JPS6116551B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic welding device that corrects the aiming position of a torch based on the orientation of the torch and enables groove profile control particularly suitable for welding inclined pipes.

Conventionally, groove profile control has been performed by detecting fluctuations in the groove position and moving a torch to a target groove position based on the information.

However, in cases such as circumferential welding of inclined pipes, even if the groove variation in the direction perpendicular to the weld line can be controlled, the welding position changes from downward, upward, and sideways, so the bead may droop depending on the torch position, resulting in beats. Variations in shape occur, making it impossible to obtain a homogeneous bead shape.
It is not possible to perform high quality welding.

The present invention takes into consideration the above-mentioned conventional drawbacks and provides an automatic welding device that can perform good profile control even in circumferential welding of inclined pipes, etc., and in addition to a groove variation detector, it provides an automatic welding device that can control the welding position. The present invention is characterized in that it includes an attitude detector for detecting the attitude, and a correction signal generator for generating a correction signal for follow-up control based on the attitude.

Next, the present invention will be described in detail with reference to drawings showing one embodiment thereof.

FIG. 1 shows a block diagram of an automatic welding device according to the present invention. In the figure, reference numeral 1 indicates a groove variation detection unit that detects groove position variation in a direction perpendicular to the welding line and outputs a basic signal for controlling the aim of the torch. It consists of conventional contact or non-contact sensors. 2 is the downward direction of the torch,
A posture detector detects welding postures such as upward or sideways and outputs a posture signal. 3 is a correction signal generator, which outputs a correction signal of a target value for torch profile control based on the posture signal of the posture detector 2. do.

Reference numeral 4 denotes a signal processing device which outputs a control signal of a target value for profile control based on the basic signal of the groove variation detector 1 and the correction signal of the correction signal generator 3. 5 is a torch drive device that drives the welding torch 6;
The torch 6 is displaced by a predetermined amount in accordance with a control signal from the signal processing device 4.

Next, the operation of the apparatus shown in FIG. 1 will be explained.

FIG. 2 shows an example of the relationship between welding posture and correction signal. This relationship can change depending on the degree of inclination in the case of inclined pipe welding and whether the first layer is welded or the second layer or subsequent layers are welded.

Figure 3 shows the locus of the torch position in the direction perpendicular to the weld line when an inclined pipe is circumferentially welded from the inside, the horizontal axis represents the amount of movement of the cart along the weld line, and the broken line represents the trajectory according to the present invention. The control results: The solid line shows the results of conventional profiling control.

Figures 4a, b, and c are explanatory diagrams of the inclined pipe.

As shown in FIG. 4, the groove variation detector 1 outputs a basic signal for aim control X(l), which is the groove position. Here, l indicates the length along the weld line.

Attitude detector 2 outputs an attitude signal θ. Here, θ is the angle that the welding position makes with the origin A at the lowest end of the welding line with respect to the central axis of the iron pipe B within a plane that includes the circular welding line.

The correction signal generator 3 outputs a correction signal Y (θ, ψ) of the target value for aim control based on the attitude signal θ. Here, ψ is the inclination angle of the iron pipe B, and in the case of a horizontal pipe, ψ=0, and in the case of a vertical pipe, ψ=π/2.
Then, Y(θ, ψ) is given by the following equation based on θ and ψ.

Y (θ, ψ)=−α·sin2ψ·cosθ (π/2≦θ≦3/2π)=0 (others) Here, α is a value determined from experimental data, and is, for example, 2 mm.

Next, the signal processing device 4 processes the basic signal X(l)
and the correction signal Y (θ, ψ), a control signal W(l), which is a target value for aim control, is output, and is given by the following equation.

W(l)=X(l)+Y(θ, ψ) Then, the torch driving device 5 outputs the control signal W(l)
The torch 6 is displaced by a predetermined amount.

By the way, in the past, the aiming position of the torch was controlled only by the detection signal of the groove variation detector, so there was no problem when the torch was facing downwards or upwards, but when the bead was facing sideways, the bead would sag due to the influence of gravity. The trend was noticeable.

However, according to this invention, in consideration of the hanging of the bead when the bead is in a position where it is most significantly affected by gravity, the aiming position of the torch is adjusted upward in advance relative to the original bevel position. The sag will form the bead shape that you originally want to weld.

Note that the signal processing device 4 has a built-in torch position detector if necessary, and performs addition/subtraction, multiplication/division, or a mixture thereof from the basic signal for profiling control and the correction signal, and if necessary, the torch position signal. , a control signal to the torch driving device 5 may be generated.

As described above, the automatic welding apparatus of the present invention includes a groove variation detector that detects the groove position variation in the direction perpendicular to the welding line and outputs a basic signal for torch aim control, and a groove variation detector that detects the welding posture and outputs the basic signal for torch aim control. an attitude detector that outputs a signal; a correction signal generator that outputs a correction signal for a target value for aiming control of the torch based on the attitude signal; and a control signal for the target value for aim control from the basic signal and the correction signal. By having a signal processing device that outputs a The control method makes it possible to automate circumferential welding of inclined pipes, which required fine adjustments by welding technicians.

[Brief explanation of the drawing]

The drawings show one embodiment of the automatic welding apparatus of the present invention, with Fig. 1 being a block diagram, Fig. 2 being a diagram showing the relationship between welding posture and correction signals, and Fig. 3 showing the relationship between the amount of cart movement and the amount of torch position variation. Figures 4a, 4b and 4c are explanatory diagrams. 1... Groove variation detector, 2... Posture detector, 3
...Correction signal generator, 4...Signal processing device, 5...
...Torch drive device, 6...Torch.

Claims (1)

[Claims] 1. A groove variation detector that detects the groove position variation in the direction perpendicular to the welding line and outputs a basic signal for controlling the torch aim; an attitude detector that detects the welding attitude and outputs an attitude signal; a correction signal generator that outputs a correction signal of a target value for torch aim control; a signal processing device that outputs a control signal of the target value for aim control from the basic signal and the correction signal; An automatic welding device comprising: a torch drive device that displaces a torch by a predetermined amount.