Electroslag welding device, control method for electroslag welding device, and program

Abstract

To suppress the influence of installation accuracy of a device in electroslag welding and improve user convenience.SOLUTION: An electroslag welding device includes: a welding torch for performing electroslag welding; an imaging device positioned to image the molten slag bath within a groove formed by a base material; specification means that specifies the area of the molten slag bath from the image captured by the imaging device; and adjustment means that adjusts the tip position of the welding torch in the first direction on the basis of a difference in the first direction between the position of the area specified by the specification means and the tip position of the welding torch within the groove.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to an electroslag welding apparatus, a control method for an electroslag welding apparatus, and a program. [Background technology]

[0002] Vertical welding is used in the manufacture of structures in the fields of shipbuilding and steel frame construction. For example, electroslag welding (ESW) using Joule heat of molten slag as a heat source is used for this vertical welding, and automation is being promoted. In electroslag welding, heat is generated in the molten slag to melt the wire and base material, so no arc radiation heat is generated, and there is little generation of fumes and spatter, making it suitable for improving the working environment. In addition, since the weld metal is shielded from the atmosphere by the molten slag, no shielding gas is required, the shielding effect does not deteriorate even if the plate thickness increases, and the intrusion of nitrogen and other substances present in the atmosphere into the molten metal can be effectively prevented regardless of the plate thickness. Therefore, the mechanical properties of the weld metal are good.

[0003] In vertical welding such as electroslag welding, for example, Patent Document 1 discloses a configuration for maintaining the depth of a slag bath at a level suitable for welding without providing a detector for detecting the slag bath. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6460910 Summary of the Invention [Problem to be solved by the invention]

[0005] In vertical welding, the device performs welding while rising along a rail installed parallel to the groove of the welding target, i.e., the upward direction. At this time, it is required to install the rail, which is the movement path of the device, exactly parallel, but this is difficult to do manually, and deviations in the left and right directions may occur. In vertical welding, it is necessary to keep the welding torch and copper plate in the center of the groove, and if deviations occur, they are adjusted manually. To address this issue, for example, a mechanical copying device that inserts a roller into the groove of the groove can be used as a configuration for automatically performing welding while correcting the deviation. However, such a configuration causes issues such as high cost, large degree of error, and restrictions on handling the groove width.

[0006] In view of the above problems, an object of the present invention is to reduce the influence of the installation accuracy of an apparatus in electroslag welding and to improve user convenience. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention has the following configuration. That is, an electroslag welding apparatus includes: a welding torch for performing electroslag welding; A photographing device arranged so as to be able to photograph the molten slag bath in the groove made of the base material; A means for identifying an area of ​​the molten slag bath from the image captured by the imaging device; An adjustment means for adjusting a tip position of the welding torch in the first direction based on a difference in a first direction between the position of the region identified by the identification means and the tip position of the welding torch in the groove; has.

[0008] According to another aspect of the present invention, there is provided a method for controlling an electroslag welding apparatus, comprising the steps of: An acquisition step of acquiring an image captured by an image capturing device arranged so as to be able to capture an image of the molten slag bath in the groove formed of the base material; identifying an area of ​​the molten slag bath from the image; an adjustment process of adjusting a tip position of the welding torch in the first direction based on a difference in a first direction between the position of the region identified in the identification process and a tip position of the welding torch in the groove; Has.

[0009] In addition, another aspect of the present invention has the following configuration. That is, the program comprises: On the computer, An acquisition step of acquiring an image captured by an image capturing device arranged so as to be able to capture an image of the molten slag bath in the groove formed of the base material; identifying an area of ​​the molten slag bath from the image; an adjustment process of adjusting a tip position of the welding torch in the first direction based on a difference in a first direction between the position of the region identified in the identification process and a tip position of the welding torch in the groove; Execute the command. Effect of the Invention

[0010] According to the present invention, in electroslag welding, it is possible to suppress the influence of the installation accuracy of the device and improve the convenience for the user. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram showing an example of the configuration of a welding system according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a block diagram showing an example of a functional configuration of a welding system according to an embodiment of the present invention. [Figure 3A] FIG. 2 is a schematic diagram showing an example of a groove configuration according to an embodiment of the present invention. [Figure 3B] FIG. 2 is a schematic diagram showing an example of a groove configuration according to an embodiment of the present invention. [Figure 3C] FIG. 2 is a schematic diagram showing an example of a groove configuration according to an embodiment of the present invention. [Figure 4] FIG. 13 is an example diagram showing an example of an image according to an embodiment of the present invention. [Figure 5A] 5A to 5C are exemplary views for explaining image processing according to an embodiment of the present invention. [Figure 5B] 5A to 5C are exemplary views for explaining image processing according to an embodiment of the present invention. [Figure 5C] 5A to 5C are exemplary views for explaining image processing according to an embodiment of the present invention. [Figure 6A] FIG. 13 is an example diagram showing an example of an image according to an embodiment of the present invention. [Figure 6B] FIG. 13 is an example diagram showing an example of an image according to an embodiment of the present invention. [Figure 6C] FIG. 13 is an example diagram showing an example of an image according to an embodiment of the present invention. [Figure 6D] FIG. 13 is an example diagram showing an example of an image according to an embodiment of the present invention. [Figure 7] FIG. 4 is a graph illustrating control timing according to an embodiment of the present invention. [Figure 8] FIG. 4 is a graph illustrating control timing according to an embodiment of the present invention. [Figure 9] 4 is a flowchart of a control process according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings. Note that the embodiment described below is one embodiment for explaining the present invention, and is not intended to be interpreted as limiting the present invention, and all configurations described in each embodiment are not necessarily essential configurations for solving the problems of the present invention. In addition, in each drawing, the same components are given the same reference numbers to indicate their correspondence.

