KR100259880B1 - Method of welding gun control and apparatus thereof - Google Patents

Abstract

PURPOSE: A method and a device for controlling a welding gun are provided to quickly and exactly control the welding gun. CONSTITUTION: A controller of a welding gun contains a near distance sensor(15) to output a detecting signal by connecting with a controller(6) and detecting an interval between a tip of the welding gun(3) and a welded material(8); and a detected signal processing unit(16) to output a control signal of the welding gun for continuously approach the welding gun(3) toward the welded material(8) by comparing the detected interval with a reference value. The near distance sensor(15) is installed under the welding gun(3). Thereby, the welding gun is controlled precisely.

Description

Robot Welding Welding Gun Control Method and Device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding gun control method and apparatus for robot welding, and more particularly, to a method and apparatus configured to quickly and accurately perform welding gun control in performing robot welding.

As is well known, as the so-called mechatronics-related technology is rapidly developing, it is a reality that various types of robots can be witnessed in the industrial field. As a common example, in the case of automobile production sites, there are a plurality of welding robots which are sequentially arranged in a welding line.

The welding robot includes a welding gun for direct current spot welding (spot welding) by applying current to a welding object, a joint part for inducing opening and closing movement of a welding gun having a tong shape, a support part for supporting these main parts, and an overall operation. It is configured to include a control unit for control.

Meanwhile, in controlling the welding gun, an on-line method and an off-line method are described as follows.

First, the on-line method is a form in which a worker directly visually confirms the positional relationship between the welding gun and the object to be joined in a teach pendant and simultaneously moves the welding gun little by little to approach the target welding target site.

The off-line method, which uses a CAD / CAM system, refers to a form in which the welding gun automatically approaches the corresponding welding target site according to a pre-written off-line program. Of course, in this case, due to factors such as the accumulation of tolerances between the parts constituting the welding robot itself, the work accuracy is lower than the on-line method that the operator directly controls the naked eye.

In the case of the actual work site, as the various electronic measurement and control technology is improved, what was on-line in the early stage is gradually transformed to off-line. However, even if the above-described off-line method is adopted, since the welding gun is close to the welding target part to some extent, the operator directly controls it precisely.

However, such a conventional welding gun control method and apparatus had the following fundamental problems.

In other words, whether the on-line or off-line method is used, the final precision control is dependent on the operator's naked eye, and the accuracy of the control is inferior and the time required for the work is long. Of course, the productivity and welding quality was accompanied by a decrease.

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a method and apparatus capable of quickly and accurately controlling the welding gun in performing robot welding.

1 is a schematic view showing a conventional welding method for welding welding robots,

2 is a schematic view showing a welding gun control method according to an embodiment of the present invention.

<Explanation of symbols for main parts of drawing>

1: support part 2: joint part

3: welding gun 4: welding robot

5: teaching controller 6: controller

7: stroke adjusting device 8: welding object

14: welding robot 15: proximity sensor

16: detection signal processing unit

According to the welding gun control method and apparatus of the present invention for achieving this object, it is characterized in that the welding gun is automatically controlled based on the distance between the welding gun and the welding object detected by the proximity sensor (sensor) on the welding gun. have. That is, in the present invention, the welding gun is controlled in an off-line manner.

Hereinafter, a welding gun control method and apparatus of an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

First, according to FIG. 1 schematically showing a conventional welding gun control method and related apparatus, a welding robot 4 including a support 1, a joint 2, and a welding gun 3 is used as the teaching manipulator 5. It is configured to control. For example, the operator controls the operation of the welding gun 3 by manipulating the teaching manipulator 5 installed at a certain distance from the welding robot, for example, on-line control.

On the other hand, the controller 6 shown between the support 1 and the teaching manipulator 5 is a part which receives various electric signals from the teaching manipulator 5 and sends various control signals directly to the welding robot 4. In other words, these controllers 6 and the teaching operator 5 may be integrated into one controller.

Moreover, the stroke adjuster 7 attached to the lower end of the welding gun 3 is for arbitrarily adjusting the space | interval between the tip of the welding gun 3 according to the thickness of the welding object 8, etc.

As mentioned above, considerable care must be taken to accurately approach the welding gun 3 to the welding target site on the object 8. Therefore, the related air input is excessive, as well as the resulting productivity problems. In addition, when the approach and welding process is not performed correctly, the deterioration of the welding quality is inevitably mentioned above.

