JP2001179447A - Method for controlling groove profile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for controlling a groove profile, which can cope with various weld line shapes and long sizing of the weld line. SOLUTION: In a method in which a boom 2 extending in the weld line 23 direction is provided turnably and laterally movably in the groove width direction on a moving vehicle 1 and welding is performed while a welding machine 3 mounted at the tip part of the boom 2, is allowed to move on the surfaces of members to be welded, by oscillating two preceding and succeeding groove profile sensors 6a, 6b arranged in front of the welding machine 3 in the direction crossing the groove, a shift quantity in a position in the groove width direction and a shift angle in the proceeding direction of the welding machine, are detected, and the boom 2 is allowed to laterally move and turn in the groove width direction so that the detected shift quantity in a position and shift angle are corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a groove tracking control method for automatic welding of large members such as hull blocks.

[0002]

2. Description of the Related Art Generally, a groove copying apparatus of an automatic welding machine is provided for controlling a fluctuation of a welding torch in a groove width direction, and the welding torch is supported by a slide block moving in the groove width direction. It has a structure. The slide block moves in accordance with groove position information detected by a groove copying sensor such as an arc sensor, and corrects the position of the welding torch to a target position on a predetermined welding line. FIGS. 11 and 12 show a conventional example of such a groove copying apparatus.
Shown in All are schematic views, FIG. 11 is a front view, and FIG. 12 is a plan view. 11 and 12, 110
Is a member to be welded, 111 is a groove, 112 is a welding machine bogie, 1
13 is a welding torch, 114 is a slide block, 115
Is a wheel of the welding machine truck 112, and a rail on which the welding machine truck 112 runs.

In the case where the welding line is straight as shown in FIG. 11, a rail 116 is installed substantially parallel to the welding line, and welding is performed while the welding machine cart 112 runs along the rail 116. The movable range of the welding torch 113 by the slide block 114 is usually 100 to 200 mm.

[0004] Fig. 12 shows a case in which the welding line is curved, which is common in the welding of large members. Welding must be stopped at point A in the middle.
In addition, it is very troublesome to adjust the rail to the shape of the welding line each time to avoid the occurrence of the non-weldable point A.

On the other hand, in the case of a welding line as shown in FIG. 12, an articulated welding robot may be used. But,
Since it is necessary to create and input a welding torch automatic follow-up program for each welding block, this control program becomes very complicated and requires enormous development time and cost.

[0006]

Since large-sized structural members such as hull blocks have various shapes, welding lines often have various shapes. Moreover, the welding length is very long, and the groove width often changes. Therefore, it is undesirable and impractical to install a rail for a welding machine truck. Welding robots are also difficult to adopt because of the problems mentioned above. In addition, increasing the stroke of the slide block to increase the movable range of the welding torch requires a heavy and long slide block, which increases the weight of the welding machine on which the slide block is mounted, and requires a large amount of energy for traveling of the welding machine. It is not a good idea because it requires a large amount of labor and a large amount of labor for transportation.

SUMMARY OF THE INVENTION In view of the above technical background, an object of the present invention is to provide a groove tracking control method capable of coping with various welding line shapes and lengthening of welding lines.

[0008]

According to the present invention, there is provided a groove tracking control method according to the present invention, wherein a movable vehicle is provided with a boom extending in a welding line direction so as to be pivotable and laterally movable in a groove width direction. In the method of welding the welding machine attached to the welding machine while moving the surface of the member to be welded, by oscillating the two front and rear groove profiling sensors disposed in front of the welding machine in a direction crossing the groove. Detecting the position shift amount in the groove width direction and the shift angle in the welding machine traveling direction, and laterally moving and turning the boom in the groove width direction so as to correct the detected position shift amount and the shift angle. It is characterized by the following.

In the present invention, with the above configuration, the welding torch of the welding machine can be automatically made to follow the welding line by turning and laterally moving the boom. Since the movement of the welding machine in the groove width direction can be greatly increased by the boom, it is possible to sufficiently cope with various welding line shapes and a long welding line.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a plan view showing an outline of an automatic welding apparatus for implementing a groove tracking control method according to the present invention, and FIG. 2 is a side view of the automatic welding apparatus. This example shows a case where upward butt welding is performed on a bottom plate of a ship. 1 and 2
, 1 is a mobile vehicle having an autopilot function.
Drive 00. Reference numeral 2 denotes a boom installed on the mobile vehicle 1, and a welding machine 3 is attached to a tip of the boom. The welding machine 3 includes welding torches 5 a and 5 b attached to the slide block 4, and runs on the lower surface of the member 110 to be welded. Further, two groove profiling sensors 6a and 6b are mounted on the connecting plate 7 at the front of the welding machine 3, and these groove profiling sensors 6a and 6b are fixed by a swing shaft 8 in a direction crossing the groove. Swings at the amplitude of The coordinate position of the swing shaft 8 is detected by an encoder 10 attached to a swing motor 9. 11 is a cylinder device for moving the boom 2 up and down,
Reference numeral 12 denotes a boom turning axis for turning the boom 2 about the pin 14, and reference numeral 13 denotes a boom lateral movement axis for moving the boom 2 in the groove width direction.