[0013] <First embodiment> Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0014] [Welding system] FIG. 1 is a schematic diagram showing a configuration example of an electroslag welding apparatus 100 according to the present embodiment (hereinafter, referred to as the welding apparatus 100). Although omitted in FIG. 1, the welding apparatus 100 further includes a welding power source, a wire feeder, and an operation box (not shown). Each part may be connected via various cables such as a power cable and a signal cable. FIG. 1 shows a coordinate system of the welding apparatus 100 consisting of three axes, the X-axis, the Y-axis, and the Z-axis. The X-axis is the thickness direction of the base material 3, the Y-axis is the direction in which the pair of base materials are arranged, that is, the horizontal direction along the surface of the base material 3, and the Z-axis is the direction along the weld line of the base material 3, that is, the up-down direction.

[0015] As shown in FIG. 1, the welding apparatus 100 according to this embodiment includes a fixed copper strip 1, a sliding copper strip for welding 13 (hereinafter also referred to as copper strip 13), a welding torch 4, a flux supply device 14, a welding control device 15, a traveling carriage 16, a traveling carriage control device 17, an imaging device 18, and a display device 19.

[0016] In the welding device 100, a fixed copper backing 1 is arranged on the back side of the groove of a pair of base materials 3, which are steel plates, and a copper backing 13 is arranged as a sliding plate on the front side of the groove. Here, instead of the copper backing 1 on the back side, a backing material made of heat-resistant ceramic may be used. Also, the copper backing 13 on the front side is a copper backing that slides in the vertical direction, and is cooled, for example, by water cooling. In this embodiment, copper is given as the material of the copper backing 13, but it is not limited to copper, and any material may be used as the backing as long as it has good thermal conductivity. In this embodiment, for convenience, the side on which the fixed copper backing 1 is arranged is referred to as the "back side of the groove" or the "rear side of the groove", and the side on which the copper backing 13 is arranged is referred to as the "front side of the groove" or the "front side of the groove", but the copper backing 13 may be arranged on both sides of the groove.

[0017] The copper backing 13 is configured to be movable upward, i.e., in the Z-axis direction, by the traveling carriage 16, and also configured to be movable left and right, i.e., in the Y-axis direction, by control described later. The copper backing 13 is installed by being pressed against the base material 3 with a predetermined force in the X-axis direction before welding begins. Although not shown in FIG. 1, a slag detection terminal for detecting the surface (upper surface) of the molten slag bath 7 may be provided on the upper part of the copper backing 13.

[0018] The welding torch 4 supplies a welding current 8 supplied from a welding power source 200 to the welding wire 6 to weld the base material 3. The welding torch 4 also has a contact tip 5, which guides the welding wire 6 and supplies the welding current 8 to the welding wire 6.

[0019] A welding wire 6 is fed from the tip of a contact tip 5 of a welding torch 4 into a groove surrounded by a base metal 3, a copper strip 1, and a copper strip 13, and is fed into a molten slag bath 7 formed in the groove. A welding current 8 flows from the welding wire 6 through the molten slag bath 7 to the molten metal 9. At this time, Joule heat is generated by the welding current 8 flowing through the molten slag bath 7 and the resistance of the molten slag bath 7, and the welding progresses while melting the welding wire 6 and the base metal 3.

[0020] As the vertical welding progresses, the sliding copper welding strip 13 moves upward along the front surface of the groove. The flux supply device 14 supplies the flux 12 by scattering it into the molten slag bath 7. Since the flux 12 melts to become molten slag, the amount of the molten slag bath 7, i.e., the depth, increases by supplying the flux 12.

[0021] The flux supply device 14 adjusts the amount and timing of the flux 12 to be supplied to the molten slag bath 7 based on instructions from a welding control device 15. The control of the timing of supplying the flux 12 will be described later.

[0022] As vertical welding progresses, the molten metal 9 cools to become the weld metal 10, and a portion of the molten slag bath 7 becomes a molten slag layer formed between the copper backing 1 and the weld metal 10, and between the copper backing 13 and the weld metal 10, and this molten slag layer cools to become solidified slag 11. In this way, the molten slag bath 7 is consumed as the welding progresses, and the depth Ls of the molten slag bath 7 decreases. To compensate for this decrease in the molten slag bath 7, flux 12 that melts to become the molten slag bath 7 is additionally supplied.

[0023] The amount of solidified slag 11 covering the bead surface varies depending on the bead width and the width of the welding groove. The amount of solidified slag 11 also varies depending on the degree of adhesion between the copper backing 1 or copper backing 13 and the base material 3, and the cooling state of the copper backing 1 or copper backing 13. Therefore, the amount of solidified slag 11 is not constant, and in order to keep the depth Ls of the molten slag bath 7 constant, it is necessary to change the amount of flux 12 supplied. Here, "constant" does not necessarily mean that the depth Ls of the molten slag bath 7 is always one value, but also includes the case where the depth Ls of the molten slag bath 7 shows a value within a certain range taking into account an error. In other words, the depth Ls of the molten slag bath 7 is controlled so as to be maintained within a predetermined depth range.

