A Visual Guidance Method for Laser Processing

Abstract

The present invention discloses a vision guidance method for laser processing, which relates to the technical field of automatic welding control; the method includes the following steps: S10, position calibration, the laser calibrates multiple points at different positions on the surface of the product and records the coordinates of the corresponding points; S20, affine transformation of coordinates, the vision system is located above the X-axis. When the product is in the first position, the coordinates of the surface calibration points of the product under the vision system are recorded; when the product moves to the second position, the affine transformation formula is used to convert the coordinates under the vision system into the coordinates in the motion axis coordinate system; S30, identification of welding points on the long side segment; S40, identification of welding points on the short side segment; S50, welding of the product, the motion axis drives the laser to move to form a motion trajectory to complete the welding; the beneficial effect of the present invention is that this method can absorb the incoming material position error and accurately realize the welding trajectory guidance.

Description

Technical Field

[0001] The present invention relates to the technical field of automatic welding control, and more specifically, to a vision guidance method for laser processing. Background Art

[0002] In the field of welding, there is an increasing demand for automated welding. However, it is difficult to ensure the consistency of the incoming materials during welding, especially when welding large-area products. Therefore, welding equipment requires vision guidance to eliminate the influence caused by inconsistent incoming materials. Sensors are often used for scanning and identifying welding trajectories, and then the identified paths are converted into the welding trajectories of the robot. The conversion relationship used in this conversion process comes from the results of hand-eye calibration.

[0003] In order to improve the welding efficiency during the welding process, a scanning welding mode of scanning while welding is generally adopted, and many trajectories are not straight lines but complex and variable. This requires continuously changing the welding trajectory of the robot during the welding process.

[0004] In the prior art, when performing vision-guided welding, due to the existence of incoming material errors, error calibration is required after multiple weldings. This method will result in a large welding error at a certain stage, and repeated error calibration also has the problem of low welding efficiency. Summary of the Invention

[0005] In order to overcome the deficiencies of the prior art, the present invention provides a vision guidance method for laser processing, which can absorb the incoming material position error and accurately realize the welding trajectory guidance.

[0006] The technical solution adopted by the present invention to solve its technical problems is: a vision guidance method for laser processing, which is improved in that the method includes the following steps:

[0007] S10. Position calibration: The carrier drives the product to move uniformly in the X-axis direction, moving uniformly from the first position to the second position; the moving axes of the laser move along the Y-axis and Z-axis directions, and the laser calibrates multiple points at different positions on the surface of the product and records the coordinates corresponding to the multiple points;

[0008] S20. Affine transformation of coordinates: When the product is at the first position, the vision system located above the X-axis records the coordinates of the surface calibration points of the product under the vision system; when the product moves to the second position, the affine transformation formula is used to convert the coordinates under the vision system into the coordinates in the moving axis coordinate system;

[0009] S30. Identification of welding points on the long side segment: The vision system grabs the endpoints at both ends of the long side segment of the product and converts the coordinates of the two endpoints into the coordinates in the moving axis coordinate system according to the affine transformation of coordinates;

[0010] S40. Identification of the welding points on the short side segment. The vision system obtains the vision coordinates of multiple points on the short side segment of the product, and through the affine transformation of the coordinates, converts them into the coordinates in the galvanometer coordinate system.

[0011] S50. Welding of the product. According to the coordinates in the moving axis coordinate system in step S30 and the coordinates in the galvanometer coordinate system in step S40, the moving axis drives the laser to move, forming a moving trajectory to complete the welding.

[0012] Further, step S10 includes the following steps:

[0013] S101. An induction sheet is provided on the carrier, and a first optoelectronic switch and a second optoelectronic switch are provided in the X-axis direction. The carrier drives the product to move a distance L1 in the X-axis direction.

[0014] S102. The laser welds a point at position A1 on the product surface, and marks the coordinates of A1 as (X1, Y1).

