JP2003001418A - Welding condition monitoring device - Google Patents

Abstract

(57) [Problem] To enable stable and high-quality welding work even when a groove assembly error occurs. A slit light beam is provided in front of a welding torch in a traveling direction, and a slit light beam is radiated to a groove surface. Two-dimensional light receiving means, second two-dimensional light receiving means arranged to obliquely observe the arc image of the tip of the welding torch, and a casing surrounding the light emitting means and the first and second two-dimensional light receiving means. An image capture trigger signal generator for outputting either a weaving center signal or an image capture reference synchronization signal; and first and second two-dimensional light receiving sections synchronized with a signal output from the trigger signal generator. And an image processing device for storing desired images and detecting desired information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic welding apparatus, detects deviation of a groove position from a welding torch position and groove shape information, and automatically detects a groove position and welding conditions based on the detected information. Involved in welding equipment while controlling

[0002]

2. Description of the Related Art As a conventional automatic welding apparatus of this type, an example disclosed in Japanese Patent Laid-Open No. 5-138354 is known. In addition, a sensor for an automatic welding device is disclosed in JP-A-5-138.
The example described in Japanese Patent No. 353 publication is known.

Among these, in Japanese Patent Laid-Open No. 5-138354, the internal shape of the groove obtained from the visual information in the welded portion obtained from the ITV camera and the light cutting line of the groove projected by the laser slit light is calculated. , Find the welding torch deviation,
A method of performing welding torch position control is shown.

In Japanese Patent Laid-Open No. 5-138353, a sensor box having a laser slit light and a CCD camera and having a cooling function is incorporated into a welding torch and a means for sucking and discharging welding fumes and an electric motor around the welding torch. A laser sensor constituted by a rotation drive unit rotated by a motor is shown.

[0005]

DISCLOSURE OF THE INVENTION Even when the line to be welded is deviated from the welding line previously taught at the time of setting the member to be welded or the shape of the groove is changed, the groove position is shifted or the shape is changed. Is detected, and the detected welding profile is corrected using these detection information,
By performing welding while adaptively controlling the welding conditions, it is possible to obtain high quality weld beads.

For this purpose, the position to be welded and the groove shape must be accurately measured, the welding torch must be correctly traced by this measurement information, and welding must be performed under appropriate welding conditions.

The example disclosed in the above-mentioned Japanese Patent Laid-Open No. 5-138354 is based on the slit light irradiated to the bead of the front welding pass in the front of the welding advancing direction or the groove including the bead surface immediately after welding in the rear of the welding advancing direction. Is a method for controlling the target position of the welding torch by obtaining the groove position or the torch position deviation with respect to the welding bead contact from the image of the ITV camera that captures both the reflection image of the welding torch and the tip of the welding torch.
However, although this example shows a method of obtaining the torch position deviation during welding and controlling the copying, the welding carriage in which the laser slit light emitting unit for detecting the groove shape and the ITV camera move in the welding line direction. It is a structure installed in. For this reason, when the groove position greatly shifts in the vertical direction or the horizontal direction, the groove image is displaced from the screen, which makes it difficult to detect the groove shape.

The example disclosed in the above-mentioned Japanese Patent Laid-Open No. 5-138353 is a rotary drive unit which is incorporated in a sensor box for housing a laser slit light and a CCD camera and a welding torch and is rotated by an electric motor around the welding torch. This is a method that enables detection when the groove position is largely displaced in the vertical direction or the horizontal direction by configuring with. In this example, the detection unit for detecting the groove position has a structure integrated with the welding torch. Therefore, in weaving welding when the gap or groove width of the groove is large, the detection portion vibrates in a direction orthogonal to the welding proceeding direction, and the image also vibrates in the screen, making it difficult to detect the groove position. Become.

