JP2002192344A - Monitoring method of weaving in arc welding and its apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a monitoring method of weaving and its apparatus capable of detecting a moving amount of arc welding that moves by means of weaving of a welding torch. SOLUTION: CCD camera having a suitable filter in the monitoring method of weaving and its apparatus regarding arc welding is provided, and welding arc is photographed while synchronized with weaving of welding torch, that is, both of moving edges of reciprocating welding torch. Based on the photographed image of the welding arc, a center of balance of the image itself of the welding arc is calculated, and a moving range of the welding arc can be detected from the calculated result. Consequently, these signals can be outputted to a control apparatus after the range of the welding arc is judged whether it is correct or not.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to weaving in arc welding in which the welding arc of a reciprocating welding torch is imaged and the amount of movement of the welding arc is detected to output whether or not the amount of movement of the welding arc is correct. The present invention relates to a monitoring method and a monitoring device.

[0002]

2. Description of the Related Art In arc welding, welding is usually performed with the position of a welding torch fixed. However, in order to obtain a wider weld fusion zone than the fixed welding torch method, the welding torch is reciprocated at a fine pitch. A weaving technique that can achieve a wide weld fusion zone is used. However, with a normal monitor for arc welding, welding current, welding voltage and welding time can be monitored,
Due to the weaving of the welding torch, it is not possible to monitor whether the welding arc is correctly moving in a predetermined area of the weld.

Therefore, as a method of detecting weaving in arc welding, there is a method of measuring a moving amount of a welding torch. However, in this method of measuring the amount of movement of the welding torch, it is not clear whether the welding arc itself has moved to a predetermined position, even if the amount of movement of the welding torch is appropriate. As another method of detecting weaving in arc welding, there is a method of imaging a weld fusion point after welding and processing the image. The method of image processing the image of the welding fusion point can detect the gap and the pitch between adjacent welding points, but cannot measure the movement amount of the welding arc itself due to weaving.

Further, in Japanese Patent Application Laid-Open No. 9-295146, in a welding line copying method in weaving welding, the shape of a weld pool at a welding portion during welding is imaged, and the left and right edges of the groove and the insertion position of the welding line wire are determined from the image itself. By recognizing and calculating the welding torch, the welding seam is controlled while controlling the weaving center position. However, even in this method, the molten pool of the welding material is imaged, and the welding arc itself having high brightness cannot be imaged.

[0005]

In view of the above situation, the present invention makes it possible to capture an image of a welding arc itself in arc welding, thereby making the range of the welding arc moving by weaving of a welding torch possible. It is an object of the present invention to provide a method and apparatus for monitoring welding arc weaving, which can detect a welding arc and determine whether or not the range of the welding arc is correct, and output those signals to a control device. .

[0006]

In order to solve the above-mentioned problems, a weaving monitoring method for detecting a welding arc movement amount of a welding torch reciprocating at a fine pitch according to the present invention comprises a moving end of a reciprocating welding torch. Imaging a welding arc with a CCD camera through a filter in synchronization with the process, a step of measuring the center of gravity of the welding arc based on the imaged welding arc image, and whether the welding arc moves within a predetermined range from the measured value of the center of gravity. A step of determining whether or not the range of the moved welding arc is correct is adopted.

Further, the weaving monitoring method of the present invention employs a step of imaging the welding arc with a CCD camera having a filter whose filter absorbs or polarizes light other than light having a predetermined wavelength. Further, the weaving monitoring device in arc welding of the present invention is a weaving monitoring device that detects a welding arc movement amount of a welding torch that reciprocates at a fine pitch, and performs welding in synchronization with both moving ends of the reciprocating welding torch. A CCD camera having a filter for imaging the arc is provided, and a center-of-gravity position measuring circuit is provided for measuring the center of gravity of the welding arc based on the imaged welding arc image.The welding arc moves within a predetermined range from the measured center-of-gravity position. It is preferable to provide a center-of-gravity position determination circuit for determining whether the welding arc is present and an OK signal output circuit for outputting whether or not the range of the moved welding arc is correct.

Further, the weaving monitoring device of the present invention employs a CCD camera having a filter for absorbing or polarizing light other than light having a predetermined wavelength. That is, in the present invention, a CCD camera having a filter for imaging a welding arc in synchronization with both moving ends of the reciprocating welding torch is provided, so that the welding arc reciprocating at a high speed is periodically imaged. Thus, it is possible to provide a method and an apparatus for monitoring the reciprocating motion, that is, weaving of a welding arc in arc welding.