[0015] S103. Keeping the product position unchanged, the moving axis moves to positions A2 and A3 on the Y-axis respectively, and records the corresponding coordinates of the moving axis (X2, Y2), (X3, Y3).

[0016] S104. After the carrier drives the product to move a distance L2 in the X-axis direction, it stops at point B1, and records the coordinates of this point (X4, Y4). The laser welds a point at position B1.

[0017] The moving axis moves to points B2 and B3 respectively and stops, and records the corresponding coordinates (X5, Y5), (X6, Y6) respectively. The laser welds a point at positions B2 and B3 respectively.

[0018] S106. The moving axis continues to move, and dots are made at positions C1, C2, and C3 in sequence, and the coordinates of positions C1, C2, and C3 (X7, Y7), (X8, Y8), (X9, Y9) are recorded respectively.

[0019] Further, in step S20, the following steps are included:

[0020] S201. The carrier drives the product to return to the starting position in the X-axis direction, and then moves uniformly in the X-axis direction at a preset speed. When the induction sheet passes through the first optoelectronic switch, the first camera and the second camera are triggered to take pictures, obtaining two pictures. Both pictures include a total of nine points with known moving axis coordinate positions A1, A2, A3, B1, B2, B3, C1, C2, C3 and pixel dimensions.

[0021] S202. Import the coordinate data into the affine transformation formula, solve for the unknowns in the formula, and obtain the complete affine transformation formula.

[0022] Further, in step S202, the coordinates of point a1 on the product surface in the vision system are (X1, Y1), and the coordinates of point a1 in the moving axis coordinate system are (X1′, Y1′). The affine transformation formula is as follows:

[0023] X1′ = (X1 - X0)cosθ + (Y1 - Y0)sinθ;

[0024] Y1′ = -(X1 - X0)sinθ + (Y1 - Y0)cosθ;

[0025] Wherein, the coordinate system in the vision system is XOY, the coordinate system in the moving axis coordinate system is X'O'Y', θ is the angle between the rectangular coordinate system XOY and X'O'Y', and the positive direction is counterclockwise; the position of the origin O' of the coordinate system X'O'Y' in the XOY coordinate system is (X0, Y0).

[0026] Further, in step S50, when performing the long side segment welding, the following steps are included:

[0027] S501. The carrier drives the product to pass through the first optoelectronic switch at a preset speed in the X-axis direction, and two cameras of the vision system respectively identify the starting point a1 and the ending point a2 of the long side segment.

[0028] S502. Through the affine transformation formula, obtain the coordinates of the starting point a1 and the ending point a2 in the moving axis coordinate system after the product triggers the second optoelectronic switch and reaches the welding position.

[0029] S503. According to the coordinates in step S502 and the speed information of the product, fit the welding trajectory.

[0030] S504. The product repeatedly moves from the original position to the welding position, and the laser moves along the welding trajectory to complete the welding.

[0031] Further, in step S50, when performing the short side segment welding, the following steps are included:

[0032] S505. The carrier drives the product to pass through the first optoelectronic switch at a preset speed in the X-axis direction, and two cameras of the vision system respectively identify the starting point a1 and the ending point a2 of the short side segment.

[0033] S506. Through the affine transformation formula, obtain the coordinates of the starting point a1 and the ending point a2 in the galvanometer system after the product triggers the second optoelectronic switch and reaches the welding position.

[0034] S507. Fit the welding trajectory based on the coordinates in step S506 and the speed information of the product;

[0035] S508. The product repeatedly moves from the original position to the welding position, and the laser moves along the welding trajectory to complete the welding.

[0036] Further, in step S201, when the carrier passes the first optoelectronic switch, it passes at a constant speed of 200 mm / s.

