JP3434423B2 - Groove tracking control apparatus and method for electrogas arc welding - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention opens an automatic welding machine by photographing the vicinity of electrogas arc welding with a television camera and recognizing the relative position between the groove and the torch based on the image signal of the television camera. The present invention relates to a device and a method for controlling the copy-ahead.

[0002]

2. Description of the Related Art Electrogas arc welding in a horizontal position is shown in FIG. 2, and electrogas arc welding in a vertical position is shown in FIG. In both drawings, the z direction is the vertical direction (height direction)
Is. As shown in FIGS. 2 and 3, the tip 1 of the welding torch mounted on a traveling carriage (not shown) is inserted into the groove 3, rocks in the thickness direction x, and cools so as to cover the welding arc. The sliding plate 2 is applied to the groove 3 and slid according to the welding rod (y direction or z direction). The cooling sliding plate 2 has a shield gas discharge port (not shown), which encloses the welding arc and the molten metal surrounded by the groove and the cooling sliding plate 2 with the shield gas and prevents the molten metal from dripping. There is a function to assist the bead formation. The carriage traveling speed is controlled to be high when the welding current value exceeds a predetermined value and low when the welding current value is less than the predetermined welding current value, so that the protruding length of the welding wire 7 can be kept substantially constant. Be lucked.

In the groove tracing control of electrogas arc welding, it is necessary to keep the distance between the lower edge 9 and the wire 7 constant in the horizontal posture (FIG. 2), and the left edge and the right edge in the vertical posture (FIG. 3). It is necessary to keep the wire 7 in the center. The welding torch is supported by an electric copying shaft on the carriage for copying control, and the welding torch and the cooling slide plate are electrically driven in the groove width direction (z direction in FIG. 2, y direction in FIG. 3). There is a copying mechanism. When the copying control is performed, the electric copying shaft driven by the electric motor is moved by a predetermined distance, but the sliding load of the cooling slide plate 2 causes the electric copying shaft to bend, cooling the welding torch (tip 1) and cooling. The sliding plate 2 does not necessarily move by the scanning shaft drive amount. That is, the amount of movement of the welding torch and the cooling slide plate varies with the amount of drive of the scanning shaft.

Generally, in the groove copying control, a contact type sensor such as a roller type is attached in front of the welding arc to detect the groove position, and the welding torch position is corrected according to the detected groove position. In this case, since the welding torch position is not detected, it is necessary that the relative positional relationship between the sensor and the welding torch at the start of the copying control is maintained as it is at any point during the copying control. However, in electrogas arc welding, the relative positional relationship between the sensor and the welding torch cannot be kept constant due to the bending of the copying shaft and the like due to the sliding load of the cooling sliding plate 2 and its fluctuation. Therefore, good scanning control cannot be performed by detecting the position of only the groove.

As a method for solving this problem, Japanese Patent Laid-Open No. Sho 5
In 9-94583, a welding wire and a groove during arc welding of narrow groove welding are photographed by a television camera, image data of a photographing screen is processed, and a position of the welding wire with respect to the groove is determined, A groove tracking control method has been proposed in which the welding torch position is adjusted so as to correct the positional deviation of the welding wire with respect to the groove. Both sides of the screen (corresponding to the surface of the steel plate) are shaded against the arc or molten pool radiant light so that the groove is brightly photographed, and the welding wire is photographed in the shade almost at the center of the groove. Has been done.

Therefore, it is said that the groove position, the width and the wire position can be measured by discriminating the luminance data by setting an appropriate threshold value in the groove width direction of the photographed image data. A method of providing an appropriate luminance threshold value and making a discrimination in this way is called a binarization method.

As described above, in the method of controlling the groove profile using the image data obtained by photographing the welding wire and the groove with the television camera, the groove and the wire position can be detected at the same time. It is possible to perform the scanning control so as to keep the relative distance constant, and it should be possible to perform the satisfactory scanning control even if the scanning shaft or the like is bent.

The case where this method is applied to the horizontal orientation of electrogas arc welding will be described. FIG. 1 shows a photographing screen obtained by photographing the tip 1 of the welding torch to be electrogas arc welded, the cooling sliding plate 2, and the vicinity of the groove 3 with the TV camera 20 from above the groove as shown in FIG. .
FIG. 5 shows the luminance distribution on the scanning line L1 in FIG.

From FIG. 1 and FIG. 5, a- on the scanning line L1
Between the points b and ef, the brightness is low due to the shadow on the surface of the steel sheet, and between the points bc and de, the inside or groove of the groove illuminated by arc light or molten pool radiant light. The brightness is high on the hypotenuse, and the background brightness is high between the points c and d. The inside of the groove or the hypotenuse of the groove is shielded by the wire and the brightness is low.

FIG. 6 shows the luminance distribution on the scanning line L1 in a dark image of only the radiant light of the molten pool, where the arc is extinguished due to a short circuit during droplet transfer. FIG. 7 shows a luminance distribution on the scanning line L1 of an image when the arc length is long, the arc flame is large, the wire is wrapped, the whole is bright, and the shadow of the wire is thin.