As a means for solving the above problems, a method is used in which a welding operator judges the deviation between the welding torch and the groove by visual inspection or a remote monitor camera, and performs welding while manually correcting the welding torch position. However, there is a practical problem that it requires skill, it is difficult to perform welding with high precision, and that it takes time to correct the position.

An object of the present invention is to advantageously solve the above-mentioned problems. The deviation of the groove position from the welding torch position and the groove shape information are detected, and the groove position copying and welding conditions are detected based on this detected information. It is to provide a device for welding while automatically controlling the welding.

[0011]

In order to achieve the above-mentioned object, the present invention provides a projecting means for irradiating a slit-shaped light beam arranged in front of the welding torch in the traveling direction, and the slit-shaped light beam on the groove surface. A first two-dimensional light receiving means arranged so as to obliquely observe the scattered image obtained upon irradiation, and a second two-dimensional light receiving means arranged so as to obliquely observe the arc image of the welding torch tip. , The light projecting means and the first
And a casing enclosing the second two-dimensional light receiving means, and a partition provided in the lower portion of the casing and having a hole only in the observation optical axis of the second two-dimensional light receiving means are integrally configured. It has a structure to be attached to. Further, an image capture trigger signal generator for outputting either a weaving center signal or an image capture reference synchronization signal, and a signal output from the trigger signal generator are obtained by the first and second two-dimensional light receiving means. An image processing device that stores a desired image and detects desired information, and a control device that controls the groove position deviation and welding conditions based on the detection information obtained from the image processing device.

At the time of weaving welding, an image is captured by a signal synchronized with the weaving center signal output from the trigger signal generator. Further, during welding without weaving, image capture is performed with a signal synchronized with the image capture synchronization signal output from the trigger signal generator. As a result, even in the case of welding in which a large groove misalignment occurs or when welding is performed using weaving, the misalignment of the groove position with respect to the welding torch position and the groove shape information are detected, and the groove is detected based on this detection information. It becomes possible to perform welding while automatically controlling the position copying and welding conditions.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a schematic configuration diagram showing an embodiment of a welding condition monitoring apparatus of the present invention. In the figure, 1 is a welding torch, 2 is a welding wire fed from the center of the welding torch, and 3 and 4 are members to be welded. 5 is members to be welded 3 and 4
The welding line of the V joint according to (hereinafter, the vicinity of this welding line is referred to as a groove), 7 is a light projecting means for irradiating the slit-shaped light beam 11, and 8 is a first two-dimensional light receiving means such as ITV.
Reference numeral 34 is an interference filter that transmits only the emission wavelength of the slit-shaped light beam 11. The two-dimensional light receiving means 8 receives a reflection image (hereinafter, referred to as a light section image) 12 when the members 3 and 4 to be welded are irradiated with the slit-shaped light beam 11 through the reflection mirrors 14 and 15 from an oblique edge of the groove. Observe (imaging). Reference numeral 9 is a second two-dimensional light receiving means, and reference numeral 35 is a filter for dimming an arc light image during welding. The filter 35 is driven by an electric motor (not shown) or the like to be arranged on the front surface of the two-dimensional light receiving means during welding, and has a movable structure so as to be removed from the front surface of the two-dimensional light receiving means when not welding. . Two-dimensional light receiving means 9
Observes (images) the welding wire tip through the reflection mirror 19. The reflecting mirrors 19, 14 and 19 have a structure (not shown) that can be rotationally adjusted in the illustrated arrow directions θx and θy. Rectangular groove 10, circular holes 13 and 18
Each has an optical transparent window mounted therein, and has a structure (not shown) that can be replaced when it is contaminated by fumes generated by welding. Reference numeral 6 denotes a housing, which is a slit-shaped light projecting means 7, an interference filter-34, a two-dimensional light receiving means 8, a filter-35, a two-dimensional light receiving means 9, and a reflection mirror 1.
4, 15, and 19 are shielded from the outside air (hereinafter referred to as a sensor head including the housing and each component). Also, the housing 6
Has a closed structure, and air can be injected from the outside into the inside (not shown). Reference numeral 16 is a partition having a hole formed on the observation optical axis of the two-dimensional light receiving means 9, and is attached to the outer lower portion of the housing 6. The screen 16 has a replaceable structure (not shown). Reference numeral 20 is a virtual plane provided in the housing 6. The slit-shaped light beam projecting means 7, the interference filter-34, the two-dimensional light receiving means 8, the filter-35, the two-dimensional light receiving means 9, the reflection mirrors 14, 15 and 1 described above.
9. The central axes of the rectangular groove 10, the circular groove 10 and the circular holes 13 and 18 are all arranged in the plane 20.