[0037] Further, step S30 includes the following steps:

[0038] S301. Use contour matching to grab a positioning point on the product;

[0039] S302. Taking the positioning point as a reference, offset in perpendicular directions in turn. After determining the straight-edge grabbing range, grab the short-side straight line and the long-side straight line within the grabbing range;

[0040] S303. After offsetting the short-side straight line towards the positioning point by a preset distance, identify the intersection point of the offset straight line and the long-side straight line. This intersection point is a starting point of the straight-line segment of the product;

[0041] S304. Identify the end point of the straight-line segment of the product in the manner of steps S301 to S303. The connection line between the starting point and the end point is the trajectory of the straight-line segment.

[0042] Further, step S40 includes the following steps:

[0043] S401. Use contour matching to grab a positioning point on the product;

[0044] S402. Taking the positioning point as a reference, offset in perpendicular directions in turn. After determining the straight-edge grabbing range, grab the short-side straight line and the long-side straight line within the grabbing range;

[0045] S403. Taking the positioning point as a reference, offset towards the intersection of the short-side straight line and the long-side straight line, and determine the arc grabbing range. Grab the short-side straight line within the arc grabbing range;

[0046] S404. Calculate the diagonal line based on the short-side straight line and the long-side straight line. The intersection point of the diagonal line and the arc is the welding point at the arc;

[0047] S405. Offset the short-side straight line twice by a preset distance to obtain the intersection points with the long-side straight line; offset the long-side straight line by a preset distance to obtain the intersection points with the short-side straight line.

[0048] The beneficial effects of the present invention are as follows: A visual guidance method for laser processing provided by the present invention converts different trajectory coordinates each time into the coordinates of the motion axis system, thereby absorbing the incoming material position error and accurately realizing the welding trajectory guidance; it can be compatible with the errors in mechanism design. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a schematic process flow diagram of a visual guidance method for laser processing of the present invention.

[0050] Figure 2 It is a schematic structural diagram of a square shell battery of the present invention.

[0051] Figure 3 It is a schematic structural diagram of the top cover of the square shell battery of the present invention.

[0052] Figure 4 It is a schematic diagram of pixel size calculation of the present invention.

[0053] Figure 5 It is a schematic diagram of the welding points on the short side section of the present invention.

[0054] Figure 6 It is a schematic diagram of the identification of the welding points on the short side section of the present invention.

[0055] Figure 7 It is a schematic diagram during the welding of the long side section of the present invention.

[0056] Figure 8 It is a schematic diagram during the welding of the short side of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0057] The present invention will be further described below in conjunction with the drawings and embodiments.

[0058] The concept, specific structure and technical effects generated by the present invention will be clearly and completely described below in conjunction with the embodiments and drawings to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative work shall fall within the scope of protection of the present invention. In addition, all the connection / connection relationships involved in the patent do not refer only to the direct connection of components, but refer to the more optimal connection structure that can be formed by adding or reducing connection accessories according to the specific implementation situation. The various technical features in the present invention can be combined with each other without conflicting with each other.

[0059] Referring to Figure 1 as shown, the present invention discloses a visual guidance method for laser processing. In this embodiment, this method is applied to a square shell battery, such as Figure 2 、Figure 3 As shown, the square shell battery includes a top cover located above and a square shell below. The top cover needs to be fully welded to the square shell, including the welding of two long sides and two short sides. Therefore, full welding is achieved at four workstations, and there will be overlapping parts in the welding tracks of the long sides and the short sides. The overlapping amount needs to be adjusted according to the process conditions.

[0060] To adapt to a vision-guided method for laser processing of the present invention, a supporting system needs to be set up. The system includes a carrier, a vision system, a laser with a galvanometer, and a magnetic drive arranged along the X-axis direction. The carrier is arranged on the magnetic drive and reciprocates in the X-axis direction through the drive of the magnetic drive. The square shell battery to be welded is fixed on the carrier. The vision system includes a first camera and a second camera arranged along the X-axis direction, and the square shell battery on the carrier is photographed through the first camera and the second camera; the laser head is arranged above the X-axis, and the laser head is driven by a motion axis to move in the Y-axis direction and the Z-axis direction; a magnetic grating ruler and an induction sheet are installed on the mover of the carrier, and a first photoelectric switch and a second photoelectric switch are arranged outside the magnetic drive corresponding to the induction sheet.

