A welding wire curvature correction feeding system and method based on visual sensing

Abstract

The application discloses a welding wire curvature correction wire feeding system and method based on visual sensing, and relates to the technical field of welding wire feeding systems, and aims to improve the welding quality. The system comprises a control system, a mounting mechanism, a wire feeding nozzle, a driving wheel, a driven wheel, a correction wheel and a gear set. The wire feeding nozzle is used for conveying the welding wire to a target position. The driving wheel and the driven wheel are used for conveying the welding wire to move in the direction of the wire feeding nozzle. The correction wheel is used for correcting the wire feeding curvature of the welding wire at the wire feeding nozzle. On one hand, the control system controls the movement of the driving wheel through the gear set, and the driven wheel rotates simultaneously through the action of friction, thereby driving the welding wire to advance. On the other hand, the control system is used for collecting the appearance image of the welding wire at the wire feeding nozzle in real time, calculating the actual curvature of the welding wire at the wire feeding nozzle according to the appearance image of the welding wire, controlling the movement of the correction wheel according to the actual curvature of the welding wire, adjusting the pressure between the correction wheel and the welding wire, and making the welding wire feed out at the wire feeding nozzle with a constant curvature radius. The application can accurately feed the end of the welding wire to the specified position of the electric arc or the molten pool all the time, and improves the welding quality.

Description

Technical Field

[0001] This invention relates to the field of robotic welding equipment technology, and more specifically to a wire feeding system and a wire curvature correction method based on vision sensing. Background Technology

[0002] Robotic automated welding of non-consumable electrode gas shielded welding is widely used and crucial in modern industry, especially in fields with extremely high requirements for welding quality, precision, cleanliness, and material properties.

[0003] The placement of the wire feed is crucial to welding quality; incorrect feed can lead to insufficient or excessive penetration, directly impacting joint strength and reliability. Coiled welding wire is the most common method of wire storage, with the wire tightly wound around a central axis. However, the pre-tension curvature of the wire varies at different thicknesses on the coil. Without proper handling, this results in inconsistent curvature at the wire feed nozzle. Because there is a distance between the nozzle and the arc, wires with different curvatures cannot be precisely delivered to the designated arc or molten pool position.

[0004] Therefore, it is necessary to identify the curvature of the welding wire online and correct the curvature according to the actual situation to achieve precise wire feeding. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a wire feeding system and a wire curvature correction method based on vision sensing, so as to ensure that the wire feeder can output wires with consistent curvature during long-cycle welding.

[0006] Technical Solution: The present invention discloses a wire feeding system for correcting the curvature of welding wire based on vision sensing, comprising: a wire feeder and a control system. The wire feeder includes an installation mechanism, a wire feeding nozzle, a driving wheel, a driven wheel, a correcting wheel, and a gear set. The wire feeding nozzle 7 is installed at the wire outlet of the installation mechanism and is used to transport the welding wire to the target position. The driving wheel and the driven wheel are used to transport the welding wire towards the wire feeding nozzle. The correcting wheel is used to correct the curvature of the welding wire at the wire feeding nozzle. The control system, on the one hand, controls the movement of the driving wheel through the gear set, and the driven wheel rotates simultaneously through friction, driving the welding wire forward. On the other hand, it is used to collect the morphological image of the welding wire at the wire feeding nozzle in real time, calculate the actual curvature of the welding wire at the wire feeding nozzle based on the morphological image, and control the movement of the correcting wheel based on the actual curvature of the welding wire, adjusting the pressure between the correcting wheel and the welding wire so that the welding wire exits at the wire feeding nozzle with a constant radius of curvature.

[0007] Optionally, the driving wheel includes a first driving wheel and a second driving wheel. A wire feeding channel is provided between the first driving wheel and the driven wheel. The first driving wheel and the driven wheel are a set of pulleys with parallel axes. The common tangent of the pulley grooves of the first driving wheel and the driven wheel is parallel to the wire inlet and wire outlet of the mounting mechanism. The pulley groove between the first driving wheel and the driven wheel is V-shaped.

