Visual guidance welding method for fan base

Abstract

The application discloses a visual guiding welding method for a fan base, comprising the following steps: acquiring welding seam data of adjacent welding seams; extracting coordinates of starting and ending points P1, P2, P3 and P4 of first and second welding seams respectively; performing first step judgment: judging whether the three points P1, P2 and P4 are collinear; if the three points P1, P2 and P4 are collinear, second step judgment is performed: judging whether P3 is on the straight line P1P2; if the three points P1, P2 and P4 are not collinear, a plane M is determined; third step judgment is performed: judging whether P3 is on the plane M; if P3 is on the plane M, fourth step judgment is performed: judging whether the straight line P1P2 is parallel to the straight line P3P4; if the straight line P1P2 is not parallel to the straight line P3P4, an intersection point of the straight line P1P2 and the straight line P3P4 is found, and a welding track is fitted according to the intersection point; the method can automatically connect non-intersecting welding seams, generate a welding track to a welding seam intersection point, and realize automatic welding without manual intervention in a welding process, and work efficiency is improved while ensuring the overall consistency of workpiece welding. 2、 2、 ​​

Description

Technical Field

[0001] This application relates to the field of wind turbine welding, and in particular to a visually guided welding method for wind turbine bases. Background Technology

[0002] The fan base is the fundamental structure supporting the main fan equipment, used to fix the motor or bearing housing, and connecting the entire fan into a whole for easy installation. Welding the fan base is a crucial process in the entire fan production process. The fan base is typically made of steel, and its welding formation and weld accuracy are key factors affecting the overall quality of the fan. The welds in the fan base are primarily double-sided fillet welds. Ensuring the overall consistency of the welds places very high demands on the welding workers' skills and experience. However, manual welding is inefficient, and with increasing labor costs, a shortage of professional welders, and the inability to strictly control the aesthetics and consistency of manual welds, there is an urgent need for automated welding to replace manual welding for a large amount of welding work.

[0003] Currently, commonly used automated welding solutions include two types: purely manual teaching welding and welding combining manual teaching and visual positioning. Purely manual teaching can significantly reduce the need for professional welders, but this method requires extremely high precision in incoming materials and strict control of splicing errors. To achieve this, the installation difficulty of the workpiece increases, and additional tooling is needed to ensure accuracy. In addition, since the wind turbine industry mainly produces small batches of products with a wide variety, the teaching time is greatly increased. The combination of manual teaching and visual positioning can reduce errors in tooling and workpieces, but visual positioning has poor overall consistency for welding double-sided corner welds, requiring timely manual intervention to ensure weld length, and cannot operate stably for a long time. Therefore, a visually guided welding method suitable for wind turbine base welding is needed. This method needs to be able to adapt to the installation errors of tooling and the errors in incoming materials, and can automatically intersect or connect welds. If the weld trajectory fails to intersect or connect, without intervention, it will lead to welding trajectory deviation or weld omissions, thus affecting work efficiency and product quality. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides a visually guided welding method for wind turbine bases, which can automatically generate weld intersections for adjacent straight lines that do not intersect or connect, comprising the following steps:

[0005] Step S1: The weld area of ​​the workpiece to be welded is scanned by the vision guidance system, and the captured images are sent to the industrial control computer. The industrial control computer calculates and reconstructs the three-dimensional information of the workpiece to be welded from the images to obtain the weld data.

[0006] Step S2: Based on the weld data obtained from the scan, determine the existence of intersection points between two adjacent welds. Specifically:

[0007] Obtain the coordinates of the start and end points of the first weld segment P1(x1,y1,z1) and P2(x2,y2,z2) respectively, and the coordinates of the start and end points of the second weld segment P3(x3,y3,z3) and P4(x4,y4,z4) respectively.

[0008] Determine whether points P1, P2, and P4 are collinear. If P1, P2, and P4 are on the same straight line, then continue to determine whether P3 is on the same straight line. If P1, P2, and P4 are not on the same straight line, then determine a plane M based on the three non-collinear points P1, P2, and P4.

