KR20050070348A - The automatic welding system using laser vision sensor - Google Patents

Abstract

The present invention relates to an automatic welding system using a laser vision sensor to automatically perform a submerged arc welding (SAW) narrow gap welding process applied to a large pressure vessel manufacturing.

The present invention is difficult to observe the shape of the weld joint according to the thick plate narrow improvement by applying a welding control mechanism combined with a laser vision sensor in order to overcome the limitation of welding automation by manual or mechanical sensors when applying the thick plate narrow narrow welding. It can automatically and accurately track the welding line change due to the elimination of parts and irregular welding line and the sliding by the transfer, and by using this result, the automatic continuous welding is possible by controlling the welding condition according to the change of the welding part. And uniform welding can be performed and welding productivity can be improved.

Description

The Automatic Welding System Using Laser Vision Sensor

The present invention relates to an automatic welding system, and more particularly, to an automatic welding system using a laser vision sensor that can automatically perform a submerged arc welding (SAW) narrow gap welding process applied to a large pressure vessel. will be.

In general, the welding of large vessels and tanks is divided into longitudinal welding and circumferential welding according to the direction of the weld, and the shape of welding improvement is divided into general improvement and narrowing. As the thickness increases, a submerged arc welding (SAW) welding process is performed on a narrow line improvement rather than a general welding improvement.

Here, the narrow-impedance welding has a much smaller welding amount than the general improved welding, and thus, the work speed is fast, and the heat input of the welding is small, so that the heat deformation and structure change of the weld due to the welding heat can be minimized. .

However, the precise control of the welding drive unit and the constant observation of the operator are required due to the improvement of the welding, which is a problem in the automation of the welding process.

In other words, the conventional SAW narrow-impedance welding performs welding operations such as welding line follow-up observation and welding control by using manual or mechanical sensors that depend on skilled workers.In automated welding, welding line tracking automation using mechanical or contact sensors is performed. However, it is sensitive to the environment around the tracking unit and its applicability is lowered due to the limitation of tracking reliability.

In addition, the laser vision sensor is a visual sensor device capable of obtaining three-dimensional image data in a non-contact manner using a laser camera, and is a unit functional component that can be used in an automated process apparatus.

In addition, since the concentration of light is high because the laser is used, the wavelength is different from the arc generated at the time of welding, and the arc can be perfectly captured even in the arc light. Located in front of the torch, the shape of the welding part to be welded can be captured in advance to track the weld line and provide information for controlling the welding condition according to the size of the gap of the weld joint. It can be used for inspection of weld condition by measuring bead shape after inspection or welding.

Recently, the welding seam tracking using the laser vision sensor has been studied, but since the research on the sensor self-measurement method and operation algorithm development is being conducted, there is a problem that the practical welding automation system for the heavy plate weldment is not made. .

The present invention is to solve the problems as described above, the object of the welding control mechanism combined with a laser vision sensor in order to overcome the limitations of welding automation by manual or mechanical sensor application when applying a thick plate multi-layer narrow line welding application. By applying, it provides automatic welding system using laser vision sensor that can solve the difficulty of observing the shape of weld joint according to thick plate narrowing and automatically track the change of welding line due to irregular welding line and push by transfer. It is.

Another object of the present invention is to enable automatic continuous welding by controlling the welding conditions according to the shape change of the welded portion so that quality improvement and uniform welding can be performed and welding productivity can be improved.

A feature of the present invention for solving the object as described above is fixed integrally to the front surface of the welding torch, by measuring the image information of the narrow line weld joint to the lower center point (Gap Center Point) of the narrow line weld joint A laser vision sensor for controlling the welding position of the welding machine by controlling it in the vertical / vertical direction, positioning it in a right position, tracking an automatic welding line, and outputting a predetermined control signal; According to the servo control by the laser vision sensor to implement an automatic welding system using a laser vision sensor including a narrow line welding unit including a regulator, a slider, a welding head whose welding torch nozzle tilt angle is controlled to a specified value.

Here, the laser vision sensor converts the information obtained by photographing the narrow line weld joint into three-dimensional coordinates, calculates the coordinates of the welding torch, and then corrects the position of the welding torch using the position unit according to the welding torch coordinates. When the projecting mart attached to the specimen is recognized by the magnetic sensor, the PLC controller is driven to signal the welding torch tilting motor to be operated left and right. It characterized in that to provide.