[0024] Here, the distance from the tip of the contact tip 5 to the upper surface of the molten slag bath 7 is defined as the welding wire length Ld (hereinafter referred to as the dry extension Ld). This is based on the premise that the tip of the contact tip 5 is generally the current-carrying position between the welding wire 6 and the contact tip 5. For example, if the tip of the contact tip 5 is protected by ceramic or the like and a current-carrying portion between the welding wire 6 and the contact tip 5 is provided above the tip of the contact tip 5, the position of this current-carrying portion becomes the basis for determining the dry extension Ld.

[0025] The traveling carriage 16 is configured to mount the welding torch 4, the welding sliding copper backing 13, the flux supply device 14, the welding control device 15, the traveling carriage control device 17, and the photographing device 18. The traveling carriage 16 moves upward on rails (not shown), i.e., in the Z-axis direction, while welding, thereby raising and lowering the welding device 100. That is, the traveling carriage 16 moves integrally with the welding torch 4, the welding sliding copper backing 13, the flux supply device 14, the welding control device 15, the traveling carriage control device 17, and the photographing device 18, so that the relative positional relationship between them does not change. The traveling carriage 16 rises, and thus vertical welding is performed along the Z-axis direction. The rails (not shown) are manually installed around the base material 3 along the welding direction before welding begins.

[0026] Welding control device 15 controls various functions in addition to the image processing according to this embodiment. Traveling cart control device 17 controls the operation of traveling cart 16 by increasing or decreasing the traveling speed of traveling cart 16 based on an instruction from welding control device 15. Note that, although welding control device 15 and traveling cart control device 17 are configured separately in the example of Fig. 1, they may be integrated into one control device.

[0027] The photographing device 18 is disposed above the molten slag bath 7 in the Z-axis direction so that the area of ​​the molten slag bath 7 can be photographed during welding. In FIG. 1, Lc indicates the distance between the surface of the molten slag bath 7 in the Z-axis direction and the lens position of the photographing device 18. The positional relationship between the photographing device 18 and the traveling cart 16 is assumed to be constant during welding. The installation position of the photographing device 18 is not particularly limited, but may be, for example, installed above the groove formed by the base material 3, and configured to have Ls=30 cm, etc. In addition, the photographing device 18 is configured to be equipped with, for example, an ND (No Density) filter or the like, and to acquire an image by reducing the light generated during welding to a certain degree (for example, 1 / 8 reduction).

[0028] The display device 19 displays, for example, an image captured by the photographing device 18 and the results of various image processing described later. The display device 19 and the welding device 100 may be connected by wire or wirelessly via an external interface (not shown). The display device 19 may be configured to be capable of communicating with an external device different from the display device 19 via an external interface (not shown). In this case, the display device 19 may be configured to transmit the image captured by the photographing device 18 and the image obtained by performing various processing described later to the external device.

[0029] The various control devices provided in the traveling cart 16 are composed of a processing unit and a storage unit. The processing unit may be composed of, for example, a central processing unit (CPU), a micro processing unit (MPU), a digital single processor (DSP), or a dedicated circuit. The storage unit is composed of, for example, a hard disk drive (HDD), a read only memory (ROM), a random access memory (RAM), or other volatile or non-volatile memory. The processing unit executes a computer program for power supply control stored in the storage unit to realize various control processes.

[0030] (Functional configuration) 2 is a block diagram showing an example of a functional configuration of welding control device 15 according to this embodiment. Welding control device 15 includes an image acquisition unit 201, an image processing unit 202, an image analysis unit 203, a welding control unit 204, a flux dispersion control unit 205, and an output control unit 206.

[0031] The image acquisition unit 201 acquires an image captured by the photographing device 18. The image acquisition unit 201 may control the timing of photographing by the photographing device 18. The image processing unit 202 applies various types of image processing to the image acquired by the image acquisition unit 201. The types of image processing are not particularly limited, and may include, for example, filtering processing, blurring processing, binarization processing, area extraction processing, and filling processing.

[0032] Image analysis unit 203 analyzes the area and state included in the image by using the image acquired by image acquisition unit 201 and the image processed by image processing unit 202. Welding control unit 204 controls each part of welding device 100 based on the analysis result by image analysis unit 203. For example, welding control unit 204 issues instructions to traveling cart control device 17 and controls oscillation of welding torch 4. A specific example of the oscillation operation according to this embodiment will be described later, but the oscillation operation refers to the operation of swinging welding torch 4 in a predetermined direction.

[0033] The flux spray control unit 205 controls the timing and amount of flux sprayed by the flux supply device 14 based on the analysis result by the image analysis unit 203. The output control unit 206 displays the images captured by the image acquisition unit 201 on the display device 19 and outputs various messages related to welding.

[0034] [Example of bevel] 3A to 3C show examples of grooves formed in a base material to be welded by the welding device 100 according to this embodiment. 3A to 3C are schematic views seen from the top along the Z-axis direction, that is, from the direction photographed by the photographing device 18. Although omitted in Figs. 3A to 3C, the welding device 100 is installed on the side of the sliding copper backing 13 for welding.

[0035] FIG. 3A shows an example of a V-shaped groove G. The groove G is configured to be surrounded by the base material 3a and base material 3b arranged along the Y-axis direction, and the copper strip 1 and the welding sliding copper strip 13 arranged along the X-axis direction. The examples shown in the images described later all show examples of the V-shape. FIG. 3B shows an example of an I-shaped groove G. Also, FIG. 3C shows an example of a L-shaped groove G.

