JP2719966B2 - Backside groove information detection method for single-sided automatic welding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a groove gap amount, a groove difference amount and a groove center position which are back surface groove information for back bead control in single-sided automatic welding. How to detect.

[Related Art] Conventionally, in producing a back bead in butt welding, the back surface is welded after the back surface is welded. Further, as a recent technology, as shown in an explanatory view of FIG. 5, a visual sensor 16 and a display mounted on a welding cart 15 for one-side automatic welding.
Using 17, the width, length, temperature, etc. of the molten pool shape 18 are ascertained, and the front side welding conditions are controlled based on this to achieve appropriate back bead formation.

However, the former method of welding the back surface is difficult in narrow places where people can not enter the back surface, especially in the case of penstock, in an attempt to reduce the gap between the tunnel and the iron pipe and reduce the cost of civil engineering work. The use of single-sided automatic welding has been awaited.

In addition, the method of grasping with the visual sensor from one side of the latter,
There is no established technology for the relationship between the weld pool shape and the back bead.In addition, it is difficult to recognize images, that is, it is difficult to determine the boundary between the weld pool and the groove surface, and it is difficult to grasp the image due to the disturbance of the arc light of high intensity. In addition, it is difficult to form an appropriate back bead by automatic control of surface welding conditions due to the problem of response speed and the like, and the system configuration becomes complicated and expensive.

[Problems to be Solved by the Invention] The present invention has been proposed in view of such circumstances, and includes a groove gap amount, a gap difference amount, and a groove center which are back surface groove information by a simple device. Positioning can be accurately detected, and feedback can be made to the welding conditions of single-sided welding to enable high-quality back bead formation, and thus high-quality single-sided automatic welding that does not require welding repair can be achieved. It is an object to provide a method for detecting backside development information.

[Means for Solving the Problems] For this purpose, the present invention performs automatic back bead control by running a back side bogie in synchronization with a groove front side welding bogie for performing single-sided automatic welding and feeding back back side groove information to welding conditions. On the basis of the change in the sensor output voltage obtained by moving the laser displacement sensor installed on the back trolley at right angles to the welding direction on the back surface of the groove, the groove gap amount, the difference between the groove positions, and the center of the groove The position is calculated.

[Effect] According to the present invention, the groove gap amount, the difference between the groove positions, and the groove center position, which are the back surface groove information, can be accurately detected by a simple device, and feedback is provided to the welding conditions for single-sided welding. As a result, it is possible to obtain a backside groove information detection method for single-sided automatic welding that enables high-quality backside bead formation and that can achieve high-quality single-sided automatic welding work that does not require welding repair.

[Embodiment] One embodiment of the method for detecting backside groove information of single-sided automatic welding according to the present invention will be described with reference to the drawings. FIG. 1 is a side view of a detecting device for carrying out the method of the present invention, and FIG. FIGS. 3 and 4 show the detection procedure of the method according to 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. It is explanatory drawing of a groove information detection concept.

First, an apparatus for carrying out the method of the present invention will be described with reference to FIGS. 1 and 2. FIG.
The groove 2 of the butt joint has a groove gap amount G and a groove difference amount H. The welding torch 3 facing the groove 2
Is mounted on the inner surface of the tube so as to be able to travel along the welding line, while the outer surface of the tube, that is, the back surface of the groove 2, is provided with a backing truck 6 having a backing material 5 at the welding line. It is arranged so as to be able to travel along the vehicle, and the latter follows the former according to the speed change of the former by a synchronous sensor 7 attached to both carriages 4, 6.

Distance L _W forward position from the front of the welding torch 3 of the rear carriage 6, in a posture that faces the back surface 2a of the groove 2, mounted on the X axis 9 laser displacement sensor 8 traverses the groove rear surface 2a An X-axis motor 10 and an encoder 11 are connected to the X-axis 9. In addition, the back side carriage 6 has a back side control device 12 for receiving a detection value of the laser displacement sensor 8.
Is installed, and the welding control device installed on the welding cart 4 from here
The back face groove information 14 is sent to 13.

With such a device configuration, the groove gap amount of groove 2
G, procedure a third diagram for detecting an included tongue and groove amount H and the groove center position X _C, with reference to Figure 4 will be described.

A voltage V proportional to the distance L from the groove back surface 2a is output to the laser displacement sensor 8. The encoder 11 determines the groove left-right position, that is, the X-axis position. As shown in FIG. 3, a relationship diagram of the output voltage V with respect to the groove left-right position X is obtained. By the method shown in FIG. 4 on the basis of the third drawing, calculating detection groove gap amount G, the groove tongue and groove amount H and the groove center position X _C.

That is, in FIG. 4, the data obtained from the laser displacement sensor 8 are (x ₁ , V ₁ ), (x ₁ , V ₂ ) _,.
V _i ),... (X _imax , V _imax ) in this order
Is obtained.

Therefore, longer distances from x ₁ to L _X (experience value) of the content location _{i = a (X a, V} a) determine the least squares method between the i = 1 to a: Gives an equation _{V = A a · X + B} a straight line LXL.