[0009] If P3 is located on the straight line formed by points P1, P2, and P4, the output result is: the first weld segment and the second weld segment are on the same straight line; if P3 is not located on the straight line formed by points P1, P2, and P4, the output result is: P4 is the intersection point of the two adjacent weld segments.

[0010] When plane M is determined, it is determined whether P3 is located on plane M. If P3 is located on plane M, then lines P1P2 and P3P4 are on the same plane, and the next step of judgment is performed. If P3 is not on plane M, then lines P1P2 and P3P4 are on opposite planes, and the adjacent welds do not have an intersection.

[0011] When the lines P1P2 and P3P4 are in the same plane, determine whether they are parallel. If P1P2 is parallel to P3P4, then the welds containing points P1 and P2 do not intersect with the welds containing points P3 and P4. If P1P2 is not parallel to P3P4, calculate the intersection point of P1P2 and P3P4, and denote it as point P. r ;

[0012] Step S3: Extend both straight lines P1P2 and P3P4 to the intersection point Pr, generate the welding trajectory extended to the intersection point Pr, and output the weld data so that the robot can perform welding along the welding trajectory.

[0013] Preferably, according to the two-point form equation of the spatial straight line passing through points P1 and P2 (Formula 1), point P4 is substituted into Formula 1. If the equation holds true, then P4 lies on the straight line passing through points P1 and P2; if the equation does not hold true, then P4 does not lie on the straight line passing through points P1 and P2.

[0014]

[0015] Preferably, the coordinates of point P3 are substituted into Formula 1. If the equation holds true, then P3 is located on the line P1P2. If the equation does not hold true, then P3 is not on the line P1P2.

[0016] Preferably, in space, a plane can be uniquely determined by three non-collinear points, and the equation of the plane M containing points P1, P2, and P4 can be obtained according to Formula 2:

[0017]

[0018] Preferably, the equation of plane M is obtained, and the coordinates of P3 are substituted into the equation of plane M. If the equation holds, then P3 lies on plane M; if the equation does not hold, then P3 does not lie on plane M.

[0019] Preferably, for line P 12 With line P 34 Whether they are parallel can be determined by vector P. 12 =|P2-P1|, P 34 =|P3-P4| Determine, according to formula 3, if N is an integer, then the line P 12 Parallel to line P 34 If N is not an integer, then the line P 12 Parallel to line P 34 :

[0020]

[0021] Preferably, in the welding method, a start-end connection verification is also provided for adjacent straight lines. After confirming that the welds are adjacent welds, all weld data are cyclically judged according to whether the last group of welds is closed. If closed, the first group of output weld data is cleared and the first weld data is recalculated in the form of a closed trajectory. If not closed, the calculation continues from the starting point to the last weld data.

[0022] Preferably, the method further includes determining the splicing point of the corner weld type where the adjacent weld trajectories are straight-straight-straight lines. Using two pairs of the three welds as a set of fitting planes, the endpoint of the third weld after being projected onto the fitting plane is obtained. It is determined whether the endpoint is near the intersection of the two welds used for the fitting plane. The other two sets of fitting planes are judged in turn. If the endpoint is near the intersection of the two welds used for the fitting plane at least once, it is considered to conform to the corner weld type. The intersection of the two welds at that time is the splicing point of the corner weld.

[0023] Preferably, after obtaining the splicing point of the corner weld, the lengths of the three welds are manually input. The weld length is calculated with the splicing point of the corner weld as the endpoint, the start and end points of the weld are determined and the weld position is given, the weld direction is calculated, and the weld is fitted.