[0036] [Example image] FIG. 4 is a diagram showing an example of an image handled in this embodiment. In the three-dimensional coordinate system shown in the following image, the setting of the coordinates and the origin in the image is not particularly limited, and it is sufficient that the corresponding positions in the image and between the images can be specified. In addition, the coordinates of the coordinate system of the welding device 100 and the coordinate system of the camera 18 are assumed to be associated with each other so as to be convertible. Therefore, they may be associated in an absolute coordinate system or in a relative coordinate system. Therefore, the coordinates specified from the image captured by the camera 18 are configured to be able to be reflected in the parameters when controlling the operation of the welding device 100. In addition, the image captured by the camera 18 is acquired so that at least the groove, that is, the area of ​​the molten slag bath 7, is included near the center, and the angle of view and the image size are not particularly limited. As described above, the camera 18 is installed before the start of welding.

[0037] The image 400 in FIG. 4 is an image captured from above along the Z-axis direction by the image capture device 18. The image 400 includes a bright region Rt corresponding to the molten slag bath 7 and a dark region Ro surrounding the bright region Rt. As described above, the base materials 3a and 3b, the copper strip 1, and the welding sliding copper strip 13 are located around the molten slag bath 7. The image 400 also includes a welding torch 4. Point Cb indicates the center of gravity of the region Rt of the groove, which is closer to the copper strip 1 (the back side of the groove) than the center in the X-axis direction. Point Ct indicates the tip position of the welding torch 4.

[0038] Fig. 5A shows an example of an original image 500 captured by the image capture device 18. Fig. 5B shows an example of an image 510 obtained by applying a binarization process to the image 500 of Fig. 5A. The binarization process divides the image into a bright area having a brightness equal to or greater than a predetermined threshold, i.e., an area 511 corresponding to the molten slag bath 7, and the other areas 512.

[0039] FIG. 5C shows an example of calculating the point Cb of the region Rt corresponding to the molten slag bath 7 based on the image 500 and the image 510. The point Cb indicates the position of the center of gravity of the region Rt from the center of the groove to the copper backing 1 side along the X-axis direction. In this embodiment, the center of gravity is derived by focusing on a predetermined range in the X-axis direction of the region Rt. Here, an example is shown in which the point Cb is derived for the region in the back half of the region Rt as the predetermined range. On the copper backing 13 side, that is, the front side of the molten slag bath 7, there are the shadow of the welding torch 4 and the cut of the copper backing 13, which may be a factor in reducing the accuracy of coordinate detection depending on the degree of flux accumulation and the inclination of the welding torch 4. Therefore, in this embodiment, the center of gravity is derived excluding such regions. Note that the above-mentioned predetermined range is not particularly limited. For example, the range of the region from which the center of gravity is derived may be specified according to the angle of view and the shooting direction of the shooting device 18.

[0040] FIG. 6A shows an example of an image 600 when the welding torch 4 moves to the rear side in the X-axis direction, i.e., toward the copper backing 1, by the oscillation operation. FIG. 6B shows an example of an image 610 when the welding torch 4 moves to the front side in the X-axis direction, i.e., toward the copper backing 13, by the oscillation operation. In this embodiment, the welding torch 4 performs an oscillation operation in the X-axis direction, i.e., in the front-rear direction of the welding device 100. The oscillation width in the front-rear direction during the oscillation operation varies depending on the thickness of the base material 3. Comparing the image 600 in FIG. 6A and the image 610 in FIG. 6B, the range of the region Rt corresponding to the molten slag bath 7 extracted from the image is different. In particular, the image 600 in which the welding torch 4 is located on the front side in the X-axis direction allows a larger region Rt to be detected.

[0041] 6C shows an example of an image 620 immediately after flux is sprayed on the groove. Comparing the image 500 in FIG. 5A and the image 620 in FIG. 6C, the brightness of the image, more specifically, the brightness of the periphery of the molten slag bath 7, decreases immediately after the flux is sprayed. Therefore, in the image immediately after the flux is sprayed, the accuracy of extraction of the area corresponding to the molten slag bath 7 decreases.

[0042] FIG. 6D shows an example of an image 630 in which the tip of the welding torch 4, i.e., the welding wire 6, is exposed from the surface of the molten slag bath 7 and an arc is visible (hereinafter referred to as an "open arc"). As shown in the image 630, an open arc occurs when the depth of the molten slag bath 7 is insufficient. When an open arc occurs, a smoky region 631 occurs. This region 631 has a high proportion of predetermined pixel values, specifically, blue (B) and green (G), so the occurrence of an open arc can be detected by identifying these pixel values. In other words, the accuracy of extracting the region corresponding to the molten slag bath 7 decreases from the image when an open arc occurs. For example, the upper and lower limits of (B, R, G) = (140, 0, 100) to (255, 220, 245) may be used as the threshold value for the pixel value used to determine an open arc. Here, an example is shown in which three colors B (blue), R (red), and G (green) are each represented by 8 bits in each pixel.

[0043] [Example] In this embodiment, the position of the tip of the welding torch 4 in the left-right direction, i.e., in the Y-axis direction, is adjusted using the image as described above. The welding torch 4 performs an oscillating motion along the X-axis direction. As shown in FIG. 4, in this embodiment, the coordinates of a point Cb corresponding to the center of gravity of the molten slag bath 7 and a point Ct corresponding to the tip position of the welding torch 4 can be identified. If the positions (coordinates) of these points in the Y-axis direction are misaligned, the left-right position of the tip position of the welding torch 4 is adjusted.

