JPH0695010B2 - Groove position detector for automatic pipe welding - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a groove position detecting device for automatic pipe welding, which is manufactured by bending a flat plate into a cylindrical shape and joining longitudinal joints of a pipe by welding. Is.

[Prior art and its problems]

Conventionally, in order to produce a pipe by welding, an apparatus as shown in FIG. 11 has been used in the following work procedure.

The pipe (2) having the tab plates (2a) (2a ') attached to both ends of the pipe (2) is received by the loading / unloading carriage (11) from the upstream side of the production process.

Stop the dolly (11) just below the welding machine (12).

Pipe rotation mechanism (15) installed on the dolly (11)
Drive and set the pipe (2) so that the wire (2b) to be welded is in the "heaven" position.

The welding torch (14) is lowered by the welding torch drive mechanism (13), and the tip of the welding torch is inserted into the groove (3).

The arc is started on the tab plate (2a) and the carriage (11) is run to start welding work.

During welding, the welding torch drive mechanism (13) controls the lateral alignment (positioning in the X-axis direction) by manual operation so that the relative position between the welding torch (14) and the groove (3) is always constant. Extension control (positioning in the Y-axis direction) is performed.

When the welding reaches the rear tab plate (2a '), the traveling of the carriage (11) and the arc are stopped.

A welding torch drive mechanism (13) raises the welding torch (14).

The pipe (2) is carried out to the downstream side.

It is performed while repeating the above-mentioned work. Among these ,,,, are considered to be important work performed by the worker. Especially for work, since the pipe itself has bending and twisting, the processing line (welding line) to be welded
Is not actually a straight line, and until now the worker has judged this welding line with the eyes, and the worker pays close attention, but due to differences in experience and skill level. There are variations in skills among individual workers, and it takes a lot of work to perform continuous work for a long time, and even an excellent worker always carries out good welding work due to the effects of fatigue and the like. Not necessarily. Under such circumstances, it has been desired to automate the welding work in order to guarantee the welding quality and stabilize the quality, but it was difficult to automate the above items. .

The present invention solves such a problem, and provides a groove position detecting device for automatic pipe welding which can automate a seam welding process of a pipe and guarantee good quality welding by the groove position detecting device. Is.

[Means for solving problems]

In order to achieve the above object, the groove position detecting device for automatic pipe welding of the present invention is one fan-shaped light which can change the direction of the projected light to the top position of the welding line and the welding line tracing control position. At least two fan-shaped light projectors in which the position of the top of the projector or the welding line and the direction of the light projected to the welding line tracing control position are slightly different from each other, an imager for capturing the cross-sectional shape of the groove portion, and an imager Automatic pipe characterized by a pipe surface position calculator that calculates the position of the pipe surface part from the image captured by and a groove position calculator that calculates the position of the groove edge from the image captured by the imager Groove position detector for welding. It consists of an imager, a pipe surface position calculator that calculates the position of the pipe surface from the image captured by the imager, and a groove position calculator that calculates the position of the edge of the groove from the image captured by the imager. Is.

〔Example〕

Hereinafter, drawings showing an embodiment of the present invention will be described. FIG. 1 shows the basic configuration of the groove position detecting device of the present invention. (1) is a projector for irradiating a welding laser beam (3) of a pipe (2) which is a material to be welded with a fan-shaped laser beam.
As shown in FIGS. 2 (a) and 2 (b), this floodlight (1) images the surface to be imaged such that the welding line is at the top position (a) and the welding line tracing control position (b). The irradiation angle can be freely changed on the side of the projector (1) so that the welding line is at the top position (a) and the welding line tracing control position (b) so that it can handle different distances from the device. The projector is capable of projecting a fan-shaped light or at least two projectors (1) (1 ') having slightly different projection directions, and is used at a position where the distance from the image pickup device is long ( 1
a) and (1b) in other cases. Reference numeral (4) is an image pickup device for picking up an image of the cross-sectional shape of the groove portion (3) by a known light cutting method using a band of light from the light projector (1). 5), and transfers it to the groove edge position calculator (6).

3 and 4 show the principle for detecting the groove portion (3) by the light section method and calculating the position of the pipe surface portion from the image captured by the imager (4). ) And the pipe (2) are shown as (a), (b), and (c) in the case where they approach each other continuously with time. The position to hit is point A,
These are points B and C. That is, the imager (4) initially has 3
Although the image of the pipe surface is not captured at the position of FIG. 7A, as the distance between the image pickup device (4) and the pipe surface approaches (b) and (c), the irradiated position of the light is B.
The shape of the image captured at that point becomes the point C and the point C, as shown in (b) and (c) of FIG. Therefore, if it is possible to calculate the vertical position on the screen of the light band (7) indicating the pipe surface, the distance between the pipe surface and the image pickup device (4) can be measured.