In FIG. 5, by setting the threshold value B1 of the brightness and binarizing the image data (by cutting out the groove high brightness parts SU and SD on both sides of the wire), SU, S
The groove position and width are obtained from the position of D and the width in the Z direction, and S
The position of the wire with respect to the groove (Z direction) is found by finding the relative position of the low brightness portion (corresponding to the wire) between U and SD with respect to SU and SD in the Z direction. However, the arc disappears, and in FIG. 6, SU and SD cannot be cut out unless the threshold value is lowered from B1 to B2. In FIG. 7 where the arc length is long, unless the threshold value is raised from B1 to B3,
It is not possible to cut out the low-luminance portion corresponding to the wire from the high-luminance portion (SU to SD). That is, the wire position cannot be measured.

As described above, in the binarization method, it is necessary to set an appropriate threshold value according to the variation in the brightness of the captured image. In the welding arc phenomenon, fluctuations in brightness are frequent and large,
The determination of the threshold is a big issue, and stable measurement is difficult.

[0013]

As described above, in electrogas arc welding, since bending of the scanning shaft and the like due to the sliding load of the cooling sliding plate is unavoidable, good scanning control is not possible by position detection of only the groove. Can not. The method of detecting the groove and the welding wire by the binarization method using the image data of the welding wire and the groove during arc welding taken by a TV camera is because the brightness of the arc light fluctuates drastically. It is difficult to set the threshold value.

The present invention realizes stable groove position detection and welding wire position detection even under such conditions.
It is an object of the present invention to provide a groove tracking control method with high reliability and stability.

[0015]

[Means for Solving the Problems]

(1) A groove (3) during welding, a wire (7), and a cooling slide plate (2) in a device for controlling the groove copying of electrogas arc welding using image data taken by a TV camera
A television camera (20) that shoots in the field of view, an image memory (13) that writes the image data obtained by shooting, a wire image (7 m) on the shooting screen represented by the image data, and a cooling slide that is continuous with it. Image recognition means (10) that detects the wire position (z / y) by extracting the area containing the plate image (2m), and drives the welding torch and cooling slide plate in the groove width direction (z / y) Electric copying shaft (33) for
Control means (10 to 11) for adjusting the positions of the welding torch and the cooling slide plate in the groove width direction (z / y) via the electric copying shaft (33) according to the detected wire position (z / y). ), Is provided.

In order to facilitate understanding, the reference numerals of corresponding elements in the embodiments shown in the drawings and described later are added for reference.

It is desirable that the detection of the groove, the wire, and the tip position in the groove copying control can be performed at a position as close to the welding arc as possible from the accuracy of the copying. However, the welding arc is hidden by the cooling sliding plate, and the positions closest to the detectable welding arc are the cooling sliding plate and the groove, and the intersections of the cooling sliding plate and the wire. Wire image (7 m) and cooling slide plate image (2
The position (distribution) and brightness on the screen are significantly different from m), and relative identification by image processing is easy.

In the present invention, since the image (2m) of the cooling slide plate is used to identify (recognize) the image area including the wire image (7m), the recognition accuracy of the image area is high and Accurate detection of the wire position (z / y) at the wire intersection is achieved.

[0019]

DETAILED DESCRIPTION OF THE INVENTION

(2) In the pre-copy control image data that was taken while welding was performed before the copy control in the method for controlling the groove copy of the electrogas arc welding in the horizontal position using the image data taken by the TV camera (Fig. 2). From the above, the image data of the region (P2) including the welding wire is stored as the teaching pattern K1, and the image data of the region (P1) including the lower edge and the cooling slide plate is stored as the teaching pattern K2. A region I1 having a high correlation with the teaching pattern K1 is searched for from the welding control image data including the welding wire, the groove, and the image data including the cooling sliding plate, which is photographed in synchronization with the swing, to determine the welding wire position. Then, the region I2 having a high correlation with the teaching pattern K2 is searched to determine the welding lower edge position, and the welding torch and the cooling slide plate position are determined according to the determined relative position between the wire position and the lower edge position. And controlling the vertical (z) position.

(3) In the method of controlling the groove profile of the electrogas arc welding in the horizontal position using the image data captured by the television camera (FIG. 2), the welding wire and the wire which were captured while welding were performed before the profile control. From the image data before copy control consisting of the image data including the tip and the cooling sliding plate,
The image data of the region (P2) including the welding wire is used as the teaching pattern K1 and the region (P1) including the lower groove edge and the cooling slide plate is used.
The image data of the image is stored as the teaching pattern K2, and the image data of the region (P3) including the groove upper edge and the cooling sliding plate is stored as the teaching pattern K3, and the image is taken in synchronization with the swing of the welding torch during the scanning control. From the image data during the copying control consisting of the image data including the welding wire, the groove and the cooling sliding plate,
A region I1 having a high correlation with the teaching pattern K1 is searched to determine a welding wire position, a region I2 having a high correlation with the teaching pattern K2 is searched to determine a welding lower edge position, and a region I3 having a high correlation with the teaching pattern K3. To determine the upper edge position, control the welding torch and cooling slide plate position up and down according to the determined relative position of the wire position and the lower edge, and determine the relative position of the determined lower edge and upper edge. It is characterized in that the welding conditions are switched according to the conditions. (4) Welding wire, groove and cooling taken before welding control in welding in the method of controlling the groove tracing of vertical electrogas arc welding using image data taken by a TV camera (Fig. 3). Area including welding wire from the image data before copy control that consists of image data including sliding plate
The image data of (P2) is the teaching pattern K1, the area of the left edge of the groove and the cooling sliding plate is the teaching pattern K2, and the area of the right edge of the groove and the cooling sliding plate is ( The image data of P3) is stored as a teaching pattern K3, and the image data during the copying control is composed of the image data including the welding wire, the groove and the cooling sliding plate, which is photographed in synchronization with the swing of the welding torch during the copying control. , A region I1 having a high correlation with the teaching pattern K1 is determined to determine a welding wire position, a region I2 having a high correlation with the teaching pattern K2 is determined to determine a welding left edge position, and a high correlation with the teaching pattern K3 is obtained. The region I3 is searched to determine the right edge position, and the welding torch position and the cooling slide plate are laterally controlled according to the determined relative positions of the wire position and the left edge and right edge positions.