Similarly, the position i = b the distance of the rightmost x _imax than L _X min
(X _b , V _b ) is obtained and the least squares method is used between i = b and _imax : Gives the equation V = A _b · X + B _b of the straight line LXR.

Then obtain the maximum output voltage value V _max, than this H
_The points i = c (left) and i = d (right) close to the voltage value (V _max -H _V2 ) decreased by _V2 (experimental value) are obtained. Furthermore H _V1 (experience value) than a point obtained previously only up voltage value (V _a + H _V1) point near the i = e (left), from point b only H _V1 up voltage value (V _b + H _V1 ) Is obtained (i = f (right side)).

Least-squares method between these obtained i = e to c and i = d to f: Gives the equation V = A _ec · X + B _ec of the straight line LVL, Obtains the equation V = A _df × X + B _df of the straight line LVR.

From the straight lines obtained above, the intersections (X _j , V _j ) of the straight lines LXL and LVL,
The intersection (X _k , V _k ) of the straight line LXR and LVR is obtained.

Thus, groove gap amount G from these two points, groove tongue and groove amount H, the groove center position X _C is determined as follows.

_{G = (X k -X j)} + ΔG H = (V k -V j) × k V X C = (X k + X j) / 2 where, .DELTA.G is empirically derived proportional to the laser spot diameter value ( mm), k _V is such conversion values (mm / V) further penstock output voltage, either the left or right side of the groove second surface is completed in a straight tube, for example, Figure 4 in the left linear If it is a tube, it is considered that θ _L in the figure is an amount inclined between the X axis 9 and the iron tube 1. Therefore, the actual gap amount and the like are corrected as follows.

G ′ = (X _k −X _j ) × cos θ _L − (V _k −V _j ) × sin θ _L +
ΔGH ′ = ｛(X _k −X _j ) × sin θ _L + (V _k −V _j ) × cos
θ _L ｝ × k _V where θ _L = tan ⁻¹ (A _a ) The thus detected groove gap amount G and groove difference amount H are subjected to welding control as back surface groove information 14 via the back side control device 12. The welding conditions such as welding speed, welding current, and weaving width of the welding torch 3 are sent to the groove 2.
Feedback control is performed according to the state of the back surface of the substrate to form an appropriate back bead. However to distance L _W of the welding torch 3 position and the laser displacement sensor 8 position, the welding controller 13
The welding torch 3 when moved by L _W, and a delay position control to use the back surface development information 14 before its address the deviation.

Also based on the groove center position X _C, rear controller 12 controls the travel of the rear carriage 6, so that cormorants accurately against the backing strip 5 into groove 2.

[Effects of the Invention] In short, according to the present invention, when the back bogie is run in synchronization with the groove front side welding bogie for performing one-sided automatic welding, the back side groove information is fed back to the welding condition, and the back bead automatic control is performed. Based on the change of the sensor output voltage obtained by moving the laser displacement sensor installed on the back trolley at right angles to the welding direction on the back of the groove, the groove gap, the difference between the grooves and the center position of the groove are calculated. This makes it possible to accurately detect the groove gap amount, groove difference amount and groove center position, which are back surface groove information, with a simple device,
By providing feedback on the welding conditions of single-sided welding, it is possible to form a high-quality back bead, and thus obtain a backside groove information detection method for single-sided automatic welding that can achieve high-quality automatic single-sided welding that does not require welding repair. The invention is of great industrial value.

[Brief description of the drawings]

FIG. 1 is a side view of a detecting apparatus for implementing the method of the present invention in one embodiment of the method for detecting backside groove information of the single-sided automatic welding of the present invention, and FIG. 2 is a side view of the entire single-sided automatic welding apparatus for implementing the method of the present invention. FIGS. 3, 3 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 concept of groove information detection. is there. FIG. 5 is an explanatory diagram of a conventional back groove information detection method. DESCRIPTION OF SYMBOLS 1 ... iron pipe, 2 ... groove, 2a ... back surface of groove, 3 ... welding torch, 4 ... welding bogie, 5 ... backing material, 6 ... back bogie, 7 ... synchronous sensor, 8 …… Laser displacement sensor, 9 …… X axis, 10 …… X axis motor, 11 …… Encoder, 12 …… Back side control unit, 13 …… Welding control unit, 14…
... Backside groove information, G... Groove gap amount, H...

Continued on the front page (72) Inventor Hiroshi Shimoyama 2-1-1, Shinhama, Arai-machi, Takasago City, Hyogo Prefecture Inside the Takasago Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Inventor Nozomi Watanabe 1-1-1, Wadazakicho, Hyogo-ku, Kobe City, Hyogo Prefecture 1 Kobe Shipyard, Mitsubishi Heavy Industries, Ltd. (56) References JP-A-59-169669 (JP, A) JP-A-3-90282 (JP, A)

Claims (1)

(57) [Claims] A back bogie is run in synchronism with a front bogie on which a single-sided automatic welding is to be performed, and back side groove information is fed back to welding conditions to perform back bead automatic control. The single-sided surface is characterized in that a groove gap amount, a gap difference amount, and a groove center position are calculated based on a change in a sensor displacement voltage obtained by moving a laser displacement sensor at right angles to a welding direction on a groove back surface. Automatic welding backside groove information detection method.