JP6974950B2 - Welding equipment, welding methods and programs - Google Patents

Description

The present invention relates to welding equipment, welding methods and programs.

Several techniques have been proposed in connection with automatic welding equipment.
For example, in the technique of Patent Document 1, the automatic welding apparatus captures an image of a welded portion and obtains the position of a molten pool based on the difference in brightness of the image. In this automatic welding device, the difference between the left end position of the molten pool in the groove and the left end position of the molten pool in the groove surface layer, and the right end position of the molten pool in the groove and the melting in the groove surface layer. Based on the difference from the right end position of the pond, the tip position of the welding wire in the left-right direction is adjusted to control the welding line tracing in the groove surface layer portion.

Japanese Patent No. 3408749

According to the technique described in Patent Document 1, it is possible to perform welding with high accuracy by copying a welding line with an automatic welding apparatus using a consumable electrode.
On the other hand, in the automatic welding apparatus using the non-consumable electrode, the control becomes more complicated in that the electrode and the welding wire are separately provided.

The present invention provides a welding device, a welding method and a program capable of performing welding in an automatic welding device using a non-consumable electrode with higher accuracy.

According to the first aspect of the present invention, the welding apparatus includes a photographing unit for photographing an electrode and a welding wire installed toward a welding portion of an object to be welded, and a tip of the electrode in an image taken by the photographing unit. At the electrode tip position, which is the position, the groove position, which is the groove position in the captured image, the wire tip position, which is the tip position of the welding wire in the captured image, and the tip position of the molten pool in the captured image. The position of the tip of a certain molten pool is detected, and among the predetermined areas with respect to the position of the tip of the wire in the captured image, the entire area where the brightness is equal to or less than the predetermined brightness threshold is covered by two horizontal sides and two in the vertical direction. The position of the welded portion based on the image processing unit that detects the size of the outer rectangle, which is the smallest of the rectangles surrounded by the sides, as the size of the droplet, the electrode tip position, and the groove position. A first control unit that controls the left and right positions of the electrode with respect to the welded portion, and a second control unit that controls the left and right positions of the welded wire with respect to the position of the welded portion based on the position of the tip of the electrode and the position of the tip of the wire. and parts, the molten pool tip position, and, on the basis of the wire tip position, have a row position control of the welding wire, the droplet at the tip of the welding wire based on the detection result of the size of the droplet A third control unit for moving the welding wire downward when the presence or absence is determined and the presence or absence of droplets is determined is provided.

Based on the electrode tip position and the groove position, the first control unit controls the left and right positions of the electrode so that the electrode is located at the center in the width direction of the groove. You may.
The second control unit is located at the left and right positions of the welded wire so that the tip position of the wire in the left-right direction of the captured image is aligned with the position of the electrode based on the position of the tip of the electrode and the position of the tip of the wire. Control may be performed.
The third control unit may control the vertical position of the welded wire so as to keep the difference in the vertical relative position between the molten pool tip position and the wire tip position constant.
The third control unit sets a position above the tip position of the molten pool by a predetermined distance in the captured image as the target position, and controls the upper and lower positions of the weld wire so that the tip position of the wire approaches the target position. May be done .

The welding device may be provided with a bandpass filter that suppresses the luminance value of the captured image of the photographing unit.
The image processing unit detects the position of the tip of the molten pool based on the captured image to which the bandpass filter is not applied, and the electrode tip is based on the captured image to which the bandpass filter is applied. The position, the wire tip position, and the groove position may be detected.

The photographing unit may capture a plurality of the captured images at different shutter speeds.
The image processing unit detects the position of the tip of the molten pool based on the captured image captured at the first shutter speed, and the image captured at the second shutter speed, which is slower than the first shutter speed. The electrode tip position, the wire tip position, and the groove position may be detected based on the image.
The photographing unit may acquire a plurality of the photographed images at different timings of the arc currents.
The photographing unit detects the position of the tip of the molten pool based on the captured image captured at the timing of the peak current of the arc current, and is based on the captured image captured at the timing of the base current of the arc current. The electrode tip position, the wire tip position, and the groove position may be detected.
The welding device further includes a control unit for determining whether or not the luminance value of the captured image is equal to or higher than a predetermined threshold value, and the image processing unit includes the captured image determined to have a luminance value equal to or higher than the threshold value. The electrode tip position, the wire tip position, and the wire tip position, based on the dark image which is the captured image obtained by detecting the molten pool tip position based on a certain bright image and determining that the luminance value is less than the threshold value. , The groove position may be detected.
The image processing unit detects two diagonal lines as straight lines of the contour of the tip of the electrode from the contour obtained by edge extraction with respect to the captured image, and the intersection of the detected two diagonal lines is the position of the tip of the electrode. It may be detected as.
The image processing unit has a luminance value in the horizontal profile based on a horizontal profile showing a horizontal luminance value of the captured image at a position shifted downward by a predetermined distance from the electrode tip position in the captured image. A position lower than a predetermined threshold value may be detected as the groove position.
The image processing unit may detect a region of white pixels from the image obtained by binarizing the captured image, and may detect the uppermost portion of the detected region as the wire tip position.
The image processing unit may apply a min filter to the captured image and further binarize the image to which the max filter is applied.
The image processing unit counts the number of white pixels for each vertical pixel line of the image obtained by binarizing the captured image, and detects and detects a range in which the number of white pixels in the vertical direction is equal to or greater than a predetermined value. The area may be scanned horizontally to detect the area of the white pixel.
The image processing unit detects the luminance boundary in the image obtained by binarizing the captured image as the contour line of the molten pool, and scans downward from a position advanced by a predetermined distance to the left and right from the wire tip position. , The point where the contour line of the molten pool is reached may be detected as the position of the tip of the molten pool .

According to the second aspect of the present invention, in the welding method, the electrode tip position, which is the tip position of the electrode in the photographed image of the electrode and the welding wire installed toward the welding point of the object to be welded, and the photographed. The groove position, which is the groove position in the image, the wire tip position, which is the tip position of the welding wire in the captured image, and the molten pool tip position, which is the tip position of the molten pool in the captured image, are detected. Of the predetermined region based on the wire tip position in the captured image, the smallest rectangle among the rectangles surrounding the entire region whose brightness is equal to or less than the predetermined brightness threshold with two horizontal sides and two vertical sides. The size of the outer rectangle, which is Based on the position and the position of the tip of the wire, the left and right positions of the weld wire are controlled with respect to the position of the weld, and the position of the weld wire is controlled based on the position of the tip of the molten pool and the position of the tip of the wire. controls had lines, based on the detection result of the size of the droplet to determine the presence or absence of droplet at the tip of the welding wire, when it is determined that there droplet, including processing for moving the welding wire downward ..