In these embodiments, the television camera
Region I detected by correlation search on the shooting screen of (20)
1 is the teaching pattern K written in the memory (10) in advance.
Similar to 1 (P2), it includes welding wire,
The position of the wire image (7m) in 1 is the teaching pattern K1 (P2)
It is substantially the same as the position of the wire image (7m) inside. Similarly,
The area I2 detected by the correlation search is previously stored in the memory (10).
Similarly to the teaching pattern K2 (P1) written in, the image includes an image corresponding to the groove on the photographing screen and an image corresponding to the surface of the steel plate continuous to the groove, and the lower edge of the groove or the left in the region I2. The position of the edge is substantially the same as the position of the groove image in the teaching pattern K2 (P1). Teaching pattern K2 (P1) and area I
The positional relationship between the two can be seen from the positions of both areas on the shooting screen. On the other hand, since the positional relationship between the teaching pattern K1 (P2) and the teaching pattern K2 (P1) is predetermined, the area I1
/ Relative positional relationship between areas I2 and teaching pattern K1 (P2) /
The position of the wire appearing in the region I1 with respect to the groove edge appearing in the region I2 can be calculated based on the relative positional relationship between K2 (P1).

For example, on the photographing screen of the television camera (20), the area P2 shown in FIG.
When 1 is set as the teaching pattern K2, the distance between the center of the regions in the groove width direction Z between P2 and P1 (z corresponds to z in FIG. 2 and y in FIG. 3) is set to Zt, and the region I1 and the region on the screen are set. If the area center line distance from I2 is Zr, the area P2 in the memory is
Compared to when the P1 image data was written (reference time), Z
The welding wire 7 is displaced in the groove width direction Z with respect to the groove 3 by r−Zt, and based on this relationship, the relative position between the groove 3 / welding wire 7 at the time of the reference is calculated. The relative position of is obtained. The details will be described below.

Generally, the image signal output from the television camera is an analog voltage according to the brightness, but the image signal output order is that the brightness signal in the horizontal direction Z from the upper end to the lower end in FIG. 1 changes from the left end to the right end of the screen. The signals are sequentially output in the vertical direction Y. Therefore, in order to handle it as image data, the number of pixels in the horizontal direction Z (s pixels) and the number of pixels in the vertical direction Y (t pixels) are determined in advance, and the number of memories corresponding to the total number of pixels (s × t pixels) is determined. ) Is prepared, and the analog voltage (image signal) of the luminance signal output in the above order is digitalized while timing so that the luminance at an arbitrary position on the screen is associated with the data at a predetermined address in the memory. The data is converted into data (image data) and the data is stored in a predetermined address of the memory. That is, in the arc welding state before the start of the copying control, the groove is photographed in the same manner as during the copying control, and a predetermined size (m) is selected from the screen (s × t pixels) that can be regarded as a reference or standard. The image data of a region of × n pixels (m and n are positive integers, s> m, t> n) in which a specific image appears at a predetermined position is cut out to teach pattern K.
1 (P2), K2 (P1), K3 (P3) are stored in the memory. Alternatively, all the image data of the screen (s × t pixels) is stored in the memory and the teaching pattern K1 is used.
Area information (diagonal corner address of the area) to be cut out as K3 is stored in the memory.

When the teaching pattern K1 (P2) is a wire teaching pattern including the welding wire image 7m at a predetermined position, first, the region P2 shown in FIG.
Image data is stored in a memory as a teaching pattern K1 (m × n pixels). Screen shot during copy control (s ×
t) has an image similar to P2 in FIG. 1 although there are variations in the positions of the groove, wire and arc and variations in brightness. At the top left corner of this shooting screen Z = 1,
Y = 1, that is, (1,1) is the upper left corner, and (m,
n) is the lower right corner of the area (the same size as the teaching pattern K1) image data input pattern (m × n)
I1 is defined, and teaching pattern K1 and input pattern I
1 The upper left corner of each pattern is set to (1, 1), numbers are given up to the mth in the horizontal direction and up to the nth in the vertical direction, and the teaching pattern K1 at the i-th position in the horizontal direction and the j-th position in the vertical direction. Assuming that the brightness represented by the image data of the input pattern I1 is W (i, j) and U (i, j), respectively, the correlation coefficient R11 between the brightness W of the teaching pattern K1 and the brightness U of the input pattern I1. Is calculated by the following formula (1).

