KR920006680B1 - Welding wire pursuit device - Google Patents

Abstract

The apparatus automatically tracks even an unfanlanced weld line using a tracking algorithm to enhance the weld precision and efficiency. The weld line tracking apparatus comprises Y table (2) mounted on a carriage (1), X table (2') also mounted on the Y table (2), an actuator (3) connected to a controller (4) and a torch (5), an arc sensor controller (6) connected to almost all the members, and a power source (7). The control algorithm samples the error distance between the torch position and the weld line, and compensates the error value computed in CPU.

Description

Weld Seam Tracking Device Using Microprocessor

1 shows the relationship between welding current and wire protrusion length.

2 is the shape of the change in current that occurs when rocking the welding torch.

3 shows left and right position correction algorithms in butt joints and pellet joints.

4 is a left and right position correction algorithm when using a plurality of electrodes.

5 is a schematic diagram of a mechanism.

6 is a block diagram of a controller.

The present invention relates to an automatic welding device, and relates to a welding line tracking device capable of increasing welding quality and precision of an automatic welding device for welding by connecting a welding torch to a trolley.

Conventional welding using the welding bogie cannot be applied when the welding line is not a straight line, and even if the welding line is a straight line, the welding line changes due to the processing deviation of the weldment and the thermal deformation of the welding line due to the welding heat input. You must keep an eye on it.

As a conventional technique, there is a welding line tracking method for detecting a welding line by detecting a change in welding current or welding voltage without attaching an external sensor to the welding apparatus.

Generally, GMA welding uses a constant voltage power supply.

In this case, as the length of the wire protrusion changes as shown in FIG. 1, the current changes with each other, and there is some inverse relationship between them. When the height of the welding torch is fixed and the torch is swung by a certain width in the welding improvement, the lowest current is obtained at the center of the improvement, and high current values are obtained at the left and right. If the center of oscillation is on the left side of the weld line, the current value on the left side will be greater than the right side, and the opposite result is obtained when the center of oscillation is on the right side.

From this fact, as shown in FIG. 2, when the positional deviation between the center of the swing and the welding line occurs, the welding line can be tracked by determining the correction direction and adjusting the left and right positions. However, the correction amount, i.e., the distance between the center of rotation and the welding line, has a complex interrelationship with many variables such as the type of the welded object and the welding rod, the surface treatment state in the weld improvement, and the type of the protective gas. Can't calculate Therefore, it is common to make corrections using these values obtained by preliminarily obtaining the correction amount through various experiments.

In addition, these methods require expensive processing devices to achieve real-time control, and are often included as an option of welding robot controllers, so they are not universal.

It is a first object of the present invention to provide a flexible universal weld line tracking device that can be freely attached to welding using a trolley or other simple automatic welding device used in a general production site.

The second object of the present invention is to provide a welding line tracking device of low cost and simple configuration by implementing the tracking algorithm in software using a microcomputer and simplifying the algorithm.

Such a feature of the present invention is that by using the existing welding power supply, the balance weaving machine, etc. as it is without deformation, it is possible to perform the welding line tracking function by adding only this controller and the XY table, and also butt weld and fillet welding Both sides of the unit can be applied as it is without any modification of the device.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The Y table (2) is installed on the carriage (1), the X table (2 ') is installed on the Y table (2), and the actuator (3) is installed on the X table (2'). 4) and torch (5) and connect the arc sensor controller (6) to the power source (7), torch shunt (8 ') actuator controller (4) and X table (2') Y table (2), Connected to the carriage (1) and the control unit is the CPU (280A), the X, Y regulators (10) and (11) memory (12), and the actuator controller (4) and the power source (7) via the ADC and FILT AND PRE AMP. ) Is connected to).

In the present invention as described above, when the torch swings from side to side at a fixed height, a change in current value appears. At this time, when the deviation from the welding line appears, there is a difference between the current integration value when returning from the center to the center again and the current integration value when returning from the center to the right again.

The direction of the deviation can be determined according to the correlation of the magnitudes. However, since the amount of deviation from the magnitude of the current integration value is not directly known, the center of the swing is moved by a certain distance in the direction in which the deviation is cancelled. This travel distance is externally adjustable.

Repeating the correction while continuing the swing as shown in the tracking algorithm shown in FIG. 3 results in tracking the weld line deformed from side to side.

This upper and lower position correction is based on the current integration value of one swing section obtained at the beginning of welding, and this value is compared with the sum of the left and right current integration values obtained in the above left and right tracking process. If it is small, it is made by adjusting downward.

This apparatus is adapted to be applied to a welding apparatus using a plurality of electrodes without the oscillation of the welding torch if the software produced separately is mounted.

Figure 4 shows the left and right correction algorithm in this case. In this case, the left and right welding electrodes are continuously sampled by a certain number of currents, and then the values are compared with each other, and the welding torch is traced by moving the welding torch in a direction in which the difference is offset. Therefore, the present invention can automatically weld the weld line despite the imbalance of the weld seam, it is possible to construct a welding machine that improves the welding precision and efficiency.

Claims (1)

The Y table (2) is installed on the carriage (1), the X table (2 ') is installed on the Y table (2), and the actuator (3) is installed on the X table (2') so that the actuator (3) is the controller (4). ) And torch (5) and the arc sensor controller (6) to the power source (7) torch shunt (8 ') actuator controller (4) and X table (2') Y table (2), carriage ( In the known welding line automatic tracking device connected to 1), the control device is an actuator controller (CPU 280A) via an X, Y regulator 10 (11), a memory (12), and an ADC and a filter and a preamplifier. 4) and the welding source using a microprocessor, characterized in that the error distance between the torch and the welding line is sampled as a current value, so that the correction distance can be calculated by the CPU and the welding line can be automatically tracked. Tracking device ".

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