Aim position setting method, aim position setting device, and program

Abstract

To provide an aiming position setting method, aiming position setting apparatus, and program which can correctly set an aiming position of a torch of forming a weld bead when molding a molded object.SOLUTION: An aiming position setting method comprises: a shape profile acquisition step of acquiring a shape profile Fp by measuring a shape of a laminate Wh in the middle of molding by a shape measurement sensor 25; an intersection position acquisition step of acquiring an intersection position Pi at which a straight line Lp extending in the lamination direction of a weld bead B intersects with the shape profile Fp; an information amount calculation step of calculating an information amount of the shape profile Fp within preset ranges A1, A2 with the intersection position Pi as a reference; and an aiming position extraction step of extracting an aiming position candidate of a torch 11 when forming the weld bead B to be laminated next with the intersection position Pi as a reference when the information amount is equal to or greater than a threshold Nth.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a target position setting method, a target position setting device, and a program. [Background technology]

[0002] In recent years, there has been a growing need for 3D printers as a means of production, and research and development is being conducted in the aircraft industry, etc., with a view to practical application of 3D printers to metal materials in particular. 3D printers that use metal materials use a heat source such as a laser or arc to melt metal powder or metal wire, and then layer the molten metal to create a model.

[0003] Patent Document 1 discloses a technology for forming a shaped object with an internal space by stacking beads of melted and solidified filler metal on a base to form opposing side walls, and then stacking the beads laterally from the upper ends of the side walls to connect the upper ends of the side walls. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-66027 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, when a shaped object is formed by stacking beads, the shape of the stacked body during the process of being formed is measured using a measurement sensor to obtain a shape profile, and the target position of the torch for forming the bead in the next pass is set.

[0006] However, when measuring the shape of a laminate during construction, it can be difficult to fully grasp the shape profile information required for laminating the beads in the next pass, depending on blind spots and the surface properties of the beads in the laminate.

[0007] In such cases, it becomes difficult to accurately determine the target position of the torch when forming the bead in the next pass, which may result in lamination failure or equipment error. In particular, since the formation of overhanging portions requires accurate setting of the target position of the torch, insufficient shape profile information makes it difficult to form an object with an overhanging portion.

[0008] Therefore, an object of the present invention is to provide a target position setting method, a target position setting device, and a program that enable accurate setting of the target position of a torch that forms a weld bead when forming a shaped object. [Means for solving the problem]

[0009] The present invention comprises the following configurations. (1) A method for setting a target position when forming a weld bead with a torch on a stack of multiple weld beads, comprising: a shape profile acquisition step of measuring the shape of the laminate during modeling using a shape measurement sensor to acquire a shape profile; an intersection position acquisition step of acquiring an intersection position where a straight line extending in a lamination direction of the weld bead intersects with the shape profile; an information amount calculation step of calculating an information amount of the shape profile within a predetermined range based on the intersection position; a target position extraction step of extracting a candidate target position of the torch when forming the weld bead to be next laminated based on the intersection position when the amount of information is equal to or greater than a threshold value; in this order, How to set the target position. (2) A target position setting device for setting a target position when forming a weld bead with a torch on a stack of multiple weld beads, a shape profile acquisition unit that measures the shape of the laminate during modeling using a shape measurement sensor and acquires a shape profile; an intersection position acquisition unit that acquires an intersection position where a straight line extending in a lamination direction of the weld bead intersects with the shape profile; an information amount calculation unit that calculates an information amount of the shape profile within a predetermined range based on the intersection position; a target position extraction unit that extracts a candidate target position of the torch when forming the weld bead to be next laminated based on the intersection position when the amount of information is equal to or greater than a threshold value; Including, Aim position setting device. (3) A program for setting a target position when forming a weld bead by a torch on a stack of multiple weld beads, On the computer, a shape profile acquisition function of measuring the shape of the laminate during modeling using a shape measurement sensor to acquire a shape profile; an intersection position acquisition function for acquiring an intersection position where a straight line extending in a lamination direction of the weld bead intersects with the shape profile; an information amount calculation function for calculating an information amount of the shape profile within a predetermined range based on the intersection position; a target position extraction function that extracts the intersection position as a candidate target position for the torch when forming the weld bead to be next stacked when the amount of information is equal to or greater than a threshold value; In order to realize this, program. [Effects of the Invention]