[0025]

[Equation 1]

A correlation coefficient R11 between the teaching pattern K1 and the input pattern I1 is obtained. Next, a pixel (2, 1 pixel below the upper left corner (1, 1) of the screen imaged during the scanning control is selected.
Correlation coefficient R of input pattern I1 with 1) as the upper left corner
21 is similarly calculated by the equation (1). In this way, the calculation for obtaining the correlation coefficient RIJ is performed in the upper left corner of one screen during the scanning control.
When one line from (1,1) to (s-m, 1) is executed, this is similarly repeated for the line (pixels in the Z direction) to the right (the direction in which Y increases), and the line of t-n. To run. When this is finished, if the position (I = Zc, J = Yc) having the largest correlation coefficient RIJ is obtained, (Zc, Y
c) is the upper left corner, (Zc + m-1, Yc + n-1)
Is an area I1 (extraction pattern) including a wire image, which is similar to or similar to the teaching pattern K1.

At this time, as shown in FIG. 8, the brightness of the teaching pattern K1 (P2) is plotted on the abscissa, and the brightness of the extracted pattern obtained as described above corresponding to this is plotted on the ordinate. If the luminance of each pixel of m × n is plotted in association with each other, when the teaching pattern K1 and the input pattern I1 have almost the same brightness, the luminance is distributed around a line of about 45 ° (Q1). However, when the extraction pattern I1 is darker, it is distributed below the 45-degree line as indicated by Q2, and when the extraction pattern is brighter, it is above the 45-degree line as indicated by Q3. Distributed in.

What is important here is Q1, Q2 in FIG.
The spread of the brightness plot distributed in Q3 corresponds to the correlation coefficient R, but there is little difference in the spread of the plots of Q1, Q2, and Q3. That is, the correlation coefficient R is little affected by the change in brightness.

Each of the areas P1 to P5 shown in FIG.
It is enlarged and shown in FIGS. If the areas P1, P3, P4 and P5 are used as the teaching pattern, the position of the image in each area can be similarly detected by the above method.

Therefore, as a method for obtaining the wire position in the groove, in the lateral posture (FIG. 2), the area P2 or P5 containing the wire image 7m or the area P containing the chip image 1m is obtained.
4 is similarly detected by the above method, the area P1 including the lower edge image 9m of the groove is similarly detected by the above method, and the detected area P is detected.
2, The position of the wire or chip with respect to the lower edge of the groove is calculated from the difference in the Z direction between P5 or P4 and P1.

In the vertical posture (FIG. 3), not only the area P1 including the left edge of the groove but also the area P3 including the right edge are detected by the above method, and the positions of these areas P1 and P2 in the Z direction are detected. Is calculated and the midpoint of those positions is calculated as the groove center, and the position of the wire or the tip with respect to this midpoint is calculated.

As a method of obtaining the groove width, the lower edge region P1 and the wire region P2, P5 or P4 in the horizontal orientation (FIG. 2) are extracted and the wire position with respect to the lower edge is calculated. In the vertical posture (FIG. 3), the left edge region P1 and the right edge region P3, and the wire region P2, P5 or P4.
And are extracted, and the wire position with respect to the groove center is calculated.

The image extraction region is shown in FIGS. 1 and 9 to 13, and P1, P2, P3, P4 and P5 are shown in FIGS.
The reasons for setting 1, 12, and 13 will be described. It is desirable that the detection of the groove, wire, and tip positions in the groove tracking control can be performed at a position as close to the welding arc as possible from the scanning accuracy. However, the welding arc is hidden by the cooling slide plate 2, and the position closest to the detectable welding arc is the cooling slide plate 2 and the groove 3, and the intersection of the cooling slide plate 2 and the wire 7.

If the extraction areas of the lower edge and the upper edge are areas not including the image 2m of the cooling slide plate 2 as shown by P1 and P3 in FIG. 14, the area P1 is the area in FIG. Meanwhile, P3 detects an arbitrary position Z between W and W. Since the image capturing is not necessarily parallel and right angle to the groove, as shown in FIG. 14, when the chip image 1m and the wire image 7m are inclined with respect to the Y axis of the screen, the wire lower edge detection is close to A. , If the upper edge is located at a position close to c, a large error will occur when obtaining the groove width. In some cases, P1 in FIG. 14 detects the upper side of the chip and P3 detects the lower side of the chip, and stable detection cannot be performed. Therefore, the extraction regions P1 and P3 of the lower edge and the upper edge (the teaching pattern K
2, K3) is preferably a region including the image 2m of the cooling slide plate 2 as shown in FIGS. 1, 9 and 11.

Assuming that the teaching pattern of the tip is P4 as shown in FIG. 14, the insertion angle of the tip is not necessarily parallel to the groove, so an arbitrary position between the oak and the rake of the tip is set. If detected, the distance between the lower edge and the chip fluctuates, and stable detection cannot be performed. Therefore, it is preferable that the extraction region P4 (teaching pattern) of the chip includes the chip and the wire as shown in FIG.

The teaching pattern of the wire is assumed to be P in FIG.
Even if the image 2m of the cooling slide plate 2 is not included as in 2,
Since the length of the image of the wire 2 is short, the fluctuation of the detection position is small. Therefore, FIG. 13 including the image 7m of the wire 7 or the image 7m of the wire and the image 2m of the cooling slide plate 2
Stable detection can be performed also in FIG.