FIG. 2 is a schematic diagram showing an embodiment of the automatic welding apparatus of the present invention. In the figure, the same parts as those in FIG. 1 are denoted by the same symbols. Reference numeral 21 is a slit light drive control circuit for driving and controlling the slit light projecting means 7, 22 and 2
Reference numeral 3 is a control circuit for the two-dimensional light receiving cameras 8 and 9 which outputs an analog video (image) signal to the outside. A video distributor 24 obtains a plurality of video output signals from the video input signal.
The image distributor 24 in the figure has two types of image inputs from two types of image inputs.
Get two video output signals.

Reference numeral 28 denotes a welding torch having the welding torch 1 attached to the tip end thereof, which is movable above the members 3 and 4 to be welded to freely move in the welding line direction X, the welding line orthogonal direction Y, and the vertical direction Z shown in FIG. It is a position control mechanism. The welding torch position control mechanism 28 is a device such as an articulated robot having six-axis movement degrees of freedom. The sensor head 6 is arranged integrally with the welding torch 1. 29 is a welding torch position control device for driving and controlling the welding torch position control mechanism 9;
Reference numeral 30 is an external trigger generation circuit, and 36 is a welding power source.

An image processing apparatus 27 is composed of the following parts (not shown). An image input unit for inputting multi-valued image data by A / D converting the analog image signals output from the light receiving unit control circuits 22 and 23 into a digital amount, a multi-valued image storage unit for storing multi-valued image data, a multi-valued image An arithmetic unit processing unit that detects various groove shape information such as a desired groove position deviation, a gap and a groove area from the multi-valued image data stored in the image storage unit, and a main control unit that integrally controls these Etc.

Reference numeral 25 is a video switcher which selectively outputs only one image signal from the plurality of analog image signals to the outside. Reference numeral 26 is a TV monitor, which displays output video signals from the light receiving means control devices 22 and 23 and outputs and displays the processing result from the image processing device 27.

Reference numeral 31 is an overall control device for integrally controlling the image processing device 27, the slit light drive control circuit 21, the welding torch position control device 29, and the welding power source 36, and is constituted by a personal computer or the like. Overall control device 3
Reference numeral 1 denotes a function of preliminarily storing a target copying position of a welding torch with respect to a position of a member to be welded for performing welding, and a welding torch based on the target position tracking of the welding torch and groove position deviation information obtained from the image processing device 12. And a welding line tracing control function for outputting the aiming position information to the welding torch position control device 29. In addition, welding condition data such as welding current, voltage, and welding speed can be stored, and these data can be corrected before starting welding. Further, it has a function for determining welding conditions from the groove shape detection information obtained from the image processing device 27, and a welding condition control function for outputting the welding condition information to the welding power source 36. Reference numeral 33 is a housing in which the above devices 21 to 32 are incorporated.

FIG. 3 shows an example of setting the members 3 and 4 to be welded, which is viewed from above. This is a case where the length L from the start point S to the end point E on the right side of the drawing is joined by welding.
The size of the root gap at the welding start point S is 0, the size of the root gap at the welding end point E is G, and the root gap changes substantially linearly from S to E.