[0010] According to the present invention, when manufacturing a shaped object, it is possible to accurately set the target position of a torch that forms a weld bead. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing the overall configuration of an additive manufacturing system. [Figure 2] FIG. 2 is an explanatory diagram that schematically shows how a shape is measured by a shape measuring sensor. [Figure 3]FIG. 3 is an explanatory diagram that schematically shows the target position of the torch on the laminate. [Figure 4] FIG. 4 is a functional block diagram of the target position setting device. [Figure 5] FIG. 5 is a flowchart showing the procedure for setting the target position by the target position setting device. [Figure 6] FIG. 6 is a schematic diagram illustrating the process of acquiring a shape profile. [Figure 7] FIG. 7 is a schematic diagram illustrating the process of correcting the measurement conditions. [Figure 8] FIG. 8 is a schematic diagram illustrating a method of measuring a shape using a shape measuring sensor in a modified example. [Figure 9] FIG. 9 is a schematic diagram illustrating the process of generating a composite shape profile. [Figure 10] FIG. 10 is a schematic diagram illustrating the process of extracting the intersection positions. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The additive manufacturing system shown here uses a heat source device to melt a filler material (welding wire) held by a manipulator to form a weld bead, and then repeatedly stacks the formed weld beads into a desired shape to form a shaped object. The target position setting device in the additive manufacturing device that forms such a shaped object sets the target position of a torch with respect to the stacked body being built.

[0013] <Additive manufacturing system configuration> An example of the configuration of an additive manufacturing system including the above-described target position setting device will be described. FIG. 1 is a schematic diagram showing the overall configuration of an additive manufacturing system. The additive manufacturing system 100 includes a manufacturing control device 15, a manipulator 17, a filler material supply device 19, a manipulator control device 21, and a heat source control device 23.

[0014] The manipulator control device 21 controls the manipulator 17 and the heat source control device 23. A controller (not shown) is connected to the manipulator control device 21, and an operator can instruct any operation of the manipulator control device 21 via the controller.

[0015] The manipulator 17 is, for example, an articulated robot, and a torch 11 attached to the tip shaft supports a filler material M so that it can be continuously supplied. The torch 11 holds the filler material M protruding from the tip. The tip shaft of the manipulator 17 is also provided with a shape measurement sensor 25 along with the torch 11. The position and orientation of the torch 11 and the shape measurement sensor 25 can be set arbitrarily in three dimensions within the range of the degrees of freedom of the robot arm constituting the manipulator 17. The manipulator 17 preferably has six or more degrees of freedom and is preferably capable of arbitrarily changing the axial direction of the heat source at the tip. The manipulator 17 may be variously configured, such as a four- or more-axis articulated robot as shown in FIG. 1, or a robot equipped with angle adjustment mechanisms on two or more orthogonal axes.

[0016] The torch 11 has a shield nozzle (not shown), through which shielding gas is supplied. The shielding gas blocks the atmosphere and prevents oxidation and nitridation of the molten metal during welding, thereby suppressing welding defects. The arc welding method used in this configuration may be either a consumable electrode type such as shielded metal arc welding or carbon dioxide gas arc welding, or a non-consumable electrode type such as TIG (Tungsten Inert Gas) welding or plasma arc welding, and is selected appropriately depending on the object to be formed. Here, gas metal arc welding will be used as an example. In the case of a consumable electrode type, a contact tip is disposed inside the shield nozzle, and a filler material M to which current is supplied is held by the contact tip. The torch 11 holds the filler material M and generates an arc from the tip of the filler material M in a shielding gas atmosphere.

[0017] The filler material supply device 19 supplies the filler material M toward the torch 11. The filler material supply device 19 includes a reel 19a around which the filler material M is wound, and a feeding mechanism 19b that feeds the filler material M from the reel 19a. The filler material M is fed to the torch 11 by the feeding mechanism 19b while being sent in the forward or reverse direction as needed. The feeding mechanism 19b is not limited to a push type that is arranged on the filler material supply device 19 side and pushes out the filler material M, but may also be a pull type or a push-pull type that is arranged on a robot arm or the like.

[0018] The heat source control device 23 is a welding power source that supplies the power required for welding by the manipulator 17. The heat source control device 23 adjusts the welding current and welding voltage supplied when forming a bead by melting and solidifying the filler material M. In addition, the filler material supply speed of the filler material supply device 19 is adjusted in conjunction with the welding conditions such as the welding current and welding voltage set by the heat source control device 23.

