JPH08276268A - Copy welding method - Google Patents

Abstract

PURPOSE: To enable the precise copy welding by executing the approximate processing to the optical cutting image to extract the coordinate of the feature point of the groove, and putting the initializing value at the point of the center of gravity of the arc light image to correct the position of the wire tip of a welding torch. CONSTITUTION: A welding truck 2 is horizontally moved along a traveling rail 4 which is installed approximately parallel to the joint groove of a material to be welded. A welding torch 3 supported by a welding arm 5 is arranged to the lower part of the welding truck 2, and a longitudinally moving means 6, a vertically moving means 7, and a horizontally turning means 8 are operated by a welding equipment control device 9. A sensor unit 11 detects the groove shape or the position of the wire tip of the welding torch 3, and is provided with a laser beam irradiating equipment and a photographing equipment of the arc light image. An image processor 15 extracts the coordinates of the feature point of the groove from the light cutting image through the straight line and curved line approximation, and the wire tip position is calculated by putting the initializing value to the point of the center of gravity of the arc light image, and controlled by the welding equipment control means 9. The accurate copy welding can be achieved thereby.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a profile welding method for welding while following a joint groove in a horizontal position or a downward position, and particularly to profile welding for automatically performing a welding profile using a laser beam and an optical system. It is about the method.

[0002]

2. Description of the Related Art Since the strength of the furnace body of a blast furnace depends on the strength of the steel shell, it is desired to perform high-quality steel shell welding in the blast furnace repair work. However, in recent years, it is difficult to secure a skilled welder, and since the blast furnace iron shell is a thick plate, automation of the iron shell welding has been attempted in order to make the welding quality uniform and improve the welding efficiency.

Conventionally, as this kind of automation technology, various technologies have been proposed for automatically performing welding copying using a laser beam, an optical system, etc., for example, Japanese Patent Laid-Open No. 62-330.
Invention relating to the "automatic multi-layer welding device" disclosed in Japanese Patent Laid-Open No. 64 (hereinafter referred to as "Citation 1") and Japanese Patent Publication No.
The invention relating to the "welding position detecting device" disclosed in Japanese Patent Publication No. -16226 (hereinafter referred to as "Citation 2") can be mentioned.

In the cited example 1, "an image pickup device for picking up an image of a molten pool, an arc and its front side, a slit light for obliquely projecting a slit light to a filter group and a base material provided in front of this image pickup device. A sensor system consisting of a projector, an image processing system that captures and stores the shape of the projected slit light and reads the shape characteristics of the molten pool, and is connected to this image processing system to calculate the read groove shape characteristic values. And a controlled system that controls the copying and welding conditions by comparing the groove shape characteristic values with the arc and molten pool characteristic values. "

That is, in the cited example 1, the powerful radiant light from the arc / molten pool is removed by opening / closing the electric filter in synchronization with the timing signal of the arithmetic unit when the groove shape information is taken in by the slit light. Along with avoiding the problems of practical space and control time delay,
It is possible to control welding conditions in real time by detecting the state of the molten pool and the shape of the groove.

Further, in the second reference, "While observing an arc with an observation optical system, a linear converging light beam is irradiated on the groove surface near the arc point, and the reflected light is reflected by the observation optical system. By arranging the optical system so that it is observed at the same time as the arc observation, the arc image and the groove light cutting image are directly brought into the field of view of the two-dimensional optical position detector of one observation optical system. The images are detected at the same time. "

That is, in the reference example 2, by arranging optical systems for irradiating the linear condensed light beam and for observing, and detecting the arc image and the groove light cutting image directly in the visual field of the observing optical system. The aim is to improve the welding copying accuracy and downsize the apparatus.

[0008]

By the way, in the reference example 1, the arc / molten pool is opened and closed by opening and closing the electric filter in synchronization with the timing signal of the arithmetic unit when the groove shape information is taken in by the slit light. Although it blocked the intense synchrotron radiation from, it was still difficult to completely eliminate the effect. Also, when performing image processing, it is difficult to remove the influence of welding spatter scattered in the image.

Therefore, in order to avoid the influence of arc light and spatter, it is necessary to separate the laser irradiation part and the welding part to some extent, but on the other hand, when the distance between them increases, thermal deformation of the groove and the tip of the wire. However, there is a problem in that it is difficult to cope with the bending and the like, and it is impossible to perform precise copy welding.