FIG. 4 shows the welded member shown in FIG.
It is a figure which shows an example of the welding method in the case, a welding torch tip
It is the figure which looked at the movement of from above. W1, W2 and W3 are open
Welding torch weaving centered on the tip center line C
Width. In the present invention, of the welding length L, L₀Between
Welding without servicing, L₁W between₁The weaving width of
Weaving welding held, L₂W between₂Weaving
Weaving welding with width, L₃W between₃Weebe
Weaving welding with a wide width is performed. L _FourBetween
It is an example of the processing at the end of contact₃From the weaving width of
Do not slightly advance in the direction of travel until the weaving width reaches 0.
Welding is performed by gradually changing the temperature. Welding situation monitoring of the present invention
As described above, the device includes slit-shaped light beam projecting means 7,
A sensor head including the two-dimensional light receiving means 8 and 9 is welded.
It is arranged integrally with the arch 1. Therefore, the above-mentioned weebi
The two-dimensional light receiving means 8 and 9 when performing the welding operation.
The resulting image appears to shake left and right. This is a groove type
It becomes a problem when detecting the condition.

FIG. 5 shows an external trigger generating circuit 3 according to the present invention.
FIG. 3 is a block diagram showing the internal configuration of 0 and the image capture timing. The same devices as those in FIG. 2 are denoted by the same symbols. In the figure, the signal S1 is a rectangular wave pulse signal output from the welding torch position control device 29 at a timing indicating the weaving width center position during the weaving welding shown in FIG. It is called). Signal S2 is used during weaving welding.
Low level, Hig when not weaving welding
This is a rectangular wave pulse signal output from the welding torch position control device 29 so as to be at the h level.

Reference numeral 36 is a pulse generator which outputs a rectangular wave pulse signal at a constant frequency only when the signal S2 is at a high level. The signal S3 is a signal output from the pulse generator 36. As the signal S3, a rectangular wave pulse signal is output at a constant frequency only when the signal S2 is at a high level, that is, when weaving welding is not performed. An OR circuit 37 receives the signals S1 and S2 as inputs and outputs a signal S4 to the outside. The signal S4 is the signal S1 and the signal S2.
When any one of them becomes High level, it becomes High level, and the other becomes Low level and is output to the image processing device 27. S5 is a command signal from the overall control device 31 for the image processing device to detect information such as a desired groove position deviation and groove shape. Image processing device 27
I _{1 of} is an interface for receiving the signal S4. I ₂ is an interface for bidirectionally transmitting and receiving signals between the overall control device 31 and the image processing device, and is, for example, an RS-232C serial interface.

FIG. 6 is a light-section image taken by the two-dimensional light receiving means 8 when there is a root gap between the members 3 and 4 to be welded at a given groove position and a positional deviation occurs in the groove. It is a schematic diagram of. In the figure, L ₁ is a scattered image by the slit light from the member 3 to be welded, and L ₂ is a scattered image by the slit light from the member 4 to be welded. Like a normal image, a bright (high brightness) part is represented as white and a dark (low brightness) part is represented as black. In the image from the two-dimensional light receiving means 8, the slit light scattering images L ₁ and L ₂ are bright,
The background becomes dark. W ₀ (I _w0 , J _w0 ) indicates the groove reference position obtained by aligning the welding torch tip with the groove position and detecting the groove position from the groove light section image imaged at this position. The position of the groove may be arbitrarily determined. The groove reference position in FIG. 6 is a case where the midpoint coordinates of the shoulder S _{1 of the} member 3 to be welded and the shoulder S ₂ of the member 4 to be welded are set. W ₁ (I _w1 , J _w1 ) is the groove position at the time when this image is captured. From this image,
The position of W ₁ (I _w1 , J _w1 ) can be detected, and the groove position shift on the screen can be detected by the following equation.

