JPH0390283A - Method for detecting rear groove information of one-side automatic welding - Google Patents

Abstract

PURPOSE:To perform welding without necessitating welding repair by detecting the groove gap quantity, the groove dislocation quantity and the groove central position by the change of the voltage obtained by traversing a laser displacement sensor on the groove face. CONSTITUTION:The groove gap quantity G and the groove dislocation quantity H exist in a groove 2 of a butt joint of an iron pipe 1 to by subjected to one- side welding. A welding carriage 4 supporting a welding torch 3 in opposition to the groove 2 travels along a weld line one the pipe interior. A rear side carriage 6 provided with backing material 5 travels in synchronization with the welding carriage 4 on the pipe exterior side. The laser displacement sensor 8 is fitted and traversed on an X axis traverse shaft 9 to cross the groove rear 2a at the position opposite to the rear 2a of the groove 2 on the rear side carriage 6. The sensor 8 outputs the voltage in proportion to the distance L with the groove rear 2. This is converted into the groove gap quantity, the groove dislocation quantity and the groove central position and control is carried out by a rear side controller 12 and a welding controller 13 so that optimum welding is performed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides back groove information for back bead control in single-sided automatic welding, such as groove gap amount, groove misalignment amount, and groove center position. Concerning how to detect.

[Conventional technology]

Conventionally, when creating a back bead in butt welding, the front side is welded and then the back side is welded. Also, as a recent technology? As shown in the lJS diagram explanatory diagram, the width, length, temperature, etc. of the molten pool shape 18 are ascertained using the visual sensor 16 and display 17 attached to the welding cart 15 for automatic one-sided welding, and the front side welding is performed based on the information. The conditions are controlled to form an appropriate back bead.

However, the former method of welding the back side is difficult in narrow spaces where people cannot get into the back side, and in particular for penstocks, etc., attempts are being made to reduce the cost of civil engineering work by reducing the gap between the tunnel and the iron pipe. has been carried out, and the adoption of single-sided automatic welding is awaited.

In addition, the latter method of grasping the relationship between the molten pool shape and the back bead using a visual sensor does not have established technology, and there are also difficulties in image recognition, i.e., difficulty in determining the boundary between the molten pool and the groove surface. It is difficult to form an appropriate back bead through automatic control of surface welding conditions due to the difficulty in grasping the image due to strong arc light disturbances and the problem of response speed, and the system configuration is complicated and expensive. Become something.

[Problem to be solved by the invention] The present invention was proposed in view of the above circumstances, and
With a simple device, the groove gap amount, which is the back side groove information,
A high-quality single-sided automatic system that can accurately detect the groove opening amount and groove center position, feed back to the welding conditions of single-sided welding, enable high-quality back bead formation, and eliminate the need for welding repairs. The purpose of the present invention is to provide a method for detecting groove information on the back side of automatic one-sided welding that can be coupled with welding operations.

[Means for Solving the Problems] To achieve this, the present invention automatically controls the back bead by causing a back side cart to run in synchronization with the groove front side welding cart that performs automatic one-sided welding, and feeding back groove information to the welding conditions. In this process, the groove gap amount, groove opening amount, and groove center position are detected based on changes in the sensor output voltage obtained by traversing the laser displacement sensor installed on the back side of the groove on the back side of the groove. It is characterized by

[Function] According to the present invention, the back groove information such as the groove gap amount, the groove opening amount, and the groove center position can be accurately detected using a simple device, and the information can be fed back to the welding conditions for single-sided welding. Accordingly, it is possible to obtain a method for detecting groove information on the back surface of automatic one-sided welding, which enables high-quality back bead formation and, in turn, achieves high-quality one-sided automatic welding construction that does not require welding repairs.

[Example 1] An embodiment of the method for detecting groove information on the back side of automatic single-sided welding according to the present invention will be explained with reference to the drawings. Fig. 1 is a side view of a detection device for implementing the method of the present invention, and Fig. 2 is a side view of a detection device for implementing the method of the present invention. 3 and 4 are a side view of the entire single-sided automatic welding apparatus to be carried out, and show the detection procedure of the method of the present invention. The figure is an explanatory diagram of the concept of detecting information.

First, to explain the apparatus for carrying out the method of the present invention with reference to FIGS. 1 and 2, the groove 2 of the butt joint of the iron pipe 1 to be welded on one side from the inside has a groove gap fiGε groove free speed jlH. A welding cart 4 equipped with a welding torch 3 facing the groove 2 is disposed on the inner surface of the tube so that it can run along the welding line, while a A rear truck 6 equipped with the material 5 is disposed so as to be able to run along the welding line, and synchronization sensors 7 attached to both trucks 4.6 cause the latter to follow changes in the speed of the former.

This back stand! Distance Lw from the front welding torch 3 of tL6
At the front position, a laser displacement sensor 8 is mounted on an X-axis traverse shaft 9 that traverses the back surface 2a of the groove 2, facing the back surface 2a of the groove 2. An on-axis motor 10 and an encoder 11 are connected. Further, a back side control device 12 is installed on the back side truck 6 to receive the detected value of the laser displacement sensor 8, and back side groove information 14 is sent from there to a welding control device 13 installed on the welding truck 4.

With such a device configuration, the groove gap amount Q of groove 2
, % The method of detecting the free groove speed H and the groove center position XC will be explained with reference to FIGS. 3 and 4.