Further, in the second reference example, as in the first reference example, since the arc light is only blocked by the neutral density filter, the influence of the intense arc light on the image processing should be completely removed. Was difficult. Further, there is a problem that the structure is complicated and it is difficult to align the optical axis, and the applicable groove shape is limited.

In view of the above problems, an object of the present invention is to relatively reduce the arc light and the molten pool radiation light with respect to the high-power pulse laser linear light, and also to obtain the thermal deformation of the groove and the wire. Even if the laser irradiation part and the welded part are brought close to each other in order to cope with bending of the tip, etc., the influence of arc light and spatter can be completely avoided, so a very precise welding copying method can be performed. To provide.

[0012]

In order to achieve the above object,
The copy welding method according to the present invention is performed during 1 pass 1 rare welding,
A linear laser beam of a high-power pulse laser is applied to a groove located immediately in front of the direction of travel of the welding torch, and an interference filter is transmitted through an imaging device equipped with a high-speed electronic shutter that operates in synchronization with the irradiation. A light cutting image and an arc light image are taken, and the light cutting image is approximated to extract the groove feature point coordinates, and an initial setting value is added to the center of gravity of the arc light image, and the wire tip position of the welding torch is added. Is calculated, and the wire tip position of the welding torch is corrected based on these values.

In the above structure, it is preferable that the high-power pulse laser is set to an output of 1 to 200 W.

Preferably, the laser linear light is
The groove is positioned 30 to 100 mm forward of the welding torch in the traveling direction.

Further, preferably, the shutter speed of the high-speed electronic shutter is set to 0.1 to 1 msec.

Preferably, the interference filter is set to have a wavelength of the laser beam of ± 10 nm or less.

Further, preferably, the light section image and the arc light image are picked up a plurality of times, each image is binarized, and the groove feature point coordinates are extracted by a logical product calculation process.

Further, when the ratio of the average value of the welding currents before and after the groove exceeds a predetermined value, it is judged that the tip position of the wire is at the back of the groove, and based on this, the wire of the welding torch is determined. The tip position is corrected.

[0019]

According to the configuration of the above-described copy welding method, the high-speed electronic shutter of the image pickup device is operated in synchronization with the irradiation of the laser linear light from the high-power pulse laser. This is because the laser is emitted in an extremely short time and the electronic shutter is opened only at that moment, thereby increasing the intensity of the laser light and relatively reducing intense arc light, molten pool radiation, etc. It removes the influence.

Further, the laser linear light of the high-power pulse laser is applied to the groove located immediately in front of the direction of travel of the welding torch. This is to bring the laser light irradiation part and the welding part close to each other so as to cope with the shape deformation of the groove due to welding heat. Even if the laser light irradiation portion and the welded portion are brought close to each other in this way, the intensity of the laser light is increased, and intense arc light, molten pool radiation light, etc. are relatively reduced, and
Since the light section image and the arc light image are taken through the interference filter for increasing the relative intensity of the laser light, it is possible to completely avoid the influence of the arc light, the molten pool radiation light and the like.

The groove feature point coordinates are extracted by the approximation process, that is, the linear approximation and / or the curve approximation, from the light section image thus captured, and an initial setting value is added to the center of gravity of the arc light image. By calculating the wire tip position, which is the arc point, and comparing the calculated value with the groove feature point coordinates obtained from the above optical cutting image, and adding the deviation to the torch target position as a correction value, a precise welding profile can be obtained. Is what you can do.

In particular, the pulse laser output is 1 to 200 W.
Although it depends on the pulse width, it is necessary to have a high output capable of sufficiently capturing an image with a high-speed electronic shutter. That is,
If it is less than 1 W, it is difficult to capture an image with the high-speed electronic shutter, and if it exceeds 200 W, it is not practical.

If the laser linear light is applied to the groove located 30 to 100 mm forward of the welding torch in the traveling direction, thermal deformation of the groove can be surely dealt with. The reason why it is set to 30 to 100 mm forward of the welding proceeding direction is that if it is less than 30 mm, the influence of the arc light is too strong, and if it exceeds 100 mm, it becomes difficult to deal with shape deformation of the groove due to welding heat. .

Further, the shutter speed of the high-speed electronic shutter is set to 0.1 to 1 msec in order to perform high quality imaging in consideration of the relationship with the output of the pulse laser. That is, an electronic shutter having a shutter speed of less than 0.1 msec is not practical, and if it exceeds 1 msec, the imaging time is too long in relation to the pulse laser.