[0024] Beneficial effects: This application acquires weld data through a vision-guided system and automatically connects non-intersecting welds, generating a welding trajectory to the weld intersection. It can adapt to tooling installation errors and workpiece material errors, and the welding process does not require manual intervention to adjust the weld length, thus automatically achieving welding. This can improve work efficiency while ensuring the overall consistency of the workpiece welding. Attached Figure Description

[0025] Figure 1 This is a flowchart of a visually guided welding method for a wind turbine base as described in an embodiment of this application;

[0026] Figure 2 This is the solution path in the form of a closed trajectory for the end-to-end verification of a visually guided welding method for a wind turbine base as described in the embodiments of this application;

[0027] Figure 3 This is the solution path in the form of a closed trajectory verified by the beginning and end of the visually guided welding method for the wind turbine base described in the embodiments of this application;

[0028] Figure 4 This is a physical schematic diagram of adjacent welds as described in the embodiments of this application;

[0029] Figure 5 yes Figure 4 A schematic diagram of the weld seam extracted from the image. Detailed Implementation

[0030] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described in this application are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0031] Example 1

[0032] like Figure 1 As shown, a visually guided welding method for wind turbine bases can automatically generate weld intersections for non-intersecting or connected welds. For adjacent welds with a weld trajectory of straight lines, the welding method specifically includes the following steps:

[0033] Step S1: Scan the target workpiece using a vision-guided system to obtain weld data of adjacent welds on the fan base;

[0034] In this embodiment, the selected vision-guided automatic welding scheme is a line laser plus a CCD industrial camera. After entering the workflow, the line laser emitter first projects a laser beam onto the workpiece to be welded. The laser beam emitted by the line laser emitter is refracted by a cylindrical mirror to form a laser plane. The laser plane intersects the surface of the workpiece to be measured on a straight line to form laser stripes. The deformation of the laser line (i.e., the laser stripes on the surface of the workpiece) on the surface of the workpiece displays the three-dimensional information of the surface of the workpiece. Then, the CCD industrial camera takes a picture of the laser line after it is distorted by the height modulation of the workpiece surface, and transmits the picture to the industrial control computer. The industrial control computer calculates and processes the picture based on the depth information provided by the laser line to obtain the three-dimensional point cloud data of the weld.

[0035] Step S2: Based on the weld data obtained from the scan, determine the existence of intersections between adjacent welds;

[0036] Specifically, before calculating the intersection point, the system first uses preset parameters, such as the weld type and direction, and the scanned weld data to determine whether there is an intersection point between two adjacent welds in the current group. If an intersection point exists, the intersection point P is calculated based on the current weld data. r The coordinates of the weld are determined; if no intersection point exists, the current weld group is skipped, the output result is: no intersection point exists, and the process proceeds to the next weld group.

[0037] The method for determining whether there is an intersection between two adjacent weld seams in the current group includes: First, obtaining the coordinates of the start and end points of the two weld seams in the current group. Let the starting point coordinates of the first weld seam be P1(x1,y1,z1) and the ending point coordinates be P2(x2,y2,z2), and the starting point coordinates of the second weld seam be P3(x3,y3,z3) and the ending point coordinates be P4(x4,y4,z4). Then, proceed to the first step of judgment: determine whether the starting point P1 and ending point P2 of the first weld seam and the ending point P4 of the second weld seam are on the same straight line. When the coordinates of two points in space are known, the two-point equation of a straight line in space can be used to determine whether a point is on the straight line formed by the two points. Therefore, formula 1 can be used to determine whether points P1, P2, and P4 are a straight line.

[0038]

[0039] Substituting P4 into Formula 1, if the formula is true, then P4 lies on the line P1P2, meaning that points P1, P2, and P4 are collinear; if the formula is false, then P4 does not lie on the line P1P2, meaning that points P1, P2, and P4 are not collinear.

[0040] Based on the result of the first step, proceed to the next step. If points P1, P2, and P4 are on the same straight line, proceed to the second step: determine whether the starting point P3 of the second weld segment is on the straight line P1P2. Substitute the coordinates of P3 into Formula 1. If the formula is true, then P3 is on the straight line formed by points P1, P2, and P4, that is, the straight line P1P2 and the straight line P3P4 are the same straight line. If the formula is not true, then P3 is not on the straight line formed by points P1, P2, and P4. In this case, the straight line P1P2 and the straight line P3P4 are not the same straight line, and P4 is the intersection point Pr of the first weld segment and the second weld segment.