The laser displacement sensor 8 has a distance 111 from the groove back surface 2a.
A voltage V proportional to 1L is output. In addition, the left and right positions of the groove, that is, the X-axis position, are determined by the encoder 11.
As shown in FIG. 3, a relationship diagram of the output voltage V with respect to the left and right positions lx of the groove is obtained. Based on this figure '13, the groove gear amount G, free speed iH, and groove center position rllXc are calculated and detected by the method shown in FIG.

That is, in FIG. 4, the data obtained from the laser displacement sensor 8 is (xl, ■,).

(X2 + v2)J...(X+, Vl),...
(X's□.

(1□l) The output voltage V for the encoder position X is obtained in this order.

So, from this, from xl, the distance is 1lIl (experience value)
Find the position i-a (X,,V,>, and use the least squares method between i-1 and a: By the straight line LXL (7) equation V-A, -X+B.

get.

Similarly, position I=b for a distance of Lx from the right end x −,,
Find (xi, Vl, ), l-b ~1,
, , the equation of the straight line LXR is obtained by the least squares method: VA, .XrBb.

Next, obtain the maximum output voltage value v,,8, and from this HV2
The voltage value (V,...) has decreased by (empirical value).

Find points 1-c (left side) and 1-d (right side) close to HV2). Furthermore, a point ime that is close to the voltage value (V, + Hv+) that is higher than the previously determined point a by HVI (empirical value)
(Left side), voltage value increased by HV from point b (Vb+
Find a point i-f (on the right side) close to 'Hvt).

Least squares method between these calculated t-e-c, 1-d-f: Niyori, straight 11L, VL equation V-A, -X+B,
.

At the same time, we obtain the equation of the straight line LVR V −A at ・X
+ Get B a t.

From the straight lines obtained above, the intersection of straight lines LXL and LVL (Xr,
V, ), straight line LXR and LVR17) intersection (Xm, V, )
is found.

Thus, from these two points, the groove gap JIG, groove free speed ff1H, and groove center position Xc are determined as follows.

C; -(Xm -XI) +ΔG H-(V, -V,)xkv Converted value (+++m
/V) Furthermore, in penstocks, etc., either the left or right side of the two grooves is a straight pipe. For example, if the left side in Figure 4 is a straight pipe, 01 in the figure is X. It is considered that the melon is tilted between the axis traverse Ith9 and the iron pipe 1. Therefore, the actual gap amount etc. are corrected as follows.

G' = (Xh - Xr) X cosθt, -
(Vm −Vr)X sinθL+ΔG” = I(Xi −XI)Xs!nθL+ (
Vm - VH) x cos θLIXkv However, θL -jan -' (A a ) The groove gap ff1G thus detected and the groove error amount H are
The back groove information 14 is sent to the welding control bag rI 113 via the back side control device 12, and the welding conditions such as the welding speed of the welding torch 3, welding current, and weaving width are fed back according to the back side condition of the groove 2. A controlled and proper back bead is formed. However, with respect to the interval Lw between the welding torch 3 position and the laser displacement sensor 8 position, the welding control device 13 performs delay position control to use the previous back groove information 14 when the welding torch 3 moves by LW, Coping with deviation: Also, based on the groove center position Xcl:, the back side control device 12 controls the traveling of the back side cart 6 so that the true member 5 is placed in accurate contact with the groove 2.

[Effects of the Invention] In short, according to the present invention, when automatically controlling the back bead by running the back side cart in synchronization with the groove front side welding cart that performs one-sided automatic welding and feeding back the back groove information to the welding conditions, By detecting the groove gap amount, groove opening amount, and groove center position based on the change in the sensor output voltage obtained by traversing the laser displacement sensor on the back side of the groove on the back side of the groove. With a simple device, it is possible to accurately detect the back groove information such as the groove gap amount, groove opening amount, and groove center position, which is fed back to the welding conditions of single-sided welding to form a high-quality back bead. The present invention is industrially extremely useful because it provides a method for detecting groove information on the back surface of automatic one-sided welding that enables high-quality automatic one-sided welding without the need for welding repairs.

[Brief explanation of drawings]

FIG. 1 is a side view of a detection device that implements the method of the present invention in an embodiment of the method for detecting groove information on the back surface of automatic single-sided welding of the present invention, and FIG. 2 is a side view of the entire single-sided automatic welding device that implements the method of the present invention. , X43, and 4 show the detection procedure of the method of the present invention, FIG. 3 is a diagram showing the relationship between the position of the laser displacement sensor and the output voltage, and FIG. 4 is an explanatory diagram of the groove information detection concept. . FIG. 5 is an explanatory diagram of a conventional back surface groove information detection method. 1... Iron pipe, 2... Bevel, 2a... Bevel back side,
3... Welding torch, 4... Welding cart, 5... Backing material, 6... Back side cart, 7... Synchronization sensor 8...
・Laser displacement sensor 9...X-axis traverse axis,
10...X-axis top 11...Encoder 1
2... Back side control device, 13... Welding control device, 14
...back groove information, G...groove gap amount, H...
・Bevel opening amount.

Claims (1)

[Claims] The backside cart is run in synchronization with the groove front side welding cart that automatically performs one-sided welding, and the backside groove information is fed back to the welding conditions to automatically control the back bead.In order to automatically control the back bead, the laser displacement sensor installed on the backside cart is activated. Based on the change in the sensor output voltage obtained by traversing the front and back surfaces,
A method for detecting groove information on the back surface of one-sided automatic welding, characterized by detecting a groove gap amount, a groove misalignment amount, and a groove center position.