[0061] A vision-guided method for laser processing of the present invention includes the following steps:

[0062] S10. Position calibration. The carrier drives the product to move uniformly in the X-axis direction, moving uniformly from the first position to the second position; the motion axis of the laser moves in the Y-axis and Z-axis directions, and the laser calibrates multiple points at different positions on the surface of the product and records the coordinates of the corresponding points.

[0063] In this embodiment, the step S10 includes the following steps:

[0064] S101. The magnetic drive drives the carrier to move. When the induction sheet touches the second photoelectric switch, the reading of the magnetic grating ruler is cleared, and the magnetic grating ruler starts to count; the carrier moves a distance L1 in the X-axis direction; in this embodiment, L1 = 10 mm.

[0065] S102. The laser welds a point at the A1 position on the surface of the product, and the coordinates of A1 are (X1, Y1).

[0066] S103. The position of the product remains unchanged, and the motion axis moves to the A2 position and the A3 position on the Y-axis respectively, and records the corresponding coordinates (X2, Y2), (X3, Y3) of the motion axis.

[0067] S104. After the carrier drives the product to move a distance L2 in the X-axis direction, it stops at point B1, and records the coordinates (X4, Y4) of this point. The laser welds a point at the B1 position; in this embodiment, L2 = 10 mm.

[0068] The moving axes move to points B2 and B3 respectively and stop, recording the corresponding coordinates (X5, Y5) and (X6, Y6). The laser welds a point at each of the positions B2 and B3 respectively.

[0069] S106. The moving axes continue to move, and dot at positions C1, C2, and C3 in sequence, and record the coordinates (X7, Y7), (X8, Y8), and (X9, Y9) at positions C1, C2, and C3.

[0070] After that, the carrier drives the square shell battery back to the starting position. At this time, the distance between the induction sheet and the first optoelectronic switch is L3. It is necessary to ensure that the magnetic drive accelerates to a preset speed of 200 mm / s and passes through the first optoelectronic switch at a constant speed. In this embodiment, L3 = 30 mm.

[0071] S20. Affine transformation of coordinates. When the product is at the first position, the vision system located above the X-axis records the coordinates of the surface calibration points of the product under the vision system; when the product moves to the second position, the affine transformation formula is used to convert the coordinates under the vision system into the coordinates in the moving axis coordinate system.

[0072] In the step S20, the following steps are included:

[0073] S201. The carrier drives the product to return to the starting position in the X-axis direction. After that, it moves at a constant speed in the X-axis direction at a preset speed. The induction sheet passes through the first optoelectronic switch, triggering the first camera and the second camera to take pictures, obtaining two pictures. Both pictures include nine points with known moving axis coordinate positions and pixel sizes.

[0074] S202. Import the coordinate data into the affine transformation formula, and find the unknowns in the formula to obtain the complete affine transformation formula. [[ID=?]]

[0075] Refer to Figure 4 As shown, the present invention provides the process of calculating the pixel size: Given the moving axis coordinates and pixel coordinates of points A and B, the actual length between points A and B:

[0076]

[0077] The pixel length between points A and B:

[0078]

[0079] Pixel size A = L / L' mm / pixel.

[0080] Further, in the step S202, the coordinates of point a1 on the surface of the product under the vision system are (X1, Y1), and the coordinates of point a1 in the moving axis coordinate system are (X1′, Y1′). Its affine transformation formula is:

[0081] X1′=(X1-X0)cosθ+(Y1-Y0)sinθ;

[0082] Y1′=-(X1-X0)sinθ+(Y1-Y0)cosθ;

[0083] The coordinate system under the visual system is XOY, the coordinate system under the motion axis coordinate system is X'O'Y', θ is the angle between the rectangular coordinate systems XOY and X'O'Y', and is positive in the counterclockwise direction; the position of the origin O' of the coordinate system X'O'Y' in the XOY coordinate system is (X0, Y0).

