A method for determining an optimized welding direction of a joint plane; a method for determining an optimized joining plane for joining two components; method for welding two components

Abstract

The invention relates to a method for determining an optimized welding direction (112) of a joint plane (106), a welding beam (108) being intended to be moved to cover an edge of the joint plane (106) in the optimized welding direction (112) while maintaining a constant predetermined angle with respect to the optimized welding direction (112), the method comprises, for each of a plurality of potential welding directions (112) passing through a center of the joint plane (106), determining a thickness of the joint plane (106) as a function of a location in the welding direction (112), the thickness being taken into account along a straight line forming a predetermined angle with the welding direction (112) and passing through the associated location, and calculating a weldability score as a function of the thickness as a function of the position in the welding direction (112), and selecting a potential welding direction (112) with an optimal weldability score as an optimized welding direction (112).

Description

Technical Field

[0001] This invention relates to a method for determining an optimized welding direction for a joint plane, a method for determining an optimized joint plane, and a corresponding computer program and system.

[0002] This invention is an industrialized technical solution specifically for mechanically welded components (part of a mechanical system). The invention focuses on the concept of assembling metal components using a fusion welding method. Background Technology

[0003] To date, mechanically welded components have been defined based on mechanical strength and dimensional studies conducted by the design department, with significant modifications made to some assembly interfaces, particularly the mating planes. When the mating plane profile is a candidate for welding, trials are conducted on representative specimens and similar or closely related production equipment. Based on measurements taken during these tests, a weld range is established to define the optimal parameters to be applied to the weld, and partial or complete redefinition of the mating plane is performed. Once the mating plane is selected, the primary method for determining the weld direction to be used is through iterative trials on test specimens and feedback from topologically similar welded components.

[0004] Current methods for defining weld orientation are limited by their manual and situation-specific nature. Testing representative weld specimens can be costly and does not guarantee rapid convergence to the optimal joint plane. Furthermore, feedback can trap designers in historical profiles based on outdated or unreasonable specifications and technical expertise.

[0005] Therefore, it may be desirable to provide a method for determining the optimal welding direction in the joint plane that avoids at least some of the aforementioned problems and constraints.

[0006] Furthermore, Chinese patent application CN 105 817 785 A describes a laser welding method for workpieces with variable cross-sections and thicknesses. Additionally, a paper titled "Optimal trajectory scheme for robotic welding along complex joints using a hybrid multi-objective genetic algorithm," published in IEEE ACCESS by J. Ogbemhe et al., describes how to find a trajectory for an articulated arm to manufacture joints, thereby avoiding collisions, discontinuities in velocity and acceleration, and bumps. Summary of the Invention

[0007] Therefore, a method for determining an optimized welding direction for a joint plane is proposed, wherein a welding bundle is configured to move to travel along the edge of the joint plane in the optimized welding direction while maintaining a constant predetermined angle relative to the optimized welding direction, characterized in that the method includes: -For each of the multiple potential welding directions: • Determine the thickness of the mating plane as a function of its position in the welding direction, measured along a straight line forming a predetermined angle with the welding direction and passing through the relevant position. • The weldability score is calculated based on the thickness as a function of the position in the welding direction; and - Select the potential welding direction with the best weldability score as the optimized welding direction.

[0008] The present invention may also include one or more of the following optional features in any technically possible combination: Optionally, calculating the weldability score includes calculating an evaluation value of the cumulative weld thickness and calculating the weldability score based on the evaluation value of the cumulative weld thickness, such that the weldability score is better when the evaluation value of the cumulative weld thickness decreases.

[0009] Alternatively, the thickness can be determined for multiple discrete locations in the welding direction, and the evaluation value of the cumulative thickness to be welded is: the sum of polynomials of these discrete thicknesses, the degree of which is greater than or equal to 2, such as the sum of squares of the discrete thicknesses; or the product of the squares of the discrete thicknesses, and the weldability score is calculated based on this sum of squares.

[0010] Alternatively, determining the thickness as a function of position in the welding direction includes, for each of a plurality of discrete positions spaced at constant intervals in the welding direction, counting the number of points of a grid superimposed on the joint plane, the counted points being those strictly contained in strips inclined relative to the welding direction, the strips being centered on the relevant discrete position, and the width of the strips being such that the plurality of strips are adjacent, the number of points being the thickness of the joint plane at the relevant discrete position.