[0008] Optionally, the straightening wheel is a variable radius wheel, and the wheel is equipped with a pressure sensor to measure the pressure between the straightening wheel and the welding wire in real time and feed back the precise pressure status to the control system.

[0009] Optionally, the gear set includes a first pinion, a large gear, a second intermediate gear, a second pinion, a first intermediate gear, and a third intermediate gear. The first pinion meshes with the large gear, the first intermediate gear is coaxial with the large gear, two second intermediate gears are located on both sides of the first intermediate gear and mesh with it, the second pinion meshes with the third intermediate gear, the two second intermediate gears drive the drive wheel connected to them to rotate, and the third intermediate gear drives the straightening wheel connected to it to rotate.

[0010] Optionally, the control system includes: a vision module, an electronic control system, a first stepper motor and a second stepper motor. The electronic control system is used to control the movement of the first stepper motor and the second stepper motor. The first stepper motor drives the drive wheel to rotate sequentially through a first pinion, a large gear, a first intermediate gear and two second intermediate gears. The second stepper motor drives the correction wheel to rotate sequentially through a second pinion and a third intermediate gear, thereby achieving precise rotation of the correction wheel.

[0011] Optionally, the mounting mechanism includes a mounting base and a pressure seat disposed on the back of the mounting base. The mounting base is used to mount the wire feed nozzle, the drive wheel, the driven wheel, and the straightening wheel. The pressure seat is connected to the driven wheel and the straightening wheel and is used to adjust the position of the driven wheel and the straightening wheel in the vertical direction, thereby adjusting the vertical distance between the driven wheel and the straightening wheel and the drive wheel, and limiting the welding wire.

[0012] The present invention discloses a method for correcting the curvature of welding wire in a vision-sensing-based welding wire curvature correction feeding system, comprising the following steps:

[0013] During the wire feeding process, the control system acquires the shape image of the welding wire extruded from the wire feeding nozzle, processes the welding wire shape image, extracts the welding wire centerline, and selects N equally spaced points on the welding wire centerline near the wire feeding nozzle outlet to fit the arc using the moving least squares method. The radius of curvature of the welding wire at the wire feeding nozzle outlet is obtained based on the ratio of the welding wire shape image to the actual welding wire.

[0014] The control system drives the straightening wheel to rotate through the gear set based on the obtained radius of curvature, and controls the pressure between the straightening wheel and the welding wire by combining the real-time collected pressure between the straightening wheel and the welding wire, so that the radius of curvature of the welding wire at the wire feed nozzle is maintained at a constant value.

[0015] Furthermore, the method for extracting the center line of the welding wire is as follows: the center line of the welding wire is extracted through sub-pixel edge detection and center line fitting algorithm.

[0016] Furthermore, the method for extracting the centerline of the welding wire is as follows: The method for calculating the radius of curvature of the welding wire at the wire feed nozzle exit is as follows:

[0017] The selected welding wires are arranged in order along their center lines. There are 1 point, denoted as _ . ,in, The first one on the center line of the welding wire One point, , , The first one on the center line of the welding wire Points The coordinates;

[0018] According to the general equation of a circle , , For parameters, Let be the radius of curvature of the welding wire. Expanding the expression for the fitted circular arc, we get:

[0019]

[0020] make , , , ;

[0021] but , , is a linear expression. , , As a parameter, for the selected For each point, the result is obtained by minimizing the weighted sum of squared residuals. , , The corresponding value is the actual radius of curvature of the welding wire obtained by fitting. .