[0084] In the above embodiment, it can be understood that the principle of implementing plane coordinate system conversion through affine transformation belongs to the content of the existing technology, so its specific content will not be described in detail in this embodiment.

[0085] Moreover, the above content implements the calibration of the long side of the square shell top cover. When implementing the calibration of the short side, the difference is that in the step S101, after recording the X-axis and Y-axis coordinates (X1, Y1) of the motion axis, the coordinates of the galvanometer controller at this time (X z1 , Y z1 ), the galvanometer controller's coordinates are fixed, securing the entire galvanometer system and enabling welding of products of varying sizes. Subsequently, when welding nine coordinate points on the product surface, the galvanometer system controls the laser to create these nine points and records the nine coordinates of the galvanometer system. Therefore, when the first and second cameras capture a photo, the resulting photo shows the nine points with known coordinates of the galvanometer system.

[0086] S30, identification of welding points of the long side segment: the visual system captures the endpoints of the two ends of the long side segment of the product and converts the coordinates of the endpoints into coordinates under the motion axis coordinate system according to the affine transformation of the coordinates;

[0087] The step S30 includes the following steps:

[0088] S301. Using contour matching, grasp a positioning point in the product; in this embodiment, the positioning point is the negative electrode column on the top cover;

[0089] S302: Using the positioning point as a reference, offset in perpendicular directions in sequence to determine the straight line grabbing range, and then grab the short side straight line and the long side straight line within the grabbing range;

[0090] S303: After offsetting the short side straight line toward the positioning point by a preset distance, the intersection of the offset straight line and the long side straight line is identified. The intersection is the starting point of a straight line segment of the product. In this embodiment, the short side straight line is offset downward by 2.4 mm.

[0091] S304. Identify the end point of the straight segment of the product in the manner of steps S301 to S303. The line connecting the starting point and the end point is the trajectory of the straight segment.

[0092] It can be understood that in steps S301 - S304, when more points need to be captured, only need to offset the short - side straight line multiple times, calculate more intersection points, form more trajectory points, and the connection of the trajectory points is the trajectory of the straight segment.

[0093] S40. Identification of the welding points on the short - side segment. The vision system obtains the vision coordinates of multiple points on the short - side segment of the product and converts them into coordinates in the galvanometer coordinate system according to the affine transformation of the coordinates.

[0094] In step S40, the following steps are included:

[0095] S401. Use contour matching to capture a positioning point in the product; in this embodiment, the positioning point is the negative pole column on the top cover.

[0096] S402. Taking the positioning point as a reference, offset in the perpendicular directions in turn. After determining the straight - edge grabbing range, grab the short - side straight line and the long - side straight line within the grabbing range.

[0097] S403. Taking the positioning point as a reference, offset towards the intersection of the short - side straight line and the long - side straight line, and determine the arc - edge grabbing range. Grab the short - side straight line within the arc - edge grabbing range.

[0098] S404. According to the short - side straight line and the long - side straight line, calculate the diagonal line. The intersection point of the diagonal line and the arc is the welding point at the arc; refer to Figure 5 As shown, the welding points at the arc are point 3 and point 7.

[0099] S405. Offset the short - side straight line twice by a preset distance to obtain the intersection points with the long - side straight line; offset the long - side straight line by a preset distance to obtain the intersection points with the short - side straight line.

[0100] In this embodiment, refer to Figure 5 、 Figure 6 As shown, offset the short - side straight line to the left by 2.96 mm and 4.6 mm respectively, and find the intersection points with the two long - side straight lines, namely points 1, 2, 8, and 9, a total of four points; offset the upper long - side straight line downward by 4.6 mm to intersect with the short - side straight line to find point 4; offset the lower long - side straight line upward by 4.6 mm to intersect with the short - side straight line to find point 6; find the center line through the two long - side straight lines, and the intersection point of the center line and the short - side straight line is point 5; thus, a total of nine welding - trajectory reference points are found.