The reason why the interference filter is set to a wavelength of the laser beam of ± 10 nm or less is that the wavelength of the semiconductor laser has a variation of about ± 10, and therefore the filter needs to have a similar half width.

Further, the light cutting image and the arc light image are picked up a plurality of times, each image is binarized, and the groove characteristic point coordinates are extracted by the logical product calculation process. This is because a large amount of noise image components such as the above is included, so that these noises appearing at unspecified locations are removed by performing a logical product operation process between the binarized images of a plurality of surfaces.

When the ratio of the average values of the welding currents before and after the groove exceeds a predetermined value, it is determined that the tip position of the wire is inside the groove. That is, the average value and standard deviation of the welding current when moving from the front to the back of the groove are taken, and if the standard deviation is within a certain set value, the average value is recorded. Next, take the average value and standard deviation of the welding current at the back of the groove, compare the average value recorded when the standard deviation is within a certain set value with the average value at the back of the groove, and then calculate the ratio. If it is within a certain set value, it is determined that the wire tip position is inside the groove. Based on this determination, precise welding copying is performed.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the copy welding method according to the present invention will be described below in detail with reference to the accompanying drawings. The profile welding method according to the present embodiment is performed using a profile welding apparatus as shown in FIG. As shown in the figure, the welding carriage 2 of the profile welding apparatus 1 is configured to travel along a traveling rail 4 while supporting the welding torch 3.

The traveling rail 4 is installed substantially parallel to the joint groove of the object to be welded (not shown) in a horizontal posture or a downward posture. Therefore, the welding carriage 2 travels substantially horizontally along the longitudinal direction of the traveling rail 4. A straight traveling rail and an arcuate traveling rail can be used for the traveling rail 4, and an object to be welded having a curved surface can also be a welding target. Therefore, if the arcuate traveling rail is used, the copy welding apparatus 1 of the present embodiment can be applied to the welding of the circumferential joint of the blast furnace iron shell.

A welding torch 3 is disposed below the welding carriage 2 and supported by a welding arm 5. The welding arm 5 is connected to the welding carriage 2 via a front-back movement means 6, a vertical movement means 7 and a horizontal rotation means 8 arranged on the welding carriage 2.

The front-rear moving means 6 moves the welding torch 3 in the plate thickness direction of the object to be welded, and the vertical moving means 7 moves the welding torch 3.
Is moved in the vertical direction, and the horizontal rotating means 8 moves the welding torch 3
For rotating in a horizontal plane, each of which is connected to the welding machine controller 9.

Therefore, the front-rear moving means 6 and the up-down moving means 7
The horizontal rotation means 8 is operated by a gear mechanism (not shown) driven by a motor according to the rotation speed / position calculated by the welding machine control device 9. In particular, the horizontal rotation means 8 controls the rotational speed and position of the motor so that the axis of curvature of the workpiece and the axis of the welding torch 3 are always parallel.

That is, the welding torch 3 is moved by the forward / backward moving means 6.
The welding torch 3 can be moved up and down by the up-and-down moving means 7, and by controlling these by the welding machine control device 9, the aim of the welding torch 3 can be freely decided up, down, left and right. it can.

Further, the horizontal rotating means 8 can rotate the welding torch 3 in a horizontal plane. Therefore, when the traveling rail 4 and the object to be welded have different curvatures, the horizontal rotating means 8 is operated so that the direction of the welding torch 3 can always be maintained in a constant direction with respect to the object to be welded. As a result, several types of traveling rails 4 can be used according to the curvature of the workpiece.
Therefore, it is possible to weld the objects to be welded having different curvatures with one type of traveling rail 4.

The torch mounting portion of the welding arm 5 is provided with vertical rotating means 10 having an arc shape. The vertical rotating means 10 is means for rotating the welding torch 3 in the vertical plane, and is operated by a gear mechanism (not shown) driven by a motor according to the rotation speed and position calculated by the welding machine control device 9. Is made like. Since the welding torch 3 is rotated by the vertical rotating means 10 while drawing an arc around the welding wire tip (welding arc point),
Welding torch 3 in the vertical plane without the welding arc swinging
The tilt angle of can be changed.

A sensor unit 11 shown in FIG. 2 is connected to the welding carriage 2 so as to detect the groove shape of the joint and the position of the wire tip of the welding torch 3. As shown in the figure, in the sensor unit 11,
A laser irradiation device 12 that irradiates the joint groove with laser linear light, and an imaging device 13 that captures a light cut image of the laser linear light and an arc light image of the welding torch 3 are housed.