[0037]

FIG. 15 shows the construction of an automatic welding apparatus used in the embodiment of the present invention, and FIG. 16 shows the construction of a control apparatus. Swing shaft motor 34 of welding torch, cooling slide plate 2, TV camera 20
The electric copying shaft 33 to which is attached the traveling carriage 3 that travels on the rail 31 arranged in parallel in the groove 3 via the rotating shaft 35.
It is attached to 2. The cooling slide plate 2 is pressed against the groove 3 with a constant load to form a bead during welding.
Welding torch and cooling slide plate 2, T
The V camera 20 integrally moves in the groove width direction. The TV camera 20 was installed at the position shown in FIG. 4 and shot the range shown in FIG. A microcomputer 10 including a CPU and a memory detects a signal from a limit switch 15 for detecting the position before the swing of the welding torch, and the switch 1
The analog image signal from the TV camera 20 is converted into a digital signal by the A / D converter 14 at substantially the midpoint of the period when 5 is closed, and the image data for one screen is 480 pixels vertically by 480 pixels horizontally. The image data of 512 pixels was stored in the image memory 13. The limit switch 15 is closed once in each stroke of the reciprocating motion of the swing shaft 34.

The microcomputer 10 uses the image data (one screen) of the image memory 13 to read the teaching pattern K1 (P2, P4 or P5) stored in its internal memory.
Regions I1 (P2, P4 or P5), I2 (P1) and I3 (P3) having high correlation function values with respect to K2 (P1) and K3 (P3) are extracted, and the groove is calculated from the extracted relative position between the regions. The Z position of the wire with respect to is calculated, and a signal corresponding thereto is commanded to the servo amplifier 11 to control the copying shaft motor 12 of the copying shaft 33. The analog image signal from the TV camera 20 is input to the VTR 21 via the distributor 23, and the image of the groove 3, the wire 7, the chip 1, the cooling sliding plate 2 and the like during the copying control is stored. .

The photographing range was adjusted so that the distance on the steel plate surface was 0.06 mm per pixel.

As a method of confirming the copying controllability, the copying control image during welding was recorded by the VTR 21, and after the completion of welding, the image was reproduced on the monitor TV 22 and was actually measured on a scale for conversion.

[Example 1] In horizontal electrogas arc welding, an example of using the groove profile control method and apparatus of electrogas arc welding according to the present invention will be described. The welding test plate used was a die groove as shown in FIG. 17, with a plate thickness of 16 mm, a surface gap of 12 mm, a back gap of 6 mm,
A test plate having a length of 500 mm and a backing material 4 attached was used. The welding conditions were welding current 360 (A) and welding voltage 3
2 (V), flux-cored wire 1.6 (mmφ), welding speed 14.7 (cm / min), rocking frequency 42 (times / time)
min) was used.

1-1 Experimental Method The traveling carriage 32 is caused to travel and welding is started. The operator optimally set the position of the wire in the z direction with respect to the lower edge of the groove, and started driving the swing shaft 34. In response to the closing signal of the limit switch 15, the microcomputer 10 designates areas P2 and P1 in the photographed image, sets the areas, and stores them in the internal memory as teaching patterns K1 and K2. And the designated area P
2 and P1 position difference (wire / lower edge position difference) Z
s = ZP2-ZP1 is calculated, and Zs is used as the scanning control reference.
Stored in the internal memory.

After that, the microcomputer 10 writes the image data of one shot image in the image memory 13 in response to the closing signal of the limit switch 15, and then from the image memory 13, the wire teaching pattern K1 ( P
The input pattern of the same size as 2) was taken out sequentially while changing the position, and the correlation coefficient with the teaching pattern was calculated according to equation 1. When the largest correlation coefficient is 0.6 or more, the wire position is determined and the coordinate position ZP2 in the groove width direction is stored.

Similarly, a region having a high correlation with the lower edge teaching pattern K2 (P1) in the image of the image memory 13 is extracted, its position ZP1 is detected, and the wire / lower edge distance Zt = ZP2-ZP1 is determined. It was calculated. Then, the calculated distance Zt is the scanning control reference Z stored in the internal memory.
The position of the copying shaft 33 was corrected by instructing the servo motor 12 in the direction that coincides with s (start of copying control).

After that, the above steps are repeated to compare the wire / lower edge distance Zt = ZP2−ZP1 during the scanning control with the scanning control reference Zs, and the servo motor 12 is instructed to reduce the difference, and the scanning shaft 33 is scanned. Was corrected (continuation of copying control).

1-2 Experimental Results It was confirmed that the scanning control can be satisfactorily performed within a range of ± 0.3 mm.

[Embodiment 2] An embodiment in which the method and apparatus for controlling the groove profile of electrogas arc welding according to the present invention is used in horizontal electrogas arc welding will be described. Using the welding test plate used with the backing material 4 attached, as shown in FIG. 18, with a die groove, plate thickness 25 mm, surface gap 10 to 15 mm, back gap 4 to 9 mm, length 50.
Using a 0 mm test plate, the welding conditions are welding current 350
(A), welding voltage 31 (V), flux-cored wire 1.6 (mmφ), welding speed 10.4 (cm / mi)
n) and the number of times of rocking 42 (times / min) were used.