According to the third aspect of the present invention, the program causes the computer to control the photographing unit to photograph the electrode and the welding wire installed toward the welding portion of the object to be welded, and the photographing unit of the photographing unit. The electrode tip position, which is the tip position of the electrode in the captured image, the groove position, which is the groove position in the captured image, the wire tip position, which is the tip position of the welding wire in the captured image, and the captured image. The position of the tip of the molten pool, which is the position of the tip of the molten pool in The size of the outer rectangle, which is the smallest of the rectangles surrounded by the two sides and the two sides in the vertical direction, is detected as the size of the droplet , and the welding is performed based on the electrode tip position and the groove position. The left and right positions of the electrode are controlled with respect to the position of the welded portion, and the left and right positions of the welded wire are controlled with respect to the position of the welded portion based on the position of the tip of the electrode and the position of the tip of the wire, and the melting is performed. The position of the welding wire is controlled based on the position of the tip of the pond and the position of the tip of the wire, and the presence or absence of droplets at the tip of the welding wire is determined based on the detection result of the size of the droplet. If it is judged droplet, Ru to perform the control for moving the welding wire downwards, a program for.

According to the above-mentioned welding apparatus, welding method and program, welding in an automatic welding apparatus using non-consumable electrodes can be performed with higher accuracy.

It is a schematic block diagram which shows the functional structure of the welding apparatus which concerns on embodiment of this invention. It is a perspective view which shows the structural example of the main body part which concerns on the same embodiment. It is a figure which shows the example of the image taken by the photographing part which concerns on the same embodiment. It is a schematic block diagram which shows the functional structure of the welding control apparatus which concerns on the same embodiment. It is a figure which shows the example of the image which the photographing part which concerns on the same embodiment took an image at a relatively slow shutter speed. It is a figure which shows the example of the image which the photographing part which concerns on the same embodiment took an image with a relatively fast shutter speed. It is a figure which shows the example of the image which the photographing part took at the timing of the arc current | base current in the same embodiment. It is a figure which shows the example of the image which the photographing part which concerns on the same embodiment took an image using a bandpass filter. It is a flowchart which shows the example of the processing procedure which welds the welding object by the welding apparatus which concerns on the same embodiment. It is a flowchart which shows the example of the processing procedure which the welding apparatus which concerns on the same embodiment photographed the vicinity of the welding part and detects the position of each part. It is a flowchart which shows the example of the processing procedure which performs the position control of each part by the welding apparatus which concerns on the same embodiment. It is a figure which shows the example of the processing procedure which the image processing part which concerns on the same embodiment detects the electrode tip position. It is a figure which shows the example of the straight line detected by the image processing unit which concerns on the same embodiment. It is a figure which shows the example of the processing procedure which the image processing part which concerns on the same embodiment detects a groove position. It is a figure which shows the example of the position set by the image processing unit which concerns on the same embodiment. It is a graph which shows the example of the horizontal profile which concerns on the same embodiment. It is a figure which shows the example of the processing procedure which the image processing part which concerns on the same embodiment detects the wire tip position. It is a figure which shows the example of the region extracted by the image processing part which concerns on the same embodiment. It is a figure which shows the example of the processing procedure which the image processing part which concerns on the same embodiment detects a molten pool. It is a figure which shows the example of the luminance boundary detected by the image processing unit which concerns on the same embodiment. It is a figure which shows the example of the processing procedure which the image processing part which concerns on the same embodiment detects a droplet. It is a figure which shows the example of the region detected by the image processing unit which concerns on the same embodiment.

Hereinafter, embodiments of the present invention will be described, but the following embodiments do not limit the invention according to the claims. Also, not all combinations of features described in the embodiments are essential to the means of solving the invention.
FIG. 1 is a schematic block diagram showing a functional configuration of a welding apparatus according to an embodiment of the present invention. As shown in FIG. 1, the welding device 1 includes a main body 100 and a welding control device 200.

The welding device 1 arc-welds a welding target such as a steel plate. Specifically, the main body 100 executes arc welding under the control of the welding control device 200.
FIG. 2 is a perspective view showing a configuration example of the main body 100. FIG. 2 shows the configuration of the main body 100 in the vicinity of the welded portion.
In the example shown in FIG. 2, the main body 100 includes an electrode 110, a wire feeding mechanism 120, and a photographing unit 130. Further, a bandpass filter 131 that passes only infrared rays is attached to the lens group of the photographing unit 130.
Further, FIG. 2 shows the definition of the direction in three-dimensional Cartesian coordinates. As shown in FIG. 2, the longitudinal direction of the gap of the welding object 900 in the horizontal direction is referred to as a front-rear direction. Of the horizontal directions, the width direction (direction orthogonal to the longitudinal direction) of the gap of the welding object 900 is referred to as a left-right direction. The vertical direction is called the vertical direction.

A welding wire 800 is set in the wire feeding mechanism 120, and the tip portion of the welding wire 800 is melted by an arc discharge from the electrode 110. The liquid phase metal in which the welding wire 800 is melted forms a molten pool in the gap between the two steel plates which are the objects to be welded 900. When the metal in this liquid phase cools and solidifies, the object to be welded 900 is welded.
The electrode 110 and the wire feeding mechanism 120 move relative to each other along the gap of the object to be welded 900, so that the entire gap of the object to be welded 900 is welded. The electrode 110 and the wire feeding mechanism 120 may be moved, or the object to be welded 900 may be moved.

The photographing unit 130 photographs the vicinity of the welded portion. The image captured by the photographing unit 130 is used to detect the position of each unit. In the example of FIG. 2, in the example of FIG. 2, the photographing unit 130 is installed at a position where the electrode 110 and the welding wire 800 are viewed from diagonally above in order to capture the object of the position control on the same image.
Hereinafter, the image taken by the photographing unit 130 is also referred to as a photographed image of the photographing unit 130.