[0011] The boom 2 has a welding machine 3 connected to a pin 15 at the tip.
, And the intermediate portion is supported by the pin 16 with the cylinder device 1.
One base rod is connected to the boom pivot shaft 12 by a pin 17. A cylinder case of the cylinder device 11 is connected to an outer frame of the boom pivot shaft 12 by a pin 18.

Each of the swing shaft 8, the boom turning shaft 12, and the boom lateral movement shaft 13 is composed of a known ball screw mechanism, and is configured to move the slide block in the axial direction. The slide block 4 of the welding machine 3 to which the welding torches 5a and 5b are attached also has a similar ball screw mechanism. The boom pivot 12 is the boom lateral movement axis 1.
3, the entire welding machine 3 including the boom 2 can be laterally moved in the groove width direction by laterally moving the boom lateral movement shaft 13. In the figure, reference numeral 20 denotes a support, and reference numeral 21a denotes drive wheels of the mobile vehicle 1, which has an automatic steering mechanism. 21b is a free wheel of the mobile vehicle 1, and 22 is a wheel of the welding machine 3.

Each origin (oscillation center) of the groove copying sensors 6a, 6b and each center of the welding torches 5a, 5b are arranged on the same straight line, and the boom 2 extends in parallel with the welding line 23. The traveling vehicle 1 travels substantially in the direction of the welding line, and the welding machine 3 is moved by the cylinder device 11 via the boom 2 to the workpiece 1.
Welding is performed while being moved while being pressed against the lower surface of 10. At this time, a groove displacement sensor in the groove width direction with respect to the welding line 23 and a displacement angle in the welding machine advancing direction are detected by the groove copying sensors 6a and 6b which continuously swing in front of the welding machine 3.

The method of detecting the displacement and the displacement angle will be described with reference to FIGS. Groove scanning sensor 6a, 6
The position b in the groove width direction between the rocking center of the laser sensors 6a and 6b and the groove center is continuously set in the direction b across the groove by using a laser sensor, for example. The shift amount is detected.

First, as shown in FIG. 3, a groove width or a groove opening width is detected. The groove 24 is open at the lower surface for the sake of welding (the curved tip portions of the welding torches 5a and 5b are inserted from below through this opening to perform tandem welding). The member to be welded 11 is swung rightward (or rightward to leftward).
Measure the distance to the lower surface of 0. The distance measured by the laser sensor is used as the position of the swing coordinate of the swing shaft 8 (the encoder 10).
FIG. 3 shows the relationship between the left end 24a and the right end 24b of the groove 24.
The measurement distance changes suddenly at each position. Therefore, a fixed threshold value 25 is provided for the measurement distance, and when the threshold value 25 is exceeded, the coordinate position (-x) of the groove opening left end 24a and the coordinate position (+ x) of the groove opening right end 24b are detected, and these coordinates are detected. By obtaining the difference between the positions, the opening width G of the groove 24 can be detected.

Further, as shown in FIG.
The groove center 26 of the laser sensor and the distance from the oscillation center (the position of the origin 0) 27 of the laser sensor are obtained, whereby the position shift amount W in the groove width direction of the laser sensor with respect to the groove center 26, ie, the welding line 23 Can be detected.

Since two laser sensors are provided before and after,
The position shift amounts Wf and Wr can be detected for the respective laser sensors 6a and 6b. FIG. 5 is a diagram showing a case where the welding line 23 is shifted to the left with respect to the traveling direction of the welding machine 3. FIG. It is a figure showing the relation with a position. Assuming that the distance between the laser sensors 6a and 6b is L, the welding machine advances with respect to the welding line 23 from the positional deviation amount Wf of the front laser sensor 6a and the positional deviation amount Wr of the rear laser sensor 6b detected as described above. The direction deviation angle θ can be obtained by equation (1).

[0018]

(Equation 1)

The displacement angle θ and the displacement W
By correcting f and Wr to be zero, the welding torches 5a and 5b can follow the welding line 23. That is, the welding machine 3 attached to the boom 2 is moved to the boom turning shaft 12 and the boom lateral movement shaft 13 on the basis of the information on the positional deviation amount and the deviation angle from the welding line 23 detected by the groove copying sensors 6a and 6b. To perform a correction so that the center of oscillation of the groove scanning sensors 6a and 6b, in other words, the welding torches 5a and 5b are always positioned on the groove center line (welding line).