2-1 Experimental method The traveling carriage 32 is caused to travel and welding is started. The operator optimally set the position of the wire in the z direction with respect to the lower edge of the groove, and started driving the swing shaft 34. In response to the closing signal of the limit switch 15, the microcomputer 10 selects areas P4 and P from the captured image.
3 and P1 are designated and the area is set, and teaching pattern K
1, K2 and K3 stored in internal memory. Then, a positional difference (wire / lower edge positional difference) Zs = ZP4-ZP1 between the designated areas P4 and P1 was calculated, and Zs was stored in the internal memory as a scanning control reference.

After that, the microcomputer 10 writes the image data of one shot image in the image memory 13 in response to the closing signal of the limit switch 15, and then, from the image memory 13, the wire teaching pattern K1 ( P
The input pattern of the same size as 4) was sequentially taken out by changing the position, and the correlation coefficient with the teaching pattern was calculated according to the equation 1. When the largest correlation coefficient is 0.6 or more, the wire position is determined and the coordinate position ZP4 in the groove width direction is stored.

Similarly, areas (P1, P3) having a high correlation with the lower edge teaching pattern K2 (P1) and the upper edge teaching pattern K3 (P3) of the image in the image memory 13 are extracted and their positions are extracted. ZP1 and ZP3 were detected, and the wire / lower edge distance Zt = ZP4-ZP1 and the groove width Zw = ZP3-ZP1 were calculated. Then, the calculated distance Zt is the scanning control reference Z stored in the internal memory.
The position of the copying shaft 33 was corrected by instructing the servo motor 12 in the direction that coincides with s (start of copying control and welding condition control). Further, the welding conditions were switched according to the conditions shown in Table 1 according to Zw. After that, the wire under control of copying /
Distance between lower edges Zt = ZP2-ZP1 and scanning control reference Z
s, and the servo motor 12
To correct the scanning axis 33, and Zw = ZP3-Z
The welding conditions were modified according to P1 and Table 1 (continuation of copying control and welding condition control).

[0051]

[Table 1]

2-2 Experimental Results The results confirm that the scanning control can be satisfactorily performed within a range of ± 0.3 mm. FIG. 21 shows the result of the condition switching control state after welding. At the welding distance of 200 mm, the condition 1 →
The condition was switched to the condition 2, and the condition 2 was switched to the condition 3 at the welding distance of 400 mm, and it was confirmed that the fluctuation of the surface gap and the condition switching could be performed accurately and accurately.

[Embodiment 3] An embodiment in which the method and apparatus for controlling the groove profile of electrogas arc welding according to the present invention are used in horizontal electrogas arc welding will be described. The welding test plate used was a die groove as shown in FIG. 19, with a plate thickness of 12 mm, a surface gap of 15 to 10 mm, a back gap of 9 mm.
A test plate having a length of up to 4 mm and a length of 500 mm with the backing material 4 attached is used. The welding conditions are welding current 340 (A),
Welding voltage 31 (V), flux cored wire 1.6 (m
mφ), welding speed 15.1 (cm / min), and rocking frequency 42 (times / min). The groove was installed with an inclination of 10/500 mm with respect to the rail.

3-1 Experimental Method The experiment was carried out in the same manner as in Example 2, but the teaching pattern K of the wire was used.
1 was changed to P5 and carried out.

3-2 Experimental Results The results confirmed that scanning control could be favorably performed within a range of ± 0.3 mm. FIG. 22 shows the result of the condition switching control state after welding. The condition 3 is switched to the condition 2 when the welding distance is 100 mm, and the condition 2 is switched to the condition 1 when the welding distance is 300 mm. It was confirmed that the switching could be done accurately and accurately.

[Embodiment 4] An embodiment in which the method and apparatus for controlling the groove tracking of electrogas arc welding according to the present invention is used in the upright electrogas arc welding will be described.
The welding test plate used was a V-shaped groove as shown in FIG.
Using a test plate having a plate thickness of 25 mm, a surface gap of 17 to 25 mm, a back gap of 5 to 10 mm, and a length of 700 mm, the welding conditions are welding current 420 (A) and welding voltage 41.
(V), flux-cored wire 1.6 (mmφ), welding speed 11.0 (cm / min), swing width 8 mm, swing frequency 30 (times / min) were used. Further, as the copying control condition, since the vertical welding posture is as shown in FIG. 3,
By rotating the camera 90 degrees clockwise and installing it, a photographing screen in the same manner as the photographing screen shown in FIG. 1 can be obtained. In this case, the Z direction of the screen is the x direction shown in FIG. 3, and the Y direction of the drawing is the z direction shown in FIG.

4-1 Experimental method The traveling carriage 32 is caused to travel and welding is started. The operator determines the x, y of the wire with respect to the lower edge of the groove.
The directional position was optimally set and driving of the swing shaft 34 was started. In response to the closing signal of the limit switch 15, the microcomputer 10 designates areas P2 and P1 and P3 in the photographed image, sets the areas, and sets the teaching pattern.
Stored in internal memory as K1 and K2 and K3. The positional difference between the designated areas P1 and P3 (groove width)
Zw = ZP3-ZP1 is calculated and the position Zw of the intermediate point is calculated.
p = ZP3 + Zw / 2 was calculated, and the positional difference Zs = Zwp−ZP2 of the designated area P2 with respect to Zwp was calculated, and this was stored in the internal memory as the scanning control reference Zs.

