An automatic welding apparatus and a multi-layer correction method

Abstract

The application discloses an automatic welding equipment and a multi-layer deviation rectifying method, and belongs to the technical field of welding automation equipment. The equipment comprises a multi-axis cooperative motion mechanism, a welding unit, a front locating processing mechanism with a gun cleaning and wire cutting function and a locating module. The application takes a consumable electrode wire with a standard dry extension length as a physical electric contact sensing probe, and obtains accurate spatial coordinates when a weak voltage is conducted through a control system. Compared with traditional laser or visual locating, the application is completely immune to smoke, arc light and spatter interference in the welding process from the physical principle. In combination with the method of off-line programming and inter-layer thermal deformation contact rectification proposed in the application, high-precision coordinate system remapping can be carried out on thick plate complex components, such as binary slotted impellers, and unmanned, demonstration-free adaptive locating welding is realized, so that the qualified rate and production efficiency of welding are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of industrial robots and welding automation control technology, and in particular to an automatic welding equipment and a multi-layer correction method. Background Technology

[0002] In turbomachinery, the quality of the welded joints of binary slotted impellers directly determines the overall operating efficiency and safe service life of the equipment, as these impellers operate under extremely high speeds and complex alternating stresses for extended periods. The blades of binary slotted impellers have a twisted three-dimensional spatial shape, and the assembly welds between the blades and the impeller disc / cover are often narrow, deep, and variable-section double-groove bevels.

[0003] Currently, the industry mainly employs manual welding, manual teaching automated welding, or optical automatic positioning technology for MIG welding of this type of impeller. Firstly, due to the complex spatial trajectory of the impeller weld seam, manual welding is extremely inefficient.

[0004] Secondly, the MIG welding process generates dense fumes, blinding arc light, and a large amount of metal spatter, while the workpiece surface is often covered with cutting oil. These factors can cause severe optical interference or even lens damage to the laser emitter or industrial camera, making it impossible for them to accurately extract the bevel features inside the deep groove, resulting in a significant decrease in positioning accuracy and defects such as off-center welding and incomplete welding.

[0005] Finally, binary slotted impellers are typically thick-plate structures, requiring multi-layer, multi-pass welding. After the first root pass weld, the massive heat input causes unpredictable three-dimensional thermal deformation of the impeller. Traditional mechanical contouring cannot penetrate deep grooves; and simply following a predetermined trajectory leads to misalignment of subsequent filler and capping welds, necessitating frequent shutdowns for manual adjustment.

[0006] In view of the above problems, there is an urgent need for an automatic welding equipment and a multi-layer correction method to solve the above technical problems. Summary of the Invention

[0007] In view of this, this application provides an automatic welding device and a multi-layer correction method. The main purpose is to solve the technical problem that existing laser / vision positioning technology is easily interfered with and fails in environments with smoke and splashes.

[0008] According to a first aspect of the present invention, an automatic welding device is provided, comprising: a motion mechanism for carrying and driving a welding torch and a workpiece with a complex spatial curved surface to perform relative motion in multiple dimensions of space; A welding unit is used to provide the welding torch with a consumable electrode wire having a preset extension length; The positioning module is electrically connected to the consumable electrode welding wire and is used to apply a safe positioning detection voltage to the consumable electrode welding wire in a non-welding state. Based on the electrical conduction circuit signal generated when the end of the consumable electrode welding wire makes physical contact with the workpiece, it captures the actual three-dimensional coordinate data of the contact moment. The control unit is communicatively connected to the motion mechanism, the welding unit, and the positioning module, respectively. The control unit internally stores offline programming theoretical trajectories generated based on the workpiece digital model; The control unit calculates a position deviation matrix based on the actual three-dimensional coordinate data in the space and the theoretical coordinate data in the offline programming theoretical trajectory, and uses the position deviation matrix to perform a correction motion on the current welding coordinate system to drive the motion mechanism to perform welding operations along the corrected actual trajectory. The correction motion includes at least translation and / or rotation transformation.

[0009] Furthermore, the automatic welding equipment further includes a processing mechanism, which is disposed within the motion envelope of the motion mechanism; The processing mechanism includes a wire-cutting and torch-cleaning assembly, which is used to cut off the end droplets of the consumable electrode welding wire before the positioning module performs the positioning action, so as to ensure that the extension length of the consumable electrode welding wire when used as a contact probe is strictly maintained at a consistent reference length.