[0101] S50. Welding of the product. The motion axis drives the laser to move according to the coordinates in the motion axis coordinate system in step S30 and the coordinates in the galvanometer coordinate system in step S40, forming a motion trajectory to complete the welding.

[0102] Referring to Figure 7 As shown, in step S50, when performing long side segment welding, the following steps are included:

[0103] S501. The carrier drives the product to pass through the first optoelectronic switch at a preset speed of 20 mm / s in the X-axis direction, and two cameras of the vision system respectively identify the starting point a1 and the ending point a2 of the long side segment.

[0104] In this embodiment, referring to Figure 7 , that is, the first camera and the second camera at position A take pictures; the starting point a1 and the ending point a2 of the trajectory are obtained, and the camera coordinates are obtained as (X1, Y1), (X2, Y2);

[0105] S502. Through the affine transformation formula, the coordinates of the starting point a1 and the ending point a2 in the motion axis coordinate system after the product triggers the second optoelectronic switch and reaches the welding position are obtained.

[0106] In this embodiment, that is, the motion axis coordinates of the starting point a1 and the ending point a2 of the trajectory at position B are obtained, and the motion axis coordinates are sent to the motion control card;

[0107] S503. According to the coordinates in step Ss02 and the speed information of the product, the welding trajectory is fitted.

[0108] In this embodiment, the motion control card receives the coordinates of the two points and the motion speed information of the top cover, automatically fits a straight line, and according to the interpolation principle, the position coordinates of N points on the trajectory are ensured so that when reaching each point, the X-axis and the Y-axis move to the specified coordinate positions at the same time.

[0109] S504. The product repeatedly moves from the original position to the welding position, and the laser moves according to the welding trajectory to complete the welding.

[0110] In the above embodiment, L1 is the displacement that occurs between the two departure optoelectronic switches, L2 is the moving distance after the second optoelectronic switch departs, and the translation distance is determined by the magnetic grating ruler.

[0111] Furthermore, referring to Figure 8 As shown, in step S50, when performing short side segment welding, the following steps are included:

[0112] It should be noted that there seems to be an error in the speed value in step S501 in the original text where it says "preset speed 200mm / s", which might be a typo as it is later mentioned as "20mm / s" in the translation note. The translation is based on the corrected speed value of 20mm / s for better logical consistency. If the original speed value is indeed 200mm / s, the translation of step S501 should be adjusted accordingly.S505. The vehicle drives the product to pass through the first optoelectronic switch at a constant speed of 200 mm / s in the X-axis direction. Two cameras of the vision system respectively identify the starting point a1 and the ending point a2 of the short side segment. In this embodiment, that is, the first camera and the second camera at position A are triggered to take pictures, and the camera coordinates are obtained as (X1, Y1) and (X2, Y2).

[0113] S506. Through the affine transformation formula, obtain the coordinates of the starting point a1 and the ending point a2 under the galvanometer system after the product triggers the second optoelectronic switch and reaches the welding position; and send the coordinates to the laser control card.

[0114] S507. According to the coordinates in step S506 and the speed information of the product, fit out the welding trajectory.

[0115] In this embodiment, the laser control card automatically fits out a straight line according to the received nine-point coordinates and the speed information, and according to the interpolation principle, the position coordinates of N points on the trajectory are ensured so that when reaching each point, the X-axis and the Y-axis move to the specified coordinate positions at the same time.

[0116] S508. The product repeatedly moves from the original position to the welding position, and the laser moves according to the welding trajectory to complete the welding. In this embodiment, the product is repeatedly transported from position A to position B, the galvanometer system walks out the motion trajectory according to the commands of the laser control card, and controls the laser to complete the welding; during the welding process, the moving axis is always in a uniform motion state.