FIG. 3 is a diagram showing an example of an image taken by the photographing unit 130. In the example of FIG. 3, the electrode 110, the welding wire 800, the molten pool 810, and the groove of the welding object 900 are photographed. The groove referred to here is the boundary between the welding object 900 and the gap. As in the example of FIG. 3, the photographing unit 130 photographs the electrode 110 and the welding wire 800 installed toward the welding portion of the welding object 900.

The welding control device 200 detects the electrode tip position P11, the wire tip position P12, the groove position P13, and the molten pool tip position P14 in the image taken by the photographing unit 130. The groove position P13 is a predetermined position of the groove of the welding object 900, which is determined by a position relative to the electrode 110.
The molten pool tip position P14 is the position of the tip portion of the molten pool 810. In the example of FIG. 3, the electrode 110 and the welding wire 800 move relative to the lower side of the figure with respect to the object to be welded 900. Therefore, P14, which is the position of the lower end of the molten pool 810, is the position of the tip of the molten pool.
The relative positions of the electrode 110 and the wire feeding mechanism 120 with respect to the photographing unit 130 are fixed, and in the image photographed by the photographing unit 130, the image of the welding object 900 moves to the upper side of the image.

FIG. 4 is a schematic block diagram showing a functional configuration of the welding control device 200. As shown in FIG. 4, the welding control device 200 includes a communication unit 210, an operation input unit 220, a display unit 230, a storage unit 280, and a control unit 290. The control unit 290 includes an imaging control unit 291, an image processing unit 292, a first control unit 293, a second control unit 294, a third control unit 295, and a welding control unit 296.

The communication unit 210 communicates with other devices. In particular, the communication unit 210 receives the image captured by the photographing unit 130 as image data. Further, the communication unit 210 transmits a control signal to each unit of the main body unit 100.
The operation input unit 220 includes an input device such as a keyboard and a mouse or an operation panel, and receives user operations.
The display unit 230 includes, for example, a display screen such as a liquid crystal panel or a display device such as a display panel, and displays various information.

The storage unit 280 is configured by using a storage device included in the welding control device 200, and stores various information.
The control unit 290 controls each unit of the welding control device 200 to execute various functions. The control unit 290 is configured by, for example, a CPU (Central Processing Unit) included in the welding control device 200 reading a program from the storage unit 280 and executing the program.

The shooting control unit 291 controls the shooting unit 130 to perform shooting.
In particular, the shooting control unit 291 controls the shooting unit 130 to shoot a plurality of images at different shutter speeds.
FIG. 5 is a diagram showing an example of an image taken by the photographing unit 130 at a relatively slow shutter speed. When the photographing unit 130 takes a picture at a relatively slow shutter speed, the image becomes bright as shown in the example of FIG. This makes it easier for the welding control device 200 to detect the molten pool tip position P14.

FIG. 6 is a diagram showing an example of an image taken by the photographing unit 130 at a relatively high shutter speed. When the photographing unit 130 takes a picture at a relatively high shutter speed, the image is relatively less affected by the arc light as shown in the example of FIG. This makes it easier for the welding control device 200 to detect the electrode tip position P11, the wire tip position P12, and the groove position P13.

The shooting control unit 291 may control the shooting timing of the shooting unit 130 in relation to the arc current in addition to or instead of controlling the shutter speed.
When the photographing unit 130 takes an image at the timing when the arc current is the peak current, the image becomes relatively bright due to the arc light as shown in the example of FIG.

FIG. 7 is a diagram showing an example of an image taken by the photographing unit 130 at the timing when the arc current is the base current. When the photographing unit 130 takes an image at the timing when the arc current is the base current, the image is relatively less affected by the arc light as shown in the example of FIG. 7.
As in the case of the shutter speed, the welding control device 200 may use different images based on the shooting timing. Specifically, the welding control device 200 detects the molten pool tip position P14 in the image taken at the timing of the peak current of the arc current, and the electrode tip position P11 in the image taken at the timing of the arc current at the base current. , The wire tip position P12 and the groove position P13 may be detected.

Further, as in the example of FIG. 2, a bandpass filter 131 is attached to the lens group of the photographing unit 130. The photographing unit 130 may be fixed in a state where the bandpass filter 131 is attached. Alternatively, the bandpass filter 131 may be removable. When the photographing unit 130 performs imaging, the photographing control unit 291 may switch whether or not the bandpass filter 131 is applied.

FIG. 8 is a diagram showing an example of an image taken by the photographing unit 130 using the bandpass filter 131. FIG. 8A shows an example of an image when the bandpass filter 131 is not applied. FIG. 8B shows an example of an image when a bandpass filter is applied. FIG. 8B shows an example of an image taken by the photographing unit 130 by applying the bandpass filter 131 at the timing when the arc current peaks and at a relatively slow shutter speed.
When the photographing unit 130 shoots at the timing when the arc current peaks and at a relatively slow shutter speed, the influence of the arc light is affected as in the example of FIG. 8A unless the bandpass filter 131 is applied. The image becomes brighter.
On the other hand, when the photographing unit 130 takes an image using the bandpass filter 131, the reflection of the arc light is suppressed as in the example of FIG. 8, and the position of each part described in the welded portion can be easily detected.

As in the case of the shutter speed, the welding control device 200 may use the image properly based on whether or not the bandpass filter 131 is applied. Specifically, the welding control device 200 detects the molten pool tip position P14 in the image to which the bandpass filter 131 is not applied, and the electrode tip position P11 and the wire tip position in the image to which the bandpass filter 131 is applied. The P12 and the groove position P13 may be detected.
The image processing unit 292 performs image processing on the image captured by the photographing unit 130. In particular, the image processing unit 292 performs image processing for detecting the electrode tip position P11, the wire tip position P12, the groove position P13, and the molten pool tip position P14 from the image taken by the photographing unit 130.

The first control unit 293 controls the left and right positions of the electrode 110 with respect to the position of the welded portion based on the photographed image of the photographing unit 130. Specifically, the first control unit 293 is an electrode so that the electrode 110 is located at the center of the left and right grooves based on the electrode tip position P11 and the groove position P13 shown in the captured image of the photographing unit 130. The left and right positions of 110 are controlled.

The second control unit 294 controls the left and right positions of the welding wire 800 with respect to the position of the welded portion based on the captured image of the photographing unit 130. Specifically, the second control unit 294 welds the wire tip position P12 to the electrode 110 in the left-right direction of the image based on the electrode 110 and the wire tip position P12 shown in the captured image of the photographing unit 130. The left and right positions of the wire 800 are controlled.