The _{ΔI 1 = I W1 - I W0} ... Number _{1 ΔJ 1 = J W1 - J} W0 ... Number 2 further groove position deviation amount on the screen (ΔI _1, ΔJ ₁₎ from projecting to irradiate the slit light The geometrical arrangement of the light means 7 and the two-dimensional light receiving means 8, the imaging magnification of the two-dimensional light receiving means, and the like are converted into positional deviation amounts (ΔY, ΔZ) in the coordinate system on the groove surface. By performing scanning control using this positional deviation information, it becomes possible to correctly align the welding torch tip portion with the groove position. Similarly, the bottom end point B of the welded member 3
₁ and the bottom end point B ₂ of the member 4 to be welded are detected, and the gap G is calculated from the distance between the welding line and the horizontal direction (horizontal direction of the screen in FIG. 6).
It becomes possible to ask. By using this gap information and controlling the welding conditions as shown in FIG. 4, for example,
It is possible to ensure good welding quality with and without a gap.

FIG. 7 shows a processing procedure in the image processing apparatus 27 according to the present invention. The processing is performed by the image processing start signal (see FIG.
Unless S5) of step 1 is turned on, the processing procedure 1 for successively capturing new images sequentially, the processing procedure 2 for executing the image processing using the image input immediately before, and the image processing result to the overall control device 18. It is roughly classified into a processing procedure 3 for executing transfer. The contents of each processing step in the flowchart of FIG. 7 will be described below.

In the processing step F1, the overall control unit 18
It is determined whether or not an image processing end command has been transmitted from. When the processing end command is transmitted, the process proceeds to step F10 to end the process, and when the process end command is not transmitted, the process proceeds to step F2.

In the processing step F2, it is judged whether or not the signal S4 from the external trigger generating circuit 30 has changed from the low level to the high level. The signal S4 is taken in until it changes to the high level, and when it changes to the high level, the process proceeds to step F3.

At the processing step F3, the desired image is fetched and stored, and the processing proceeds to the processing step F4.

In the processing step F4, the overall control unit 18
It is determined whether or not a command to start image processing is transmitted from. When the processing start command is transmitted, the process proceeds to step F1. When the processing start command is transmitted, the process proceeds to step F5.

In the processing step F5, the overall control unit 18
In response to the image processing (Busy) signal, the process proceeds to step F6.

In the processing step F6, for example, as shown in FIG. 6, the image is processed to execute the detection processing for the purpose such as the groove position deviation and the gap, and after the execution is completed, the processing proceeds to the processing step F7.

In the processing step F7, the overall control unit 18
In response to this, an image processing (Busy) signal OFF is output and the process proceeds to step F8.

In process step F8, the overall control unit 18
It is determined whether or not an image processing result response command is transmitted from. The processing result response command is repeatedly received until it is transmitted, and when the image processing result response command is received, the process proceeds to processing step F9.

In processing step F9, the image processing apparatus transmits the result of the image processing executed in processing step F6 to the overall control device 18, the processing proceeds to processing step F1, and the above processing is repeatedly executed.

In the above, FIG. 6 obtained from the first light receiving means 8
The example in which the image is processed to detect the groove position deviation, the gap, and the like as shown in FIG. 6 is shown. However, the arc direct view image including the welding wire obtained from the second light receiving means 9 is processed to detect the position deviation of the welding torch. The same is possible when doing.

In the above electrode scanning control operation, the overall control device 31 becomes the main station for managing the overall operation, and the image processing device 27, the welding torch position control device 29, and the welding power source 36.
Have a relationship of slave stations. That is, the slave image processing device 2
7, welding torch position control device 29, and welding power source 36
Performs a predetermined operation according to a command from the overall control device 31, which is the main station.

Although the welding condition monitoring apparatus of the present invention shown in FIG. 1 is configured separately from the welding torch position control apparatus 29 and the overall control apparatus 31 which controls the welding torch position control apparatus 29, The overall control device 31 that performs overall control may be integrated.