[0011] Optionally, the potential welding direction passes through the center of the joint plane.

[0012] Alternatively, the center of the joint plane is the centroid of the points of the grid superimposed on the joint plane, which lie within the joint plane.

[0013] A method for determining an optimal joint plane between two components to be welded is also proposed, the method comprising: - Defines the initial engagement plane between the two components; - Starting from the initial bonding plane, iterate through the following steps: • The optimal welding direction in the joint plane is determined according to the method of the invention, and the weldability score of the found optimal welding direction is associated with the joint plane, and • If the weldability score does not meet the output conditions of the iteration, modify the joint plane and continue the iteration; otherwise, use the joint plane with the best weldability score as the optimized joint plane.

[0014] Optionally, defining the initial engagement plane includes the position and geometry of the guide points, the geometry continuously connecting the guide points to form a closed curve, and modifying the engagement plane includes modifying the position of at least some of the guide points.

[0015] A computer program is also proposed, which can be downloaded from a communication network and / or recorded on a computer-readable medium, characterized in that the computer program includes instructions that, when the program is executed on a computer, are used to perform the steps of the method according to the invention.

[0016] A method for welding two components is also proposed, the method comprising: - determining an optimal welding direction for a joint plane between the two components according to the invention, or determining an optimal joint plane between the two components according to the invention; and - welding the two components by moving a welding bundle to travel along the edge of the joint plane in the optimal welding direction while maintaining a predetermined constant angle of the welding bundle relative to the optimal welding direction.

[0017] A data processing system configured to perform the method according to the invention is also proposed. Attached Figure Description

[0018] The invention will be better understood by the following description, given only by way of example and with reference to the accompanying drawings, in which: - Figure 1 This is a three-dimensional view of the welded two components, specifically showing the joint plane between the two components. - Figure 2 This is a simplified view of a data processing system used for welding optimization. - Figure 3 This is a block diagram of a method for determining the optimal welding direction for the mating plane. - Figure 4 Is using Figure 3 The diagram shown is a block diagram of a method for determining the optimal joint plane. - Figure 5 Is using Figure 4 A block diagram of the welding method for the two components shown, and - Figure 6 It is a view of the joint plane and the potential welding direction, and shows an example of determining the thickness of the joint plane along the welding direction. Detailed Implementation

[0019] Reference Figure 1 An example of component 100 obtained by welding will now be described.

[0020] Component 100 includes two parts 102 and 104 designed to be welded together. More specifically, each of the two parts 102 and 104 has a flat welding surface. These flat welding surfaces have mirror geometry and are designed to be placed together and aligned with each other for welding. Thus, these flat surfaces form a joint plane 106 between the two parts 102 and 104.

[0021] For welding, a welding beam 108 is launched in the plane of the mating plane 106 by a suitable welding device 110 to reach the edge of the mating plane 106. The welding beam 108 moves along the edge of the mating plane 106 to fuse the two components 102, 104 at the mating plane 106. More precisely, the welding beam 108 moves along the welding direction 112, i.e., parallel to the welding direction 112. The welding beam extends in the plane of the mating plane 106 and, for example, passes through the center of the mating plane 106. During the movement of the welding beam, the welding beam maintains a constant predetermined angle relative to the welding direction 112 (e.g., as shown in...). Figure 1 (Vertical in the example shown).

[0022] exist Figure 1 In the diagram, welding equipment 110 and welding beam 108 are shown located at three consecutive positions along the welding direction 112. Fusion welding includes, for example, tungsten inert gas / metal inert gas (TIG / MIG) welding, laser welding, plasma welding, and electron beam welding (FE).

[0023] The thickness E(s) of the joint plane 106 can be defined at each position s along the welding direction 112, and this thickness E(s) is measured along the weld bundle 108 passing through the relevant position s in the welding direction 112. Figure 1 In the example shown, the thickness E(s) is measured along a perpendicular line to the welding direction 112 passing through the relevant position s. This is the thickness that the welding bundle 108 must pass through each position s to weld the entire joint plane 106.