[0010] Furthermore, the motion mechanism includes a frame, a welding robot, and a rotary positioner; The end flange of the welding robot is fixedly connected to the welding gun, and the clamping end of the rotary positioner is used to fix and install the binary slotted impeller. The welding robot and the rotary positioner are connected to the control unit via an industrial Ethernet bus to form an external axis collaborative linkage system with at least seven axes.

[0011] Furthermore, the clamping end of the rotary positioner is equipped with a zero-point quick-change positioning fixture, which includes a base mother plate and a replaceable daughter plate adapted to impellers of different specifications, so as to ensure the consistency of the mechanical reference coordinate system.

[0012] Furthermore, the positioning module integrates a high-voltage isolation protection circuit. When the welding unit starts arcing, the high-voltage isolation protection circuit cuts off the low-voltage sensing detection circuit of the positioning module to isolate the electromagnetic impact of the welding current.

[0013] Furthermore, the control unit is equipped with a multi-layer, multi-pass thermal deformation compensation module. After completing the welding of the (N-1)th layer of the thick plate multi-layer welding, the thermal deformation compensation module controls the welding torch to use the cut consumable electrode welding wire to re-execute the touch-and-position command on the side wall of the binary slotted impeller bevel or the surface of the (N-1)th layer weld that has undergone thermal deformation, calculate the interlayer dynamic deviation matrix, and correct the theoretical trajectory of the Nth layer welding according to the interlayer dynamic deviation matrix.

[0014] According to a second aspect of the present invention, an automatic welding multi-layer correction method based on the equipment described in the above-described invention is provided, comprising the following steps: S1. Generate offline trajectory: Import the 3D model of the complex spatial curved surface workpiece, extract the bevel features through offline programming software and plan the theoretical welding trajectory with multiple layers and multiple passes, and import the theoretical welding trajectory into the control unit. S2. Standardized probe preparation: The control unit schedules the motion mechanism to the processing mechanism according to the theoretical welding trajectory and performs the wire cutting action so that the exposed consumable electrode welding wire at the welding torch nozzle reaches the preset extension length. The motion mechanism includes a welding robot. S3, Reference Contact Positioning Stage: Cut off the welding power supply, turn on the positioning module, and control the end of the welding gun to approach at least three reference surfaces of the workpiece bevel at a preset speed. When the end of the welding gun touches the reference surface and generates electrical conduction, record the actual three-dimensional machine coordinates of each reference contact point. S4, Deviation Calculation and Coordinate System Mapping Stage: The control unit compares the measured actual three-dimensional machine coordinates with the theoretical starting coordinates in S1, calculates the deviation between the two, and generates a comprehensive position deviation matrix including three-dimensional translation and spatial rotation angle, and performs global or local offset correction on the workpiece coordinate system. S5. Execute the positioning and correction welding command: Close the welding power supply, and the motion mechanism starts arc welding according to the corrected actual trajectory; S6, Interlayer Thermal Deformation Adaptive Cycle: When multiple layers and multiple passes of welding are required, for bevels that have undergone geometric deformation due to the heat input of the previous welding pass, steps S2 to S5 are repeated before each layer of welding begins to dynamically track and correct the interlayer thermal deformation of welding in real time.

[0015] Furthermore, the reference contact positioning in step S3 specifically includes 1D unidirectional positioning, 2D corner positioning, or 3D internal hole positioning modes. Before performing the positioning and contact, the welding unit is controlled to output protective gas for a short time to disperse impurities on the reference surface to be contacted.

[0016] Furthermore, in step S4, if the control unit determines that the offset of any axis in the position deviation matrix exceeds the preset safety tolerance threshold when calculating the deviation, it directly triggers an audible and visual alarm and stops executing step S5 to prevent collision accidents caused by serious workpiece clamping errors.

[0017] Furthermore, the curved workpiece is a binary slotted double-groove bevel impeller used in turbine machinery; During the welding process in step S5, the welding robot and the rotary positioner perform multi-axis spatial interpolation linkage, so that the binary slotted weld seam of the impeller is always in the optimal ship-shaped welding position.