[0022] Furthermore, during the initial wire feeding process, an open-loop soft-start method is used, only feeding the welding wire to the wire feed nozzle without correcting the curvature; the pressure between the straightening wheel and the welding wire during this stage... The calculation formula is:

[0023] ;

[0024] in, This is the soft-start coefficient. This is the elastic modulus of the welding wire material, which is related to the welding wire material. , where is the moment of inertia of the welding wire cross section, The diameter of the welding wire; This is the distance between the feed nozzle outlet and the contact point of the straightening wheel. The initial silk-coating process time;

[0025] After the initial wire feeding process is completed, normal wire feeding is carried out. Under normal wire feeding conditions, the pressure between the straightening wheel and the welding wire is adjusted. The calculation formula is:

[0026] ;

[0027] in, This is the stiffness gain coefficient, which is related to the contact stiffness of the straightening wheel. The effective contact length between the welding wire and the driving wheel and straightening wheel, when the actual radius of curvature is... At that time, the pressure applied between the straightening wheel and the welding wire is zero, and the radius of curvature of the welding wire is not changed; when the actual radius of curvature is... At that time, positive pressure is applied between the straightening wheel and the welding wire. Increase the radius of curvature of the welding wire until the actual radius of curvature is reached. after This achieves curvature correction of the welding wire, ensuring that the radius of curvature of the welding wire at the wire exit point is maintained at a certain value. It can accurately reach the designated location.

[0028] Beneficial effects: Compared with the prior art, the significant technical effect of the present invention is as follows: A vision module is added to the wire feeding nozzle of the wire feeder. The vision module captures the image of the welding wire at the wire feeding nozzle. After image preprocessing by the electronic control system, extraction of the welding wire centerline, and fitting of the arc using the moving least squares method, the bending direction and radius of curvature of the welding wire are accurately identified. Furthermore, a second stepper motor drives a second pinion gear, which in turn drives a third gear to rotate, controlling the rotation of the variable radius straightening wheel. Combined with a pressure sensor, the pressure between the straightening wheel and the welding wire is precisely controlled, thereby achieving curvature correction of the welding wire at the wire exit, ensuring that the welding wire can accurately reach the designated position and guaranteeing smooth wire exit. Attached Figure Description

[0029] Figure 1 A schematic diagram of a traditional wire feeding mechanism and welding torch;

[0030] Figure 2 The structure of the welding wire curvature adjustment system;

[0031] Figure 3This is a front view of the welding wire curvature adjustment system;

[0032] Figure 4 The gear structure is for the welding wire curvature adjustment system;

[0033] Figure 5 Top view of the welding wire curvature adjustment system;

[0034] Figure 6 Methods for controlling the curvature of welding wire;

[0035] Figure 7 This is the control logic diagram of the electronic control system;

[0036] Figure label:

[0037] 1. Welding wire spool; 2. Welding wire; 3. Traditional wire feeding mechanism drive wheel; 4. TIG welding torch; 5. Electric arc; 6. Workpiece to be welded; 7. Wire feed nozzle; 8. Mounting base; 9. First drive wheel; 10. Second drive wheel; 11. Driven wheel; 12. Groove; 13. Correction wheel; 14. Vision module; 15. Pressure seat; 16. Electrical control system; 17. First stepper motor; 18. Second stepper motor; 19. First pinion; 20. Large gear; 21. Second intermediate gear; 22. Second pinion; 23. First intermediate gear; 24. Third intermediate gear; 25. Wire inlet; 26. Wire outlet. Detailed Implementation

[0038] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0039] Traditional wire feeding mechanisms such as Figure 1 As shown, in a conventional wire feeding mechanism, the master and slave wheels of drive wheel 3 feed the welding wire at a constant speed. During long-cycle welding, the curvature of the welding wire 2 at different positions on the wire spool 1 varies. For example, the radius of a brand-new wire spool 1 is... The radius of the welding wire spool roller is Actual radius of curvature of welding wire 2 satisfy The actual radius of curvature of the welding wire 2 at the wire feed nozzle 7 position is affected by the amount of wire remaining on the wire spool. The end of the welding wire 2 cannot be accurately delivered to the designated position, such as the arc column area 5 of the TIG welding torch 4 or the center of the molten pool on the workpiece 6 to be welded. When the welding current is small, the arc 5 and the molten pool are small, and the slight deviation at the end of the welding wire 2 affects the welding wire melting efficiency and is prone to forming defects.