[0024] The thickness curve E(s) represents the thickness history (or gradient) of the joint plane 106 traversed by the welding beam 108 as it moves along the welding direction 112.

[0025] Reference Figure 2An example of a data processing system 200 designed to optimize the mating plane 106 and the welding direction 112 will now be described.

[0026] For example, system 200 is a computer system including a data processing unit 202 (e.g., a microprocessor) and a main memory 204 (e.g., RAM memory) accessible by the processing unit 202. Computer system 200 also includes, for example, a network interface and / or computer-readable media, such as local media 206 (e.g., a local hard disk) or remote media (e.g., a remote hard disk accessible via a communication network through a network interface) or removable media (e.g., a USB key, a Universal Serial Bus, or a Compact Disc (CD) or Digital Versatile Disc (DVD)) readable by a suitable drive in computer system 200 (e.g., a USB port or a CD and / or DVD drive). A computer program 208 containing instructions for the processing unit 202 is stored on local media 206 and / or can be downloaded via the network interface. This computer program 208 is intended, for example, to be loaded into main memory 204 so that the processing unit 202 can execute the instructions of the computer program. For easier description of computer program 208, the instructions will be described below as being organized into software modules. However, this presentation method does not predetermine the form of the computer program, which can be of any kind.

[0027] Alternatively, all or some of these modules may be implemented as hardware modules, i.e., electronic circuits (e.g., microwires), without including computer programs.

[0028] Therefore, computer program 208 includes module 210 for determining an optimized welding orientation in the mating plane. Module 210 is specifically configured to implement method 300 for determining the welding orientation (see below for example). Figure 3 (A more detailed description).

[0029] Computer program 208 also includes module 212 for determining an optimized joint plane using module 210. Module 212 is specifically configured to implement process 400 for determining the optimized joint plane (see below for example). Figure 4 (A more detailed description).

[0030] Reference Figure 3 An example of a method 300 for determining the optimal welding direction in the mating plane 106 will now be described.

[0031] For each of the multiple potential welding directions passing through the center of the joint plane 106, perform the following steps 302, 304, 306.

[0032] For example, potential welding directions are spaced at fixed angular intervals (e.g., between 1° and 20°). Preferably, the potential welding directions cover up to 180° of the plane of the joint plane.

[0033] For example, when a mesh is superimposed on a joint plane, the center of the joint plane is the centroid of the mesh points located within the joint plane. For instance, when determining the centroid, the points of the mesh have the same weight. To achieve this, the mesh should preferably consist of sufficiently small (flat) surface elements to discretize the geometry of the joint plane. As an example, it is suggested that the maximum element surface area be one twenty-fifth of the surface area of ​​the joint plane. Preferably, the elements should be of the same geometric type (e.g., triangles or quadrilaterals).

[0034] In step 302, the thickness E(s) of the joint plane is determined as a function of the position s in the relevant welding direction. Therefore, in this invention, the thickness E(s) is the thickness of the joint plane perpendicular to the relevant welding direction (i.e., the length of the portion extending on the joint plane perpendicular to the relevant welding direction, as previously referred to). Figure 1 The function (as explained).

[0035] For example, the thickness E(s) of the joint plane is determined for multiple discrete locations along the welding direction. The center of the joint plane is, for example, one of these locations, and the other locations are spaced apart from each other, for example, at a fixed interval. This interval is preferably on the same order of magnitude as the average distance between two adjacent nodes in the grid, i.e., between 0.5 and 1.5 times that distance. Preferably, the discrete locations extend on any side of the center of the joint plane at a distance of at least 1.1 times the distance between the center and the node furthest from the center in the grid within the joint plane. This condition ensures that the discrete locations extend along the entire length of the joint plane.

[0036] In this case, for each position s in the welding direction, for example, the number of grid points strictly contained in a strip inclined at a predetermined angle of the welding bundle 108 relative to the welding direction 112 is counted. The strip is centered on the relevant position s, and the width of the strip is such that multiple strips are adjacent to each other, for example, when the predetermined angle is a right angle (a strip perpendicular to the welding direction), the width of the strip is equal to the spacing between the positions. The number of points is represented by the thickness E(s) of the joint plane at the relevant position s.