[0044] 6A and 6B, the range of the area corresponding to the molten slag bath 7 as seen from the image capture device 18 varies depending on the oscillation of the welding torch 4. Therefore, in this embodiment, an image in which the tip of the welding torch 4 is positioned on the front side is used so that the range of the area corresponding to the molten slag bath 7 can be captured as widely as possible.

[0045] 6C, immediately after the flux is dispersed, the accuracy of extraction of the area corresponding to the molten slag bath 7 from the image taken by the photographing device 18 decreases. Therefore, in this embodiment, in order to improve the accuracy of extraction of the area corresponding to the molten slag bath 7, images taken within a certain time period after the flux is dispersed are not used.

[0046] FIG. 7 is a diagram for explaining the fluctuation in the X-axis direction of the region corresponding to the molten slag bath 7 identified from the image. In FIG. 7, the horizontal axis indicates time [seconds], and the vertical axis indicates coordinates [pixels] in the X-axis direction. Graph 701 indicates the center of gravity position of the region corresponding to the molten slag bath 7 identified from the image taken by the photographing device 18, i.e., the coordinates in the X-axis direction of point Cb in FIG. 4. Graph 702 indicates the timing of spraying the flux. In graph 702, the peak position is the timing at which the flux is sprayed.

[0047] With reference to the graphs 701 and 702, it can be seen that the coordinates of the point Cb fluctuate immediately after the flux is dispersed. That is, immediately after the flux is dispersed, there is a concern that a position different from the coordinates of the actual point Cb may be detected, and the detection accuracy is reduced. Therefore, in order to further increase the accuracy of extraction of the region corresponding to the molten slag bath 7, images within a certain time after the flux is dispersed are not used.

[0048] 6D, when an open arc occurs, the accuracy of extracting the area corresponding to the molten slag bath 7 from the image captured by the image capture device 18 decreases. Therefore, in this embodiment, in order to increase the accuracy of extracting the area corresponding to the molten slag bath 7, the image in which the open arc occurs is not used.

[0049] 8 is a graph showing a control example in electroslag welding in which welding is performed along a rail that is set 9 mm to the left in the Y-axis direction between the initial position and the final position when the welding device 100 is set. In other words, it is more preferable that the rail (not shown), which is the movement path of the welding device 100, is set parallel to the groove direction without any deviation. However, in reality, such a setting is difficult, and therefore deviations may occur in the setting positions of the rail at the start and end positions of welding.

[0050] In Fig. 8, the horizontal axis indicates the passage of time [seconds], and the vertical axis indicates the relative left and right positions [mm] from the start position of welding. In this embodiment, left and right correspond to the Y-axis direction. In addition, in the Y-axis direction, the left direction is positive and the right direction is negative. In the example of Fig. 8, the upward direction on the vertical axis corresponds to the positive (left direction).

[0051] The dashed line 801 indicates the assumed center position of the molten slag bath 7. As described above, when the start position is 0, the end position is shifted 9 mm to the left. The thresholds Thl and Thr are thresholds for correcting the tip position of the welding torch 4. The threshold Thl is a threshold for the shift to the left, and the threshold Thr is a threshold for the shift to the right. Each threshold may be determined according to the accuracy of welding, and is determined in advance and stored in a memory unit or the like.

[0052] Graph 802 shows the position of the welding torch 4 in the Y-axis (left and right) direction. Graph 803 shows the position of the copper backing 13 in the Y-axis (left and right) direction. The welding torch 4 and the copper backing 13 may be configured to perform the same operation in synchronization in the Y-axis direction, or may be configured to be able to adjust their positions separately. Graph 804 shows the position of the molten slag bath 7 in the Y-axis (left and right) direction, identified based on the image acquired by the photographing device 18, and will be described here as the position of point Cb, which is the center of gravity of the molten slag bath 7, as shown in FIG. 4 and other figures.

[0053] In this embodiment, when the position of point Cb of the molten slag bath 7 shown in the graph 804 exceeds the threshold value, that is, when it is shifted to the left or right by more than the threshold value, the positions of the welding torch 4 and the copper backing 13 are corrected. In the example of Fig. 8, it is assumed that a shift of more than the threshold value occurs at around 190 seconds, 250 seconds, 290 seconds, 380 seconds, 510 seconds, 620 seconds, and 660 seconds from the start time, and the positions of the welding torch 4 and the copper backing 13 are adjusted to the left. Note that in the example of Fig. 8, the values ​​from the start of welding to about 100 seconds are merely influenced by the effects immediately after the start of welding, and are not considered here.

[0054] [Processing flow] 9 shows a flowchart of the control process according to this embodiment. This process flow is realized, for example, by a processing unit included in welding device 100 reading out a corresponding program from a storage unit and executing it. This process flow is executed in a state where welding device 100 is placed relative to base material 3 to be welded. Here, for the sake of simplicity, the processing subject will be collectively described as welding device 100.

[0055] In S901, welding apparatus 100 starts welding. The welding may be started according to a user's instruction or when a predetermined condition is satisfied. The welding includes the lifting operation of welding apparatus 100 by controlling traveling carriage 16, the feeding of welding wire 6, and the like.

[0056] In S902, the welding device 100 starts photographing the molten slag bath 7 with the photographing device 18. By this photographing, images such as those shown in FIG.

[0057] In S903, the welding device 100 starts the copy control of the welding torch 4. In this embodiment, the copy control is executed by performing an oscillating motion of the welding torch 4 along the X-axis direction.