[0019] The heat source for melting the filler material M is not limited to the arc described above. Other heat sources may be used, such as a heating method that combines an arc and a laser, a heating method that uses plasma, or a heating method that uses an electron beam or a laser. Heating with an electron beam or a laser allows for more precise control of the amount of heat, which can maintain the state of the formed bead more appropriately and contribute to further improving the quality of the laminated structure. The material of the filler material M is also not particularly limited. The type of filler material M used may vary depending on the characteristics of the object W, such as mild steel, high-tensile steel, aluminum, aluminum alloy, nickel, or nickel-based alloy.

[0020] Shape measurement sensor 25 is provided alongside torch 11 and moves together with torch 11. Shape measurement sensor 25 measures the shape of the base portion when forming weld bead B. For example, a laser sensor that acquires reflected light of an irradiated laser beam as height data is used as shape measurement sensor 25. Note that a three-dimensional shape measurement camera may also be used as shape measurement sensor 25.

[0021] The molding control device 15 controls the above-mentioned parts in an integrated manner.

[0022] The additive manufacturing system 100 configured as described above operates in accordance with a manufacturing program created based on a manufacturing plan for the object W. The manufacturing program is composed of a large number of command codes and is created based on an appropriate algorithm depending on various conditions, such as the shape, material, and heat input of the object. According to this manufacturing program, the torch 11 is moved while the supplied filler material M is melted and solidified, and a linear weld bead B, which is a molten solid of the filler material M, is formed on the base 13. That is, the manipulator control device 21 drives the manipulator 17 and the heat source control device 23 based on a predetermined program provided from the manufacturing control device 15. In response to a command from the manipulator control device 21, the manipulator 17 moves the torch 11 while melting the filler material M with an arc to form the weld bead B. By sequentially forming and stacking the weld beads B in this manner, a desired object W is obtained.

[0023] 2, in additive manufacturing system 100, as weld beads B are sequentially formed and stacked, shape measurement sensor 25 measures the shape of stacked body Wh in the middle of being built to obtain a shape profile. Then, as shown in Fig. 3, based on the shape profile, target position Pt of torch 11 for forming weld bead B of the next pass is set, and torch 11 is positioned at this target position Pt to form weld bead B.

[0024] Incidentally, when measuring the shape of the laminated body Wh during manufacturing, it may be difficult to obtain sufficient shape profile information required for stacking the weld bead B in the next pass, depending on the blind spot in the measurement range Ma (see FIG. 2) of the shape measurement sensor 25 and the surface properties of the weld bead B of the laminated body Wh. In particular, when manufacturing an overhanging portion, blind spots are likely to occur, and accurate setting of the target position Pt of the torch 11 is required, so manufacturing may be difficult if the shape profile information is insufficient.

[0025] Therefore, in the layered manufacturing system 100 according to this embodiment, the manufacturing control device 15 functions as a target position setting device and accurately obtains the shape profile of the weld bead B of the layered body Wh in the middle of being manufactured, which serves as the base.

[0026] 4 is a functional block diagram of the forming control device 15. The forming control device 15 includes a shape profile acquisition unit 31, an intersection position acquisition unit 33, an information amount calculation unit 35, and a target position extraction unit 37, and functions as a target position setting device. Details of each unit will be described later, but the general functions are as follows.

[0027] The shape profile acquisition unit 31 measures the shape of the laminated body Wh in the middle of being modeled using the shape measurement sensor 25 to acquire a shape profile.

[0028] The intersection position acquisition unit 33 acquires the intersection position where a straight line extending in the stacking direction, which is determined based on a predetermined stacking direction and the target position of the weld bead B when forming the weld bead B that constitutes the stacked body Wh, intersects with the shape profile.

[0029] The information amount calculation unit 35 calculates the information amount of the shape profile within a calculation range that is set in advance based on the intersection position.

[0030] In the target position extraction step, when the amount of information in the shape profile is equal to or greater than a threshold, the intersection position is extracted as a candidate target position for torch 11 when forming weld bead B in the next pass.

[0031] The molding control device 15, which functions as the target position setting device, is configured by hardware using an information processing device such as a PC (Personal Computer). Each function of the molding control device 15 is realized by a control unit (not shown) reading and executing a program having a specific function stored in a storage device (not shown). Examples of the storage device include a memory such as a volatile storage area, such as a random access memory (RAM), a non-volatile storage area, such as a read-only memory (ROM), and storage such as a hard disk drive (HDD) or a solid state drive (SSD). Examples of the control unit include a processor such as a central processing unit (CPU) or a microprocessor unit (MPU), or a dedicated circuit. In addition to the above configurations, the molding control device 15 may be another computer remotely connected to the additive manufacturing system 100 via a network or the like.