The third control unit 295 controls the position of the welding wire 800 based on the melting state of the welding wire 800 determined from the image taken by the photographing unit 130. In particular, the third control unit 295 controls the vertical position of the welding wire 800 based on the state of the tip portion of the welding wire 800.
Here, in an automatic welding apparatus using a non-consumable electrode, it is necessary to control the position of the welding wire 800 in the vertical direction in addition to controlling the position of the welding wire 800 in the left-right direction.

For example, when the tip of the welding wire 800 is lifted upward due to the warping habit of the welding wire 800 and the tip of the welding wire 800 is melted by arc heat before being inserted into the molten pool 810, the metal of the liquid phase in which the welding wire 800 is melted is a ball. After the shape is formed, it falls into the molten pool 810. In this case, the ball-shaped liquid metal is called a droplet.
If the tip of the welding wire 800 is further lifted, the welding wire 800 may not be completely melted and may collide with the electrode 110. When the welding wire 800 collides with the electrode 110, the electrode 110 and the welding wire 800 are short-circuited and the arc discharge is interrupted. Further, the welding wire 800 may collide with the electrode 110, which may damage the electrode 110.

In order to prevent the welding wire 800 from colliding with the electrode 110, it is required to move the welding wire 800 downward in a state where droplets are generated.
On the other hand, if the welding wire 800 is displaced too downward with respect to the center of the molten pool, the welding wire 800 is too far from the arc heat source, resulting in insufficient melting and causing poor melting.
Therefore, the third control unit 295 controls the position of the tip of the welding wire 800 in the vertical direction so as to keep the position of the tip of the welding wire 800 at an appropriate position with respect to the tip P14 of the molten pool. The third control unit 295 controls the welding wire 800 in the vertical direction so as to keep the difference between the average position of the molten pool tip position P14 and the wire tip position P12 in the vertical direction constant. The third control unit 295 moves the welding wire 800 upward when the difference in relative positions is small, and moves the welding wire 800 downward when the difference in relative positions is large.
The appropriate position of the tip of the welding wire 800 is a position moved downward by a predetermined distance from the position of the tip of the electrode 110 in the captured image of the photographing unit 130. This position in the captured image may be set as the target position, and the third control unit 295 may control the position of the tip of the welding wire 800 in the captured image to be closer to the target position.

The welding control device 200 detects the electrode tip position P11, the wire tip position P12, the groove position P13, and the molten pool tip position P14 in the image taken by the photographing unit 130. The groove position P13 is a predetermined position of the groove of the welding object 900, which is determined by a position relative to the electrode 110.
The molten pool tip position P14 is the position of the tip portion of the molten pool 810. In the example of FIG. 3, the electrode 110 and the welding wire 800 move relative to the lower side of the figure with respect to the object to be welded 900. Therefore, P14, which is the position of the lower end of the molten pool 810, is the position of the tip of the molten pool.

The target position of the tip of the welding wire 800 in the captured image may be determined based on the position of the tip of the molten pool. As shown in FIG. 2, when the imaging unit 130 photographs the vicinity of the welded portion from diagonally above and the tip of the welding wire 800 moves up and down, the distance between the tip of the molten pool and the tip of the welding wire 800 in the captured image changes. .. For example, in the image of FIG. 3, the lower the position of the tip of the welding wire 800, the smaller the distance between the wire tip position P12 and the molten pool tip position P14. Further, the higher the position of the tip of the welding wire 800, the larger the distance between the wire tip position P12 and the molten pool tip position P14. Therefore, the third control unit 295 sets a position above the molten pool tip position P14 by a predetermined distance as the target position in the captured image, and the tip of the welding wire 800 is set so that the wire tip position P12 approaches the target position. The position may be controlled in the vertical direction.

The welding control unit 296 controls the main body unit 100 to perform welding. In particular, the welding control unit 296 controls the magnitude of the current flowing through the electrode 110. Further, the welding control unit 296 moves the welding object 900 so that the electrode 110 and the wire feeding mechanism 120 move relative to each other along the gap of the welding object 900. Alternatively, the welding control unit 296 may move the electrode 110 and the wire feeding mechanism 120. Further, the welding control unit 296 controls the wire feeding mechanism 120 to feed the welding wire 800 by the amount of melting of the welding wire 800.

Next, the operation of the welding apparatus 1 will be described with reference to FIGS. 9 to 23.
FIG. 9 is a flowchart showing an example of a processing procedure in which the welding apparatus 1 welds the welding object 900. The welding apparatus 1 starts the process of FIG. 9, for example, when it receives a user operation instructing the start of welding.
In the process of FIG. 9, the photographing unit 130 takes an image under the control of the photography control unit 291 and the image processing unit 292 performs image processing on the photographed image (step S101). The image processing unit 292 performs image processing on the captured image of the photographing unit 130 to detect the electrode tip position P11, the wire tip position P12, the groove position P13, and the molten pool tip position P14.

Then, the first control unit 293, the second control unit 294, and the third control unit 295 position each part based on the detected electrode tip position P11, wire tip position P12, groove position P13, and molten pool tip position P14. Control is performed (step S102). With the position of each part controlled, the main body 100 performs welding under the control of the welding control unit 296.
After that, the control unit 290 determines whether or not a user operation for instructing the end of welding has been performed (step S103).
If it is determined that the user operation for instructing the end of welding has not been performed (step S103: NO), the process returns to step S101.
On the other hand, when it is determined that the user operation for instructing the end of welding has been performed (step S103: YES), the process of FIG. 9 is terminated.

FIG. 10 is a flowchart showing an example of a processing procedure in which the welding apparatus 1 photographs the vicinity of the welded portion and detects the position of each portion. The welding apparatus 1 performs the process of FIG. 10 in step S101 of FIG.
In the process of FIG. 10, the shooting unit 130 changes the shutter speed according to the control of the shooting control unit 291 to perform shooting (step S201). The photographing unit 130 may take one image by one process of step S201, or may take a plurality of images.