[0040] like Figures 2 to 5As shown, the wire feeding system mainly includes a wire feeder and a control system. The wire feeder includes a mounting mechanism, a wire feed nozzle 7, a drive wheel, a straightening wheel 13, and a gear set. The mounting mechanism includes a mounting base 8 and a pressure seat 15 located on the back of the mounting base 8. The wire feed nozzle 7 is mounted on the side of the mounting base 8 and is used to feed the welding wire 2 to the target position. The drive wheel includes a first drive wheel 9, a second drive wheel 10, and a driven wheel 11 for feeding the welding wire. The first drive wheel 9 drives the driven wheel 11 to move, thereby driving the welding wire to move towards the wire feed nozzle. The welding wire output ends of the first drive wheel 9 and the driven wheel 11 are respectively provided with the second drive wheel 10 and the straightening wheel 13. The second drive wheel drives the welding wire 2 to move forward, and the straightening wheel 13... Used to correct the curvature of the welding wire at the wire feed nozzle; the gear set includes a first pinion 19, a large gear 20, a second intermediate gear 21, a second pinion 22, a first intermediate gear 23, and a third intermediate gear 24. The first pinion 19 is mounted on the back of the mounting base 8 and meshes with the large gear 20. The first intermediate gear 23 and two second intermediate gears 21 are arranged between the large gear 20 and the mounting base 8. The first intermediate gear 23 is coaxially arranged with the large gear 20. The two second intermediate gears 21 are located on both sides of the first intermediate gear 23 and mesh with the first intermediate gear 23. The second pinion 22 and the third intermediate gear 24 are mounted on the back of the pressure base 15 and mesh with each other.

[0041] The control system includes: vision module 14, electronic control system 16, first stepper motor 17 and second stepper motor 18.

[0042] The electronic control system 16 is used to control the movement of the first stepper motor 17 and the second stepper motor 18. The first stepper motor 17 is connected to the first pinion 19 and is used to drive the first pinion 19 to rotate. The first pinion 19 drives the large gear 20 to rotate. The large gear 20 drives the first intermediate gear 23, which is coaxial with it, to rotate. The first intermediate gear 23 drives the two second intermediate gears 21 on both sides to rotate. The two second intermediate gears 21 drive the first driving wheel 9 and the second driving wheel 10 to rotate respectively. The driven wheel rotates simultaneously through friction, driving the welding wire forward. The second stepper motor 18 is connected to the second pinion 22 and is used to drive the second pinion 22 to rotate. The second pinion 22 drives the third intermediate gear 24, which is meshed with it, to rotate. The third intermediate gear 24 drives the straightening wheel 13, which is connected to it, to rotate, realizing the precise rotation of the straightening wheel. The vision module 14 is mounted on the mounting base 8 to capture the image of the welding wire at the wire feed nozzle (the direction of the welding wire and the offset angle), and feed it back to the electrical control system in real time. The electrical control system 16 calculates the radius of curvature of the welding wire at the wire feed nozzle after preprocessing (noise suppression, dynamic threshold segmentation, morphological optimization, etc.) based on the image obtained by the vision module 14. The electrical control system sets the pressure between the straightening wheel and the welding wire according to the calculated radius of curvature according to formula (2). At the same time, the straightening wheel 13 is a variable radius wheel and is equipped with a pressure sensor to measure the pressure between the straightening wheel and the welding wire in real time and feed it back to the electrical control system for accurate pressure. The electrical control system compares the actual pressure value fed back by the pressure sensor with the set pressure value and makes timely closed-loop control of the second stepper motor. Through the above gear meshing relationship, the straightening wheel 13 is driven to rotate, and the pressure between the straightening wheel and the welding wire is adjusted until the actual pressure value between the welding wire and the straightening wheel is equal to the set pressure value. The radius of curvature of the welding wire can be changed to achieve the welding wire being fed out at the wire feed nozzle with a constant radius of curvature.