[0041] If the three points P1, P2, and P4 determined in the first step are not on the same straight line, then a plane in space can be uniquely determined based on these three non-collinear points, which can be denoted as plane M. Plane M can be obtained using formula 2:

[0042]

[0043] Based on the coordinates of points P1, P2, and P4, the values ​​of A, B, C, and D are obtained, thus obtaining the equation of plane M: Ax + By + Cz + D = 0 (Formula 3). At this point, we proceed to the third step: determine whether P3 is on plane M. Substitute the coordinates of P3 into Formula 3. If the formula is true, then P3 is on plane M, meaning that lines P1P2 and P3P4 are both on plane M, which means that the first weld segment and the second weld segment are coplanar. If the formula is false, then P3 is not on plane M, meaning that lines P1P2 and P3P4 are not on the same plane, which means that the first weld segment and the second weld segment are skew.

[0044] Based on the result of the third step, proceed to the next step of the operation process. If P3 is not on plane M, the output result is: the first weld segment and the second weld segment do not intersect, and the current group of welds is skipped to proceed to the next group of welds.

[0045] If P3 lies on plane M, then proceed to the fourth step: determine whether lines P1P2 and P3P4 are parallel. The parallelism between lines P1P2 and P3P4 can be determined by vector P. 12 With vector P 34 Given the coordinates of P1, P2, P3, and P4, we can obtain the vector P. 12 =|P2-P1|, P 34 =|P3-P4|, the parallelism between lines P1P2 and P3P4 is obtained using formula 3:

[0046]

[0047] If N is an integer, then the line P 12 Parallel to line P 34If the first weld segment is parallel to the second weld segment, meaning there is no intersection between the first weld segment and the second weld segment, the output result will be: there is no intersection between the first weld segment and the second weld segment, and the current group of welds will be skipped and the judgment of the next group of welds will be entered.

[0048] If N is not an integer, then the line P 12 Not with line P 34 Parallelism means that the first and second weld segments intersect at a point. In this case, we can write the equations of the lines passing through points P1P2 and P3P4 to obtain the coordinates of the intersection point P of the first and second weld segments. r .

[0049] Step S3: Extend both lines P1P2 and P3P4 to their intersection point P. r For the welding point, perform path planning, fit a spatial straight line between the coordinates of the two points, and use their coordinates as the starting and ending positions to generate a path extending to point P. r P1P r The P4 generates the welding trajectory and welding pose of the welding robot. The industrial control computer sends the welding trajectory and welding pose to the PLC, and then the PLC issues instructions to the welding robot to complete the welding along the welding path.

[0050] For adjacent straight lines, this invention also includes a head-to-tail connection verification. After confirming that the welds are adjacent welds, all weld data are iteratively judged based on whether the last group of welds is closed. If closed, the first group of output weld data is cleared, and the first weld data is recalculated in the form of a closed trajectory. The calculation path is: starting point → intersection of the first weld and the next weld → intersection of the second weld and the next weld → intersection of the third weld and the next weld → intersection of the fourth weld and the first weld → starting point. The detailed path is as follows: Figure 2 As shown, L1 is the first weld, L2 is the second weld, L3 is the third weld, L4 is the fourth weld, and P... s Starting from point P, N1 is intersection point 1, N2 is intersection point 2, N3 is intersection point 3, and N4 is intersection point 4, i.e., P s →N1→N2→N3→N4→P s If the weld is not closed, the calculation starts from the starting point and continues to the last weld data. The calculation path is: starting point → intersection of the first weld and the next weld → end point of this weld, as shown in the image. Figure 3 As shown, L1 is the first weld, L2 is the second weld, and P s Starting from point P, with N1 as the intersection point 1, and P as the starting point. e This marks the end point of this weld.