Next, the control unit 290 determines the brightness of the image captured by the photographing unit 130 (step S202). For example, the control unit 290 determines whether or not the luminance value of the captured image of the photographing unit 130 (for example, the average value of the luminance values in each pixel) is equal to or higher than a predetermined threshold value.
When it is determined that the image is a dark image (step S202: dark image), the image processing unit 292 detects the electrode tip position P11 (step S211), detects the groove position P13 (step S212), and The wire tip position P12 detection process (step S213) is performed.
The processing order of steps S211, S212, and S213 shown in FIG. 10 is an example, and is not limited to this. Further, the image processing unit 292 may process each of the processes of steps S211, S212, and S123 in parallel or sequentially.

Next, the control unit 290 determines whether or not the processing has been completed for both the dark image path and the bright image path (step S231).
If it is determined that there is a path for which processing has not been completed (step S231: NO), the process returns to step S201.
On the other hand, when it is determined that the processing is completed for both the dark image path and the bright image path (step S231: YES), the processing of FIG. 10 is terminated.

On the other hand, when it is determined in step S202 that the image is a bright image (step S202: bright image), the image processing unit 292 detects droplets (step S221) and detects the tip position P14 of the molten pool (step). S222) is performed. When no droplets are generated, the image processing unit 292 detects the size of the image area of the droplets as 0 × 0 in the vertical direction in step S221 and proceeds to step S222.
The processing order of steps S221 and S222 shown in FIG. 10 is an example, and is not limited to this. Further, the image processing unit 292 may process each of the processes of steps S221 and S222 in parallel or sequentially.
After the processing of steps S221 and S222, the process proceeds to step S231.

The brightness of the image captured by the photographing unit 130 is not limited to the two stages of the dark image and the bright image. The photographing unit 130 may perform photography with three or more levels of brightness. In this case, the image processing unit 292 selects any brightness for each detection target and performs each unit detection processing. For example, the detection target may be predetermined for each brightness of the image. The image processing unit 292 detects the detection target defined in association with the brightness of the image for each image taken by the photographing unit 130.
Further, when the photographing unit 130 captures a plurality of images in one process of step S201, the image processing unit 292 processes the dark image path process and the bright image path process in parallel. It may be processed sequentially.

FIG. 11 is a flowchart showing an example of a processing procedure in which the welding apparatus 1 controls the position of each part. The welding apparatus 1 performs the process of FIG. 11 in step S102 of FIG.
In the process of FIG. 11, the third control unit 295 determines the presence or absence of droplets (step S301). Specifically, the third control unit 295 determines whether or not a droplet is detected in step S221 of FIG.
When it is determined that there is no droplet (step S301: no droplet), the first control unit 293 determines whether or not there is a positional deviation between the electrode 110 and the groove (step S311). Specifically, the first control unit 293 determines whether or not the electrode 110 is located at the center of the left and right grooves based on the electrode tip position P11 and the groove position P13 detected by the image processing unit 292. do.

When it is determined that there is no misalignment (step S311: no misalignment), the second control unit 294 determines whether or not there is a misalignment between the welding wire 800 and the electrode 110 (step S321). Specifically, in the second control unit 294, the electrode tip position P11 and the wire tip position P12 deviate from each other in the left-right direction of the image based on the electrode tip position P11 and the wire tip position P12 detected by the image processing unit 292. Judge whether or not.

When it is determined that there is no misalignment (step S321: no misalignment), the third control unit 295 determines whether or not there is a misalignment between the welding wire 800 and the molten pool 810 (step S331). Specifically, the third control unit 295 determines the wire tip position P12 and the molten pool tip position P14 in the vertical direction of the image based on the wire tip position P12 and the molten pool tip position P14 detected by the image processing unit 292. Determine if the interval is within a predetermined range.
When it is determined that there is no deviation (step S331: NO), the process of FIG. 11 is terminated.

On the other hand, when it is determined in step S301 that there is a droplet (step S301: there is a droplet), the third control unit 295 controls the vertical position of the welding wire 800 (step S302). In the case of step S302, the third control unit 295 moves the wire feeding mechanism 120 downward. For example, the third control unit 295 moves the wire feeding mechanism 120 downward by a predetermined distance according to the welding conditions.
After step S302, the process proceeds to step S311.

On the other hand, when it is determined in step S311 that there is a deviation (step S311: there is a deviation), the first control unit 293 controls the left-right position of the electrode 110 (step S312). Specifically, the first control unit 293 moves the electrode 110 left and right so that the electrode 110 is located at the center of the left and right grooves.
After step S312, the process proceeds to step S321.

On the other hand, when it is determined in step S321 that there is a deviation (step S3211: there is a deviation), the second control unit 294 controls the left-right position of the welding wire 800 (step S322). Specifically, the second control unit 294 moves the wire feeding mechanism 120 left and right so that the tip position of the welding wire 800 coincides with the tip position of the electrode 110 in the left-right direction of the image.
After step S322, the process proceeds to step S331.

On the other hand, when it is determined in step S331 that there is a deviation (step S3311: there is a deviation), the third control unit 295 controls the vertical position of the welding wire 800 (step S332). Specifically, the third control unit 295 moves the welding wire 800 up and down so that the wire tip position P12 and the molten pool tip position P14 are at a predetermined distance in the vertical direction of the image.
After step S332, the process of FIG. 11 is terminated.

The processing procedure of FIG. 11 is an example and is not limited to this. The execution order of steps S301, S311, S321, and S331 is not limited to the order shown in FIG. 11, and may be various orders. Further, the welding control device 200 may sequentially process the processes of steps S301 to S302, the processes of steps S31 to S312, the processes of steps S321 to S322, and the processes of steps S331 to S332 in parallel. It may be processed.

FIG. 12 is a diagram showing an example of a processing procedure in which the image processing unit 292 detects the electrode tip position P11. The image processing unit 292 performs the processing of FIG. 12 in step S211 of FIG.
In the process of FIG. 12, the image processing unit 292 performs edge extraction on the captured image of the photographing unit 130 (step S411). Specifically, the image processing unit 292 applies an edge extraction filter to the image to extract the contour. A known filter can be used as the edge extraction filter in step S411.

Next, the image processing unit 292 binarizes and removes noise from the image obtained in step S411 (step S412). A known algorithm can be used as the binarization algorithm in step S412. A known algorithm can be used as the noise removal algorithm in step S412.
Next, the image processing unit 292 performs linear detection from the image obtained in step S412 (step S413). Specifically, the image processing unit 292 detects an oblique line of the contour of the tip of the electrode 110.