[0032] <Trajectory plan correction procedure> Fig. 5 is a flowchart showing the procedure for setting the target position by the target position setting device. Fig. 6 is a schematic diagram illustrating the process of acquiring the shape profile Fp. Fig. 7 is a schematic diagram illustrating the process of correcting the measurement conditions.

[0033] As shown in FIG. 6, the shape profile acquisition unit 31 measures the shape of the laminated body Wh during fabrication using the shape measurement sensor 25 to acquire a shape profile Fp (step S1). When the shape measurement sensor 25 is a laser sensor, the shape measurement sensor 25 includes a laser irradiation unit and a detection sensor unit, and acquires the shape profile Fp using a known shape measurement method. For example, when measuring the shape using the light-section method, a slit light is emitted from the laser irradiation unit, and reflected light from the existing weld bead B is detected by the detection sensor unit, which is an image sensor. The two-dimensional image detected by the detection sensor unit includes a pattern corresponding to the height of the weld bead B, and the shape of the weld bead B is determined based on the pattern. Note that the initial condition for shape measurement may be a standard measurement condition, such as a condition in which the measurement direction of the shape measurement sensor 25 is set vertically downward. The shape profile may also be represented by a group of multiple measurement points, and the result of curve approximation of each measurement point may be treated as the shape profile. The measurement points are preferably set at equal intervals, for example, at a detection sampling interval corresponding to the sensor output, but may also be set at irregular intervals. If the sensor outputs are not at equal intervals, they may be made equal by thinning, outer layers, interpolation, etc. before carrying out the steps described below.

[0034] The intersection position acquisition unit 33 acquires an intersection position Pi where a line Lp extending in the lamination direction, determined from a predetermined lamination direction and a target position Pt when forming the weld bead B of the laminate Wh, intersects with the shape profile Fp (step S2). FIG. 6 shows a schematic broken line representing the outer edge of the weld bead B, which is the previous layer (the layer formed by the previous pass) of the weld bead of the shape profile Fp, and an example of the target position Pt when forming the weld bead of the next layer, set on the broken line. The lamination direction may be provided to the intersection position acquisition unit 33 in advance, or may be extracted as the slope of a line or curve passing through multiple target positions Pt. If the obtained shape profile Fp does not directly intersect with the line Lp extending in the lamination direction, the intersection position Pi may be acquired by extending the end of the shape profile Fp with a straight line or curve.

[0035] The information amount calculation unit 35 calculates the information amount of the shape profile Fp within the predetermined calculation ranges A1 and A2 based on the intersection position Pi (step S3). In this example, the number of measurement points Sp (white circles in FIG. 6) of the shape measurement sensor 25 is used as the information amount of the shape profile Fp, and the number of measurement points Spn is calculated. The number of measurement points Spn is calculated on each side of the calculation ranges A1 and A2, with the intersection position Pi as the boundary. Note that the information amount of the shape profile Fp may also be other data such as the measurement length.

[0036] The calculation ranges A1 and A2 for the number of measurement points Spn may be, for example, within a radius r centered on the intersection position Pi, or may be within a width d centered on a straight line Lp extending in the stacking direction. Note that these calculation ranges A1 and A2 may be set arbitrarily.

[0037] The target position extraction unit 37 compares the number of measurement points Spn, which is the amount of information in the shape profile Fp, with a preset threshold Nth and determines whether the number of measurement points Spn is equal to or greater than the threshold Nth (step S4). When calculating the number of measurement points Spn for each of the calculation ranges A1 and A2, the target position extraction unit 37 compares the number of measurement points Spn with the threshold Nth set for each of the calculation ranges A1 and A2. The threshold Nth may be a predetermined constant determined before measurement. For example, the threshold may be the minimum number of measurement points required to sufficiently match the actual bead shape when a curve simulating the bead shape is interpolated with respect to the measurement points. Alternatively, the threshold may be determined empirically from past experiments. By determining the threshold in this manner, a shape profile that closely matches the actual bead shape can be obtained, thereby accurately determining the appropriate target position.