Further, in the present invention, by mounting a filter that absorbs or polarizes light other than light of a predetermined wavelength on a CCD camera, it is possible to clearly image a high-intensity welding arc, and to achieve even higher precision. A method and apparatus for monitoring the reciprocation or weaving of a welding arc can be provided.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In arc welding, there is a weaving method in which a welding torch is reciprocated at a fine pitch to weld a wide welding portion. However, in the welding method in which the welding torch is weaved, in order to confirm whether or not the welding arc is appropriately moving within a predetermined range of the welding portion, the welding arc itself having high brightness and vibrating at a high speed is used. Clear monitoring was desired.

Therefore, the present inventor has proposed that a welding arc having a high brightness is passed through an appropriate filter that absorbs or polarizes light other than light having a predetermined wavelength, and a welding arc that vibrates at a high speed is imaged by a CCD camera. It has been found that the image of the welding arc itself can be imaged. Based on this knowledge, a CCD camera equipped with an appropriate filter is adopted in the weaving monitoring method and apparatus for arc welding of the present invention to synchronize the weaving of the welding torch, ie, both moving ends of the reciprocating welding torch. To image the welding arc. Then, based on the captured welding arc image, the center of gravity of the welding arc image itself is measured, and the moving range of the welding arc is detected from the result, thereby determining whether or not the welding arc range is correct. To output these signals to the control device.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method and apparatus for monitoring weaving in arc welding according to the present invention will be described below with reference to the drawings. First, weaving of a welding torch capable of achieving a wide welding fusion zone by reciprocating the welding torch at a fine pitch will be described. FIG. 1 schematically shows a method of weaving a welding torch for welding a large area near a butt end. In arc welding, materials to be welded 1-1,
The welding torch 3 for abutting 1-2 on each other and welding the vicinity of the abutting end of each other over a wide range is moved in the respective weaving directions 5-1 and 5-2. With the weaving of the welding torch 3, the electrode 4 and the workpiece 1 are welded.
The welding arc 2 generated between the two moves in the respective weaving directions 5-1 and 5-2.

The movement of the welding torch 3 and the welding arc 4 by weaving of the welding torch 3 in arc welding is schematically shown in FIGS. 2 (a) to 2 (e). Monitoring of weaving in arc welding has conventionally been performed by detecting the amount of movement of the welding torch 3 as described above. However, in the conventional method of detecting the amount of movement of the welding torch 3, even if the amount of movement of the welding torch 3 is a predetermined amount, it is determined whether or not the welding arc 4 itself is moving within a predetermined range. Can not.

Therefore, in the weaving monitoring device 10 of the present invention in the arc welding of the present invention, when the welding torch 3 moves, both ends of the welding arc move.
The welding arc 2 itself is imaged by the CCD camera 11 in synchronization with 1, 6-2 (shown in (b) and (d) of FIG. 5), and the welding arc 4 itself moves in a predetermined range. Determine whether or not. FIG. 3 schematically shows the weaving monitoring device 10 in arc welding according to the present invention attached to a welding robot device 20. The weaving monitoring device 10 of the present invention includes a CCD camera 11 having a filter 12 that absorbs or polarizes light other than light of a predetermined wavelength, an image processing circuit 13, a reception position measurement circuit 14, an OK signal output circuit 16, a trigger, And a circuit 17. The welding robot device 20 to which the weaving monitoring device 10 of the present invention is attached is a normal device, and a predetermined welding power from a welding power source 22 and the robot controller 2
It is activated by the control signal of No. 4.