On the other hand, according to Figure 2, the welding robot 14 constituting the welding gun control apparatus of the present invention is the controller in addition to the conventional support (1), articulation (2), welding gun (3) and stroke adjustment device (7) Proximity distance sensor 15 connected to the (6) and the associated detection signal processing unit 16 is added.

The proximity distance sensor 15 detects a gap between the welding gun 3 and the welding object 8, converts it into an electrical signal, and sends the detected signal to the detection signal processor 16. Here, the proximity distance sensor 15 is preferably a lower end of the welding gun 3 as shown, but is not particularly limited. This is because a sensing medium such as a laser beam, an ultrasonic wave, an electric force, or a magnetic force emitted from the distal end of the proximity distance sensor 15 may be a position that can reach the welding object 8 properly.

In addition, the detection signal processing unit 16 generates a new control signal by comparing the electrical signal from the proximity sensor 15 with a previously input control-related value.

In view of its functional aspect, the detection signal processing unit 16 may be installed inside the controller 6, but may be mounted on the proximity distance sensor 15.

Here, the specific control method using the welding gun control device for robot welding of the embodiment of the present invention will be described.

In the robot welding welding gun control method of the present invention, the welding gun 3 is approached to the welding object 8 to a predetermined adjacent distance A, and the proximity distance sensor 15 is operated to operate the welding gun 3. ) Detecting the gap (B) between the tip and the welding object (8) to inform it to the controller (6), and sending a signal to continue access until the gap (B) is a specific value, including 0 (zero) It is configured to include. The adjacent distance A is a value set in advance on a program, and is not a separate measurement value by the proximity distance sensor 15.

On the other hand, the distance (B) is a value measured directly by the end of the welding gun (3) close to the welding object 8 to a certain range, the proximity sensor 14 continues to fire the detection medium, such as a laser. . That is, the welding gun 3 has a characteristic of continuously changing as the welding object 3 approaches the welding object 8.

Anyway, since the welding gun 3 is always precisely controlled using the proximity distance sensor 15 and the detection signal processor 16, the control operation itself is not only accurate but also the welding quality is greatly improved.

On the other hand, in view of the fact that an appropriate pressing force is required in the final welding moment, the threshold value of the interval B is not necessarily limited to zero. That is, the tip of the welding gun 3 may be approached more closely after the complete contact with the welding object 8, so that the welding gun 3 may exert an effect of pressing the welding object 8. This is simply a matter of design dimensions and is not particularly limited here.

That is, by including the proximity distance sensor and the detection signal processing unit as a component constituting the welding gun control device for robot welding, all forms of the invention to control the entire welding gun control process up to the final welding step in an off-line manner The present invention includes.

As described above, according to the robot welding welding gun control method and apparatus of the present invention, based on the distance between the welding gun and the welding object detected by the proximity sensor, the welding gun is always precisely controlled to achieve remarkable productivity and Quality improvement effect can be obtained.

Claims (5)

Approaching the welding gun (3) to the welding object (8) to a predetermined adjacent distance (A), and operating the proximity distance sensor 15 on the welding gun (3) to the tip of the welding gun (3) and the welding object (8) Detecting the interval (B) between the notification and the controller 6, and the robot welding welding gun control, characterized in that it comprises a step of sending a continuing signal until the interval (B) is a specific value Way. According to claim 1, wherein the adjacent distance (A) is a numerical value set in advance in the program, the distance (B) is the proximity distance sensor after the tip of the welding gun (3) close to a certain range to the welding object (8) 15) is a robot welding welding gun control method, characterized in that the measured value directly by firing the detection medium. The method of claim 2, wherein the sensing medium is a laser beam. In the welding gun control apparatus for robot welding, which includes a support part (1), an articulation part (2), a welding gun (3), and a controller (6), the tip of the welding gun (3) and the object to be welded are connected to the controller (6). (8) the proximity distance sensor 15 for detecting the interval between the output and the detection signal, and the distance between the tip of the welding gun and the predetermined reference value suggested by the detection signal input from the proximity distance sensor 15 and the predetermined reference value In comparison, the robot further comprises a detection signal processing unit 16 for outputting a welding gun control signal so that the welding gun 3 continues to approach the welding object 8 until the interval converges to the reference value. Welding gun control device for welding. The welding gun control apparatus for robot welding according to claim 4, wherein the proximity distance sensor (15) is mounted at a lower end of the welding gun (3).

Images