[0018] Beneficial effects: Firstly, this invention eliminates the need for laser vision sensors, transforming the "consumable metal welding wire" essential for MIG welding into a "three-dimensional spatial physical probe." Utilizing the extremely rapid response characteristics of metal electrical contact, not only can the positioning accuracy reach ≤±0.03mm, but it also avoids interference from strong arc light, dense smoke, spatter, and surface oil from a physical standpoint.

[0019] On the other hand, this invention establishes a three-in-one control strategy of "offline programming - high-precision wire shearing and positioning - dynamic interlayer correction". Before welding each layer or key layer, the welding wire is used to "re-identify" the latest physical boundary of the bevel that has been distorted by thermal deformation, and the current local TCP coordinate system is reconstructed in real time through a matrix algorithm. This achieves adaptive cancellation of thermal deformation, enabling precise alignment in the welding of deep grooves in thick plates.

[0020] Finally, because this application introduces digital offline programming and on-site welding wire contact, it completely eliminates inefficient manual teaching. When changing to different specifications or models of binary slotted impellers with different diameters and slot widths, the new offline program can be retrieved for automatic positioning and welding. Verification has shown a significant improvement in positioning accuracy, and welding changeover and operation efficiency is more than four times higher than traditional manual teaching, demonstrating excellent industrial deployment value.

[0021] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0022] The accompanying drawings, as part of this invention, are provided to further illustrate the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation thereof. Clearly, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0023] In the attached diagram: Figure 1 A schematic diagram of the structure of an automatic welding device provided in an embodiment of the present invention is shown; Figure 2 This diagram illustrates the structure of the multi-axis cooperative motion mechanism of the automatic welding equipment provided in this embodiment of the invention, namely a six-axis robot + a dual-axis positioner. Figure 3 This invention provides another structural schematic diagram of an automatic welding device according to an embodiment of the present invention; Figure 4 A logic diagram of the automatic welding multi-layer correction method provided in an embodiment of the present invention is shown; Figure 5 A flowchart of the automatic welding multi-layer correction method provided in an embodiment of the present invention is shown.

[0024] Icon labels: 11. Frame, 12. Welding robot, 13. Rotary positioner, 3. Positioning module, 4. Processing mechanism, 6. Welding torch, 7. MIG welding power supply.

[0025] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0027] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", 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 invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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 mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] Example 1 like Figures 1-3 As shown, this embodiment discloses an automatic welding device, including its hardware topology and kinematic infrastructure: This embodiment constructs a seven-axis / eight-axis linkage MIG automatic welding center specifically designed for the complex manufacturing of binary slotted impellers. Its hardware base is a robust frame 11. To ensure seamless access to complex curved surfaces, X, Y, and Z axis linear guides are provided at the top of the frame 11, and a welding robot 12 is positioned below or corresponding to these linear guides. A dual-axis rotary positioner 13 with tilting and rotation functions is arranged horizontally opposite the welding robot 12 on the frame 11. The rotary positioning accuracy of the rotary positioner 13 is less than or equal to ±0.01°. In this embodiment, the welding robot 12 is a six-axis welding robot with an industrial robotic arm having six movable joints (six rotation axes). Its end effector is specifically designed to mount a welding torch 6, replacing manual labor for high-precision automatic welding. In addition, in this application, the dual-axis rotary positioner 13 and the six-axis welding robot are linked through CAN or EtherCAT bus to form a seven-axis cooperative motion system with a rotation accuracy of ±0.01° and a tilting mechanism that can achieve stepless adjustment from 0° to 90°.

[0030] In another feasible implementation, the dual-axis rotary positioner 13 and the X / Y / Z-axis and six-axis welding robot can also be controlled remotely, via big data (Ethernet), or Wi-Fi. In this implementation, the object being welded is a "binary slotted impeller." The blades of this impeller are three-dimensionally twisted, and the weld between two blades is an extremely narrow, deep, and continuously twisting groove. If a low-level robot, such as a 3-axis or 4-axis robot, is used, the welding torch 6 cannot adjust its tilt angle after being inserted into the deep groove, failing to weld to the deep root and even colliding with the blades. The six-axis robot in this application, after penetrating the narrow deep groove of the binary slotted impeller, uses its flexible "three-axis wrist" to freely adjust the angle of the welding torch 6. Combined with the dual-axis rotary positioner 13, it is equivalent to equipping the robot with a flip-up table, ensuring that the welding torch 6 is always aligned with the bevel at a preset, perfect angle, achieving "boat-shaped welding," that is, a perfectly stable welding posture where the molten pool is like a boat.