The laser irradiation device 12 has a wavelength of 680 ± 10.
It is composed of a semiconductor pulsed laser with a wavelength of 1 nm and an output of 1 to 200 W, and a collimator lens and a cylindrical lens for linearizing the laser light are used.

In this embodiment, the wavelength of the laser light is set to 68.
The reason why it is set to 0 nm is as follows. That is,
The spectrum of the arc light is Fe or shield gas (Ar
Etc.) close to the characteristic spectrum intensity distribution of 600 to 700
The intensity decreases at wavelengths near nm. In addition, the spectrum of the molten pool radiation increases in intensity as the wavelength becomes longer from the visible light to the infrared light wavelength range. Therefore, in this embodiment, the wavelength of the laser light used for measurement is set to 680 nm, which is less likely to be affected by the arc light and the molten pool radiation.

The output of the pulse laser is set to 1 to 200 W because it depends on the pulse width, but it is necessary to have a high output capable of sufficiently capturing an image with a high-speed electronic shutter described later.
An output of 35 to 50 mW is usually used for the copy welding.

The image pickup device 13 picks up a light section image and an arc light image, but a CCD camera equipped with a high-speed electronic shutter (not shown) that opens and closes in an extremely short time is adopted. The use of a CCD camera as the image pickup device 13 has the advantages that the CCD camera is smaller and easier to handle than an image pickup tube camera, and there are no problems such as burning, and when a two-dimensional CCD element is used. Is advantageous in that image processing such as shape recognition is easy because there are few failures because mechanical laser scanning is unnecessary and two-dimensional information is handled compared to one-dimensional ones. Because.

Further, the shutter speed of the high speed electronic shutter is set to 0.1 to 1 msec. The shutter speed is set to 0.1 to 1 msec in order to perform high quality imaging in consideration of the relationship with the output of the pulse laser.

An interference filter 15 having a wavelength of laser light (680 nm) ± 10 nm is provided in front of the image pickup lens 13a of the image pickup device 13. The wavelength of the interference filter 14 is set to the laser wavelength ± 10 nm because the interference filter is used to increase the relative intensity of the laser light, but the wavelength of the semiconductor pulse laser is ± 10 nm.
This is because the interference filter 14 needs a similar half-value width because there is a variation of about nm.

Further, the image pickup device 13 is connected to an image processing device 15 for processing the picked-up light section image and arc light image. This image processing device 15 extracts groove feature point coordinates from the light section image by approximation processing, that is, linear approximation and / or curve approximation, and adds an initial setting value to the center of gravity of the arc light image to determine the wire tip position. Is a calculation means for calculating

The image processing device 15 is connected to the welding machine control means 9 for controlling the welding torch 3 based on the calculated value and correcting the wire tip position.

The laser irradiation device 12 is set in the sensor unit 11 so as to irradiate the laser linear light perpendicularly to the groove located 30 to 100 mm forward of the welding torch 3 in the traveling direction. Has been done. Further, the image pickup device 13 picks up the light section image and the arc light image from diagonally in front of the welding torch 3 so as to pick up the image.
It is located within.

Using the profile welding apparatus 1 described above, the profile welding method of this embodiment is performed as follows. The profile welding method according to the present embodiment is used, for example, when welding a groove of a blast furnace iron shell, and is performed by a 1-pass-1 rare-torch angle changing lateral welding method. At that time, the profile welding apparatus 1 causes the welding carriage 2 to travel along the traveling rails 4, and the welding machine control device 9 causes the longitudinal movement means 6, the vertical movement means 7, the horizontal rotation means 8 and the vertical rotation means 10. The automatic torch welding is performed by weaving the welding torch 3 by controlling four axes.

In the profile welding method of this embodiment, during the one-pass / one-rare welding, the laser irradiation device 12 housed in the sensor unit 11 is installed in the groove located immediately in front of the welding torch 3 in the traveling direction. Irradiate the laser linear light of a high power pulse laser.

Specifically, the laser irradiating device 12 is 30 to 100 forward from the welding point of the welding torch 3 in the welding proceeding direction.
1 to 200 perpendicular to the groove at a position separated by about mm
The pulsed laser linear light of W output is irradiated. If the output of the pulse laser is set to 1 to 200 W, if it is less than 1 W, it is difficult to capture an image with a high-speed electronic shutter.
This is because if it exceeds W, it is not practical.