[0038] In determining the number of measurement points Spn, if the calculated number of measurement points Spn is equal to or greater than the threshold value Nth (step S4: YES), it is determined that a sufficient amount of information has been acquired about the shape profile Fp in the vicinity of the intersection position Pi, and the intersection position Pi or a position set based on the intersection position Pi is extracted as a candidate target position for the torch 11 when forming the weld bead B of the next pass (step S5).

[0039] However, as mentioned above, depending on the blind spot of the measurement range Ma of the shape measurement sensor 25 and the surface properties of the weld bead B of the laminate Wh, the number of measurement points Spn may become biased around the intersection position Pi, and the calculated number of measurement points Spn may become less than the threshold value Nth.

[0040] In this way, if the calculated number of measurement points Spn is less than the threshold value Nth (step S4: No), the target position extraction unit 37 determines that the amount of information acquired from the shape profile Fp in the vicinity of the intersection position Pi is insufficient, and modifies the measurement conditions of the shape measurement sensor 25 (step S6).

[0041] The measurement conditions of the shape measurement sensor 25 to be corrected are, for example, conditions in which at least one of the posture and position, such as the tilt angle, of the shape measurement sensor 25 is changed, and corrections are made, for example, by tilting the shape measurement sensor 25 in a direction in which the number of measurement points Spn is insufficient, or by moving the position of the shape measurement sensor 25 closer to the weld bead B of the laminate Wh. Note that when correcting the measurement conditions, it is preferable to set upper limits in advance for the tilt angle and movement amount of the shape measurement sensor 25 in order to avoid interference of the shape measurement sensor 25 with the laminate Wh.

[0042] 7, the shape measurement sensor 25, which was previously set to a measurement condition in which the measurement direction was directed vertically downward, is tilted in a direction in which the number of measurement points Spn is insufficient. By tilting the shape measurement sensor 25 in this way, a blind spot in the laminate Wh enters the measurement range Ma of the shape measurement sensor 25. This makes it possible to obtain a sufficient number of measurement points Spn, which is the amount of information in the shape profile Fp, for each of the calculation ranges A1 and A2.

[0043] Then, the process repeats the steps of obtaining a shape profile Fp (step S1), obtaining the intersection position Pi where the straight line Lp extending in the stacking direction intersects with the shape profile Fp (step S2), calculating the number of measurement points Spn in the calculation ranges A1 and A2 (step S3), comparing the number of measurement points Spn with a threshold value Nth (step S4), and correcting the measurement conditions of the shape measurement sensor 25 (step S5) until the number of measurement points Spn becomes equal to or greater than the threshold value Nth (step S4: YES).

[0044] As described above, according to this configuration example, when the amount of information on the shape profile Fp near the intersection position Pi between the straight line Lp extending in the stacking direction and the shape profile Fp is sufficient, the intersection position Pi or a position set based on the intersection position Pi is extracted as a candidate for the target position Pt of the weld bead B of the next pass. This allows the target position Pt to be appropriately corrected even if the target position Pt in the stacking plan deviates from the actual shape, and also reduces the influence of measurement errors. Therefore, it is possible to avoid interruptions or errors in the manufacturing process due to the target position Pt being set at a position that is beyond the surface of the weld bead B constituting the stack Wh or at a position that is floating above the surface of the weld bead B. Therefore, it is possible to smoothly manufacture overhanging portions, which require particularly accurate setting of the target position Pt of the torch 11.

[0045] Furthermore, when the number of measurement points Sp, which is the amount of information, is less than the threshold value Nth, it is possible to extract only the target position Pt with guaranteed reliability by correcting at least one of the attitude and position of the shape measurement sensor 25. Moreover, since the repetition of the process ends when the number of measurement points Sp, which is the amount of information, reaches the threshold value Nth, it is possible to minimize the number of repetitions of measurement.

[0046] In particular, by comparing the number of measurement points Sp, which is the amount of information on both sides of the intersection position Pi (on both sides of the bead width direction perpendicular to the weld bead stacking direction and the bead formation direction, centered on the intersection position Pi), with the threshold value Nth in a cross-sectional view of the laminate perpendicular to the bead formation direction, it is possible to extract only the highly reliable target position Pt even if there is a bias in the number of measurement points Sp near the intersection position Pi due to blind spots in the measurement, etc.