[0037] This example is in Figure 6 As shown in the figure, the process is repeated for the joint plane and the welding direction. Figure 1The reference numerals in the figures are as follows: 602 is the reference numeral for the center of the joint plane 106; 604 is the reference numeral for the current position on the welding direction 112; 606 is the reference numeral for the strip, which is perpendicular to the welding direction 112; the same applies to the weld bundle 108; 608 is the reference numeral for the grid; and D is the reference numeral for the distance from the center 602 to the grid node furthest from the center 602 in the joint plane. Figure 6 In the example shown, the number of grid points in strip 606 is forty-five. Therefore, the thickness E(604) at position 604 is 45.

[0038] return Figure 3 During step 304, the weldability score S is calculated based on the thickness E(s).

[0039] Preferably, calculating the weldability score S includes calculating an evaluation value of the cumulative thickness to be welded, and calculating the weldability score S based on this evaluation value of the cumulative thickness, such that the weldability score improves as the evaluation value of the cumulative thickness decreases. For example, the weldability score S is selected to be equal to this evaluation value of the cumulative thickness. When calculating the evaluation value of the cumulative thickness, the greater the thickness contribution at each point, the greater the thickness at that point. Therefore, the contribution (i.e., the thickness at the relevant point) accumulates in the evaluation value, where each thickness is weighted itself. Thus, using the evaluation value of the cumulative thickness to be welded degrades the weldability score S (e.g., increases the weldability score) for welding directions that will pass through large thicknesses (whether in cumulative or peak form (i.e., when the thickness increases instantaneously or for many consecutive points)); conversely, it improves the weldability score S (e.g., decreases the weldability score) for welding directions that will pass through small thicknesses. In practice, welding operations are easier when the cumulative thickness to be welded is lower.

[0040] For example, when determining the thickness E(s) for multiple discrete locations in the welding direction 112, the evaluation value of the cumulative thickness can be the sum of squares of these discrete thicknesses, from which the weldability score S is calculated, for example, equal to the sum: More generally, the weldability score S can be calculated from the sum of polynomials of degree 2 or greater, with thickness as the variable; for example, it can be equal to the sum: , where P is a polynomial of degree 2 or greater.

[0041] Alternatively, the weldability score S can be calculated as the product of the squares of the discrete thicknesses, for example, equal to this product: .

[0042] During step 306, a potential welding direction with the optimal weldability score S is selected as the optimal welding direction. For example, the optimal weldability score S is minimized when the weldability score S equals the sum of the squares of the discrete thicknesses.

[0043] Reference Figure 4 An example of a method 400 for determining an optimized joint plane will now be described.

[0044] During step 402, the operation data of the method is received, for example, the operation data of the method is received in the main control file.

[0045] The operational data includes the definition of the initial engagement plane. This definition includes, for example, the positions of the guide points, and the geometry of connecting successive guide points to form a closed curve that defines the closed surface. An example of the geometry is a series of straight line segments, each segment defined by two consecutive guide points. Alternatively, guide points can be connected by splines, each spline consisting of one or more other points (called intermediate points).

[0046] The operational data also includes mesh constraints, which enable discretization of the joint plane in the form of nodes and finite elements.

[0047] Typically, two degrees of freedom are assigned to each guide point, and these two degrees of freedom define the position of the guide point in the plane of the bonding plane. The values ​​of these degrees of freedom are initialized to initial values. For example, the position of the guide point is marked in an orthogonal reference frame. Therefore, the position of each guide point can be controlled by components Xp and Yp.

[0048] During step 404, a mesh is superimposed on the initial joining plane. This mesh allows the joining plane to be regularly discretized, enabling the definition of the topological density (i.e., the number of nodes per cell region) within the plane of the joining plane. For example, the mesh is composed of triangles and / or quadrilaterals. Preferably, the mesh should be fine enough that the thickness of the joining plane in any direction passing through the centroid of the mesh is traversed by at least four points of the mesh. For example, the number of elements in the mesh is increased until this condition is met.

[0049] Starting from the initial joint plane, iterate through the following steps 406, 408, and 410.

[0050] During step 406, the center of the current bonding plane is determined. This center is, for example, the centroid of the grid points contained in the current bonding plane as described above.