After that, the microcomputer 10 writes the image data of one screen shot in the image memory 13 in response to the closing signal of the limit switch 15, and then from the image memory 13, the wire teaching pattern K1 ( P
The input pattern of the same size as 2) was taken out sequentially while changing the position, and the correlation coefficient with the teaching pattern was calculated according to equation 1. When the largest correlation coefficient is 0.6 or more, the wire position is determined and the coordinate position ZP2 in the groove width direction is stored.

Similarly, areas of the image in the image memory 13 having a high correlation with the left edge teaching pattern K2 (P1) and the right edge teaching pattern K3 (P3) are extracted and their positions ZP1 and ZP3 are detected. Then, the positional difference (groove width) Zw = ZP3-ZP1 is calculated, the position Zwp = ZP3 + Zw / 2 of the intermediate point is calculated, and the positional difference of the designated region P2 with respect to Zwp (wire / groove center). Distance) Zt = Zwp-ZP2 is calculated, and the calculated distance Z
In the direction in which t matches the scanning control reference Zs stored in the internal memory, the servo motor 12 is instructed to scan the scanning axis 33.
The position of was corrected. In addition, the welding conditions were switched according to the conditions shown in Table 2 in accordance with the groove width Zw (start of copying control and welding condition control).

After that, the above steps are repeated to compare the wire / groove center distance Zt = Zwp-ZP2 during the scanning control with the scanning control reference Zs, and the servo motor 12 is instructed to reduce the difference. 33 is corrected, groove width Zw
Corresponding to, the welding conditions were switched according to the conditions of Table 2 (continuation of copying control and welding condition control).

[0061]

[Table 2]

4-2 Experimental Results As a result, it was confirmed that scanning control can be favorably performed within a range of ± 0.3 mm. FIG. 23 shows the condition switching state after welding. It was confirmed that the condition 1 was switched to the condition 2 at the welding distance of 180 mm, and the fluctuation of the surface gap and the condition switching could be performed accurately and accurately.

In this embodiment, each teaching pattern shown in the experimental method is stored for each welding, but when repeating welding is performed, the teaching pattern that has already been stored is used to start the copying control ( Z obtained by the procedure of the experimental method (while the operator keeps the optimum setting)
It has been confirmed that similar scanning controllability can be obtained even if the subsequent scanning control shown in the experimental method is performed after t is set as the scanning control reference Zs.

[0064]

The method of the present invention has the basic characteristic that it is not easily affected by the fluctuation of the brightness of the arc light in electrogas welding, and good scanning control can be performed. Therefore, automatic scanning control using a television camera can be performed. The reliability is dramatically increased, which can greatly contribute to automation and unmanned welding process.

[Brief description of drawings]

1 is a plan view showing a shooting screen of the TV camera 20 shown in FIG. 4 and regions P1 to P5 set on the screen.

FIG. 2 is a drawing showing a horizontal electrogas welding state, in which (a) is a horizontal cross-sectional view at the groove center, (b) is a front view, and (c) is a vertical vertical cross-sectional view.

FIG. 3 is a drawing showing a vertical electrogas welding state, in which (a) is a horizontal cross-sectional view, (b) is a front view, and (c) is a vertical vertical cross-sectional view.

FIG. 4 is an enlarged horizontal cross-sectional view at the center of the groove, showing the TV camera 20 for photographing the horizontal electrogas welding state and the welding wire portion.

5 is a graph showing a video signal level on the horizontal scanning line L1 shown in FIG. 1 when the welding arc of the TV camera 20 shown in FIG. 4 has a standard brightness.

6 is a graph showing a video signal level on the horizontal scanning line L1 shown in FIG. 1 when the welding arc of the TV camera 20 shown in FIG. 4 is short-circuited and disappears during transfer of droplets. .

FIG. 7 is a view showing a case where the arc length of the welding arc of the TV camera 20 shown in FIG. 4 along the horizontal scanning line L1 shown in FIG. It is a graph which shows a video signal level.

8 is a diagram showing the teaching pattern written in the internal memory of the microcomputer 10 shown in FIG. 16 and the input pattern on the screen photographed by the TV camera 20 shown in FIG.
It is a graph which shows the brightness | luminance distribution of each corresponding pixel.

9 is an enlarged plan view showing a region P1 shown in FIG. 1. FIG.

10 is an enlarged plan view showing a region P2 shown in FIG. 1. FIG.

FIG. 11 is a plan view showing a region P3 shown in FIG. 1 in an enlarged manner.

12 is an enlarged plan view showing a region P4 shown in FIG. 1. FIG.

13 is an enlarged plan view showing a region P5 shown in FIG. 1. FIG.

FIG. 14 is a plan view showing an example of region setting in which the wire position detection with respect to the groove is inaccurate.

FIG. 15 is a left side view showing an outline of a mechanical portion of a welding device for carrying out the present invention in one aspect, in which a steel plate shows a vertical longitudinal section.

16 is a block diagram showing a configuration of an electric control system for copyingly driving an electric copying shaft 33 of the welding apparatus shown in FIG.

FIG. 17 shows a test plate used as a welding target in Example 1 of the present invention, (a) is a front view and (b) is a right side view.