Further, the irradiation position of the pulsed laser linear light is set 30 to 100 mm forward of the welding torch 3 in the advancing direction because the influence of the arc light is too strong when the distance is less than 30 mm and exceeds 100 mm. This is because it is difficult to deal with shape deformation due to welding heat in the case of a groove with a very thick plate such as a blast furnace iron skin.

Next, by the image pickup device 13 equipped with a high-speed electronic shutter that operates in synchronization with the irradiation of the pulsed laser linear light, the light cut image of the pulsed laser linear light and the welding torch 3 are transmitted through the interference filter 14. The arc light image of. The shutter speed of the high-speed electronic shutter is set to 0.1 to 1 msec as described above. Set the shutter speed to 0.
It is not realistic to set the shutter speed to 1 to 1 msec for an electronic shutter having a shutter speed of less than 0.1 msec.
This is because if it exceeds 1 msec, the imaging time becomes too long in relation to the pulse laser. For example, when the output of the pulse laser is set to 1 W, the shutter speed of the high speed electronic shutter is set to 500 μsec.

The wavelength of the interference filter 15 is set to a wavelength of laser light (680 nm) ± 10 nm or less in order to avoid the influence of intense arc light and molten pool radiation, and the light picked up by the image pickup device 13 is used. The cut image and the arc light image are input to the image processing device 15.

As described above, in the image pickup device 13, in order to reduce the influence of the intense arc light and the molten pool radiation light, the interference filter 14 is mounted in front of the image pickup lens 13a, and the pulse laser linear light is irradiated. By instantaneously opening the high-speed electronic shutter in synchronism with the above, the relative intensity of the pulsed laser linear light with respect to the arc light and the molten pool radiation can be increased. Therefore, the single imaging device 13 can capture the light-section image and the arc light image in the same visual field.

Since the image pickup with the interference filter 14 and the high-speed electronic shutter alone is not sufficient for image measurement, the image quality is improved by image processing. That is, the imaging device 13 captures the light section image and the arc light image a plurality of times. The light-section image and the arc-light image are captured multiple times because the light-section image and the arc-light image during welding contain many noise image components such as spatter in the image. This is to remove these noises appearing at unspecified locations by performing a logical product operation process between the (black and white / grayscale process) images.

Specifically, the light section image and the arc light image captured at the first time are recorded in the image memory, the light section image and the arc light image captured at the second time are taken in, and the binary image is stored together with the recorded image. After performing the smoothing process and the smoothing process, 2
A logical product (AND) process is performed for each pixel between two images to remove a noise image. If necessary, the same logical product operation is performed on the light section image and the arc light image captured the third time.

Next, for the AND-processed image, isolated points
Remove end points. That is, after the 3 × 3 smoothing filter process (smoothing operator) is performed on the binarized image, the second binarization process is performed. X-direction differential processing (difference operator) is performed on the smoothed binary image to perform line image conversion. Then, the linear approximation method is used to extract the in-groove feature points (first layer) shown in FIG. 3A, and the desired coordinate values are obtained by three-dimensional coordinate conversion. For the second and subsequent layers, points on the extension of the straight line portion are extracted as feature points as shown in FIG.

Specifically, in order to detect the groove feature points, a linear approximation method and / or a curve approximation method called a division / synthesis method (start point / end point approximation) and a tracking method (cone intersection method) are used. calculate. The detailed contents of this approximation process are described in "Recognition and Understanding of Drawings", by Sho Osawa et al., Shokoido Co., Ltd.

That is, the groove feature points are extracted based on the feature point extraction flow shown in FIG. As shown in the figure, first, in step (ST) 1, set the search window,
The start and end points in the window are detected (ST2).

Specifically, as shown in FIG. 5, when P1, P2, and P2 'are detected by the tracking method, Ps (start point) and Pe (end point) are determined, and pixels are determined by the search window shown in FIG. To track. That is, from Ps, the downward search window shown in FIG.
From here, the upward search window shown in FIG. 6B is used.

Then, the pixel connection state in the vicinity viewed from the pixel C is checked, and the pixel having the highest priority is set as the next tracking pixel. Downward priority is PD>PRD>PLD> PR
> PL, and the upward priority is PU>PRU> PLU
>PR> PL.

If the connection is interrupted, the search window is shifted as shown in FIG. That is, the window center pixel C is shifted to the positions of C1, C2 and C3,
A window with a new center C is generated. In this case, the priority order is C1>C2> C3. If the connection cannot be found even after shifting, the original center pixel is set as the singular point.