[0051] During step 408, method 300 is used to determine the optimal welding direction for the current joint plane. Preferably, method 300 is implemented each time with the same parameters (in particular: the same grid, the same spacing between the same positions in the welding direction, the same formula for the weldability score, and the same angular spacing for the potential welding direction). Therefore, the results between joint planes can be compared. The weldability score associated with the found optimized welding direction is used as the weldability score for the relevant joint plane.

[0052] During step 410, if the weldability score of the current bonding plane does not meet the output condition of the iteration, the current bonding plane is modified to obtain a new bonding plane, and the iteration continues by returning to step 406, where the new bonding plane is used as the current bonding plane.

[0053] For example, modifying the current mating plane includes modifying the position of at least a portion of the guide points. In fact, when the position of one or more guide points is modified, the shape of the current mating plane itself is modified, resulting in a variant of the current mating plane. This parameterization allows for the definition and modification of the mating plane from a digital perspective.

[0054] Preferably, the mating plane has a region referred to as the overall dimension, and the guide points must not be located within such regions. These regions provide guidance for optimizing the shape of the mating plane and maintaining the desired overall shape of the component.

[0055] This modification can be performed, for example, by seeking a parameterized automatic optimization algorithm to optimize the weldability score. The implemented automatic parameterized optimization algorithm could be, for example, a difference algorithm that constructs and refines an interpolated response surface of the radial basis function type based on an iterative strategy. The refinement criterion between each iteration could be, for example, a theoretically optimal value identified by a difference evolution algorithm (known per se) based on the response surface constructed in the iterations. A variant could use an interpolated response surface of the multinomial regression function type, combined with an iterative enrichment strategy using a local sequential quadratic programming (SQP) algorithm.

[0056] If the weldability score of the current joint plane satisfies the output condition of the iteration, then the joint plane with the best weldability score is selected as the optimized joint plane.

[0057] For example, the output condition of the iteration could be that the weldability score S of the current bonding plane is below a predetermined threshold. In this case, the last bonding plane (i.e., the bonding plane with a weldability score below the predetermined threshold) is selected as the optimal bonding plane. Alternatively, the output condition of the iteration could be that the quality criterion R² or Q² of the RBF or polynomial regression response surface involved reaches a significant threshold, such as 0.9. In another variation, the output condition of the iteration is reaching a predetermined number of iterations, such as one hundred iterations.

[0058] In step 412, an optimized joint plane (in particular, an indication of the location of its guide point and the connection curve (straight line segment, spline, etc.) used) is provided, as well as the optimal welding direction found (e.g., expressed as an angle (in degrees) relative to a predetermined axis of the welding plane).

[0059] At least one of the following may also be provided: - For each welding direction of the optimized joint plane, a list of thickness contributions used to calculate the weldability score S along the relevant welding direction (e.g., a list of squared thicknesses provided where the weldability score is the sum of squared thicknesses); and - A weldability criterion S for each welding direction in the optimized joint plane evaluation, which enables the sorting of different possible welding directions based on the weldability score S, and thus the identification of the optimal welding direction, as well as the quantification of the gain of the weldability score S.

[0060] Previous output data may or may not be provided in a readable and editable result file (e.g., in txt format).

[0061] Reference Figure 5 An example of a method 500 for welding two parts 102 and 104 will now be described.

[0062] During step 502, method 400 is used to determine the optimized joint plane and the associated optimized welding direction of the joint plane.

[0063] During step 504, two components 102 and 104 are obtained, each component having a flat weld surface according to the determined optimized weld plane.

[0064] During step 506, the flat welding surfaces of the two components 102 and 104 are arranged together.

[0065] During step 508, the two components 102 and 104 are welded together by moving the welding beam along a determined optimized welding direction so that the welding beam passes through the edge of the joint plane.

[0066] It is possible that components 102 and 104 are provided with reinforcements intended to facilitate welding, but these reinforcements do not need to be retained for final assembly. Therefore, during optional step 510, it is possible to plane the two components 102 and 104 around the weld to remove the reinforcements.

[0067] In summary, it should be noted that the present invention is not limited to the embodiments described above. In fact, those skilled in the art will understand that various modifications can be made to the embodiments described above based on the teachings just disclosed.