[0031] In one feasible implementation, a MIG welding power source 7 is independently installed on the ground around the frame 11 or on a dedicated peripheral support platform. The MIG welding power source supports four welding modes: constant voltage, pulse, dual pulse, and low spatter, with welding parameter fluctuations ≤ ±2%. In this implementation, a 500A high-power digital pulse MIG welding power source is used, with a welding current adjustment range of 150A–350A and a voltage adjustment range of 20V–32V; the shielding gas is 98%Ar+2%O2, with a gas flow rate of 20L / min; the welding torch cooling system uses water cooling circulation, with the cooling water temperature precisely controlled at 25℃–35℃. The MIG welding power source 7, as the energy heart of the entire welding process, is connected to the welding robot 12 via a flexible large-section welding cable. In this application, the welding torch 6 is integrated and installed on the end flange of the welding robot 12. The welding wire is continuously fed through a wire feeding mechanism and finally extends outward from the conductive tip at the front end of the welding torch 6. The large current output by the MIG welding power source 7 is delivered to this conductive tip. In this application, the heavy MIG welding power supply 7 is physically separated from the motion actuator, which not only greatly reduces the load on the robot and ensures the high precision of the robotic arm's movements, but also facilitates the independent heat dissipation of the high-power equipment.

[0032] In one feasible implementation, the control unit is a built-in high-performance motion controller of the automatic welding equipment, which deeply integrates the controller of the welding robot 12 with the servo driver of the rotary positioner 13 via the EtherCAT high-speed industrial communication bus. The binary slotted impeller workpiece is fixed on the clamping plate of the dual-axis rotary positioner 13. During actual welding and positioning detection, the rotary positioner 13 performs tilting and flipping actions, and the welding robot 12 manipulates the welding torch 6 to perform precise following and interpolation, ensuring that the deep slotted bevel of the binary slotted impeller is always maintained in the "ship-shaped welding" gravity posture with optimal force on the molten pool.

[0033] Core Sensing Reconstruction: The welding wire acts as a probe. To overcome the vulnerability of optical sensors to blinding effects, this system abandons external vision sensors and develops an independent positioning module 3 for welding wire contact. Electrically connected to the consumable electrode welding wire, it applies a safe positioning detection voltage to the wire in a non-welding state and captures the actual three-dimensional spatial coordinate data at the moment of contact based on the electrical conduction circuit signal generated when the end of the welding wire physically contacts the complex spatial curved surface workpiece. This involves the following two completely independent electrical circuit switching controls: I. High-voltage burn-through prevention mechanism during welding: During normal arc ignition and welding, the MIG welding power source 7 outputs a high welding current of up to several hundred amperes to the welding torch 6. At this time, the control unit controls the high-frequency magnetic isolation relay inside the welding wire contact positioning module 3 to be forcibly disconnected, completely blocking the electromagnetic shock and burn-out risk caused by the high welding current to the precision sensing circuit.

[0034] II. Positioning Sensing Mechanism, also known as Positioning State: When the system enters the "positioning state detection," the MIG welding power supply 7 cuts off the high-current output. At this time, the positioning module 3 closes, applying a safe DC sensing voltage to the conductive tip inside the welding torch 6 and the metal welding wire passing through it. The safe DC sensing voltage includes both high-voltage and low-voltage ranges (20V-50V). The workpiece itself is properly grounded through the dual-axis rotary positioner 13. When the control unit directs the six-axis welding robot 12 to slowly approach the workpiece by manipulating the welding torch 6, the moment the end of the welding wire extending from the tip of the welding torch 6 contacts the metal bevel of the workpiece, a weak sensing current is instantly turned on and forms a closed loop. Within a microsecond period of receiving the voltage rise edge signal, the control unit immediately triggers and latches the absolute encoder values ​​of each servo axis of the welding robot 12. Through the solution of the forward kinematic mathematical equations, the control unit can instantly obtain the extremely accurate actual spatial X / Y / Z three-dimensional coordinates of the welding wire tip in the welding torch 6 at the moment of contact, i.e., the repeatability detection accuracy can reach ±0.03mm.