[0043] Furthermore, the first driving wheel 9 and the driven wheel 11 are a pair of pulleys with parallel axes. The common tangent of the groove 12 of the first driving wheel 9 and the driven wheel 11 is parallel to the wire inlet 25 and wire outlet 26 where the welding wire enters and exits from the mounting base. The first driving wheel is connected to the second intermediate gear 21. The groove between the first driving wheel and the driven wheel is V-shaped to increase the friction between the welding wire and the first driving wheel and the driven wheel, thereby achieving constant speed feeding of the welding wire by extruding the metal welding wire. The groove between the second driving wheel and the straightening wheel is also V-shaped. During normal wire feeding, the straightening wheel does not move, and the second driving wheel feeds the welding wire through the V-shaped groove. During the welding wire curvature correction process, the straightening wheel moves, generating pressure between the straightening wheel and the welding wire to adjust the welding wire curvature. The V-shaped groove is used to increase the friction between the welding wire and the second driving wheel and the straightening wheel.

[0044] like Figure 6 The wire curvature correction method of the wire feeding system based on vision sensing includes the following steps:

[0045] During the S1 wire feeding process, the vision module acquires the shape image of the welding wire extruded from the wire feeding nozzle and feeds it back to the electronic control system. The electronic control system processes the welding wire shape image, extracts the welding wire centerline, and selects N points with equal spacing on the welding wire centerline to fit an arc. Based on the ratio of the welding wire shape image to the actual welding wire, the radius of curvature of the welding wire at the outlet of the wire feeding nozzle is obtained.

[0046] The control system processes the welding wire morphology image, specifically as follows:

[0047] Image preprocessing, including noise suppression, dynamic thresholding, and morphological optimization, makes the welding wire morphology images easier for computer processing. Since welding wire images may contain interference from strong arc light, spatter, and smoke, certain preprocessing is necessary before use. Noise suppression reduces random noise from camera sensors, electromagnetic interference, or ambient light fluctuations, improving the signal-to-noise ratio. Dynamic thresholding binarizes the image, making the welding wire white and the background black for easier processing. However, the brightness of different areas of the image may still be inconsistent, posing a challenge for wire extraction. Therefore, dynamic thresholding is used. The threshold is based on the Gaussian weighted average of pixels in a specific neighborhood around a given pixel, minus a constant. In darker areas, a lower threshold is automatically applied to ensure the detection of darker welding wire portions; in brighter areas, a higher threshold is used to prevent misidentifying overly bright backgrounds as welding wire. After threshold segmentation, isolated white or black dots may remain. Morphological optimization removes foreground noise smaller than the structuring element while basically maintaining the shape and size of the original welding wire.

[0048] Extracting the centerline of the welding wire, specifically:

[0049] The welding wire centerline is extracted using sub-pixel edge detection and centerline fitting algorithms for further processing. Sub-pixel edge detection locates the welding wire edge at the position with the largest gradient magnitude, improving edge localization accuracy from "pixel level" to "sub-pixel level," typically achieving 0.1 pixel or even higher precision. The centerline fitting algorithm calculates the Hessian matrix of the grayscale distribution at each point in the image and finds the matrix's eigenvectors. The eigenvector corresponding to the largest eigenvalue points in the normal direction of the line. The center point in the normal direction is located where the first derivative is zero, which corresponds to the centerline position of the edge line. Extracting the welding wire centerline also has a certain noise suppression effect.

[0050] Determining the radius of curvature: Take 7-15 equally spaced points near the nozzle exit, fit the arc using the moving least squares method, and calculate the radius of curvature based on the ratio between the image and reality. Specifically, this includes:

[0051] After the centerline of the welding wire has been extracted, the selected welding wire centerlines are arranged in sequence. There are 1 point, denoted as _ . ,in, The first one on the center line of the welding wire One point, , , The first one on the center line of the welding wire Points The coordinates; where =7~15 is optimal.