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

In the present invention, using the laser vision sensor to implement the automation of the narrow-circuit circumferential welding process applied during heavy assembly or contrast welding of the thick plate pressure vessel and large diameter pipe in the power generation, petrochemical field, such a laser vision sensor The automatic welding system used includes a manipulator, a slider under the control of a servo motor, and a welding head in which a welding torch nozzle tilting angle is controlled to a specified value. And a laser vision sensor capable of outputting a control signal and an automatic welding line tracking function.

Here, the laser vision sensor tracks the image capturing and automatic welding line of the narrow-impedance weld joint and outputs the necessary control signals to control the proper welding variables of the welding machine. The welding system is constructed so that a one-pass or two-pass welding process is automatically and continuously performed.

1 is a schematic view of a welded part of a welded product to which SAW automatic welding system using a laser vision sensor according to the present invention is applied, that is, a narrowed joint shape, and FIG. 2 is a photograph and a schematic diagram of a narrowed torch according to the present invention. 3 is a view illustrating a photograph of an automatic welding system using a laser vision sensor according to the present invention, and FIG. 4 is a schematic diagram of an automatic welding system using a laser vision sensor according to the present invention.

The welded product to which the present invention is applied is a representative thick plate narrow welding part as a circumferential welded part of a reactor vessel and a steam generator.

At this time, the base material is made of low alloy steel, the weld joint improvement angle is 1 ~ 3˚ narrow line, the weld portion thickness is about 130mm, 250mm.

In addition, the narrowing torch 5 is configured to allow the tilting nozzle 6 of the lower end of the torch frame to swing left and right for welding application of the narrowing joint 1.

The tilting motor 7 located at the upper end of the narrow line torch 5 is controlled by the PLC program of the laser vision sensor 4 to manipulate the torch tilting feed distance to a specified value.

The structure of such an automatic welding system is largely comprised of the narrow line torch 5 of a torch tilting function, the 3-axis drive unit of servo control, the SAW welding machine 11, the laser vision sensor 4, and the control panel 9. As shown in FIG.

Here, the three-axis drive device is operated by the control of the three-axis servo motor 12 to enable the up and down / left and right control for the position control of the narrow line torch 5 and the front and rear control of the welding progress direction.

In the case of the circumferential welding application, the movement in the welding progress direction is fixed, and instead, the operation of the turning roller 20 is controlled. The turning roller 20 attaches an electromagnet to the side of the rotating body to detect the rotation of the welding member, installs a magnetic sensor 21 to detect the electromagnet, and performs rotation detection, and corresponding rotation Upon detection, the output signal is transmitted to the torch drive PLC program and sends an output signal to the tilting motor encoder 8 attached to the narrow line torch 5 so that the narrow line torch 5 is operated by the input distance. Start).

The welding process of the automatic welding system using the laser vision sensor as described above is as follows.

First, the welding process of the welding system welds one pass to the first layer and then two passes to each layer on the narrow line having an improved width of 24 mm at the top. When the operator places the welding head near the weld by manual control, the laser vision sensor 4 automatically moves the vertical & horizontal slider 13 of the servo control to the arc start point, thereby narrowing the torch to the arc start point. (1) is located.

Then, after setting the narrowing torch 1 to be positioned at the arc starting point, when the operator presses a welding start button, welding is started, and the welding improvement is performed by the laser vision sensor 4 at the same time as the turning roller 20 rotates. Automatic seam tracking starts for left and right variations.

Subsequently, when the weld is rotated once by the automatic welding, the weld rotation is sensed by the magnetic sensor 21 attached to the weld to move by the overlap length input to the PLC controller 16 to perform the next pass welding.

In addition, a tilting motor 7 with a slide motor encoder 8 capable of driving the input of a narrow line torch 1 for moving to the next pass after completion of welding for one pass can be driven by a specified value. To control the feed width.

At this time, the welding process is classified into a root layer, a main layer, and a finishing weld layer, and thus the left / right transfer method of the narrowing torch 1 controlled according to this is different. The root weld is welded at the center position of the symmetric weld improvement width without swinging of the tilting nozzle 6, and the main weld is such that the left / right swing of the tilting nozzle 6 is improved once in each of the improved left and right directions to complete the welding. do.