FIG. 5 shows the circuit configuration of the pipe surface position calculator (5). First, for the image captured by the imager (4),
The distance Yi from the top or bottom of the screen (the figure shows the case of the top) to the figure showing the band of light (7) is calculated from the left end to the right end of the screen. Next, the integrated value of the distance Yi is calculated, and the average value is calculated. Next, the difference between this average value and the preset value Yo is calculated, and the absolute value is obtained.
The final value calculated in this way corresponds to the absolute value of the deviation between the position of the captured figure and the target position.
At the final stage of the circuit, the absolute value of the deviation is compared with the preset deviation tolerance ΔYo, and if the deviation is within the tolerance, the detected shape has reached the target position. A reaching signal indicating that is output.

FIG. 6 shows the circuit configuration of the groove edge position calculator (6). For the captured image, the imager (4) first
The distance Yi from the top or bottom of the screen (the figure shows the case of the top) to the figure showing the band of light (7) is calculated from the left end to the right end of the screen.

Next, check whether the change in the distance Yi is positive, zero, or negative, and change from plus (zero component following plus counts to plus) to minus or minus (zero component following minus counts as minus). The position of the inflection point changed to plus is detected.
Next, a pattern classification to which one of preset patterns belongs is carried out by a combination of plus and minus slopes of the variation of the distance Yi with the inflection point as a boundary.

FIG. 7 shows a method of classifying the pattern and a method of calculating the edge position of the groove for the classified pattern.

For example, in the case of pattern 1 in the figure, when the change amount of the distance Yi is checked from the left side to the right side of the screen, the state is first horizontal, then negative slope, then positive slope, and finally horizontal. ing. In this case, the gradient pattern is (↓ ↑). Similarly, in the case of pattern 2, the gradient pattern is (↓ ↑ ↓ ↑).

In the case of pattern 1, the position of the left edge is predetermined so as to be calculated as the left end position of the first minus slope range, and the right edge position is calculated as the right end position of the plus slope range. Similarly, in the case of pattern 2, the left edge position is predetermined to be calculated as the left end position in the first minus slope range, and the right edge position is calculated as the right end position in the second plus slope range. To be

Next to pattern classification, the coordinates of the left and right edges of the groove are calculated by a predetermined calculation method for each pattern, and then the groove center position (Xc, Yc) is calculated as the midpoint between the left and right edge positions. To do. With respect to the X and Y coordinate values of the groove center position thus calculated, deviations from preset reference positions Xo and Yo are calculated, and both servo motors (9) (of the servo drive device (8) ( It is output to 9) as a profile control signal.

FIG. 8 shows a groove image captured by the image pickup device (4). In the case of FIG. 8A, the welded portion is in the normal position,
In the case of (b), the weld is displaced to the right,
The case of (c) shows a state in which the distance between the image pickup device (4) and the welded portion is changed, and the groove edge position calculator (6) calculates the relative positional deviation of the groove (3) from moment to moment. If the displacement is detected, the welding torch drive mechanism (13) is driven via the servo drive (8) in the direction to cancel the displacement, and the welding torch (14) and the groove (3) are calculated. ) Is always operated so that the relative position is constant.

The manner of use of the groove position detecting device for automatic pipe welding configured as described above will be described with reference to FIGS.

The pipe (2) having the tab plates (2a) (2a ') attached to both ends of the pipe (2) is received by the loading / unloading carriage (11) from the upstream side of the production process.

Stop the dolly (11) just below the welding machine (12).

The state of the fan-shaped light projector (1) is set to the projection state (1a) (at this time, nothing is imaged in the imager (4)), the pipe surface position calculator (5) is activated, and the welding torch drive mechanism ( 1
Lower the torch (14) with 3). When the imager (4) captures an image of the pipe surface and the pipe surface position calculator (5) detects that the pipe surface has reached a predetermined position, the welding torch drive mechanism (13) is stopped.

The state of the fan-shaped light projector (1) remains the projection state (1a),
The groove edge position calculator (6) is activated to drive the pipe rotating mechanism (15) installed on the carriage (11). Since the imager (4) captures the groove image on the pipe surface, the edge position of this groove image is calculated every moment, and when the center position of the groove reaches the center of the screen, the welding line (2
b) is in the “heaven” position, the pipe rotation mechanism (1
5) Stop.