[0052] The general form of a circle is , , For parameters, Let be the radius of curvature of the welding wire, which is then expanded as follows:

[0053] (1)

[0054] make , , , ;

[0055] but , , is a linear expression. , , As a parameter, for the selected For each point, we need to minimize the weighted sum of squared residuals to obtain... , , The corresponding value, where the fitted actual radius of curvature of the welding wire is... .

[0056] S2. Based on the radius of curvature obtained in step S1, the electronic control system sends corresponding commands to the second stepper motor, controlling the rotation of the second pinion gear, which in turn drives the rotation of the third intermediate gear connected to the straightening wheel. Combined with a force sensor, this controls the pressure between the straightening wheel and the welding wire. Specifically:

[0057] Under normal wire feeding conditions, the pressure between the straightening wheel and the welding wire The calculation formula is:

[0058] (2)

[0059] in, For coefficients, This is the stiffness gain coefficient (unit: m⁻¹), which is related to the contact stiffness of the straightening wheel. This refers to the effective contact length between the welding wire and the drive wheel and straightening wheel. Considering the welding wire material and actual conditions, when the material is ER70S-6 (steel), When the material is ER4043 (aluminum), ; This is the elastic modulus of the welding wire material (unit: Pa), which is related to the welding wire material. , where is the moment of inertia of the welding wire cross section, The diameter of the welding wire (unit: m). When the actual radius of curvature... At that time, the pressure applied between the straightening wheel and the welding wire is zero, and the radius of curvature of the welding wire is not changed; when the actual radius of curvature is... At that time, positive pressure is applied between the straightening wheel and the welding wire. Increase the radius of curvature of the welding wire until the actual radius of curvature is reached. after This achieves curvature correction of the welding wire, ensuring that the radius of curvature of the welding wire at the wire exit point is maintained at a certain value. It can accurately reach the designated location.

[0060] Considering that the vision module has not yet obtained a stable image when the wire feeder first starts working, directly using the above formula (2) may misidentify the curvature, resulting in excessive initial pressure and causing the welding wire to jam. Therefore, an open-loop soft-start method is used in the initial wire feeding process (first 1-2 seconds), only transmitting the welding wire to the wire feed nozzle without correcting the curvature. The pressure between the straightening wheel and the welding wire in this stage is... The calculation formula is:

[0061] (3)

[0062] in, This is the soft-start coefficient (dimensionless), which can take a value between 0.2 and 0.4. The distance between the feed nozzle outlet and the contact point of the straightening wheel (unit: m); This is the elastic modulus of the welding wire material (unit: Pa), which is related to the welding wire material. , where is the moment of inertia of the welding wire cross section, The diameter of the welding wire (unit: m). The initial wire feeding process time is given. The formula shows that the pressure increases linearly during this stage, until after 2 seconds, when the pressure between the straightening wheel and the welding wire is set using formula (1). .

[0063] like Figure 7The system control flow of the wire feeder is as follows: The electrical control system sends a corresponding signal to the first stepper motor 17 through the set wire feeding speed. The first stepper motor 17 drives the first driving wheel 9 and the second driving wheel 10 to rotate, and the first driving wheel drives the driven wheel to rotate. At the same time, the electrical control system receives images captured by the vision module, obtains the radius of curvature of the welding wire through calculation and processing, and sends a corresponding signal to the second stepper motor 18 to precisely control the pressure between the straightening wheel and the welding wire. This changes the bending angle of the welding wire exit, maintaining the radius of curvature of the welding wire exit at a certain value. , and deliver the end of the welding wire to the designated position.

