JPH08150475A - Method for remote control of welding condition - Google Patents

Abstract

PURPOSE: To correctly control the welding condition or the like by monitoring the part to be monitored with different brightness with the optimum image. CONSTITUTION: In the remotely monitoring method to monitor the welding condition by a camera, an interference filter 13 to pass the light whose wavelength is within the range of <=100nm around the center wavelength of 600-800nm is arranged before a CCD camera 3 in order to clearly photograph the conditions of the molten pool, the arc and the groove which are the objects to be monitored at the part to be welded. The information on the arc and the molten pool photographed at the optimum shutter speed suitable for each object and the information on the molten pool and the groove photographed when the voltage is low in the case of the gas shielded metal-arc welding or when the current is small in the case of the TG welding at the optimum shutter speed are respectively synthesized at the mask position of the screen to be set by an image processor 8 and monitor outputted by a control device 10 capable of selectively switching the shutter speed. The sharp and clear image is displayed thereby, and the welding condition including the copying the groove line is achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for obtaining a clear image necessary for monitoring welding conditions or controlling welding conditions.

[0002]

2. Description of the Related Art Conventionally, when remotely monitoring the welding situation,
There has been a method of monitoring the welding condition with a fixed camera diaphragm, or remotely operating the camera diaphragm with a small DC motor to monitor it according to the optimum diaphragm of the monitored object.

[0003]

However, it is difficult to obtain all the information in the molten pool and the groove at the same time due to the influence of the arc light in the monitoring by the constant diaphragm. In other words, when the aperture of the surveillance camera was adjusted to the arc part, other information was hidden by the arc and disappeared. For this reason, it has been considered that the diaphragm is moved by a DC motor and the diaphragm is changed to an optimum diaphragm according to an object to be observed and monitoring is performed. However, even in this case, there is a delay in the time required for the motor to reach the optimum aperture, and the brightness of the entire screen changes, making monitoring difficult. Moreover, if you match the arc with other information,
Although the information in the groove becomes relatively easy to see when hidden behind the arc and the aperture is opened, the entire area becomes bright and blurred due to the effect of arc light. It has caused harmful effects such as disappearing. Therefore, the present invention solves such a conventional problem, and monitors a target portion having different brightness with an optimum image, and provides a remote monitoring method of a welding condition that enables accurate control of welding conditions and the like. provide.

[0004]

SUMMARY OF THE INVENTION Therefore, according to the present invention, in a remote monitoring method for monitoring a welding condition with a camera, a state of a weld pool, an arc, or a groove, which is an object to be monitored in a welded portion, is clearly imaged. An interference filter that transmits a wavelength in the range of 100 nm or less with a center wavelength of 600 to 800 nm is arranged in front of the CCD camera, and the shutter speed is selected and adjusted by a control device that is adjusted to each target. Information on the arc and molten pool imaged by the optimum shutter speed, as well as the gas shield arc welding by the optimum shutter speed,
When the voltage is small, in TIG welding, the molten pool imaged when the current is small, the in-groove information and the mask position of the screen set by the image processing device are combined, and a clear image is output by monitor output. It is displayed and welding condition control including groove line copying is performed, and this is used as means for solving the problem.

[0005]

The influence of the arc light as a whole is reduced by the interference filter 13 arranged in front of the CCD camera 3. In order to respond to the time delay of the aperture motor, the camera shutter speed for changing the charge time of the CCD camera itself is changed by the control device instead of the aperture, and it is clear instead of the optimal aperture suitable for each object. Get the image. In addition, the information in the groove, in order to obtain an image when the arc light is low or extinguished, in gas shield arc welding,
The voltage is monitored, and in TIG welding, the current is monitored and when this becomes low, the image is taken at the optimum shutter speed. Further, it is also possible to actively and instantaneously drop the voltage or the current to eliminate the influence of the arc light, and similarly, the image can be taken at the optimum shutter speed. As a result, the in-groove information that is not affected by the arc light is obtained. For the molten pool, either or both of the images taken at the optimum shutter speed when there is an influence of arc light or the optimum shutter speed when there is no influence of the arc light are used. Next, these pieces of information are stored in the image processing device, and the in-groove information, arc, and molten pool are synthesized (overwritten) at a preset mask position or an automatically set mask position. The characteristic image is displayed clearly. Further, by using each image, it is possible to grasp an accurate welding situation and utilize it for automatic monitoring control.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A bead shape automatic control method for gas shielded arc welding according to an embodiment of the present invention will be described below with reference to FIG. The CCD camera 3 according to the above-described embodiment is arranged in the front direction of the welding torch 1 in the welding advancing direction and images the welded portion 5. On the front of the CCD camera 3, 600-800 nm
An interference filter 13 that transmits a wavelength in the range of 100 nm or less with the center wavelength of 100 nm is arranged to reduce the influence of the arc light as a whole. In the CCD camera 3, the electric potential charged in the CCD element is converted into a video signal by the camera controller 12, and the camera controller 12 displays C
It has a selection switch for switching the shutter speed of the CD camera 3 and has a function of controlling the charge time of the CCD element. The shutter speed switching device 7 has a relay circuit that switches the selection switch of the camera controller 12 so that the shutter speed instructed by the control device 10 is achieved. Further, it also has a circuit for transmitting a trigger signal for capturing the welding status when receiving an image capture command from the control device 10. The trigger circuit may be included in the image processing device 8. The image processing device 8 freezes (captures) an image with an image capture start signal instructed by the control device 10. As an image at this time, of course, an image captured at an optimum shutter speed is captured. As a result of combining the arc image, the weld pool image, and the groove image with this, T
It is displayed on the V monitor 9, and each part is displayed in an easily viewable manner. In the figure, 4 indicates a groove surface and 6 indicates a bead.