[0068] Specifically, the operational data may include at least one of the following: the length of the welding direction, the coordinates of the center of the joint plane used as the guide point for the welding direction, the discrete spacing of the welding directions, the angular spacing between two welding directions, and the dense area of ​​the welding plane.

[0069] In the above detailed description of the invention, the terminology used should not be construed as limiting the invention to the embodiments disclosed in this specification, but should be construed as including all equivalent means that a person skilled in the art could conceive of by applying his or her conventional knowledge to the implementation of the teachings that have just been disclosed.

Claims

1. A method (300) for determining an optimized welding direction (112) for a joint plane (106), wherein a welding bundle (108) is configured to move to travel along the edge of the joint plane (106) in the optimized welding direction (112) while maintaining a constant predetermined angle relative to the optimized welding direction (112), characterized in that, The method includes: -For each of the multiple potential welding directions (112): • Determine (302) the thickness of the mating plane (106), the thickness as a function of the position in the welding direction (112), the thickness being measured along a straight line forming the predetermined angle with the welding direction (112) and passing through the associated position, and • The weldability score is calculated (304) based on the thickness as a function of the position in the welding direction (112); and - Select (306) the potential welding direction (112) with the best weldability score as the optimized welding direction (112).

2. The method according to claim 1, wherein, The calculation (304) of the weldability score includes calculating an evaluation value of the cumulative weld thickness and calculating the weldability score based on the evaluation value of the cumulative weld thickness, such that the weldability score is better when the evaluation value of the cumulative weld thickness decreases.

3. The method according to claim 2, wherein, The thickness is determined for multiple discrete positions in the welding direction (112), and the evaluation value of the cumulative thickness to be welded is: the sum of polynomials of these discrete thicknesses, the degree of which is greater than or equal to 2, such as the sum of squares of the discrete thicknesses; or the product of squares of the discrete thicknesses, and the weldability score is calculated based on the sum or the product.

4. The method according to any one of claims 1 to 3, wherein, The determination (302) of thickness as a function of position in the welding direction (112) includes, for each of a plurality of discrete positions spaced at a constant interval in the welding direction, counting the number of points in a grid (608) superimposed on the joint plane (106), the counted points being those points strictly contained in strips (606) inclined at the predetermined angle relative to the welding direction (112), the strips (606) being centered at the relevant discrete position (604), and the width of the strips such that a plurality of the strips are adjacent, the number of points being the thickness of the joint plane (106) at the relevant discrete position (604).

5. The method according to any one of claims 1 to 4, wherein, The potential welding direction passes through the center of the joint plane.

6. The method according to claim 5, wherein, The center of the joining plane is the centroid of the points of the grid superimposed on the joining plane, which are located in the joining plane.

7. A method (400) for determining an optimal mating plane between two components (102, 104) to be welded, comprising: - Define the initial engagement plane between the two components; - Starting from the initial bonding plane, perform the following iterative steps: • An optimal welding direction in the joint plane is determined according to the method of any one of claims 1 to 6, wherein the weldability score of the found optimal welding direction is associated with the joint plane, and • If the weldability score does not meet the output condition of the iteration, the bonding plane is modified and the iteration continues; otherwise, the bonding plane with the best weldability score is taken as the optimized bonding plane.

8. The method according to claim 7, wherein, The initial engagement plane is defined by the position and geometry of the guide points, the geometry of which continuously connects the guide points to form a closed curve, and wherein modifying the engagement plane includes modifying the position of at least some of the guide points.

9. A computer program (208), said computer program being downloadable from a communication network and / or recorded on a computer-readable medium, characterized in that, The computer program includes instructions that, when executed on a computer, are used to perform the steps of the method according to any one of claims 1 to 8.

10. A method for welding two workpieces (102, 104), comprising: - Determine the optimal welding direction (112) of the mating plane (106) between the two components (102, 104) according to any one of claims 1 to 6, or determine the optimal mating plane between the two components (102, 104) according to claim 7 or 8; and - The two components (102, 104) are welded by moving the welding bundle (108) to travel along the edge of the joint plane (106) in the optimized welding direction (112) while keeping the welding bundle at a predetermined constant angle relative to the optimized welding direction (112).

11. A data processing system (200) configured to perform the method according to any one of claims 1 to 8.

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