After detecting a pixel in the search window, it is checked whether or not it fits in a straight line. First, the pixel is traced downward from Ps, and P1 is obtained as follows (S
T3). First, in step 3, as shown in FIG. 8, the starting point pixel Ps and the pixel Q1 to be tracked next are selected. In this case, Q1 is not necessarily the next connected pixel. Also,
Two tangents are drawn from Ps with respect to a circle having a center of Q1 and a radius of r, and the enclosed area is designated as S1. Note that Q1 is determined by the value of the radius r, and the line segment PsQ1> r. Then, Q1 is set to Qi, S1 is set to Si, and the next step 3
Go to.

In step 3, the pixel Qi + 1 connected next to Qi is searched in the search window, and this is the region Si.
If so, proceed to step 3. On the other hand, if Qi + 1 does not exist or does not exist in the region Si, Qi is set as the feature point P1.

In step 3, two tangent lines are drawn from Ps with respect to a circle having a radius r and a center Qi + 1. Then, the region surrounded by these is set to Si + 1, the common region of Si and Si + 1 is set to Si, and Qi + 1 is set to Qi, and the process returns to step 3.

Similarly, the pixel is tracked upward from Pe,
P2 is obtained (ST4). This process is the same as step 3 above.
Repeat steps similar to. However, the upward search window is used.

Next, as shown in FIG. 9, P0 is detected. However, since the line image is often interrupted in the deep part of the groove, the tracking method cannot be used, so the division / synthesis method (start point / end point approximation method) is performed. To use. A pixel having the maximum Euclidean distance with respect to the line segment having P1 and P2 obtained by the tracing method as the start point and the end point is obtained, and this is designated as P0 (ST5, ST6). That is, P
The coordinates of 1, P2 are (X1, Y1), (X2, Y2)
Then, the line segment P1P2 from the pixel Pj (Xj, Yj)
The distance Ej to is expressed by the following equation.

[Equation 1]

As shown in FIG. 10, the X direction is WX.
The distance calculation from 1 to WX2 and from Y1 to Y2 in the Y direction is performed. Then, in order to avoid the influence of noise or the like, pixel detection is performed from the forward direction and the reverse direction, and only those whose coordinates match are valid. In this case, it is 1 pixel / 1 LINE due to the X-direction differentiation.

Next, if it is the first welding (ST7), the radius r is set to a large value and P is set by the tracing method with Pe as the starting point.
2'is detected (ST8). The formula of the tangent line from the point Ps (Xs, Ys) to the circle with the radius r centered on the point Pi (Xi, Yi) is as follows.

[Equation 2] Further, since the point (a, b) is in the area surrounded by the tangent formula, the following formula is established.

(Equation 3)

Next, as shown in FIG. 11, P0 'is detected. That is, the line segment P1P2 and P
An approximate straight line for 2′P0 (passes through P1 and P2 ′) is obtained, and the intersection is defined as P0 ′ (ST9, ST10). That is, with P1 as the starting point, pixels are detected up to P0 (the same as in the division / synthesis method, the forward direction and the reverse direction are not used, and the search window is not used), and it is checked whether or not it fits on a straight line as follows. .

First, in step 9, a circle with a radius r0 centered at P0 is drawn, and two tangents are drawn from P1 to this circle. Then, it is checked whether or not the pixel Q1 next to P1 is in the area S0 surrounded by the tangent line. Q this
Repeat until 1 is detected. However, line segment P0Q1>
r, used in step 9.

In step 9, two tangent lines are drawn from P1 to a circle having a center of Q1 and a radius of r, and the enclosed area is S1.
And Then, Q1 is set to Qi and S1 is set to Si, and the process proceeds to the next step 9.

In step 9, the next pixel Qi + 1 of Qi + 1
, And if this is in the region Si, go to step 9. On the other hand, if it is not in the area Si, step 9 is repeated. The Y direction is Y0 (Y of P0
(Coordinates), the process proceeds to step 9 described later.

In step 9, a circle having a radius r is drawn centering on Qi + 1 and two tangent lines are drawn from Ps to this circle.
The area surrounded by these is defined as Si + 1, and Si and Si + 1
Of the common area of Si and Qi + 1 as Qi, step 9
Return to

In step 9, a linear equation of the line segment P1Qi is obtained. Similarly, using P2 as the starting point, a linear equation of the line segment P2Qi 'is obtained, and the intersection point of the line segment P1Qi and the line segment P2Qi' is set to P
It is set to 0 '(ST10).