With reference to the drawings, a weaving monitoring method using the weaving monitoring device 10 of the present invention will be described in more detail. FIG. 4 shows the procedure of the weaving monitoring method of the present invention. When the welding torch 3 of the welding robot device 20 starts weaving 7 during arc welding as shown in FIGS.
As shown in (a) to (e), the welding torch repeatedly moves in the weaving direction 1-1 to 1-2.
When the robot controller 23 detects both moving ends 6-1 and 6-2 of the welding arc during the repetition of the weaving, the trigger circuit 19 of the weaving monitoring device 10 of the present invention sends the moving end signal of the moving end detection signal 24 to the trigger circuit 19. ON
Send That is, when the trigger circuit 19 of the weaving monitoring device 10 receives the moving end signal ON that has detected the moving end 6-1 in FIG.
2 is operated, and the CCD camera 11 shown in FIG.
Of the welding arc that has moved to the moving end 6-1 of FIG.
The captured image data of the welding arc 2 is taken into the image processing circuit 13 to form an image. The center-of-gravity position measuring circuit 14 measures the center-of-gravity position based on the image of the image processing circuit 13. Thereafter, the center-of-gravity position determination circuit 15 determines the center-of-gravity position 7 of the welding arc shown in FIG. 5F, and if the center-of-gravity position 7 of the welding arc is at the correct position, the OK signal output circuit 16 outputs the OK signal. 18 is output to the robot controller 23. Also, the position 7 of the center of gravity of the welding arc
If the position is incorrect, the OK signal output circuit 16 outputs an NG signal 17 to the robot controller 23 to correct the moving end 6-1 of the welding arc. Further, when the weaving of the welding torch advances and moves to the moving end 6-2 in FIG. 5D, the process proceeds according to the above, and the welding arc 2 shown in FIG. The center-of-gravity position 7 is determined. If the center-of-gravity position 7 of the welding arc 2 is at a correct position, the OK signal output circuit 16 outputs an OK signal 18. If the position 7 of the center of gravity of the welding arc is not correct, the OK signal output circuit 16 outputs an NG signal 17 to correct the moving end 6-2 of the welding arc.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a method of weaving a welding torch used for welding a butt end in a wide range according to the present invention.

FIG. 2 is a diagram schematically showing movement of a welding torch and a welding arc by weaving of a welding torch in arc welding, and shows one period of weaving from (a) to (e) of FIG. 2; .

FIG. 3 is a schematic view showing a welding robot device 20 equipped with a weaving monitoring device in arc welding according to the present invention.

FIG. 4 shows a procedure of a weaving monitoring method of the present invention.

FIG. 5 is a diagram schematically showing movement of a welding torch and a welding arc by weaving of the welding torch, and shows one period of weaving from (a) to (e) of FIG. 2; FIG. 2 (f) shows the welding arc as shown in FIG. 2 (b).
FIG. 2G is a schematic diagram of a welding arc image when the welding arc is located at the moving end portion of FIG. 2. FIG. 2G is a schematic diagram when the welding arc is located at the moving end portion of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Material to be welded 2 ... Welding arc or welding arc image 3 ... Welding torch 4 ... Electrode 5, 5-1, 5-2 ... Weaving direction 6, 6-1 and 6-2 ... Moving end of welding arc 7 ... Weaving start 8 ... ON of moving end signal 10 ... Weaving monitoring device 11 ... CCD camera 12 ... Filter 13 ... Image processing circuit 14 ... Center of gravity position measurement circuit 15 ... Center of gravity position determination circuit 16 ... OK signal output circuit 17 ... NG output signal 18 OK signal output 19 Trigger circuit 20 Welding robot device 21 Welding robot 22 Welding power supply 23 Robot controller 24 Moving end detection signal

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenichi Shibayama 1-1-1 Showa-cho, Kariya-shi, Aichi F-Term in Denso Co., Ltd. (Reference) 2F065 AA09 AA17 BB15 BB29 CC00 FF04 GG09 JJ03 JJ26 LL22 LL33 PP01 PP25 QQ21 QQ28

Claims (4)

[Claims] 1. A weaving monitoring method for detecting the amount of movement of a welding arc of a welding torch reciprocating at a fine pitch, wherein the method is synchronized with both moving ends of the reciprocating welding torch,
A step of imaging the welding arc with a CCD camera through a filter; a step of measuring the center of gravity of the welding arc based on the imaged welding arc image; and a step in which the welding arc moves within a predetermined range from the measured value of the center of gravity. A weaving monitoring method in arc welding, characterized by a step of determining whether or not the range of the moved welding arc is correct. 2. The method according to claim 1, further comprising the step of imaging the welding arc with a CCD camera having a filter that absorbs or polarizes light other than light having a predetermined wavelength. 3. A weaving monitoring device for detecting the amount of movement of a welding arc of a welding torch reciprocating at a fine pitch, wherein the device is synchronized with both moving ends of the reciprocating welding torch,
A CCD camera having a filter for imaging the welding arc; and a center-of-gravity position measuring circuit for measuring a center of gravity of the welding arc based on the imaged welding arc image. Weaving monitoring in arc welding, comprising: a center-of-gravity position determining circuit that determines whether the range is moved; and an OK signal output circuit that outputs whether the range of the moved welding arc is correct. apparatus. 4. The apparatus according to claim 3, further comprising a CCD camera having a filter for absorbing or polarizing light other than light having a predetermined wavelength.