The state of the fan-shaped light projector (1) is set to (1b) (at this time, nothing is captured in the imager (4)), the pipe surface position calculator (5) is started, and the welding torch drive mechanism (13) is used to drive the torch. Lower (14) at a slow speed. Imager (4)
Captures an image of the pipe surface, and when the pipe surface position calculator (5) detects that the pipe surface has reached a predetermined position, it stops the welding torch drive mechanism (13). At this time,
The tip of the torch (14) is inserted into the groove (3).

The welding is started by starting the arc on the tab plate (2a) and running the carriage (11). This is controlled by a normal sequence controller.

During welding, the groove position detecting device (16) continues to calculate the relative positional deviation between itself and the groove (3), and if the positional deviation is detected, the welding torch is in the direction of canceling the positional deviation. The drive mechanism (13) is driven to execute the left-right matching control and the extension control so that the relative position between the welding torch (14) and the groove (3) is always constant.

In the above description, as the flow of the production line, the pipe flows from the upstream to the downstream. However, whether the pipe is carried into the welding device or the welding device moves along the pipe. Is a relative problem, and the groove position detecting device of the present invention can be applied in the same manner even when the welding device side is moved along the pipe.

〔The invention's effect〕

As described above, according to the groove position detecting device for automatic pipe welding of the present invention, one fan-shaped light projector capable of changing the direction of the projected light to the top position of the welding line and the welding line tracing control position. Alternatively, the top position of the welding line and the direction of the light projected to the welding line tracing control position are at least slightly different from each other.
Individual fan-shaped light projectors, an imager that captures the cross-sectional shape of the groove, a pipe surface position calculator that calculates the position of the pipe surface from the image captured by the imager, and an imager captured from the image captured by the imager. A groove position detector for automatic pipe welding, comprising a groove position calculator for calculating the position of the leading edge. A pipe surface position calculator that calculates the position of the pipe surface portion from the image captured by the imager, and a groove position calculator that calculates the position of the edge of the groove from the image captured by the imager Since it relates to the groove position detection device for automatic pipe welding, the truck, which was difficult to automate in the past, is temporarily stopped immediately below the welding machine, and the pipe rotating mechanism installed on the truck is driven to perform welding. Set the pipe so that the line is in the "top" position, lower the torch by the welding torch drive mechanism, and insert the torch tip into the groove. With the welding torch drive mechanism, it is possible to automate the point where left-right tracing control and extension control are performed so that the relative position to the groove is always constant, and the changes in groove position and groove shape during welding can be highly accurately performed. The quality of the welding can be guaranteed by highly accurate image information processing.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is an overall schematic configuration diagram, FIG. 2 is an explanatory diagram showing the relationship between a projector and an imager, and FIG. 3 is a diagram for detecting the position of the pipe surface. Illustration of
FIG. 4 is an explanatory diagram of a state appearing on the image pickup device, FIG. 5 is a circuit configuration diagram of a pipe surface position calculator, FIG. 6 is a circuit configuration diagram of a groove edge position calculator, and FIG. 7 is various patterns. Of FIG. 8, FIG. 8 is a diagram showing an example of a groove image, and FIGS. 9 and 10 are a simplified perspective view and a simplified plan view showing a pipe welding system to which the groove position detecting device of the present invention is applied. The figure is a simplified perspective view showing a conventional pipe welding system. (1) ... Fan-shaped projector, (4) ... Imager, (5) ... Pipe surface position calculator, (6) ... Groove edge position calculator.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideki Miyazaki Inventor Hideki Miyazaki 1 Kimitsu, Kimitsu-shi, Chiba Nippon Steel Corp. Kimitsu Steel Co., Ltd.

Claims (1)

[Claims] 1. A single fan-shaped light projector capable of changing the direction of the projected light to the position of the top of the welding line and the position of controlling the welding line or the position of the top of the welding line and the position of controlling the welding line. At least 2 that the directions of the projected light are slightly different from each other
Individual fan-shaped light projectors, an imager that captures the cross-sectional shape of the groove, a pipe surface position calculator that calculates the position of the pipe surface from the image captured by the imager, and an imager captured from the image captured by the imager. A groove position detector for automatic pipe welding, comprising a groove position calculator for calculating the position of the leading edge.