After transmitting the coordinate data (ST1
1) Return to step 2. If it is not the first welding in step 7, the coordinate data is immediately transmitted (ST11).

Further, the image pickup device 13 picks up an arc light image together with a light section image. Using a high speed shutter,
The intensity of the pulsed laser light is increased to relatively reduce the intense arc light, and the light cut image and the arc light image are captured through the interference filter 14 that increases the relative intensity of the laser light. Therefore, the intensity of the arc light can be relatively reduced and the intense arc light can be imaged in a dot shape.

The image processing device 15 binarizes the picked-up point-shaped arc light image, and then detects the center of gravity thereof. By adding the initial setting value at this center of gravity,
A desired coordinate value is obtained by calculating a wire tip position which is an arc point and converting it into a three-dimensional coordinate.

Here, the initial setting value added to the arc light image will be described. As shown in FIG. 12A, the coordinates on the camera image of the tip of the wire contacting the front and back of the groove at the welding start point are (Xa, Ya), (Xb, Yb), respectively.
In addition, as shown in FIG. 12B, the center of gravity points of the arc light image before and after the groove immediately after the start of welding are respectively (X
a ', Ya'), (Xb ', Yb'), the initial setting values are as follows.

That is, the initial setting value before the groove is DXa = X
a-Xa 'and DYa = Ya-Ya'. On the other hand, the groove back initial setting values are DXb = Xb−Xb ′ and DYb = Yb.
-Yb '.

At this time, as shown in FIG. 13, image adjustment is performed so that the maximum diameter of the arc light image is about 50 pixels, so the upper and lower limits of these are set as follows.

[Equation 4] In this way, the initial set value is calculated during welding (first weaving) and added after the second weaving to obtain a desired coordinate value.

Then, the calculated coordinate values are compared with the groove feature point coordinates obtained from the light section image, and the deviation is added as a correction value to the torch target position, and based on the result, the welding machine controller 9 Corrects the wire tip position of welding torch 3.

Specifically, the welding machine control device 9 changes the torch aiming position and the swing width on the front side and the back side of the groove online based on the calculated groove feature point coordinates. At this time, as shown in FIG. 3A, the wire tip position coordinates are compared with the groove front P2 point or the groove back P0 point respectively, and if there is a deviation, the difference is used as a correction value for the welding torch 3. Control. Further, the weaving pitch is changed to reflect the change in the laminated thickness in the next layer welding.

Further, when the ratio of the average value of the welding currents before and after the groove exceeds a predetermined value, it is determined that the wire tip position is inside the groove. Specifically, take the average value and standard deviation of welding current and voltage when moving from the front of the groove to the back of the groove, and if the standard deviation is within a certain set value,
Record the average value.

Next, the average value and standard deviation of the welding current and voltage at the back of the groove are taken, and when the standard deviation is within a certain set value, the recorded average value and the average value at the back of the groove are compared. If the ratio is within a certain set value, it is determined that the wire tip position is behind the groove.

Specifically, the front side A to the groove shown in FIG.
The average value Ia of the welding current at the position A'is represented by the following mathematical formula.

(Equation 5) Further, the average value Ib of the welding current at the groove depths BB ′ shown in FIG. 14 is represented by the following mathematical expression.

(Equation 6) K (K = Ib / I), which is the ratio of these actual values (average values)
When a) is 0.9 times or more of the set value k (k = ib / ia, ia: groove front current set value, ib: groove back current set value), the wire tip position is in the groove back. To determine.

When the wire tip position is determined, the wire tip position of the welding torch is corrected as follows. That is, when it is determined that the wire tip position is not at the groove depth, a preset correction value is added to the initial setting value for calculating the wire tip coordinate point from the center of gravity of the arc image, and this is added to the next wire tip. By using it for calculating the position, extremely precise copy welding can be performed.

As described above, the copy welding method of this embodiment is
By opening the high-speed electronic shutter in synchronization with the irradiation of the laser linear light of the high-power pulse laser, the intensity of the laser linear light is increased and the intense arc light and molten pool are relatively reduced. . Therefore, since it is possible to capture and capture the light section image and the arc light image within the same field of view of the single image pickup device 13, unlike the above-described reference example 2, the optical axis of the optical system can be easily aligned. You can

Further, by extracting the coordinates of the groove characteristic points from the light section image and calculating the wire tip position from the arc light image, it is possible to cope with thermal deformation of the groove, bending of the wire tip, etc. Welding can be performed.