Next, the image capturing method of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In the control device 10, the welding power source 1
The current and voltage values sent from 1 are A / D converted and monitored, and when this value (voltage in gas shielded arc welding, current value in TIG welding is detected) is small, a screen with a groove shape is captured. To instruct. At this time, the shutter speed switching device 7 is instructed beforehand about the optimum shutter speed for imaging the groove, and then the image capture signal is turned on (when the current and voltage values become small).
And get an image of the groove. With respect to the arc 15 at the tip of the welding wire 14, it is instructed to capture the screen of the arc 15 when the current / voltage value is larger than the specified value. As the molten pool image, the images at the time of the respective images are used, or an optimal shutter speed is instructed when the current and voltage are in an appropriate range to capture the molten pool image. The captured images are combined in the following procedure. Conversely, the optimum current (or voltage) for capturing each image from the control device 10 is set to D / A.
It is also possible to instruct through the converter, simultaneously set the shutter speed suitable for the image at that time, and turn on the image capture signal to capture each image. In each image synthesizing method, the base image is the groove image.
That is, when the image of this groove is captured, the screen of the TV monitor 9 is replaced with this image. Therefore, the image of this groove is displayed until the next image of the molten pool 16 or the arc 15 is captured. However, in reality, this frequency is low, and the arc 15 and the molten pool 16 are overwritten immediately. When the arc image is captured, the portion of the mask 1 that has been set in advance is overwritten on the new TV monitor image. Further, when the molten pool image is taken in, the portion of the mask 2 which has been preset is overwritten on the TV monitor image. By repeating this, the TV monitor can always display an image showing each feature well. Regarding the mask position, for example, in the case of the arc 15, the arc center of gravity position Ac is used as the starting point and the molten pool 16
Then, the mask range can be automatically set starting from the molten pool tip position P1. This makes it possible to automatically cope with differences in camera mounting methods, welding conditions, and groove shapes.

The circuit for changing the shutter speed can be set as shown in FIG. For example, when changing the shutter speed to 4 types, 4 switches X corresponding to this
Prepare 1, X2, X3, and X4. With this, when changing to the arc imaging shutter speed, only X1 is O
Let N. When changing the shutter speed to image the molten pool during arcing, only X2 should be ON. When changing the shutter speed to image the molten pool at the time of short circuit,
Only X3 is turned on. When changing the shutter speed to image the groove situation, only X4 is turned on. As a result, it is possible to set the shutter speed that suits each imaging target. Further, in the control device 10, the welding torch 1, the welding wire insertion position 14, the arc shape (deflection of the arc from the center of gravity) 15, the shape of the molten pool tip are utilized by using the accurate images of the respective objects as shown in FIG. By grasping the positions of the (molten state) 16, the bead shape 6, the left end 17 of the bead 17 and the right end 18 of the bead 18, it becomes possible to instruct the welding power source 11 about current and voltage. For example, by grasping the positions of the welding wire insertion position 14 and the left end 17 of the bead and the right end 18 of the bead, the left and right shafts 2 are moved to move the wire insertion position 14
It is possible to control the welding line such that the center of the position is at the left end 17 of the bead and the right end 18 of the bead.

[0009]

As described above, according to the present invention, the images of the target arcs, the molten pool, and the groove surface having different brightness are accurately captured by setting the optimum shutter speed, and the images are combined. By processing and displaying, an accurate monitor image effective for remote welding work can be provided. As a result, the respective images can be used for accurate control of welding conditions and the like from the characteristic images.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a welding status remote monitoring and controlling apparatus according to the present invention.

FIG. 2 is a diagram illustrating an image synthesizing method.

FIG. 3 is a diagram illustrating a circuit for changing a shutter speed.

[Explanation of symbols]

 1 Welding torch 2 Left-right axis 3 CCD camera 4 Groove face 5 Melting part 6 Bead 7 Shutter speed switcher 8 Image processing device 9 TV monitor 10 Control device 11 Welding power supply 12 Camera controller 13 Interference filter 14 Welding wire 15 Arc 16 Molten pool 17 bead left edge 18 bead right edge

Claims (1)

[Claims] 1. A remote monitoring method for monitoring a welding condition with a camera, in order to clearly image the weld pool, arc, and groove condition to be monitored in a weld zone, 600 to 800.
An interference filter that transmits wavelengths in the range of 100 nm or less with a center wavelength of nm is placed in front of the CCD camera, and a control device that can switch the shutter speed by selecting the shutter speed is optimal for each target. Information on arc and molten pool imaged by shutter speed,
Similarly, with the optimum shutter speed, in gas shield arc welding, when the voltage is small, in TIG welding, the molten pool imaged when the current is small, the in-groove information and the mask position of the screen set by the image processing device are set respectively. By synthesizing and outputting to the monitor, a clear image is displayed,
A remote monitoring method for welding conditions, characterized by performing welding condition control including groove line scanning.