JPS59185575A - Weld line follow-up device - Google Patents

Abstract

PURPOSE:To detect a weld line without contact by comparing each low frequency component of the left side and the right side of weaving, also comparing each low-frequency component with a set value, and discriminating a shift. CONSTITUTION:A titled device is constituted of a high-frequency signal generating part 25 which is connected between both ends of a welding torch 11 and superposes a high-frequency signal of a constant peak to a welding arc, a detecting part 26 for detecting a high-frequency signal varied in accordance with a variation of the welding arc, a position detector 21 of a weaving position of the welding torch 11, a signal processing circuit 27 for fetching a low-frequency component from a high-frequency signal varied by each of the left side and the right side of weaving by a position signal from said detector, comparing each peak value or integral value of them, and also comparing a mean value of each low frequency component or a DC component with a set value, a discriminating part 28 for discriminating a shift of the left and the right, or the upper and lower directions to a weld line of the welding torch 11 from its processing signal, and an instructing part 29 for sending a correcting signal to a driving source 6 for moving the welding torch 11 in accordance with its discriminating signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a device for following a welding line while weaving a welding torch, and in particular a high-frequency signal that superimposes a high-frequency signal with a constant peak value on the welding arc and changes in response to changes in the welding arc. , extract the low frequency components from the changing high frequency signal on each of the left and right sides of weaving, temporarily store them, compare their peak values or integrated values, and calculate the average of each low frequency component. The present invention relates to a welding line tracking device that corrects slippage of a bath welding torch with respect to a bath tangent line by comparing a value or a DC component with a predetermined set value.

Conventionally, there has been a device of this type that is not shown in FIG. In the figure, /L and /R are respectively 7i1J11. in the welding direction shown by arrow 2. The object to be welded on the right side, 3 is welding & (i.e., the place where welding is to be done with the class welded object /L), DA is a detection glove that detects contact with the weld line 3,
5 is a controller, O is a torch left/right drive section controlled by this controller 5, 7 is a torch upper/lower drive section controlled by the controller 1, and gA, &B, and gc are a controller S'', respectively. An electric cable connecting the detection globe, the torch left and right drive parts B, and the torch upper and lower drive parts 7, 9 is a weaving device, 10 is a holder that holds the detection globe and the weaving device t, // is a weaving device? 7.2 is the welding wire, //L is the welding torch // or the position when weaving to the left, /
/R is the position when the welding torch // moves 6 eaves to the right.

In addition, the torch left/right drive unit 6, the torch upper/lower drive s7,
The weaving device t and the holder /θ serve as a driving source for moving the welding torch // when it deviates from the welding line 3 .

Next, the operation will be explained. First, a detecting globe detects that the welding torch // has shifted from the welding line 3 for welding the objects /L and /R to be welded. The detected deviation signal is sent to the controller S through the electric cable gA, and the left/right or upward/downward deviation is determined by the tile. As a result, controller 3
The deviation correction signal is sent to the torch left and right drive parts B and the torch upper and lower drive parts 7 through electric cables g1B and EC, respectively. Based on this deviation correction signal, the torch left/right drive section 6 corrects the left/right position of the weaving device, that is, the left/right position of the weaving center of the welding torch //, and the torch upper/lower drive section also corrects the left/right position of the weaving device. Similarly, the upper and lower positions of the welding torch // are corrected from the upper and lower positions of the weaving device t.

Conventional devices of this type are configured as described above, so they must be installed in the area where the heat, light, and spatter of the arc can be avoided. This method has drawbacks such as a decrease in detection accuracy due to friction and the need for a delay circuit, and also has the drawback of poor durability. Furthermore, since a detection glove is required, the device is complicated and expensive.

This invention was made in order to eliminate the drawbacks of the conventional methods as described above, and it compares the low frequency components extracted from the high frequency signal that changes in response to changes in the welding arc on the left and right sides of weaving. The deviation of the welding torch from the bath tangent line is corrected by comparing it with a predetermined setting value, which eliminates the need for a detection glove and simplifies the manufacturing equipment and makes it possible to use the JS type, making it possible to weld in narrow spaces. It is an object of the present invention to provide a welding line tracking device that can be applied to the welding area and can prevent deterioration in detection accuracy and durability even under adverse environments such as heat and light spatter specific to arc welding.

An embodiment of the present invention will be described below with reference to the drawings. Second
In the figure, /L, /R, 3, Otsu, 7°, /θ, //
, //L, //R and /co are the same as those explained in FIG. , 2/ is a position detector attached to the weaving device 9 to detect the weaving position of the welding torch //, 2.2 is a welding power source, and 23 is a welding current flowing from this welding power source to the bath welding torch/l. 30 is a return line for the welding current, 2 is a high-frequency signal generator connected between both ends of the welding torch, and superimposes a high-frequency signal with a constant peak value on the welding current and therefore the welding arc. An impedance element such as a resistor 1.2 inserted into the current path 23 between the generator 25 and the welding torch // is connected to the output side of the resistor 30 and therefore the high frequency signal generator 25, and changes in the welding arc. A detection unit 1.27 that detects a high frequency signal that changes in degrees Celsius is connected to the output side of the detection unit 2 and the position detector 2/,
The low frequency components are extracted from the changing high frequency signals on each of the left and right sides of weaving according to the position signals from / and temporarily stored, and their peak values or integrated values are compared and the low frequency components are a signal processing circuit that compares the average value or DC component with a predetermined set value; 2;
g is connected to the output side of this signal processing circuit Ω7, and from the processed signal determines left/right deviation or upward/downward deviation of the welding torch// with respect to the welding line. This command section sends a deviation correction signal to the torch left/right drive section t or the torch upper/lower drive section 7 for moving the welding torch in accordance with the discrimination signal from the weaving device.