[0088]

As described above, according to the profile welding method of the present invention, the arc light and the molten pool radiation can be relatively reduced with respect to the laser linear light of the high output pulse laser. Moreover, even if the laser irradiation portion and the welding portion are brought close to each other to cope with thermal deformation of the groove, bending of the wire tip, etc., the influence of arc light and spatter can be completely avoided, so it is extremely precise. It has an excellent effect of being able to perform welding copying.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the overall structure of a profile welding apparatus used in the profile welding method of the present embodiment.

FIG. 2 is a plan view showing an internal structure of a sensor unit in the copy welding apparatus.

FIG. 3 shows the extraction situation of in-groove feature points in the profile welding method of the present embodiment, (a) is an explanatory diagram of the first layer feature points,
(B) is an explanatory view of the characteristic points of the second and subsequent layers.

FIG. 4 is an explanatory diagram showing a flow of extracting groove characteristic points in the profile welding method according to the present embodiment.

FIG. 5 is an explanatory diagram showing the concept of extracting feature points in the groove in the profile welding method of the present embodiment.

6A and 6B show a search window used for extracting a feature point in a groove in the profile welding method of the present embodiment, FIG. 6A is an explanatory view of an upward search window, and FIG. 6B is an explanatory view of a downward search window. is there.

FIG. 7 is an explanatory diagram showing a shift state of a search window used for extracting a feature point in a groove in the copy welding method according to the present embodiment.

FIG. 8 is an explanatory diagram showing a detection state of P1 by a tracking method in extraction of a feature point in a groove adopted in the present embodiment.

FIG. 9 is an explanatory diagram showing a P0 detection state by a division / synthesis method in extraction of in-groove feature points adopted in the present embodiment.

FIG. 10 is an explanatory diagram showing a P0 detection state by distance calculation in the extraction of the in-groove feature points adopted in the present embodiment.

FIG. 11 is an explanatory diagram showing a detection situation of P0 ′ by the modified tracking method in the extraction of the feature point in the groove adopted in the present embodiment.

12A and 12B show a situation of calculation of initial setting values in the detection of the wire tip position adopted in the present embodiment, FIG. 12A is an explanatory diagram of the wire tip position before welding, and FIG. FIG.

FIG. 13 is an explanatory diagram showing the relationship between the maximum diameter of the arc light and the pixel in the detection of the wire tip position adopted in this embodiment.

FIG. 14 is a diagram for explaining the range of the average value and standard deviation of the welding current / voltage for determining the groove depth in the detection of the wire tip position adopted in the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Copy welding apparatus 2 Welding trolley 3 Welding torch 4 Traveling rail 5 Welding arm 6 Forward / backward moving means 7 Up / down moving means 8 Horizontal turning means 9 Welding machine control device (robot controller) 10 Vertical turning means 11 Sensor unit 12 Laser irradiation device 13 First Imaging Device 13a Imaging Lens 14 Interference Filter 15 Image Processing Device

Claims (7)

[Claims] 1. A high-speed electron which is operated in synchronization with the irradiation of a linear laser beam of a high-power pulse laser to a groove located immediately in front of the direction of travel of a welding torch during 1-pass 1 rare welding. An optical filter and an arc light image are taken through an interference filter by an image pickup device equipped with a shutter, the groove feature point coordinates are extracted by approximating the light cut image, and the barycentric point of the arc light image is extracted. A profiling welding method characterized in that the wire tip position of the welding torch is calculated by adding the initial setting value to, and the wire tip position of the welding torch is corrected based on these. 2. The high-power pulsed laser is 1-200.
The copy welding method according to claim 1, wherein the output is set to W. 3. The copy welding method according to claim 1, wherein the laser linear light is applied to a groove located 30 to 100 mm forward of the welding torch in the traveling direction. 4. The copy welding method according to claim 1, wherein a shutter speed of the high-speed electronic shutter is set to 0.1 to 1 msec. 5. The copy welding method according to claim 1, wherein the interference filter is set to have a wavelength of the laser beam of ± 10 nm or less. 6. The method according to claim 1, wherein the light section image and the arc light image are imaged a plurality of times, each image is binarized, and the groove feature point coordinates are extracted by a logical product calculation process. The copy welding method according to any one. 7. The wire of the welding torch is determined based on the fact that the wire tip position is determined to be inside the groove when the ratio of the average values of the welding currents before and after the groove exceeds a predetermined value. The profile welding method according to any one of claims 1 to 6, wherein the tip position is corrected.