This correction method will be described with reference to FIGS. FIG. 7 is a diagram showing an automatic welding line copying mechanism, and FIG. 8 is a conceptual diagram of a control method thereof. The deviation angle is corrected by turning the boom 2. Boom swing axis 1 at this time
The two correction movement amounts (D1) are two groove scanning sensors 6
a, 6b, the position difference between the sensors (Wr-Wf), the inter-sensor length (L), and the boom pivot point 1 from the boom pivot center 14.
It can be obtained from the equation (2) with a lever ratio of a length (L2) up to 7.

[0021]

(Equation 2)

The displacement is corrected by moving the boom 2 laterally. At this time, the correction movement amount (D2) of the boom lateral movement shaft 13 is calculated by Expression (3), and the position shift amount (Wr) of the rear groove scanning sensor 6b and the position shift newly generated by correcting the shift angle of the boom 2 are calculated. The quantity (d) is added to obtain the sum. D2 = Wr + d (3)

As shown in equation (4), the new positional deviation amount (d) caused by the deviation angle correction is represented by the positional deviation amount difference (Wr-Wf) between the two groove scanning sensors 6a and 6b and the distance between the sensors. The length (L) and the lever ratio of the length (L1) from the boom turning center 14 to the rear groove following sensor 6b can be obtained.

[0024]

(Equation 3)

The boom pivot shaft 1 thus determined
2 and the correction movement amount (D1, D
2) commands the respective drive servomotors 28 and 29 to operate the both shafts 12 and 13 at the same time to perform groove profiling control.

Therefore, the amount of movement of the welding machine 3 in the groove width direction can be greatly increased by the boom 2, so that welding can be performed not only on a straight line but also on a curved welding line without generating a non-weldable point as in the prior art. Therefore, it is possible to sufficiently cope with various welding line shapes and lengths of the welding line, fluctuations in the groove width, and the like. Also, the welding torch 5a,
Since the slide block 4 to which 5b is attached only needs to be used mainly for setting for adjusting the initial target position, the size of the slide block 4 can be reduced. Of course, the slide block 4 may be used for groove profiling control based on the function of a known arc sensor.

Although the above embodiment has shown the case of upward welding, it goes without saying that the present invention can also be applied to downward welding. FIG. 9 is a side view showing an outline of a welding device in the case of downward welding, and FIG. 10 is a plan view thereof. In this case, the moving vehicle 1 only travels on the surface of the member to be welded 110, and is the same as that shown in FIGS.

[0028]

As described above, according to the present invention,
The groove can be copied by turning and laterally moving the boom, and this boom can increase the amount of movement of the welding machine in the groove width direction. We can respond enough. In addition, there is an effect that a traveling rail of the welding machine is not required, and the slide block of the welding torch can be reduced in size.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a welding device for implementing a groove copying control method of the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a diagram showing a method of detecting a groove width or a groove opening width by a laser sensor.

FIG. 4 is a diagram showing a positional shift between a swing center and a groove center of a laser sensor.

FIG. 5 is a schematic diagram showing a case where a welding line is shifted leftward with respect to a welding machine traveling direction.

FIG. 6 is a diagram showing a positional shift of a front and rear laser sensor when a welding line is shifted leftward with respect to a traveling direction of a welding machine.

FIG. 7 is a partially enlarged view showing an automatic welding line copying mechanism.

FIG. 8 is a diagram showing an automatic welding line scanning control method.

FIG. 9 is a schematic plan view of a welding apparatus showing another embodiment of the present invention.

FIG. 10 is a side view of FIG. 9;

FIG. 11 is a schematic front view showing a conventional groove copying mechanism.

FIG. 12 is a schematic plan view showing a conventional groove copying mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Moving vehicle 2 Boom 3 Welding machine 5a, 5b Welding torch 6a, 6b Groove scanning sensor 8 Swing axis 12 Boom turning axis 13 Boom lateral movement axis 23 Welding line 24 Groove

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Eiji Matsuda, Inventor 1-1-2 Marunouchi, Chiyoda-ku, Tokyo, Japan Nihon Kokan Co., Ltd. (72) Yuji Sugitani 1-2-1, Marunouchi, Chiyoda-ku, Tokyo, Japan F-term in Honko Co., Ltd. (reference) 4E081 AA12 BA02 BA40 CA07 DA05 DA18 DA21 DA72 EA14 EA34 EA47 EA54 EA56 FA15 YA01 YY03 YY07 YY14

Claims (1)

[Claims] A moving vehicle is provided with a boom extending in a welding line direction so as to be pivotable and laterally movable in a groove width direction, and a welding machine attached to a tip end of the boom is moved while moving a surface of a member to be welded. In the welding method, by oscillating two front and rear groove profiling sensors disposed in front of the welding machine in a direction crossing the groove, the amount of positional deviation in the groove width direction and the welding machine traveling direction A groove tracking control method comprising: detecting a shift angle; and laterally moving and turning the boom in a groove width direction so as to correct the detected position shift amount and the detected shift angle.