[0039]

As described above, according to the welding position automatic copying control apparatus of the present invention, the welding torch copying and the welding condition control are performed by using the groove position deviation information or the groove root gap information. Since this is performed, stable and high-quality welding can be performed even if there is an assembly error in the groove. Further, since the groove image and the like can be acquired at the center of weaving, it can be applied to the execution of weaving welding. Further, slit-shaped light projecting means,
Since the components for monitoring the welding status, such as the first and second two-dimensional light receiving means, are mounted in the housing, miniaturization can be realized. Since the inside of the case is sealed and air is injected into the case, and a partition is provided at the bottom of the case, the reliability that is not easily affected by dirt such as fume and spatter generated during welding is high. high. With this welding status monitoring device, unmanned welding can be performed because automatic copying and welding condition control can be performed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a welding status device of the present invention.

FIG. 2 is a schematic configuration diagram showing an embodiment of an automatic welding apparatus of the present invention.

FIG. 3 is a diagram showing an example of setting a member to be welded according to the present invention.

FIG. 4 is a diagram showing an example of a welding method when applying the member to be welded of the present invention.

FIG. 5 is a block diagram showing a configuration of an external trigger generating circuit and an image capturing timing of the present invention.

FIG. 6 is a schematic diagram of a light section image taken by the two-dimensional light receiving means of the present invention.

FIG. 7 is a diagram showing a processing flow of the image processing apparatus of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Welding torch 3, 4 ... Member to be welded, 6 ... Housing, 7 ...
Slit light projecting means, 8 ... First two-dimensional light receiving means, 9 ...
Second two-dimensional light receiving camera, 16 ... Partition, 14, 151
9 ... Reflective mirror, 22, 23 ... Two-dimensional light receiving camera control circuit, 24 ... Image distributor, 25 ... Image switcher, 26,
32 ... TV monitor, 27 ... Image processing device, 28 ... Welding torch position control mechanism, 29 ... Welding torch position control device,
30 ... External trigger generation circuit, 31 ... Overall control device, 3
4 ... Interference filter-, 35 ... Dimming filter-, 36 ... Welding power source.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masahiro Kobayashi             Stock Market Association, 3-2-1, Saiwaicho, Hitachi City, Ibaraki Prefecture             Inside Hitachi Hitachi Ibaraki Business Engineering (72) Inventor Tosumi Sato             3-1-1 Sachimachi, Hitachi City, Ibaraki Prefecture Stock Association             Hitachi, Ltd., Hitachi Works

Claims (4)

[Claims] 1. A device for monitoring a groove position and a shape of a welded part to control an aiming position of a welding torch and a welding condition, and a projecting means for irradiating a slit-shaped light beam arranged in front of a traveling direction of the welding torch. And a first two-dimensional light receiving means arranged so as to obliquely observe a scattering image obtained when the slit-shaped light beam is applied to the groove surface, and an arc image of the tip of the welding torch is obliquely observed. The second two-dimensional light receiving means, the housing surrounding the light projecting means, the first and second two-dimensional light receiving means, and the weaving center position signal or the image capture reference signal. The first and second image capturing trigger signal generators are synchronized with the signals output from the trigger signal generators.
2. A welding condition monitoring device, comprising: an image processing device which stores an image obtained by the two-dimensional light receiving means and detects desired information. 2. The welding condition monitoring device according to claim 1, wherein the first two-dimensional light receiving means is arranged in parallel with a welding torch, and a slit-like light scattering image is provided through a reflection mirror arranged in the housing. Welding condition monitoring device characterized by being configured to observe. 3. The welding condition monitoring apparatus according to claim 1, wherein the second two-dimensional light receiving means is arranged in parallel with a welding torch, and an arc image is observed through a reflection mirror arranged in the housing. A welding condition monitoring device having the above structure. 4. The welding condition monitoring device according to claim 1, wherein the casing is hermetically sealed and air is injected into the casing, and the observation light of the second two-dimensional light receiving means is provided below the casing. A welding condition monitoring device characterized in that a screen with a hole is provided on the shaft.