[0058] In S904, welding device 100 sequentially analyzes images captured by imaging device 18. The analysis here may be performed at a predetermined frame rate. When analyzing, image processing such as filtering, blurring, binarization, area extraction, and filling may be performed on the images. Since image processing is performed in parallel with the welding operation, it is preferable that the processing load is at a level that allows a certain level of responsiveness to be achieved.

[0059] In S905, welding device 100 determines whether or not an open arc has been detected as a result of the image analysis in S904. As shown in FIG. 6D, when an open arc occurs, an area having a predetermined pixel value occurs, and therefore the determination may be made based on the pixel values ​​of each pixel included in the image. If an open arc has been detected (YES in S905), the processing of welding device 100 proceeds to S906. On the other hand, if an open arc has not been detected (NO in S905), the processing of welding device 100 proceeds to S908.

[0060] In S906, the welding device 100 performs flux dispersion. The amount of flux to be dispersed here may be specified in advance. The flux may be dispersed in a predetermined amount all at once, or may be dispersed stepwise in a number of times. When dispersing the flux, the welding device 100 may stop other operations, such as the lifting operation. In addition, when an open arc is detected in S905, the welding device 100 may display the occurrence of an open arc on the display device 19 in addition to dispersing the flux.

[0061] In S907, the welding device 100 waits for a predetermined time. That is, the welding device 100 waits until the flux dispersed in S906 melts and no open arc occurs. The waiting time may be determined in advance according to the amount of flux dispersed. After that, the processing of the welding device 100 returns to S904 and the processing is repeated.

[0062] In S908, the welding device 100 judges whether the tip of the welding torch 4 is at a predetermined position. The welding torch 4 oscillates along the X-axis direction. As described with reference to FIG. 6A and FIG. 6B, the accuracy of identifying the center of gravity of the molten slag bath 7 changes depending on the position of the welding torch 4. In this embodiment, the predetermined position is the tip of the welding torch 4 located on the near side so that the accuracy of identifying the center of gravity is higher. The predetermined position may be the tip of the welding torch 4 located closest to the near side within the movable range. The predetermined position may be defined as a range, and for example, the tip of the welding torch 4 may be judged to be at the predetermined position when it is located at a certain ratio or more on the near side within the movable range in the X-axis direction. If it is judged that the tip of the welding torch 4 is at the predetermined position (YES in S908), the processing of the welding device 100 proceeds to S910. On the other hand, if the tip of welding torch 4 is not in the predetermined position (NO in S908), the process of welding device 100 proceeds to S909.

[0063] In S909, welding device 100 waits for a predetermined time. The wait time here may be determined based on, for example, the oscillation period of welding torch 4. Thereafter, the process of welding device 100 returns to S904, and the process is repeated.

[0064] In S910, the welding device 100 extracts an area corresponding to the molten slag bath 7 from the captured image. In this embodiment, an area such as the area Rt shown in FIG. 5C is extracted. In this embodiment, the image is subjected to Gaussian blurring, binarization based on brightness, and filling in areas other than the area with the highest brightness in this order, thereby extracting the area. These processes are well known, and therefore will not be described in detail here. The coordinates of the area in the image may also be extracted.

[0065] In S911, the welding device 100 identifies the position of the center of gravity based on the region corresponding to the molten slag bath 7 extracted in S910. In this embodiment, the coordinates of the point Cb indicating the position of the center of gravity of the region as shown in FIG. 5C are identified. As described above, the position of the center of gravity may be calculated within a predetermined range for the entire region corresponding to the molten slag bath 7. In this embodiment, the position of the center of gravity is calculated by focusing on the inner half of the entire region corresponding to the molten slag bath 7. The method of calculating the position of the center of gravity in the region corresponding to the molten slag bath 7 may use a known calculation formula and is not particularly limited.

[0066] In S912, the welding device 100 adjusts the left-right position of the tip of the welding torch 4 based on the deviation in the Y-axis direction, i.e., the left-right direction, between the center of gravity of the molten slag bath 7 identified in S911 and the tip position of the welding torch 4. Specifically, as described with reference to Fig. 8, the adjustment is performed when the deviation in the left-right direction between the center of gravity of the molten slag bath 7 identified in S911 and the tip position of the welding torch 4 becomes equal to or greater than a predetermined threshold value. At this time, the tip position of the welding torch 4 may be identified from the captured image, the installation angle, the oscillation period, etc.

[0067] In S913, welding device 100 determines whether welding is complete. Whether welding is complete may be determined based on an instruction from a user, or may be determined based on welding device 100 having moved upward by a predetermined distance. If it is determined that welding is complete (YES in S913), this process flow ends. On the other hand, if it is determined that welding is not complete (NO in S913), the process of welding device 100 returns to S904, and the process is repeated.

[0068] As described above, this embodiment makes it possible to suppress the influence of the installation accuracy of the device in electroslag welding and improve the convenience of the user. In particular, with a relatively simple configuration, it is possible to achieve highly accurate vertical welding while automatically correcting the error in rail installation. Furthermore, it is possible to perform vertical welding corresponding to various groove shapes.

[0069] In addition, the effect of flux dispersion can be taken into consideration and errors in automatic rail installation can be accurately corrected. Also, the occurrence of an open arc can be detected and the effect of the open arc can be taken into consideration and errors in automatic rail installation can be accurately corrected. Furthermore, because of the simple configuration, it is possible to prevent breakdowns in the welding equipment and reduce costs.

[0070] <Other embodiments> In the above embodiment, an example of adjusting the tip position of the welding torch 4 and the position of the welding sliding copper backing in the left-right direction has been shown. However, this is not limited to this, and a configuration may be used in which the tip position of the welding torch 4 is adjusted in the depth direction, i.e., in the X-axis direction. With such a configuration, for example, the reference position of the oscillation operation can be adjusted, and the oscillation operation can be performed with higher accuracy.