[0047] Incidentally, when the shape of the laminated body Wh is measured by the shape measurement sensor 25 attached to the tip of the manipulator 17, errors associated with the attitude control of the manipulator 17 may affect the information on the shape profile Fp. In this case, the position information of the measurement point Sp of the shape measurement sensor 25 may be corrected so as to correct the amount of error associated with the attitude control of the manipulator 17. The amount of error associated with the attitude control of the manipulator 17 can be easily extracted by simply searching the database by measuring in advance the amount of target position deviation associated with the tilt and movement of the tip of the manipulator 17 and storing the measurement data in a database.

[0048] Next, a modified example will be described. Fig. 8 is a schematic diagram illustrating a method of measuring a shape by the shape measuring sensor 25 in a modified example. Fig. 9 is a schematic diagram illustrating a process of generating a composite shape profile Fps. Fig. 10 is a schematic diagram illustrating a process of extracting intersection positions Pi.

[0049] In the modified example, in the process of acquiring the intersection position Pi by the intersection position acquisition unit 33 (step S2), multiple shape profiles Fp with different measurement conditions are synthesized to generate a composite shape profile Fps, and the intersection position Pi with a straight line Lp extending in the stacking direction is acquired from this composite shape profile Fps.

[0050] Specifically, as shown in Fig. 8, the laminate Wh is measured under different measurement conditions using the shape measurement sensor 25, and shape profiles Fp1 and Fp are obtained from measurement points Sp1 (points indicated by squares in Fig. 8) and Sp2 (points indicated by triangles in Fig. 8). At this time, as shown in Fig. 9, overlapping or adjacent portions of measurement points Sp1 and Sp2 may be converted to measurement point Sp3 (points indicated by black circles in Fig. 9) with coordinate positions averaged to obtain shape profiles Fp1 and Fp2. Thereafter, as shown in Fig. 10, the shape profiles Fp1 and Fp2 are synthesized to generate a composite shape profile Fps, and the intersection position Pi where a straight line Lp extending in the stacking direction intersects with the composite shape profile Fps is obtained.

[0051] According to this modification, even if the amount of information that can be acquired changes sensitively depending on the measurement conditions, a wide range of information amount can be secured by generating a composite shape profile Fps by combining multiple shape profiles Fp1 and Fp2, thereby enabling highly reliable target position candidates to be extracted.

[0052] Moreover, in the modified example, even if the number of measurement points Spn of the measurement points Sp1 and Sp2 obtained under each measurement condition is uneven, the shape of the weld bead B can be grasped comprehensively, and a sufficient number of measurement points Spn can be ensured in the vicinity of the intersection position Pi. Therefore, the intersection position Pi where the straight line Lp extending in the layering direction intersects with the composite shape profile Fps, or a position set based on the intersection position Pi, may be set as the target position Pt of the torch 11 when forming the weld bead B of the next pass. Furthermore, in the modified example, even if some of the shape profiles Fp1 and Fp2 contain outliers, the effect of this can be reduced, so that arc errors and positional deviations can be suppressed when the weld bead B is layered in the next pass.

[0053] In this modification, it is also preferable to generate the composite shape profile Fps by correcting errors associated with the attitude control of the shape measurement sensor 25, such as the position and inclination, by the manipulator 17 relative to the measurement location on the laminate Wh. In this way, the influence of errors associated with the attitude control of the manipulator 17 can be eliminated, thereby improving the accuracy of the information in the composite shape profile Fps. Note that, as the error due to the manipulator 17, it is also possible to obtain a value obtained by interpolating the positional deviation by determining in advance the deviation of the target position in multiple attitudes. Furthermore, it is also possible to further improve the accuracy of the information by overlaying information obtained by fitting a model function of the weld bead B onto the generated composite shape profile Fps.

[0054] As such, the present invention is not limited to the above-described embodiments, and the present invention also contemplates the mutual combination of the various components of the embodiments, as well as modifications and applications by those skilled in the art based on the description in the specification and well-known techniques, and these modifications and applications are included in the scope of protection sought.