FIG. 18 shows a test plate used as a welding target in the second embodiment of the present invention, (a) is a front view and (b) is a right side view.

FIG. 19 shows a test plate used as a welding target in the third embodiment of the present invention, (a) is a front view and (b) is a right side view.

FIG. 20 shows a test plate used as a welding target in the fourth example of the present invention, (a) is a front view and (b) is a right side view.

FIG. 21 is a graph showing the relationship between the groove width and the welding condition area set in the second embodiment.

FIG. 22 is a graph showing the relationship between the groove width and the welding condition area set in the third embodiment.

FIG. 23 is a graph showing the relationship between the groove width and the welding condition region set in the fourth embodiment.

[Explanation of symbols]

1: Chip 2: Cooling Sliding Plate 3: Groove 4: Backing Material 5: Molten Metal 6: Arc 7: Wire 8: Bead 10: Microcomputer 11: Servo Amplifier 12: Copy Axis Motor 13: Image Memory 14: A / D converter 15: Limit switch 20: TV camera 21: VTR 22: Monitor TVC 23: Distributor 31: Rail 32: Traveling carriage 33: Electric copying shaft 34: Swing shaft motor 35: Rotation shaft

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI B23K 37/06 B23K 37/06 KG01B 11/00 G01B 11/00 H G06T 7/00 G06F 15/62 400 (58) Field (Int.Cl. ⁷ , DB name) B23K 9/127 508 B23K 9/035 B23K 9/095 505 B23K 9/173

Claims (4)

(57) [Claims] Claim: What is claimed is: 1. An apparatus for controlling a groove profile of electrogas arc welding using image data captured by a television camera, the television camera capturing a groove, a wire and a cooling sliding plate during welding within a field of view. An image memory for writing the obtained image data, an image recognizing means for detecting the wire position by extracting a region containing the image of the wire on the photographing screen represented by the image data and the image of the cooling slide plate connected to the image, welding An electric copying shaft for driving the torch and the cooling sliding plate in the groove width direction, and
A groove profile control device for electrogas arc welding, comprising: a control means for adjusting the positions of the welding torch and the cooling sliding plate in the groove width direction via an electric profile axis according to the detected wire position. . 2. A method for controlling a groove profile of electrogas arc welding in a horizontal position using image data captured by a television camera, wherein from among image data before profile control captured while welding is performed before profile control in advance, Image data of a region including a welding wire is stored as a teaching pattern K1, image data of a region including a lower edge and a cooling slide plate is stored as a teaching pattern K2,
A region I1 having a high correlation with the teaching pattern K1 is searched from the image data in the copying control which is imaged in synchronization with the swing of the welding torch during the copying control and includes the welding wire, the groove, and the cooling sliding plate. The welding wire position is determined, the region I2 having a high correlation with the teaching pattern K2 is searched to determine the welding lower edge position, and the welding torch and cooling slide are determined according to the determined relative position between the wire position and the lower edge position. A groove tracking control method for electrogas arc welding in a horizontal posture, characterized in that the plate position is controlled up and down. 3. A method of controlling a groove profile of electrogas arc welding in a horizontal position using image data captured by a television camera, wherein a welding wire, a groove, and a cooling slide are captured while welding is performed before the profile control. Of the pre-copy control image data including the image data including the plate, the image data of the region including the welding wire is used as the teaching pattern K1, and the image data of the region including the groove lower edge and the cooling sliding plate is used as the teaching pattern K2. ,
Further, the image data of the region including the groove upper edge and the cooling sliding plate is stored as a teaching pattern K3, and is photographed in synchronization with the swing of the welding torch during the scanning control. The region I1 having a high correlation with the teaching pattern K1 is determined from the image data under the scanning control including the image data including the position of the welding wire to determine the welding wire position, and the region I2 having a high correlation with the teaching pattern K2 is searched to find the welding lower edge position. Decide
A region I3 having a high correlation with the teaching pattern K3 is searched to determine the upper edge position, and the welding torch and the cooling slide plate position are vertically controlled and determined according to the determined relative position between the wire position and the lower edge. A groove tracking control method for electrogas arc welding in a horizontal posture, characterized in that welding conditions are switched according to the relative positions of the lower edge and the upper edge. 4. A method for controlling a groove profile of an electrogas arc welding in a vertical position by using image data captured by a television camera, wherein a welding wire, a groove and a cooling slide are photographed before the profile control during welding. Of the pre-copy control image data consisting of the image data including the plate, the image data of the region including the welding wire is used as the teaching pattern K1, and the image data of the region including the groove left edge and the cooling sliding plate is used as the teaching pattern K2. Further, the image data of the area including the groove right edge and the cooling slide plate is stored as the teaching pattern K3, and the image is taken in synchronization with the swing of the welding torch during the copying control. From the image data during scanning control consisting of image data including the plate,
A region I1 having a high correlation with the teaching pattern K1 is determined to determine a welding wire position, a region I2 having a high correlation with the teaching pattern K2 is determined to determine a welding left edge position, and a region I3 having a high correlation with the teaching pattern K3. To determine the right edge position and control the horizontal position of the welding torch position and the cooling slide plate according to the determined relative positions of the wire position and the left edge and right edge positions. A groove tracking control method for electrogas arc welding.