[0071] In the above embodiment, an example in which one image capturing device 18 is used is shown, but the present invention is not limited to this. A configuration in which multiple image capturing devices are used to reduce blind spots caused by the welding torch 4 and to detect the area of ​​the molten slag bath 7 with higher accuracy may be used.

[0072] In the above embodiment, the image is taken from directly above the top surface of the molten slag bath 7, but the present invention is not limited to this. For example, the image of the molten slag bath 7 may be taken from the front side where the welding sliding copper pad 13 is placed. With this configuration, it is possible to determine the height of the top surface of the molten slag bath relative to the welding sliding copper pad 13. By using this to determine whether or not flux scattering is required, it is possible to improve the accuracy of the determination.

[0073] In the above example, the image processing includes blurring, binarization, and area detection, but is not limited thereto. For example, as shown in Fig. 3A to Fig. 3C, when the shape of the groove of the welding target can be specified in advance, the area may be extracted by pattern matching between the area in the image and the groove shape. In addition, the area may be detected using a trained model generated by a well-known machine learning method.

[0074] In this specification, the terms "first" and "second" are used merely to distinguish from other elements, and are not intended to be interpreted as being limited to specific components. Therefore, these terms may be interpreted appropriately depending on the configuration to which the present invention is applied.

[0075] In the present invention, a program or application for realizing the functions of one or more of the above-mentioned embodiments can be supplied to a system or device via a network or a storage medium, etc., and one or more processors in a computer of the system or device can read and execute the program.

[0076] Alternatively, the function may be realized by a circuit that realizes one or more functions, such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0077] As described above, the present specification discloses the following: (1) a welding torch (e.g., 4) for performing electroslag welding; A photographing device (e.g., 18) arranged so as to be able to photograph a molten slag bath (e.g., 7) in a groove (e.g., G) made of a base material (e.g., 3); A means for identifying the area of ​​the molten slag bath from the image captured by the photographing device (e.g., 15, 202, 203); An adjustment means (e.g., 15, 204) that adjusts the tip position of the welding torch in the first direction based on a difference in a first direction (e.g., Y-axis direction) between the position of the region identified by the identification means (e.g., Cb) and the tip position of the welding torch in the groove (e.g., Ct); An electroslag welding apparatus (e.g., 100) having According to this configuration, it is possible to suppress the influence of the installation accuracy of the device in electroslag welding and improve the convenience for users. In particular, with a relatively simple configuration, it is possible to realize highly accurate vertical welding while automatically correcting the error of the rail installation. Furthermore, it is possible to realize vertical welding corresponding to various groove shapes.

[0078] (2) A sliding plate (e.g., 13) is provided so as to be slidable relative to the base material; The electroslag welding apparatus according to (1), wherein the adjustment means further adjusts the position of the sliding plate in the first direction based on the position of the area identified by the identification means. According to this configuration, it is possible to suppress the influence of the installation accuracy of the device and improve the convenience for the user. In particular, it is possible to adjust the position of the sliding plate in accordance with the position of the groove.

[0079] (3) the welding torch oscillates along a second direction (e.g., an X-axis direction) perpendicular to the first direction; The electroslag welding apparatus according to claim 1 or 2, wherein the identification means identifies the area of ​​the molten slag bath using an image obtained when the tip of the welding torch is in a predetermined position (the front side in the X-axis direction) during the oscillating operation. According to this configuration, the area of ​​the welding slag bath can be detected with high accuracy, and the accuracy of position correction can be improved.

[0080] (4) The electroslag welding apparatus described in (3), wherein the adjustment means adjusts the tip position of the welding torch in the first direction based on the difference in the first direction between the center of gravity position (e.g., Cb) of a predetermined range on the side away from the welding torch in the second direction within the identified area of ​​the molten slag bath and the tip position (e.g., Ct) of the welding torch. According to this configuration, for example, even if misalignment in the left-right direction occurs when installing the rail, it is possible to adjust the position in the left-right direction with high precision.

[0081] (5) The electroslag welding apparatus according to (3) or (4), wherein the adjustment means further adjusts the tip position of the welding torch in the second direction based on the position of the area identified by the identification means and the tip position of the welding torch within the groove. According to this configuration, for example, it is possible to adjust the position in the direction in which the oscillation operation is performed. In addition, it is possible to reduce the workload of the user in relation to the oscillation operation, and further to reduce dependency on the user's skill.

[0082] (6) A flux dispersion control means (e.g., 14) for controlling dispersion of flux (e.g., 12) to the groove, The electroslag welding apparatus according to any one of (1) to (6), wherein the identification means identifies the area of ​​the molten slag bath using an image taken a predetermined time after flux has been sprayed onto the groove. According to this configuration, it is possible to suppress the influence of scattering of flux and perform position adjustment with high accuracy.

[0083] (7) The identification means identifies that the molten slag bath is insufficient (e.g., an open arc) when an area consisting of pixels having blue and green components having values ​​equal to or greater than a predetermined threshold exists in the image acquired by the photographing device, The electroslag welding apparatus according to claim 6, wherein the flux dispersion control means disperses the flux in response to a shortage of the molten slag bath. According to this configuration, it is possible to detect an open arc and to spray flux in response to the open arc.