[0035] Example 2 like Figures 4-5 As shown, in one feasible implementation, this embodiment discloses an automatic welding multi-layer correction method based on the equipment described in Example 1, comprising the following steps: S1. Import the 3D model of the curved workpiece, extract the bevel features through offline programming software, plan the theoretical welding trajectory with multiple layers and multiple passes, and import the theoretical welding trajectory into the control unit. S2. The control unit schedules the motion mechanism to the processing mechanism 4 according to the theoretical welding trajectory and performs the wire cutting action so that the exposed molten electrode welding wire at the nozzle of the welding gun 6 reaches the preset extension length. The motion mechanism includes the welding robot 12. S3. Cut off the welding power supply, turn on the positioning module 3, and control the end of the welding torch 6 to approach the reference surface of at least three orthogonal or specific angle directions of the workpiece bevel at a preset speed. When the end of the welding torch 6 touches the reference surface and generates electrical conduction, record the actual three-dimensional machine coordinates of each reference contact point. S4. The control unit compares the measured actual three-dimensional machine coordinates with the theoretical starting coordinates in S1, calculates the deviation between the two, and generates a comprehensive position deviation matrix including three-dimensional translation and spatial rotation angle, and performs global or local offset correction on the workpiece coordinate system. S5. Close the welding power supply, and the motion mechanism begins arc welding according to the corrected actual trajectory; S6. When multiple layers and multiple passes of welding are required, for bevels that have undergone geometric deformation due to the heat input of the previous welding pass, repeat steps S2 to S5 before each layer of welding to dynamically track and correct the interlayer thermal deformation of the welding in real time.

[0036] In this embodiment, the reference contact positioning in step S3 specifically includes 1D unidirectional positioning, 2D corner positioning, or 3D inner hole positioning modes; before performing the positioning contact, the welding unit is controlled to output protective gas for a short time.

[0037] In this embodiment, when the control unit calculates the deviation in step S4, if it determines that the offset of any axis in the position deviation matrix exceeds the preset safety tolerance threshold, it directly triggers an audible and visual alarm and stops executing step S5.

[0038] In this embodiment, the curved workpiece is a binary slotted double-groove bevel impeller for turbine machinery; during the welding process in step S5, the welding robot 12 and the rotary positioner 13 perform multi-axis spatial interpolation linkage, so that the binary slotted weld seam of the impeller is always in the boat-shaped welding position.

[0039] In this embodiment, in step S2, after the exposed consumable electrode welding wire at the nozzle of the welding torch 6 reaches the preset dry extension length, the wire clamping command is executed. A special welding torch with cylinder clamping is used to ensure the positional accuracy of the welding wire under different welding postures.

[0040] Example 3 This embodiment discloses the specific algorithm closed-loop and operation flow of Embodiment 2: offline programming + interlayer correction during thermal deformation. For complex workpieces with thick plates, multiple layers, and multiple channels, such as binary slotted impellers, the software execution logic of this invention completely overturns the traditional open-loop operation. The specific full-process correction control is as follows: Step 1 is macro-level digitalization, i.e., offline planning: In offline mode, process technicians import the 3D CAD digital model of the binary slotted impeller into offline programming software, accurately extract the surface geometric boundaries of the binary slotted impeller, and automatically plan the multi-layer theoretical operating space trajectory of the root pass, fill pass, and cover pass welding, as well as the coordinates of the starting and ending points of the arc. These grand and complex 3D spatial instruction codes are packaged and sent to the control unit.

[0041] Step 2: To eliminate sensing errors, the probe needs to be "normalized" and zeroed. In actual continuous production, after the previous weld seam is finished, the welding wire extending from the end of the welding torch 6 is not only of uneven length, but also forms irregular metal droplet balls at the tip, which leads to serious inaccuracies in the length of the "probe" used for measurement. Therefore, before performing the next positioning detection, the welding robot 12 must move to the pre-positioning processing mechanism 4, i.e., the torch cleaning wire cutter, which is fixed on the frame 11. This torch cleaning wire cutter precisely cuts off the old welding wire extending from the front end of the welding torch 6. The new welding wire after being cut not only has a sharp and flat end face, but more importantly, its "extension length" extending from the conductive tip inside the welding torch 6 is physically calibrated to a strictly fixed constant. This ensures the absolute accuracy of subsequent spatial collision coordinate calculations from the source.