Then, the image processing unit 292 scans the image upward from the intersection of the two diagonal lines obtained in step S413 to detect the electrode tip position P11 (step S414). The image processing unit 292 scans until a pixel whose luminance value is equal to or higher than a predetermined threshold value is detected, and the position of the detected pixel is set as the electrode tip position P11.
After step S414, the process of FIG. 12 is terminated.
As a pre-processing for the processing of FIG. 12, the image processing unit 292 narrows down the processing target area by cutting out the upper half of the image or extracting only the portion of the image whose brightness value is equal to or higher than a predetermined value by masking. You may do it.

FIG. 13 is a diagram showing an example of a straight line detected by the image processing unit 292.
In step S413 of FIG. 12, the image processing unit 292 extracts the line L11 and line L12 is a straight contour of the tip portion of the electrode 110.
In step S414 of FIG. 12, the image processing unit 292 scans the image upward from the point P21 which is the intersection of the line L11 and the line L12, and positions the pixel whose luminance value is equal to or higher than a predetermined threshold value at the electrode tip position P11. Detect as.

FIG. 14 is a diagram showing an example of a processing procedure in which the image processing unit 292 detects the groove position P13. The image processing unit 292 performs the processing of FIG. 14 in step S212 of FIG.
In the process of FIG. 14, the image processing unit 292 determines the position of the lower part of the electrode 110 with respect to the captured image of the photographing unit 130 (step S421). Specifically, the image processing unit 292 sets the horizontal position of the image at a position deviated downward by a predetermined distance from the electrode tip position P11.
FIG. 15 is a diagram showing an example of a position set by the image processing unit 292. In the example of FIG. 15, the image processing unit 292 sets the position indicated by the line L21. The line L21 is a line at a predetermined distance from the electrode tip position P11 and is a line in the horizontal direction of the image.

After step S421 in FIG. 14, the image processing unit 292 acquires the horizontal profile at the set position (step S422). The horizontal profile referred to here is a profile of the brightness value in the horizontal direction of the image.
Then, the image processing unit 292 detects a position where the luminance value in the horizontal profile is lower than a predetermined threshold value as the groove position P13 (step S423).
After step S423, the process of FIG. 14 is terminated.

FIG. 16 is a graph showing an example of a horizontal profile. FIG. 16 shows an example of a horizontal profile at the position of line L12 in FIG. The horizontal axis of the graph of FIG. 16 indicates the horizontal position in the image. The vertical axis shows the brightness value.
In the example of FIG. 16, the horizontal profile is lower than the predetermined threshold value at two points. The image processing unit 292 detects these two locations as the groove position P13.

FIG. 17 is a diagram showing an example of a processing procedure in which the image processing unit 292 detects the wire tip position P12. The image processing unit 292 performs the processing of FIG. 17 in step S213 of FIG.
In the process of FIG. 17, the image processing unit 292 applies the min filter to the captured image of the photographing unit 130, and further applies the max filter (step S431). The min filter is a filter that matches the predetermined pixel region (for example, 3 × 3 pixel region) of interest to have the lowest brightness. The max filter is a filter that matches the predetermined pixel region (for example, 3 × 3 pixel region) of interest with the highest brightness. A known algorithm can be used as an algorithm for applying the min filter and the max filter.
The image processing unit 292 increases the brightness of the image by applying the min filter and the max filter to the image (suppresses the frequency of the image).

Next, the image processing unit 292 binarizes and removes noise from the image obtained in step S431 (step S432). A known algorithm can be used as the binarization algorithm in step S432. A known algorithm can be used as the noise removal algorithm in step S432.

Next, the image processing unit 292 performs horizontal / vertical projection on the image obtained in step S432 (step S433). Specifically, the image processing unit 292 counts the number of white pixels in the binarized image for each pixel line in the vertical direction, and detects a range in which the number of pixels is equal to or greater than a predetermined value. When the vertical range is determined, the image processing unit 292 scans the image in the horizontal direction to detect the range of white pixels in the extracted region. As a result, the image processing unit 292 detects the contour of the white pixel region.

Then, the image processing unit 292 detects the position of the uppermost pixel in the vertical direction of the image in the region of the white pixel obtained in step S433 as the wire tip position P12 (step S434).
After step S434, the process of FIG. 18 is terminated.
Even if the image processing unit 292 cuts out the area below the electrode tip position P11 and the inside of the left and right groove positions P13 as a preprocessing for the processing of FIG. 17, the area to be processed is limited. good.

FIG. 18 is a diagram showing an example of a region extracted by the image processing unit 292.
For example, the image processing unit 292 acquires the binarized image of FIG. 18 in step S432 of FIG. Then, the image processing unit 292 detects the region of the white pixel in the region A11 in step S433. Further, the image processing unit 292 detects the uppermost portion of the white pixel region as the wire tip position P12 in step S434.

FIG. 19 is a diagram showing an example of a processing procedure in which the image processing unit 292 detects a molten pool. The image processing unit 292 performs the processing of FIG. 19 in step S221 of FIG.
In the process of FIG. 19, the image processing unit 292 narrows down the molten pool region in the captured image of the photographing unit 130 (step S441). Specifically, the image processing unit 292 cuts out the inside of the left and right groove positions P13 below the electrode tip position P11.

Next, the image processing unit 292 binarizes and removes noise from the image obtained in step S441 (step S442). A known algorithm can be used as the binarization algorithm in step S442. A known algorithm can be used as the noise removal algorithm in step S442.

Next, the image processing unit 292 detects the luminance boundary in the image binarized in step S442 (step S443). As a result, the image processing unit 292 detects the contour line of the molten pool.
Then, the image processing unit 292 detects the molten pool tip position P14 on the boundary detected in step S443 (step S444). Specifically, the image processing unit 292 starts scanning downward of the image from a position advanced by a distance from the wire tip position P12 to the left and right, and scans until the luminance boundary obtained in step S443 is reached. ..
After step S444, the process of FIG. 19 ends.

FIG. 20 is a diagram showing an example of a luminance boundary detected by the image processing unit 292.
For example, the image processing unit 292 detects the luminance boundary shown by the line L31 in step S443 of FIG. Then, in step S444, the image processing unit 292 scans the image downward from the point P31, and detects the point that reaches the luminance boundary as the molten pool tip position P14. The point P31 is a point indicating a position advanced by a predetermined distance to the left and right from the wire tip position P12.