[0117] It should be noted that in the above embodiment, the range that needs to be changed for the long side welding of the product is only in the left and right directions, so the welding can be completed by cooperating with the moving axis; when welding the short side, there are corners, and welding is realized during the movement process, and the welding route that needs to be fitted is relatively complex. In this embodiment, by controlling the complex optical path of the laser by the galvanometer within the field of view and using the coordinates of the galvanometer controller, the welding of the short side can be realized more accurately.

[0118] Based on this, a vision guidance method for laser processing provided by the present invention converts each different trajectory coordinate into the coordinate of the motion axis system, thereby absorbing the incoming material position error and finally realizing trajectory guidance; therefore, this guidance method of the present invention can be compatible with the error of the mechanism design. In the prior art, when the first welding and the second welding are not continuous welding operations (such as a right angle), it will cause the situation that the end of the first welding coincides with the beginning of the second welding, affecting the welding aesthetics; while in the present invention, through this vision guidance method, the situation of welding coincidence can be reduced.

[0119] The above is a specific description of the preferred embodiment of the present invention. However, the present invention is not limited to the described embodiment. Those skilled in the art can make various equivalent deformations or substitutions without departing from the spirit of the present invention, and these equivalent deformations or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A visual guidance method for laser processing, characterized in that, The method includes the following steps: S10. Position calibration: The vehicle drives the product to move uniformly in the X-axis direction, moving uniformly from the first position to the second position; the moving axis of the laser moves along the Y-axis and Z-axis directions, and the laser calibrates multiple points at different positions on the surface of the product and records the coordinates corresponding to the multiple points. The step S10 includes the following steps: S101. An induction sheet is provided on the vehicle, and a first optoelectronic switch and a second optoelectronic switch are provided in the X-axis direction. The vehicle drives the product to move a distance L1 in the X-axis direction. S102. The laser welds a point at the A1 position on the product surface and marks the A1 coordinates as (X1, Y1). S103. Keeping the product position unchanged, the moving axis moves to the A2 position and the A3 position along the Y-axis respectively, and records the corresponding coordinates (X2, Y2), (X3, Y3) of the moving axis respectively. S104. After the vehicle drives the product to move a distance L2 in the X-axis direction and stops at point B1, record the coordinates (X4, Y4) of this point, and the laser welds a point at the B1 position. The moving axis moves to points B2 and B3 respectively and stops, and records the corresponding coordinates (X5, Y5), (X6, Y6) respectively. The laser welds a point at the B2 and B3 positions respectively. S106. The moving axis continues to move and punches points at the C1, C2, and C3 positions in sequence, and records the coordinates (X7, Y7), (X8, Y8), (X9, Y9) of the C1, C2, and C3 positions respectively. S20. Affine transformation of coordinates: When the product is at the first position, the vision system located above the X-axis records the coordinates of the surface calibration points of the product under the vision system; when the product moves to the second position, the affine transformation formula is used to convert the coordinates under the vision system into the coordinates in the moving axis coordinate system. In the step S20, the following steps are included: S201. The vehicle drives the product to return to the starting position in the X-axis direction, and then moves uniformly in the X-axis direction at a preset speed. The induction sheet passes through the first optoelectronic switch, triggering the first camera and the second camera to take pictures, obtaining two pictures. Both pictures include a total of nine points with known moving axis coordinate positions and pixel sizes, namely A1, A2, A3, B1, B2, B3, C1, C2, and C3. S202. Import the coordinate data into the affine transformation formula, find the unknowns in the formula, and obtain the complete affine transformation formula. S30. Identification of welding points on the long side segment: The vision system grabs the endpoints at both ends of the long side segment of the product, and according to the affine transformation of the coordinates, converts the coordinates of the two endpoints into the coordinates in the moving axis coordinate system. In the step S202, the coordinates of point a1 on the product surface under the vision system are (X1, Y1), and the coordinates of point a1 in the moving axis coordinate system are (X1′, Y1′). Its affine transformation formula is: ； ； Among them, the coordinate system under the vision system is XOY, the coordinate system under the motion axis coordinate system is X'O'Y', θ is the angle between the rectangular coordinate system XOY and X'O'Y', and the counterclockwise direction is positive; the position of the origin O' of the coordinate system X'O'Y' in the XOY coordinate system is (X0, Y0). S40. Identification of the welding points on the short side segment. The vision system obtains the vision coordinates of multiple points on the short side segment of the product and converts them into the coordinates in the galvanometer coordinate system according to the affine transformation of the coordinates. S50. Welding of the product. According to the coordinates in the motion axis coordinate system in step S30 and the coordinates in the galvanometer coordinate system in step S40, the motion axis drives the laser to move, forming a motion trajectory to complete the welding.