[0042] Step 3: Intelligent Dust Removal and Spatial "Blind Men and the Elephant" (Acquiring Truth): The control unit schedules the welding robot 12 to operate the welding torch 6 to probe into the deep groove of the impeller. To prevent false contact caused by scattered insulating welding slag at the bevel of the deep groove of the impeller, the welding torch 6 releases protective gas for a few seconds before approaching the bevel to "purge and remove obstacles." Subsequently, the welding wire probe makes several slight touches on at least two mutually perpendicular reference surfaces, such as the X-axis bevel sidewall and the Y-axis base plate. Through different combinations of touch logic, such as 1D (single direction), 2D (intersection point), or 3D (spatial corner) combination touch logic, the control unit successfully obtains the three-dimensional spatial point set of the true physical boundary of the workpiece in that local area.

[0043] Step 4: Mathematical Matrix Transformation and Corrective Welding (Flexible Adaptation): The control unit extracts the reference coordinate set of the starting point of the theoretical trajectory from Step 1. and the set of real spatial points obtained by actual contact. Perform spatial fitting operations, such as least squares fitting and homogeneous transformation matrix operations. Calculate the difference in the three-dimensional translation vector of the workpiece caused by pre-processing or human error in clamping. and Euler angle rotation error .

[0044] The control unit does not need to rewrite the original, massive offline program code; it only needs to apply the error compensation matrix to the workpiece coordinate system (Wobj) in the underlying control logic. Then, the MIG welding power supply 7 is automatically turned on to connect to high voltage, the welding robot 12 ignites the arc, and the welding torch 6 can then precisely and smoothly move along the "real-world correction groove" to initiate arc welding.

[0045] Step 5: Multi-layer, multi-pass thermal deformation "micro-shaping" enables dynamic inter-layer tracking: This is the key feature of this invention for dealing with extremely difficult welding. After the root pass welding of the thick plate of the binary slotted impeller, the huge welding heat input will cause the blades to cool and shrink locally, resulting in three-dimensional thermal deformation and distortion that is difficult to detect with the naked eye but can be fatal. If the second layer of filler welding is performed directly at this time, the welding torch 6 will inevitably deviate significantly from the bevel centerline of the deformed binary slotted impeller.

[0046] To address this pain point, the present invention sets up a key interlayer interruption mechanism: after the root pass is completed and the arc is extinguished, the welding robot 12 quickly performs the wire cutting action to restore the standard probe length. The welding torch 6 returns to the starting point of the weld bead that has undergone thermal deformation. The newly cut welding wire is used as a probe to touch the side wall of the first weld bead that has just been welded.

[0047] The control unit remeasures the "new boundary coordinates" after thermal deformation and recalculates the latest error offset matrix. Subsequently, the welding robot 12, carrying the updated correction coordinate system, performs the second layer of fill welding. This dynamic tracking mechanism of "layer-by-layer mapping and coordinate compensation" completely overcomes the uncontrollable thermal deformation curse of thick plate impeller parts, fundamentally ensuring that no matter how many layers are stacked upwards, each weld bead can always be precisely aligned and tightly interlocked, achieving ultimate consistency in process quality.

[0048] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. The implementation schemes in the above embodiments can also be further combined or replaced. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. An automatic welding device, characterized in that, include: The motion mechanism is used to support and drive the welding torch (6) and the curved workpiece to perform relative motion in multiple dimensions of space; A welding unit is used to provide a consumable electrode wire for the welding torch (6); The positioning module (3) is electrically connected to the consumable electrode welding wire and is used to apply voltage to the consumable electrode welding wire in a non-welding state, and capture the actual three-dimensional coordinate data of the contact moment based on the electrical conduction circuit signal generated when the end of the consumable electrode welding wire is in physical contact with the workpiece. The control unit is communicatively connected to the motion mechanism, the welding unit, and the positioning module (3), respectively. The control unit internally stores offline programming theoretical trajectories generated based on the workpiece digital model; The control unit calculates a position deviation matrix based on the actual three-dimensional coordinate data in the space and the theoretical coordinate data in the offline programming theoretical trajectory, and uses the position deviation matrix to perform a correction motion on the current welding coordinate system to drive the motion mechanism to perform welding operations along the corrected actual trajectory. The correction motion includes at least translation and / or rotation transformation.