Automatic continuous welding is performed to the root and the main welding part using the laser vision sensor 4, and the finishing welding part is welded by moving the torch slider by manual control by an operator.

The welding progress process of the automatic welding system using the above-described laser vision sensor is described as follows.

1. In the workpiece setting process, the welding member is fixed.

2. In the welding head set-up process, the vertical slider is moved to the upper part of the welding part, and the horizontal slider is moved to fix the welding head near the welding position in the center of the welding part.

3. In the welding parameter set-up process, the welding parameters of the welder controller are adjusted to actual welding parameters.

4. In the Torch Tilting Angle Set-up process, the torch nozzle allows the nozzle to tilt from side to side by a pendulum device by the upper end of the torch frame. The motor is attached, and the tilting width is controlled by the DC motor operation. In addition, DC motor operation is operated through the PLC controller, the motor operation is performed according to the time input.

5. The Home Position Automatic Set-up process sets the X, Y, and Z axes.

6. In the Seam Tracking Starting & Welding Head Traveling process, automatic seam tracking is initiated and the narrowing torch is moved to the Arc Start Point.

7. First pass welding starting & continuous seam tracking and flux feeding system actuation process, prior to welding, supplying and retrieving the flux prior to welding. The roller is driven.

8. Slag Removal is a process performed by the operator and removes slag during welding.

9. In the welding torch tilting (2 pass welding) and next pass starting process, the torch is moved by the preset torch tilting distance when shell 1 rotation is completed. Next pass welding proceeds.

10. In the welding stop process, when the welding breakpoint is recognized by the guide sensor, the driving of the manipulator or the turning roller is stopped, and the arc stop after the input time for crater processing. After the arc stop is completed, the flux supply and recovery are stopped.

On the other hand, the embodiment according to the present invention is not limited to the above, it can be carried out by various alternatives, modifications and changes within the scope apparent to those skilled in the art with respect to the present invention.

As described above, the present invention, by applying a welding control mechanism combined with a laser vision sensor in order to overcome the limitation of welding automation by the manual method or mechanical sensor when applying a thick plate multi-layer narrow line welding, welding joint according to the thick plate narrow It is possible to automatically and precisely track the weld line change due to the elimination of the difficulty of observation of the shape and irregular welding line and the sliding by the transfer, and by using the result, the automatic continuous welding is controlled by controlling the welding condition according to the change of the weld shape. It is possible to perform quality improvement and uniform welding and to improve welding productivity.

1 is a view showing the narrow joint shape of the SAW automatic welding system using a laser vision sensor according to the present invention.

Figure 2 is a photograph and a schematic view of the narrowing torch according to the present invention.

3 is a diagram illustrating a photograph of an automatic welding system using a laser vision sensor according to the present invention.

4 is a schematic diagram of an automatic welding system using a laser vision sensor according to the present invention;

Explanation of symbols on the main parts of the drawings

1: narrow joint joint 2: image recognition

3: welding line tracking point 4: laser vision sensor

5: narrowing torch 6: tilting nozzle

7: tilting motor 8: tilting motor encoder

9: control panel 10: auxiliary control panel

11: welding machine 12: servo motor

13: Vertical & Horizontal Sliders 14: Flux Recovery Nozzles

15 flux hopper 16 PLC controller

17: server amplifier 18: slide motor encoder

19: adjuster 20: turning roller

21: magnetic sensor 22: protrusion mark

Claims (2)

It is integrally fixed to the front surface of the welding torch, and it measures the image information of the narrow line welding joint, controls the torch in the vertical / vertical direction to the lower center point of the narrow line welding joint, and tracks the automatic welding line. A laser vision sensor for outputting a predetermined control signal to control proper welding parameters of the welding machine; And a narrow-impedance welding part including a welding head in which an adjuster, a slider, and a welding torch nozzle tilting angle are controlled to a specified value according to servo control by the laser vision sensor. The method of claim 1, The laser vision sensor converts the information obtained by photographing the narrow-impedance weld joint into three-dimensional coordinates, calculates the coordinates of the welding torch, and modifies the position of the welding torch using the position unit according to the welding torch coordinates. When the projecting mart attached to the specimen is recognized by the magnetic sensor, the PLC controller is driven to signal the welding torch tilting motor to be operated left and right to provide automatic welding of narrow joints. Automatic welding system using a laser vision sensor, characterized in that.