[0051] Example 2

[0052] For corner welds with a weld trajectory of straight line-straight line-straight line, refer to [reference needed]. Figure 4 and Figure 5 First, the acquired weld data is checked. If the number of welds is less than three, an error is reported. Next, the weld data is filtered to remove image noise, and the welds are numbered, starting from number 0, with the three most recent welds grouped together (e.g., 012, 023, 234, 346, 456). It is then determined whether these three welds are coplanar. If the three welds are coplanar, ... Figure 5 As shown, weld 023 and weld 346 are both coplanar welds. Therefore, the current group of welds is exited and the judgment of the next group of welds is entered. If the included angle between the planes where the welds are located is within 10°, then the two planes are considered to be coplanar.

[0053] If the three welds are not on the same plane, such as Figure 5 As shown, welds 012, 234, and 456 are all non-coplanar welds, belonging to the corner weld type. Therefore, adjacent welds are fitted to a plane in pairs. For example, with weld 01 as a fitted plane, the projection endpoint 2 of weld 2 on the fitted plane of weld 01 is obtained. If the projection endpoint 2 is near the intersection of weld 01 and weld 01, it indicates that the corner weld type is satisfied; if the projection endpoint 2 is not near the intersection of weld 01 and weld 01, the splicing fails. Continuing, with weld 12 as a fitted plane, the projection endpoint 0 of weld 0 on the fitted plane of weld 12 is obtained. Similarly, depending on whether the projection endpoint 0 is near the intersection of weld 12 and weld 0... Next, determine whether the corner weld type is met; using weld 02 as a set of fitting planes, obtain the projection endpoint 1 of weld 1 on the fitting plane of weld 02. Similarly, determine whether the corner weld type is met based on whether the projection endpoint 1 is near the intersection of weld 02; if the corner weld type is met at least once, it is considered to meet the corner weld type; the intersection of the two welds is the splicing point of the corner weld; in the corner weld type, the length of the three adjacent welds is manually input, the weld length is calculated with the intersection of the two welds as the endpoint, the start and end points of the weld are determined and the weld position is given, the weld direction is calculated, and the weld is fitted.

[0054] The length of the weld is manually input. The weld length is calculated with the splice point as the endpoint, determining the start and end points of the weld and providing the weld position. After scanning the weld data and determining the splice point, either the start or end point of a single weld is located at the splice point. Optimization is performed based on the user-input weld length data. For example, if the input weld length is greater than the sampled weld length, the weld needs to be extended from the splice point to the input weld length. The coordinates of the portion exceeding the sampled length are provided by the algorithm. If the input weld length is less than the sampled weld length, the input weld length needs to be truncated from the splice point.

[0055] The algorithm calculates the weld direction and fits the weld. In order to achieve welding in one go, for corner weld types, the algorithm will reverse the order of one of the welds to achieve the effect of welding them one by one.

[0056] In the wind turbine base, the weld types include straight-to-straight welds that are connected end to end, which are adjacent straight welds, and corner welds that point to the same center point, i.e., straight-to-straight-to-straight welds. There are no straight-to-curved or curve-to-curved weld types. After obtaining the weld intersection point, the weld data is finally checked and judged to determine whether the welding type is one of the two types: straight-to-straight or straight-to-straight-to-straight.

