90°; The control unit calculates and compensates for the horizontal and height deviations at the tip of the welding torch in real time based on the change in the welding torch tilt angle.

9. The welding method for the type B sleeve according to claim 4, characterized in that, The method also includes an interrupted annealing step: When the filling height reaches 40% to 60% of the expected total filling height, the current filling welding is automatically interrupted, and the welding torch is controlled to move to the upper edge of the sleeve to perform at least two annealing welds. After the annealing welding is completed, control the welding torch to return to the interrupted position and continue to perform fill or cover welding.

10. The welding method for the type B sleeve according to claim 9, characterized in that, After the cap welding is completed, the following is also included: A laser sensor is used to scan the surface of the cover layer to obtain the contour data of the outer surface of the weld. Fit the slope of the straight line at the upper edge of the weld and compare it with the target slope range; If the comparison results do not meet the preset target, plan and execute the repair welding path.

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