Next, the operation of the weld line tracking device of the present invention will be explained. First, the welding torch // is connected to the welding line 3 by the weaving device 9.
Weaving, that is, periodic repetitive motion, to the left and right in a plane orthogonal to the surface.

When weaving the welding torch // in this way, the welding wire /2 of the welding torch l/ and the workpiece //
As is clear from the 21st tl force, the distance between L and //R changes periodically, so that the current path 2 of the welding torch //
The welding arc flowing through 3 also changes. Corresponding to this change in the welding arc, the superimposed high frequency signal also changes, and this changing high frequency signal is detected by the detection section 2B and sent to the signal processing circuit 27. This signal processing circuit core extracts low frequency components from the changing high frequency signals on each of the left and right sides of weaving according to the position signal sent from the position detector 2/, temporarily stores them, and temporarily stores the peak values thereof. Comrade or integral value open book thick
The average value or DC component of each low frequency component is compared with a predetermined set value. Now, if we refer to the waveform diagram in Figure 2 that shows the low frequency components extracted from the changing high frequency signal on the left and right sides of the sine wave weaving, we can see that the peak value of the low frequency component on the left side is It is louder than the peak value of the low frequency component on the right, so the welding torch/l
It can be seen that is shifted to the left from weld line 3. in this case,
The signal processing circuit 27 first generates a ten-polar processed signal, and then a non-polar processed signal, whereby the discriminating section 2g generates a discriminating signal that determines that the vehicle is "sliding to the left."

This discrimination signal is supplied from the discrimination section rg to the command section 2q. Therefore, the command unit sends a deviation correction signal to the drive source B to move the welding torch //, specifically, to the torch left and right drive units B, to correct the deviation of the welding torch // with respect to the bath tangent line 3. In other words, move the welding torch // to the right.

FIG. 3 shows the resulting processing signal 9 determinations and commands by comparing the left and right low frequency components and comparing the low frequency components and the set values.

Note that the above embodiment has been described for the case where the same set value is set for the low frequency components on the left and right sides. Good (
, the latter is effective when there is an asymmetrical welding groove or when there is a "necessary force" to shift the aiming position of the weld line and welding torch.In addition, although the above example shows the case of striped downward butt welding, other positions can be used. It is similarly effective for butt welding (horizontal, vertical 9 upward) and fillet welding in all positions.In addition, left/right shift detection is performed by differentiating the low frequency component near the weaving end, and the differential value is θ It is also possible to detect and compare the signal values at the time of .

As described above, according to the present invention, the configuration is configured to compare the low frequency components on the left and right sides of weaving, and to determine the deviation by comparing the force, force, and low frequency components with a predetermined set value. Therefore, the following effects are obtained.

l Can detect weld lines without contact.

The device is simple, compact, and inexpensive, and can be applied to narrow welding areas.

3. Even under adverse environments such as heat, light, and spatter that are typical of arc welding, there is no decrease in accuracy or durability.

It is possible to follow the weld line without malfunction or loss of accuracy, even with the noise peculiar to arc welding and the large instantaneous fluctuations of the welding current.

S It is also effective when it is necessary to shift the aiming position of the welding torch from the asymmetrical groove welding line.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a conventional welding line tracking device, Fig. 2 is a schematic diagram showing a partial block diagram of an embodiment of the present invention, and Fig. 3 is a comparison of low frequency components and processed signals according to the present invention. FIG. 1 is an explanatory diagram showing a 1 determination and an instruction. II...Welding torch, 9...Weaving device, 3...
Welding part 1.25...High frequency signal generation part, 2/...Position detector, 2B...Detection part, 27...Signal processing circuit 1.2g
...Discrimination part, 2? . . . Command section, A. . . . Torch left/right drive section, 7. . . . Torch upper/lower drive section. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Agent Masu Oiwa Yuen 1

Claims (1)

[Scope of Claim] A device for following a welding line without weaving a welding torch, comprising: a high-frequency signal generator connected between both ends of the welding torch and superimposing a high-frequency signal of a constant peak value on the welding arc; a detection section that is connected to the output side of the signal generation section and detects a high frequency signal that changes in response to changes in the welding arc; a position detector that detects the weaving position of the welding torch; the detection section and the position detection section; is connected to the output side of the detector, and extracts low frequency components from the changing high frequency signal on each of the left and right sides of the weaving according to the position signal from the position detector, and compares their peak values or integral values. At the same time, there is a signal processing circuit that compares the average value of each low frequency component or the striped DC component with a predetermined set value, and a signal processing circuit that is connected to the output side of this signal processing circuit and uses the processed signal to determine the left and right side of the welding line of the welding torch. Right shift or up/
A welding line characterized by comprising: a discriminating section for discriminating a downward deviation; and a command section connected to the output side of the discriminating section and sending a misalignment correction signal to a drive source that moves the welding torch according to the discriminating signal. Following device.