[0084] (8) An electroslag welding apparatus as described in (7) having an output means (e.g., 19) for notifying the user of a shortage of the molten slag bath when the shortage is identified. This configuration makes it possible to detect an open arc and to notify the same.

[0085] (9) An acquisition process (e.g., S902) for acquiring an image of a molten slag bath (e.g., 7) in a groove (e.g., G) made of a base material (e.g., 3) by an image acquisition device (e.g., 18) arranged so as to be able to capture the image; A step of identifying an area of ​​the molten slag bath from the image (e.g., S910, S911); An adjustment process (e.g., S912) of adjusting the tip position of the welding torch in the first direction based on a difference in a first direction (e.g., Y-axis direction) between the position (e.g., Cb) of the region identified in the identification process and the tip position (e.g., Ct) of the welding torch (e.g., 4) in the groove; A method for controlling an electroslag welding apparatus (e.g., 100) having the above structure. According to this configuration, it is possible to suppress the influence of the installation accuracy of the device in electroslag welding and improve the convenience for users. In particular, with a relatively simple configuration, it is possible to realize highly accurate vertical welding while automatically correcting the error of the rail installation. Furthermore, it is possible to realize vertical welding corresponding to various groove shapes.

[0086] (10) A computer (e.g., 15), An acquisition process (e.g., S920) for acquiring an image captured by an imaging device (e.g., 18) arranged so as to be able to capture an image of a molten slag bath (e.g., 7) in a groove (e.g., G) made of a base material (e.g., 3); A step of identifying an area of ​​the molten slag bath from the image (e.g., S910, S911); An adjustment process (e.g., S912) of adjusting the tip position of the welding torch in the first direction based on a difference in a first direction (e.g., Y-axis direction) between the position (e.g., Cb) of the region identified in the identification process and the tip position (e.g., Ct) of the welding torch (e.g., 4) in the groove; A program for executing the above. According to this configuration, it is possible to suppress the influence of the installation accuracy of the device in electroslag welding and improve the convenience for users. In particular, with a relatively simple configuration, it is possible to realize highly accurate vertical welding while automatically correcting the error of the rail installation. Furthermore, it is possible to realize vertical welding corresponding to various groove shapes. [Explanation of symbols]

[0087] 1…Copper backing 3…Base material 4. Welding torch 5…Contact tip 6…Welding wire 7…Molten slag bath 8…Welding current 9…Molten metal 10…Weld metal 11...Solidified slag 12. Flux 13...Welding sliding copper pad (copper pad) 14…Flux supply device 15...Welding control device 16...Traveling cart 17...Traveling vehicle control device 18...Photographic equipment 19...Display device 100...Welding equipment (electroslag welding equipment)

Claims

1. a welding torch for performing electroslag welding; A photographing device arranged so as to be able to photograph the molten slag bath in the groove made of the base material; A means for identifying an area of ​​the molten slag bath from the image captured by the imaging device; An adjustment means for adjusting a tip position of the welding torch in the first direction based on a difference in a first direction between a position of the region identified by the identification means and a tip position of the welding torch in the groove; Electroslag welding apparatus having

2. A sliding plate is provided so as to be slidable relative to the base material, 2. The electroslag welding apparatus according to claim 1, wherein the adjusting means further adjusts a position of the sliding plate in the first direction based on a position of the area identified by the identifying means.

3. the welding torch oscillates along a second direction perpendicular to the first direction; 2. The electroslag welding apparatus according to claim 1, wherein the identifying means identifies the region of the molten slag bath using an image obtained when the tip of the welding torch is in a predetermined position during the oscillating operation.

4. 4. The electroslag welding apparatus according to claim 3, wherein the adjustment means adjusts the tip position of the welding torch in the first direction based on a difference in the first direction between a center of gravity position of a predetermined range on a side away from the welding torch in the second direction in the identified region of the molten slag bath and a tip position of the welding torch.

5. 4. The electroslag welding apparatus according to claim 3, wherein the adjusting means further adjusts a tip position of the welding torch in the second direction based on a position of the area identified by the identifying means and a tip position of the welding torch within the groove.

6. A flux dispersion control means for controlling dispersion of flux to the groove is provided, 2. The electroslag welding apparatus according to claim 1, wherein the identifying means identifies the region of the molten slag bath by using an image taken a predetermined time after flux has been sprayed onto the groove.

7. The identification means identifies that the molten slag bath is insufficient when an area composed of pixels having blue and green components having values ​​equal to or greater than a predetermined threshold value exists in the image acquired by the photographing device, 7. The electroslag welding apparatus according to claim 6, wherein the flux dispersion control means distributes the flux in response to a shortage of the molten slag bath.

8. 8. An electroslag welding apparatus according to claim 7, further comprising an output means for notifying the user of a shortage of the molten slag bath when the shortage is identified.

9. An acquisition step of acquiring an image captured by an image capturing device arranged so as to be able to capture an image of the molten slag bath in the groove formed of the base material; identifying an area of ​​the molten slag bath from the image; an adjustment process of adjusting a tip position of the welding torch in the first direction based on a difference in a first direction between the position of the region identified in the identification process and a tip position of the welding torch in the groove; A method for controlling an electroslag welding apparatus comprising:

10. On the computer, An acquisition step of acquiring an image captured by an image capturing device arranged so as to be able to capture an image of the molten slag bath in the groove formed of the base material; identifying an area of ​​the molten slag bath from the image; an adjustment process of adjusting a tip position of the welding torch in the first direction based on a difference in a first direction between the position of the region identified in the identification process and a tip position of the welding torch in the groove; A program for executing.

Images