[0064] The working principle of this invention is as follows: The welding wire is passed through the wire inlet on the front side of the mounting base 8, and then the welding wire passes through the groove 12 between the first driving wheel 9 and the driven wheel 11, and the groove between the straightening wheel 13 and the second driving wheel 10 in sequence. Then the welding wire passes through the wire outlet and the wire feed nozzle on the rear side of the mounting base 8. Then the position of the pressure seat in the vertical direction is manually corrected, and the position of the driven wheel and the straightening wheel in the vertical direction is changed. This is combined with the first driving wheel and the second driving wheel below to limit the welding wire. Then, the first stepper motor 17 and the second stepper motor 18 are started. The first stepper motor drives the gear set, which in turn causes the driving wheel and the driven wheel to press the welding wire forward. The electrical control system calculates and sets the pressure value by obtaining the actual radius of curvature through formula (1). Combined with the actual pressure value between the welding wire and the straightening wheel fed back by the force sensor, the control signal driving the second stepper motor is changed, and the straightening wheel 13 is precisely rotated until the actual pressure value is equal to the set pressure value. This realizes the automatic change of the pressure between the straightening wheel and the welding wire, changes the radius of curvature of the welding wire, and realizes the function of automatic correction of the curvature of the welding wire.

[0065] This invention employs a V-shaped groove structure for the drive wheel, achieving constant-speed wire feeding by extruding the metal welding wire. A vision module acquires the shape of the wire extruded from the wire feed nozzle and calculates its curvature. The electrical control system provides real-time feedback based on the wire curvature and the target wire feeding position, calculating the downward pressure of the correction mechanism to correct the wire curvature. This invention effectively solves the problem of inconsistent wire curvature caused by varying amounts of wire used in traditional wire feeders when feeding spooled welding wire. During long-cycle welding, the wire tip can be precisely delivered to the designated area of ​​the arc or molten pool, improving welding quality.

[0066] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for correcting the curvature of welding wire in a wire feeding system based on vision sensing, characterized in that, The wire curvature correction and feeding system includes a wire feeder and a control system. The wire feeder includes an installation mechanism, a wire feed nozzle, a drive wheel, a driven wheel, a correction wheel, and a gear set. The wire feed nozzle is installed at the wire outlet of the installation mechanism and is used to feed the welding wire to the target position. The drive wheel and driven wheel are used to feed the welding wire towards the wire feed nozzle. The correction wheel is used to correct the curvature of the welding wire at the wire feed nozzle. The control system controls the movement of the drive wheel through the gear set, and the driven wheel rotates simultaneously through friction, driving the welding wire forward. It also collects real-time images of the welding wire morphology at the wire feed nozzle, calculates the actual curvature of the welding wire at the wire feed nozzle based on the images, and controls the movement of the correction wheel based on the actual curvature, adjusting the pressure between the correction wheel and the welding wire so that the welding wire exits at the wire feed nozzle with a constant radius of curvature. The method includes the following steps: During the wire feeding process, the control system acquires the shape image of the welding wire extruded from the wire feeding nozzle, processes the welding wire shape image, extracts the welding wire centerline, and selects N equally spaced points on the welding wire centerline near the wire feeding nozzle outlet to fit the arc using the moving least squares method. The radius of curvature of the welding wire at the wire feeding nozzle outlet is obtained based on the ratio of the welding wire shape image to the actual welding wire. The control system drives the straightening wheel to rotate through the gear set based on the obtained radius of curvature, and controls the pressure between the straightening wheel and the welding wire by combining the real-time collected pressure between the straightening wheel and the welding wire, so that the radius of curvature of the welding wire at the wire feed nozzle is maintained at a constant value. During the initial wire feeding process, an open-loop soft-start method is used, only feeding the welding wire to the wire feed nozzle without correcting the curvature; the pressure between the straightening roller and the welding wire during this stage... The calculation formula is: ； in, This is the soft-start coefficient. This is the elastic modulus of the welding wire material, which is related to the welding wire material. , where is the moment of inertia of the welding wire cross section, The diameter of the welding wire; This is the distance between the feed nozzle outlet and the contact point of the straightening wheel. The initial silk-coating process time; After the initial wire feeding process is completed, normal wire feeding is carried out. Under normal wire feeding conditions, the pressure between the straightening wheel and the welding wire is adjusted. The calculation formula is: ； in, This is the stiffness gain coefficient, which is related to the contact stiffness of the straightening wheel. The effective contact length between the welding wire and the driving wheel and straightening wheel, when the actual radius of curvature is... At that time, the pressure applied between the straightening wheel and the welding wire is zero, and the radius of curvature of the welding wire is not changed; when the actual radius of curvature is... At that time, positive pressure is applied between the straightening wheel and the welding wire. Increase the radius of curvature of the welding wire until the actual radius of curvature is reached. after This achieves curvature correction of the welding wire, ensuring that the radius of curvature of the welding wire at the wire exit point is maintained at a certain value. It can accurately reach the designated location.