2. The automatic welding equipment according to claim 1, characterized in that: It also includes a processing mechanism (4), which is disposed within the motion envelope of the motion mechanism; The processing mechanism (4) includes a gun cleaning and wire cutting assembly for removing the end droplets of the molten electrode welding wire.

3. The automatic welding equipment according to claim 1, characterized in that: The motion mechanism includes a frame (11), a welding robot (12), and a rotary positioner (13); The end flange of the welding robot (12) is fixedly connected to the welding gun (6), and the clamping end of the rotary positioner (13) is used to fix and install the binary slotted impeller. The welding robot (12), the rotary positioner (13), and the control unit are communicatively connected.

4. An automatic welding device according to claim 3, characterized in that: The clamping end of the rotary positioner (13) is provided with a zero-point quick-change positioning fixture, which includes a base mother plate and a replaceable daughter plate adapted to impellers of different specifications.

5. An automatic welding device according to claim 1, characterized in that: The positioning module (3) has a high-voltage isolation protection circuit integrated inside; When the welding unit starts arcing, the high-voltage isolation protection circuit cuts off the low-voltage sensing detection circuit of the positioning module (3) to isolate the electromagnetic impact of the welding current.

6. An automatic welding device according to claim 1, characterized in that: The control unit is internally equipped with a multi-layer, multi-channel thermal deformation compensation module. After completing the N-1 layer of thick plate multi-layer welding, the heat deformation compensation module controls the welding gun (6) to use the cut consumable electrode welding wire to re-execute the touch positioning command on the side wall of the binary slotted impeller bevel or the surface of the N-1 layer weld bead that has undergone heat deformation, calculate the interlayer dynamic deviation matrix, and correct the theoretical trajectory of the Nth layer welding according to the interlayer dynamic deviation matrix.

7. An automatic welding multi-layer correction method based on the equipment described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Import the 3D model of the curved workpiece, extract the bevel features through offline programming software, plan the theoretical welding trajectory with multiple layers and multiple passes, and import the theoretical welding trajectory into the control unit. S2. The control unit schedules the motion mechanism to the processing mechanism (4) according to the theoretical welding trajectory and performs the wire cutting action so that the exposed molten electrode welding wire at the nozzle of the welding gun (6) reaches the preset dry extension length. The motion mechanism includes a welding robot (12). S3. Cut off the welding power supply, turn on the positioning module (3), and control the end of the welding gun (6) to approach the reference surface of at least three orthogonal or specific angle directions of the workpiece bevel at a preset speed. When the end of the welding gun (6) touches the reference surface and generates electrical conduction, record the actual three-dimensional machine coordinates of each reference contact point. S4. The control unit compares the measured actual three-dimensional machine coordinates with the theoretical starting coordinates in S1, calculates the deviation between the two, and generates a comprehensive position deviation matrix including three-dimensional translation and spatial rotation angle, and performs global or local offset correction on the workpiece coordinate system. S5. Close the welding power supply, and the motion mechanism begins arc welding according to the corrected actual trajectory; S6. When multiple layers and multiple passes of welding are required, for bevels that have undergone geometric deformation due to the heat input of the previous welding pass, repeat steps S2 to S5 before each layer of welding to dynamically track and correct the interlayer thermal deformation of the welding in real time.

8. The automatic welding multi-layer correction method according to claim 7, characterized in that: The reference contact positioning in step S3 specifically includes 1D unidirectional positioning, 2D corner positioning, or 3D internal hole positioning modes. Before performing the positioning contact, the welding unit is controlled to output protective gas for a short time.

9. The automatic welding multi-layer correction method according to claim 7, characterized in that: In step S4, if the control unit determines that the offset of any axis in the position deviation matrix exceeds the preset safety tolerance threshold when calculating the deviation, it will directly trigger an audible and visual alarm and stop executing step S5.

10. The automatic welding multi-layer correction method according to claim 7, characterized in that: The curved workpiece is a binary slotted double-groove beveled impeller used in turbine machinery. During the welding process in step S5, the welding robot (12) and the rotary positioner (13) perform multi-axis spatial interpolation linkage, so that the binary slotted weld seam of the impeller is always in the ship-shaped welding position.

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