FIG. 21 is a diagram showing an example of a processing procedure in which the image processing unit 292 detects droplets. The image processing unit 292 performs the processing of FIG. 21 in step S221 of FIG.
In the process of FIG. 21, the image processing unit 292 cuts out a target area for image processing from the captured image of the photographing unit 130 (step S451). Since droplets are generated near the tip of the welding wire 800, the image processing unit 292 cuts out a predetermined range based on the wire tip position P12.

Next, the image processing unit 292 extracts a region having a luminance equal to or less than a predetermined luminance threshold value for detecting droplets from the target region cut out in step S451 (step S452).
Then, the image processing unit 292 binarizes the image and removes noise (step S453). A known algorithm can be used as the binarization algorithm in step S453. Further, the image processing unit 292 removes noise by leaving the largest region among the regions obtained in step S452.

Then, the image processing unit 292 detects the size of the outer rectangle of the region obtained in step S453 as the droplet size (step S454). The outer rectangle referred to here has two horizontal sides and two vertical sides of the image, and is the smallest rectangle among the rectangles surrounding the entire target area.
After step S454, the process of FIG. 21 is terminated.

FIG. 22 is a diagram showing an example of a region detected by the image processing unit 292.
For example, the image processing unit 292 cuts out the region A21 in step S451 of FIG. Then, the image processing unit 292 detects the region A22 of the image of the droplet in step S452. Then, in step S454, the image processing unit 292 detects the size (vertical × horizontal) of the outer rectangular region A23 of the region A22 as the droplet size.

As described above, the photographing unit 130 photographs the electrode 110 and the welding wire 800 installed toward the welding portion of the welding object 900. The first control unit 293 controls the left and right positions of the electrode 110 with respect to the position of the welded portion based on the photographed image of the photographing unit 130. The second control unit 294 controls the left and right positions of the welding wire 800 with respect to the position of the welded portion based on the captured image of the photographing unit 130. The third control unit 295 controls the position of the welding wire 800 based on the melting state of the welding wire 800 determined from the image taken by the photographing unit 130.

In this way, the welding control device 200 controls the positions of the electrodes 110 and the welding wire 800 based on the captured image. As a result, in the welding device 1, welding in an automatic welding device using a non-consumable electrode can be performed with higher accuracy.
Further, the third control unit 295 controls the position of the welding wire 800 based on the melting state of the welding wire 800, so that the welding wire 800 may come too close to the electrode 110 and collide with each other, and the welding wire 800 may collide with the electrode 110. It is possible to reduce the possibility of insufficient melting too far from 110.

Here, in a conventional arc welding device using a non-consumable electrode, the welder can see the relative position of the groove and the electrode with the naked eye or by using a camera, the position where the welding wire is inserted into the molten pool, and the electrode. The relative position with the molten pool is monitored, and if it deviates from the proper position, adjustment work is carried out.
On the other hand, the welding device 1 can automatically adjust these positions by using the captured image of the photographing unit 130, and can save labor of human resources. Further, while the conventional arc welding device requires the skill of a welder for monitoring and adjustment work, the welding device 1 automatically adjusts the welding even if there is no welder with the adjusting skill. obtain.
In order to enable automatic position control using the captured image, in the welding device 1, the electrode tip position P11, the wire tip position P12, the groove position P13 and the molten pool tip position P14 are set as feature quantities in the image, and these are automatically set. It is used as a parameter for welding.

Further, the third control unit 295 controls the vertical position of the welding wire 800 based on the state of the tip portion of the welding wire 800. In this way, by limiting the determination target to the tip portion of the welding wire 800 in which droplets may occur, the target area in which the image processing unit 292 detects the droplets can be limited, and the image processing unit 292 can be limited. The processing load can be reduced.

Further, the bandpass filter 131 suppresses the brightness value of the captured image of the photographing unit 130. As a result, the influence of the arc light on the captured image can be reduced, and in this respect, the accuracy with which the image processing unit 292 detects each unit can be improved.

Further, the photographing unit 130 captures a plurality of images at different shutter speeds. As a result, the image processing unit 292 can select an image according to the detection target, and in this respect, the accuracy of detecting each unit by the image processing unit 292 can be improved.

A program for realizing all or part of the functions of the control unit 290 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed. May be processed. The term "computer system" as used herein includes hardware such as an OS and peripheral devices.
Further, the "computer system" includes the homepage providing environment (or display environment) if the WWW system is used.
Further, the "computer-readable recording medium" refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, or a CD-ROM, and a storage device such as a hard disk built in a computer system. Further, the above-mentioned program may be for realizing a part of the above-mentioned functions, and may be further realized for realizing the above-mentioned functions in combination with a program already recorded in the computer system.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment and includes design changes and the like within a range not deviating from the gist of the present invention.

1 Welding device 100 Main body 110 Electrode 120 Wire feeding mechanism 130 Imaging unit 131 Band path filter 200 Welding control device 210 Communication unit 220 Operation input unit 230 Display unit 280 Storage unit 290 Control unit 291 Imaging control unit 292 Image processing unit 293 1st Control unit 294 2nd control unit 295 3rd control unit 296 Welding control unit 800 Welding wire 810 Welding pond 900 Welding object

Claims (20)