2. The method for correcting the curvature of welding wire according to claim 1, characterized in that, The method for extracting the center line of the welding wire is as follows: the center line of the welding wire is extracted through sub-pixel edge detection and center line fitting algorithm.

3. The method for correcting the curvature of welding wire according to claim 1, characterized in that, The method for calculating the radius of curvature of the welding wire at the wire feed nozzle exit is as follows: The selected welding wires are arranged in order along their center lines. There are 1 point, denoted as _ . ,in, The first one on the center line of the welding wire One point, , , The first one on the center line of the welding wire Points The coordinates; According to the general equation of a circle , , For parameters, Let be the radius of curvature of the welding wire. Expanding the expression for the fitted circular arc, we get: ； make , , , ; but , , is a linear expression. , , As a parameter, for the selected For each point, the result is obtained by minimizing the weighted sum of squared residuals. , , The corresponding value is the actual radius of curvature of the welding wire obtained by fitting. .

4. The method for correcting the curvature of welding wire according to claim 1, characterized in that, The driving wheel includes a first driving wheel and a second driving wheel. A wire feeding channel is provided between the first driving wheel and the driven wheel. The first driving wheel and the driven wheel are a set of pulleys with parallel axes. The common tangent of the pulley grooves of the first driving wheel and the driven wheel is parallel to the wire inlet and wire outlet of the mounting mechanism. The pulley groove between the first driving wheel and the driven wheel is V-shaped.

5. The method for correcting the curvature of welding wire according to claim 1, characterized in that, The straightening wheel is a variable radius wheel, and it is equipped with a pressure sensor to measure the pressure between the straightening wheel and the welding wire in real time and provide the control system with accurate pressure information.

6. The method for correcting the curvature of welding wire according to claim 1, characterized in that, The gear set includes a first pinion, a large gear, a second intermediate gear, a second pinion, a first intermediate gear, and a third intermediate gear. The first pinion meshes with the large gear, the first intermediate gear is coaxial with the large gear, two second intermediate gears are located on both sides of the first intermediate gear and mesh with it, and the second pinion meshes with the third intermediate gear. The two second intermediate gears drive the drive wheel connected to them to rotate, and the third intermediate gear drives the straightening wheel connected to it to rotate.

7. The method for correcting the curvature of welding wire according to claim 6, characterized in that, The control system includes: a vision module, an electronic control system, a first stepper motor, and a second stepper motor. The electronic control system is used to control the movement of the first stepper motor and the second stepper motor. The first stepper motor drives the drive wheel to rotate sequentially through the first pinion, the large gear, the first intermediate gear, and two second intermediate gears. The second stepper motor drives the correction wheel to rotate sequentially through the second pinion and the third intermediate gear, thereby achieving the precise rotation of the correction wheel.

8. The method for correcting the curvature of welding wire according to claim 1, characterized in that, The mounting mechanism includes a mounting base and a pressure seat located on the back of the mounting base. The mounting base is used to mount the wire feed nozzle, drive wheel, driven wheel, and straightening wheel. The pressure seat is connected to the driven wheel and straightening wheel and is used to adjust the position of the driven wheel and straightening wheel in the vertical direction, thereby adjusting the vertical distance between the driven wheel and straightening wheel and the drive wheel to limit the welding wire.

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