[0055] As described above, the present specification discloses the following: (1) A method for setting a target position when forming a weld bead with a torch on a stack of multiple weld beads, comprising: a shape profile acquisition step of measuring the shape of the laminate during modeling using a shape measurement sensor to acquire a shape profile; an intersection position acquisition step of acquiring an intersection position where a straight line extending in a lamination direction of the weld bead intersects with the shape profile; an information amount calculation step of calculating an information amount of the shape profile within a predetermined range based on the intersection position; a target position extraction step of extracting, when the amount of information is equal to or greater than a threshold, a target position candidate for the torch when forming the weld bead to be next laminated, based on the intersection position; A method for setting an aim position, including the following in this order: According to this target position setting method, when there is sufficient information about the shape profile near the intersection of the line extending in the stacking direction and the shape profile, a candidate target position for the weld bead of the next pass is extracted based on the intersection position. This allows the target position to be appropriately corrected even if the target position in the stacking plan deviates from the actual shape, and measurement errors can be minimized. This avoids interruptions and errors in the build caused by setting the target position to a position that is inside the surface of the weld bead that constitutes the stack or a position that is floating above the surface of the weld bead. This allows for smooth builds of overhanging parts, which require particularly accurate torch target position setting.

[0056] (2) The target position setting method according to (1), wherein, in the target position extraction step, if the amount of information is less than the threshold, at least one of the attitude and position of the shape measurement sensor is corrected, and the process from the profile acquisition step onwards is carried out. According to this target position setting method, measurements are repeated until a sufficient amount of information is obtained to extract the intersection position, so that only reliable target positions can be extracted. In addition, since the repetition ends when the amount of information reaches a threshold, the number of repeated measurements can be kept to a minimum.

[0057] (3) The target position setting method according to (1) or (2), wherein in the target position extraction step, the amount of information on both sides of the intersection position in a cross-sectional view of the laminate is compared with the threshold value. According to this target position setting method, by comparing the amount of information on both sides of the intersection position with a threshold, it is possible to extract only highly reliable target positions even if there is a bias in the amount of information near the intersection position due to blind spots in the measurement, etc.

[0058] (4) A target position setting method according to any one of (1) to (3), wherein in the intersection position acquisition step, a plurality of the shape profiles having different measurement conditions are synthesized to generate a composite shape profile, and the intersection position where a straight line extending in the stacking direction intersects with the composite shape profile is acquired. According to this target position setting method, even if the amount of information that can be acquired varies significantly depending on the measurement conditions, a wide range of information amount can be secured by synthesizing these multiple shape profiles to generate a composite shape profile, thereby enabling highly reliable target position candidates to be extracted.

[0059] (5) The target position setting method according to (4), wherein the composite shape profile is generated by correcting an error based on the position or tilt angle of the shape measurement sensor relative to the measurement point on the laminate. This target position setting method can eliminate the influence of errors associated with the position and orientation of the shape measurement sensor, such as the tilt angle, during measurement, thereby improving the accuracy of the composite shape profile information.

[0060] (6) The target position setting method according to any one of (1) to (5), wherein in the information amount calculation step, the number of measurement points of the shape of the stacked body measured by the shape measurement sensor is calculated as the information amount. According to this target position setting method, the number of measurement points obtained by the shape measurement sensor is calculated as the amount of information, and the target position can be extracted with high precision based on the amount of information formed by the number of measurement points.

[0061] (7) A target position setting device for setting a target position when forming a weld bead by a torch on a stack of multiple weld beads, comprising: a shape profile acquisition unit that measures the shape of the laminate during modeling using a shape measurement sensor and acquires a shape profile; an intersection position acquisition unit that acquires an intersection position where a straight line extending in a lamination direction of the weld bead intersects with the shape profile; an information amount calculation unit that calculates an information amount of the shape profile within a predetermined range based on the intersection position; a target position extraction unit that extracts a candidate target position of the torch when forming the next weld bead to be layered, based on the intersection position, when the amount of information is equal to or greater than a threshold value; and An aim position setting device including: This target position setting device extracts a candidate target position for the next pass weld bead based on the intersection point of a line extending in the stacking direction and the shape profile when there is sufficient information about the shape profile near the intersection point. This allows the target position to be appropriately corrected even if the target position in the stacking plan deviates from the actual shape, and also minimizes measurement errors. This avoids interruptions and errors in the build caused by setting the target position to a position that is inside the weld bead or floating above the surface of the weld bead that constitutes the stack. This allows for smooth builds of overhanging parts, which require accurate torch target position setting.