Claims

1. A visually guided welding method for wind turbine bases, capable of automatically generating the intersection points of adjacent straight weld seams, characterized in that... Includes the following steps: Step S1: Scan the weld area of ​​the workpiece to be welded using a vision-guided system to obtain weld data; Step S2: Based on the weld data obtained from the scan, determine the existence of intersection points between two adjacent welds. Specifically: Obtain the coordinates of the start and end points of the first weld segment P1(x1,y1,z1) and P2(x2,y2,z2) respectively, and the coordinates of the start and end points of the second weld segment P3(x3,y3,z3) and P4(x4,y4,z4) respectively. Determine whether points P1, P2, and P4 are collinear. If P1, P2, and P4 are on the same straight line, then continue to determine whether P3 is on the same straight line. If P1, P2, and P4 are not on the same straight line, then determine a plane M based on the three non-collinear points P1, P2, and P4. If P3 is located on the straight line formed by points P1, P2, and P4, the output result is: the first weld segment and the second weld segment are on the same straight line; if P3 is not located on the straight line formed by points P1, P2, and P4, the output result is: P4 is the intersection point of the two adjacent weld segments. When plane M is determined, it is determined whether P3 is located on plane M. If P3 is located on plane M, then lines P1P2 and P3P4 are on the same plane, and the next step of judgment is performed. If P3 is not on plane M, then lines P1P2 and P3P4 are on opposite planes, and the adjacent welds do not have an intersection. When the lines P1P2 and P3P4 are in the same plane, it is further determined whether the lines P1P2 and P3P4 are parallel. If the line P1P2 is parallel to the line P3P4, then the welds containing points P1 and P2 do not intersect with the welds containing points P3 and P4. If the line P1P2 is not parallel to the line P3P4, then the intersection point of the lines P1P2 and P3P4 is calculated and denoted as point P. r ; Step S3: Extend both lines P1P2 and P3P4 to their intersection point P. r Generate and extend to intersection point P r The robot executes welding along the welding trajectory and outputs weld data.

2. The visually guided welding method for wind turbine base according to claim 1, characterized in that: According to the two-point form equation of the straight line passing through points P1 and P2 (Formula 1), substitute point P4 into Formula 1. If the equation holds true, then P4 lies on the straight line passing through points P1 and P2; if the equation does not hold true, then P4 does not lie on the straight line passing through points P1 and P2. 。 3. The visually guided welding method for wind turbine base according to claim 2, characterized in that, Substitute the coordinates of point P3 into Formula 1. If the equation holds true, then P3 lies on the line P1P2. If the equation does not hold true, then P3 does not lie on the line P1P2.

4. The visually guided welding method for wind turbine base according to claim 1, characterized in that, In space, a plane can be uniquely determined by three non-collinear points. Using Formula 2, the plane M containing points P1, P2, and P4 can be obtained: 。 5. The visually guided welding method for wind turbine base according to claim 4, characterized in that: Find the equation of plane M, substitute the coordinates of P3 into the equation of plane M. If the equation holds true, then P3 lies on plane M; if the equation does not hold true, then P3 does not lie on plane M.

6. The visually guided welding method for wind turbine base according to claim 1, characterized in that: For line P 12 With line P 34 Whether they are parallel can be determined by vector P. 12 =|P2-P1|, P 34 =|P3-P4| Determine, according to formula 3, if N is an integer, then the line P 12 Parallel to line P 34 If N is not an integer, then the line P 12 Not with line P 34 parallel: 。 7. The visually guided welding method for wind turbine bases according to any one of claims 1-6, characterized in that: In the welding method, a head-to-tail connection verification is also provided for adjacent straight lines. After confirming that the welds are adjacent welds, all weld data are cyclically judged according to whether the last group of welds is closed. If closed, the first group of output weld data is cleared and the first weld data is recalculated in the form of a closed trajectory. If the weld is not closed, the calculation will continue from the starting point to the last weld data.

8. The visually guided welding method for wind turbine base according to claim 7, characterized in that: It also includes determining the splicing point of corner welds with adjacent weld trajectories of straight line-straight line-straight line. Using two pairs of three welds as a set of fitting planes, the endpoint of the third weld after projection onto the fitting plane is obtained. It is determined whether the endpoint is near the intersection of the two welds used for the fitting plane. The other two sets of fitting planes are judged in turn. If the endpoint is near the intersection of the two welds used for the fitting plane at least once, it is considered to meet the corner weld type. The intersection of the two welds at that time is the splicing point of the corner weld.

9. The visually guided welding method for wind turbine base according to claim 8, characterized in that: After obtaining the splicing point of the corner weld, the lengths of the three welds are manually input. The weld length is calculated with the splicing point of the corner weld as the endpoint, the start and end points of the weld are determined and the weld position is given, the weld direction is calculated, and the weld is fitted.

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