2. The visual guidance method for laser processing according to claim 1, wherein In the step S50, when performing the welding on the long side segment, the following steps are included: S501. The carrier drives the product to pass through the first optoelectronic switch at a preset speed in the X-axis direction, and two cameras of the vision system respectively identify the starting point a1 and the ending point a2 of the long side segment. S502. Through the affine transformation formula, obtain the coordinates of the starting point a1 and the ending point a2 in the motion axis coordinate system after the product triggers the second optoelectronic switch and reaches the welding position. S503. According to the coordinates in step S502 and the speed information of the product, fit out the welding trajectory. S504. The product repeatedly moves from the original position to the welding position, and the laser moves according to the welding trajectory to complete the welding.

3. The vision guidance method for laser processing according to claim 1, wherein, In the step S50, when performing the welding on the short side segment, the following steps are included: S505. The carrier drives the product to pass through the first optoelectronic switch at a preset speed in the X-axis direction, and two cameras of the vision system respectively identify the starting point a1 and the ending point a2 of the short side segment. S506. Through the affine transformation formula, obtain the coordinates of the starting point a1 and the ending point a2 in the galvanometer system after the product triggers the second optoelectronic switch and reaches the welding position. S507. According to the coordinates in step S506 and the speed information of the product, fit out the welding trajectory. S508. The product repeatedly moves from the original position to the welding position, and the laser moves according to the welding trajectory to complete the welding.

4. A vision guidance method for laser processing according to claim 1, characterized in that, In step S201, when the carrier passes through the first optoelectronic switch, it passes through at a constant speed of 200 mm / s.

5. A vision guidance method for laser processing according to claim 1, characterized in that, In the step S30, the following steps are included: S301. Use contour matching to grab a positioning point in the product. S302. Taking the positioning point as a reference, offset successively in the perpendicular directions. After determining the straight line edge-grabbing range, grab the short side straight line and the long side straight line within the edge-grabbing range. S303. After offsetting the short side straight line by a preset distance in the direction towards the positioning point, identify the intersection point of the offset straight line and the long side straight line, and this intersection point is a starting point of the straight line segment of the product. S304. Identify the ending point of the straight line segment of the product in the manner of steps S301 to S303, and the connection line between the starting point and the ending point is the trajectory of the straight line segment.

6. A vision guidance method for laser processing according to claim 1, characterized in that, In the step S40, the following steps are included: S401. Use contour matching to grab a positioning point in the product. S402. Taking the positioning point as a reference, offset successively in the perpendicular directions. After determining the straight line edge-grabbing range, grab the short side straight line and the long side straight line within the edge-grabbing range. S403. Taking the positioning point as a reference, offset towards the intersection of the short-side straight line and the long-side straight line, and determine the arc edge-gripping range. Gripping the short-side straight line within the arc edge-gripping range; S404. Calculate the diagonal line based on the short-side straight line and the long-side straight line. The intersection point of the diagonal line and the arc is the welding point at the arc; S405. Offset the short-side straight line twice by a preset distance to obtain the intersection points with the long-side straight line; Offset the long-side straight line by a preset distance to obtain the intersection points with the short-side straight line.

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