[0062] (8) A program for setting a target position when forming a weld bead by a torch on a stack of multiple weld beads, On the computer, a shape profile acquisition function of measuring the shape of the laminate during modeling using a shape measurement sensor to acquire a shape profile; an intersection position acquisition function for acquiring an intersection position where a straight line extending in a lamination direction of the weld bead intersects with the shape profile; an information amount calculation function for calculating an information amount of the shape profile within a predetermined range based on the intersection position; a target position extraction function that extracts, when the amount of information is equal to or greater than a threshold, a target position candidate of the torch when forming the weld bead to be next laminated, based on the intersection position; A program to make this happen. According to this program, when there is sufficient information about the shape profile near the intersection of the line extending in the stacking direction and the shape profile, a candidate target position for the weld bead of the next pass is extracted based on the intersection position. This allows the target position to be appropriately corrected even if the target position in the stacking plan deviates from the actual shape, and measurement errors can be minimized. This avoids interruptions and errors in the build caused by setting the target position to a position that is inside the surface of the weld bead that constitutes the stack or a position that is floating above the surface of the weld bead. This allows for smooth builds of overhanging parts that require accurate torch target position setting. [Explanation of symbols]

[0063] 11 Torch 15. Forming control device (target position setting device) 25 Shape measurement sensor 31 Shape profile acquisition unit 33 Intersection position acquisition part 35 Information amount calculation section 37 Target position extraction unit A1, A2 calculation range (range) B Weld bead Fp, Fp1, Fp2 shape profile Fps Synthetic Shape Profile Lp straight line Nth threshold Pi intersection position Pt target position Spn Number of measurement points (amount of information) Wh laminate

Claims

1. A target position setting method for setting a target position when forming a weld bead by a torch on a stack of multiple weld beads, comprising: a shape profile acquisition step of measuring the shape of the laminate during modeling using a shape measurement sensor to acquire a shape profile; an intersection position acquisition step of acquiring an intersection position where a straight line extending in a lamination direction of the weld bead intersects with the shape profile; an information amount calculation step of calculating an information amount of the shape profile within a predetermined range based on the intersection position; a target position extraction step of extracting a candidate target position of the torch when forming the weld bead to be next laminated based on the intersection position when the amount of information is equal to or greater than a threshold value; in this order, a target position setting method, wherein, in the target position extraction step, if the amount of information is less than the threshold, at least one of the attitude and position of the shape measurement sensor is corrected, and steps subsequent to the shape profile acquisition step are performed.

2. In the target position extraction step, the information amounts on both sides of the intersection position in a cross-sectional view of the laminate are compared with the threshold values. The target position setting method according to claim 1 .

3. In the intersection position acquisition step, a plurality of the shape profiles having different measurement conditions are synthesized to generate a composite shape profile, and the intersection position where a straight line extending in the stacking direction intersects with the composite shape profile is acquired. The target position setting method according to claim 1 .

4. generating the composite shape profile by correcting an error based on the position or tilt angle of the shape measurement sensor relative to the measurement point on the laminate; The target position setting method according to claim 3.

5. In the information amount calculation step, the number of measurement points of the shape of the stacked body measured by the shape measurement sensor is calculated as the information amount. The target position setting method according to any one of claims 1 to 4.

6. A target position setting device that sets a target position when forming a weld bead by a torch on a stack of multiple weld beads, a shape profile acquisition unit that measures the shape of the laminate during modeling using a shape measurement sensor and acquires a shape profile; an intersection position acquisition unit that acquires an intersection position where a straight line extending in a lamination direction of the weld bead intersects with the shape profile; an information amount calculation unit that calculates an information amount of the shape profile within a predetermined range based on the intersection position; a target position extraction unit that extracts a candidate target position of the torch when forming the next weld bead to be layered, based on the intersection position, when the amount of information is equal to or greater than a threshold value; and Including, When the amount of information is less than the threshold, the target position extraction unit corrects at least one of the attitude and position of the shape measurement sensor, and executes the shape profile acquisition unit and subsequent units.

7. A program for setting a target position when forming a weld bead by a torch on a stack of multiple weld beads, On the computer, a shape profile acquisition function of measuring the shape of the laminate during modeling using a shape measurement sensor to acquire a shape profile; an intersection position acquisition function for acquiring an intersection position where a straight line extending in a lamination direction of the weld bead intersects with the shape profile; an information amount calculation function for calculating an information amount of the shape profile within a predetermined range based on the intersection position; a target position extraction function that extracts, when the amount of information is equal to or greater than a threshold, a target position candidate of the torch when forming the weld bead to be next laminated, based on the intersection position; Realize this, a program for correcting at least one of the attitude and position of the shape measurement sensor when the amount of information is less than the threshold value in the target position extraction function, and realizing functions subsequent to the shape profile acquisition function.

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