An imaging unit that photographs the electrodes and welding wires installed toward the welded part of the object to be welded,
The electrode tip position which is the tip position of the electrode in the photographed image of the imaged portion, the groove position which is the groove position in the photographed image, and the wire tip position which is the tip position of the welding wire in the photographed image. , The position of the tip of the molten pool, which is the position of the tip of the molten pool in the captured image, and the entire region having a brightness equal to or less than a predetermined brightness threshold among the predetermined regions based on the position of the tip of the wire in the captured image. An image processing unit that detects the size of the outer rectangle, which is the smallest of the rectangles surrounded by the two horizontal sides and the two vertical sides, as the size of the droplets.
A first control unit that controls the left and right positions of the electrode with respect to the position of the welded portion based on the electrode tip position and the groove position.
A second control unit that controls the left and right positions of the welded wire with respect to the position of the welded portion based on the electrode tip position and the wire tip position.
The molten pool tip position, and, on the basis of the wire tip position, have a row position control of the welding wire, determining the presence or absence of droplet at the tip of the welding wire based on the detection result of the size of the droplet If it is determined that there are droplets, the third control unit that moves the welding wire downward and
Welding equipment equipped with. Based on the electrode tip position and the groove position, the first control unit controls the left and right positions of the electrode so that the electrode is located at the center in the width direction of the groove.
The welding apparatus according to claim 1. The second control unit is located at the left and right positions of the welded wire so that the tip position of the wire in the left-right direction of the captured image is aligned with the position of the electrode based on the position of the tip of the electrode and the position of the tip of the wire. Take control,
The welding apparatus according to claim 1 or 2. The third control unit controls the vertical position of the weld wire so as to keep the difference between the vertical relative positions of the molten pool tip position and the wire tip position constant.
The welding apparatus according to any one of claims 1 to 3. The third control unit sets a position above the tip position of the molten pool by a predetermined distance in the captured image as the target position, and controls the upper and lower positions of the weld wire so that the tip position of the wire approaches the target position. I do,
The welding apparatus according to claim 4. A bandpass filter that suppresses the luminance value of the captured image of the photographing unit is provided.
The welding apparatus according to any one of claims 1 to 5. The image processing unit detects the position of the tip of the molten pool based on the captured image to which the bandpass filter is not applied, and the electrode tip is based on the captured image to which the bandpass filter is applied. Detects the position, the wire tip position, and the groove position.
The welding apparatus according to claim 6. The photographing unit captures a plurality of captured images at different shutter speeds.
The welding apparatus according to any one of claims 1 to 7. The image processing unit detects the position of the tip of the molten pool based on the captured image captured at the first shutter speed, and the imaging taken at the second shutter speed, which is slower than the first shutter speed. Detects the electrode tip position, wire tip position and groove position based on the image,
The welding apparatus according to claim 8. The photographing unit captures a plurality of the captured images at different timings of the arc currents.
The welding apparatus according to any one of claims 1 to 9. The photographing unit detects the position of the tip of the molten pool based on the captured image captured at the timing of the peak current of the arc current, and is based on the captured image captured at the timing of the base current of the arc current. The electrode tip position, the wire tip position, and the groove position are detected.
The welding apparatus according to claim 10. Further, a control unit for determining whether or not the brightness value of the captured image is equal to or higher than a predetermined threshold value is provided.
The image processing unit detects the position of the tip of the molten pool based on the bright image which is the captured image for which the luminance value is determined to be equal to or higher than the threshold value, and determines that the luminance value is less than the threshold value. The electrode tip position, the wire tip position, and the groove position are detected based on the dark image which is the captured image.
The welding apparatus according to any one of claims 6 to 11. The image processing unit detects two diagonal lines as straight lines of the contour of the tip of the electrode from the contour obtained by edge extraction with respect to the captured image, and the intersection of the detected two diagonal lines is the position of the tip of the electrode. Detect as,
The welding apparatus according to any one of claims 1 to 12. The image processing unit has a luminance value in the horizontal profile based on a horizontal profile showing a horizontal luminance value of the captured image at a position shifted downward by a predetermined distance from the electrode tip position in the captured image. A position lower than a predetermined threshold is detected as the groove position.
The welding apparatus according to any one of claims 1 to 13. The image processing unit detects a region of white pixels from the image obtained by binarizing the captured image, and detects the uppermost portion of the detected region as the wire tip position.
The welding apparatus according to any one of claims 1 to 14. The image processing unit applies a min filter to the captured image, and further binarizes the image to which the max filter is applied.
The welding apparatus according to claim 15. The image processing unit counts the number of white pixels for each vertical pixel line of the image obtained by binarizing the captured image, and detects a range in which the number of white pixels in the vertical direction is equal to or greater than a predetermined value. The detected area is scanned horizontally to detect the area of the white pixel.
The welding apparatus according to claim 15 or 16. The image processing unit detects the luminance boundary in the image obtained by binarizing the captured image as the contour line of the molten pool, and scans downward from a position advanced by a predetermined distance to the left and right from the wire tip position. , The point at which the contour line of the molten pool is reached is detected as the position of the tip of the molten pool.
The welding apparatus according to any one of claims 1 to 17. The electrode tip position, which is the tip position of the electrode in the photographed image of the electrode and the welding wire installed toward the welding point of the object to be welded, the groove position, which is the groove position in the photographed image, and the photographed image. The wire tip position, which is the tip position of the welding wire in the image, and the molten pool tip position, which is the tip position of the molten pool in the photographed image, are detected.
Of the predetermined area with respect to the wire tip position in the captured image, the smallest rectangle among the rectangles surrounding the entire area where the brightness is equal to or less than the predetermined brightness threshold with two sides in the horizontal direction and two sides in the vertical direction. The size of an outer rectangle is detected as the size of the droplet,
Based on the electrode tip position and the groove position, the left and right positions of the electrode are controlled with respect to the position of the welded portion.
Based on the electrode tip position and the wire tip position, the left and right positions of the weld wire are controlled with respect to the position of the welded portion.
The molten pool tip position, and, on the basis of the wire tip position, have a row position control of the welding wire,
A welding method including a process of moving the welding wire downward when the presence or absence of droplets at the tip of the welding wire is determined based on the detection result of the size of the droplets and it is determined that there are droplets. On the computer
The photographing unit is controlled to photograph the electrode and the welding wire installed toward the welding point of the object to be welded.
The electrode tip position, which is the tip position of the electrode in the captured image of the photographing unit, the groove position, which is the groove position in the captured image, and the wire tip position, which is the tip position of the welding wire in the captured image. , The position of the tip of the molten pool, which is the position of the tip of the molten pool in the photographed image, is detected.
Of the predetermined area with respect to the wire tip position in the captured image, the smallest rectangle among the rectangles surrounding the entire area where the brightness is equal to or less than the predetermined brightness threshold with two sides in the horizontal direction and two sides in the vertical direction. The size of a certain outer rectangle is detected as the size of the droplet,
Based on the electrode tip position and the groove position, the left and right positions of the electrode are controlled with respect to the position of the welded portion.
Based on the electrode tip position and the wire tip position, the left and right positions of the weld wire are controlled with respect to the position of the welded portion.
The position of the welding wire is controlled based on the position of the tip of the molten pool and the position of the tip of the wire .
On the basis of the size of the detection results of the droplet is determined whether a droplet at the tip of the welding wire, when it is determined that there droplet, Ru to perform the control for moving the welding wire downwardly,
Program for.

Images