JPH04138875A - Welding starting position detecting method for automatic welding equipment - Google Patents

Abstract

PURPOSE:To surely detect the welding starting position of a lap fillet welded joint by detecting a work on an extension line at a specified angle from the specified reference position, judging with which of a vertical plate and a lower plate it is brought into contact and then, selecting a proper action to detect the proper welding starting position. CONSTITUTION:The work 7 on the extension line at the specified angle from the position separated from the vertical plate 12 by a first specified distance l1 from the proper wielding starting position Pc is detected by a welding torch 2. The welding torch 2 is then pulled up by a second specified distance h1 and with which of the vertical plate 12 and the lower plate 11 it is brought into contact is judged according to an energizing state of the welding torch 2 and the proper action is selected and the proper welding starting position Pc is detected. After all, the welding starting position of the lap fillet welded joint can be surely detected even when there is limitation on the lower plate distance of the lap fillet welded joint by detecting the work 7 at the specified angle from above a slant.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for detecting a welding start position of an automatic welding device that reproduces predetermined work contents, and is particularly applicable when automatically welding lap fillet weld joints. The present invention relates to a method for detecting the welding start position.

[Prior Art] In general, when welding a lap fillet weld joint in the presence of individual differences and installation errors in the workpieces that are worked on by a memorized and regenerated arc welding robot, the welding start position of the memorized work data is Correction, that is, detection of the actual welding start position is required.

Therefore, as shown in FIG. 4, sensing is performed using the welding torch 2, which is a sensor (a sensing voltage is applied to the welding torch 2, and the welding torch 2 is used as a sensor to detect the workpiece). In order to weld the overlap fillet weld joint 13 with the vertical plate 12 stacked on the lower plate 11,
When detecting the welding start position P', first, move the welding torch 2 to a position P that is a distance px farther from the vertical plate 12 than the welding start position P taught by the teaching workpiece 12A.

1 and move it downward (in the direction of the lower plate 1) from this position P01 to detect the lower plate 11. After that, the welding torch 2 is raised by a distance ΔZ that is smaller than the thickness of the upright plate 12, and then moved in the direction of the upright plate 12, and the end face of the upright plate
After detecting a, the wire tip protruding from the welding torch 2 can be positioned at the corner (that is, the actual welding start position P') by pulling down the amount △Z. Welding can be started from the starting position P''.

[Problems to be Solved by the Invention] By the way, when detecting the welding start position P' of the lap fillet weld joint 13 described above, the selection of the distance nX is usually
Since the lower plate 11 of the lap fillet weld joint 13 is larger than the workpiece displacement, it is determined based on the expected displacement of the workpiece and the detection time, but depending on the workpiece, the distance Qx may be There may be restrictions. For example, as shown in FIG. 5(a), if the lower plate 11 is short, the lower plate 11 cannot be detected even if the welding torch 2 is moved from the position P by a distance Qx and then moved downward. Also, the fifth
As shown in Figure (b), if the lower plate 11 is curved, depending on the degree of curvature of the lower plate 11, the welding torch 2 may be moved to a position P that is a distance QX away from the position P. Even if the lower plate 11 is detected by moving further downward and then pulled up by a distance ΔZ and moved in the direction of the vertical plate 12, the surface of the lower plate 11 is detected instead of the vertical plate end surface 12a of the vertical plate 12. In some cases.

In such cases, when creating work data (during teaching work)
By providing a function that can vary the distance Qx, it is possible to cope with the limitation of the lower plate distance, but it is necessary to measure the actual lower plate distance etc. to select the distance Qx, which requires a large amount of time for teaching work. At the same time, there were problems such as placing a burden on the teaching worker.

The present invention aims to solve such problems,
An object of the present invention is to provide a welding start position detection method for an automatic welding device that can easily and reliably detect the welding start position of a lap fillet weld joint even if there is a limit to the distance between the lower plates of the lap fillet weld joint. shall be.

[Means for Solving the Problems] In order to achieve the above object, the welding start position detection method of the automatic welding device of the present invention includes lap fillet welding between a lower plate and a vertical plate stacked on the lower plate. When detecting the welding start position of a joint, ■ A position that is a first predetermined distance away from the vertical plate from the proper welding start position is taught in advance as a reference position for welding start position detection, and ■ A predetermined position from that reference position is taught. After detecting the workpiece on the angular extension line with the welding torch, ■ raise the welding torch by a second predetermined distance; and ■ move the welding torch toward the standing plate if the welding torch is not energized in the pulled up state. After detecting the standing plate, the welding torch is lowered by a second predetermined distance to detect the proper welding start position, and if the welding torch is energized in the raised state, the welding torch is lowered from the standing plate. After moving it a third predetermined distance in the direction of separation and then pulling it down to detect the lower plate,
It is characterized in that an appropriate welding start position is detected by moving in the direction of the vertical plate by a third predetermined distance.

[Function] In the welding start position detection method of the automatic welding device of the present invention described above, the welding torch is used to move the workpiece on the extension line at a predetermined angle from a position that is a first predetermined distance away from the vertical plate than the proper welding start position. After the welding torch is raised by a second predetermined distance, it is determined whether the welding torch has touched the upright plate or the lower plate depending on the energization state, and the appropriate operation is selected to perform proper welding. A starting position is detected. In other words, by first detecting the workpiece at a predetermined angle from diagonally above, even if there is a limit to the distance between the bottom plates of lap fillet weld joints,
The lower plate position can be reliably detected, and the welding start position of a lap fillet weld joint can be easily and reliably detected without measuring the lower plate distance for selecting the distance px.

[Embodiments of the Invention] Before explaining a method for detecting a welding start position of an automatic welding device as an embodiment of the present invention with reference to the drawings,
First, with reference to FIG. 3, the configuration of an arc welding robot, which is a type of automatic welding apparatus to which the method of the present invention is applied, will be briefly described.

As shown in Figure 3, an articulated arc welding robot 1
A welding torch 2 is attached to the wrist portion 1a of the user, and its position and posture are controlled. Its control is
This is performed on the robot control panel 3 or the teaching box 4 attached to the robot control panel 3. Further, a wire is supplied to the welding torch 2 and is fed from the welding torch 2 according to welding conditions for performing welding.

In order to use the welding torch 2 as a sensor, the welding power source 6 that selectively applies a welding voltage and a sensing voltage between the welding torch 2 and the workpiece 7 is equipped with a sensing power source (not shown). ing. Wire and work 7
The energization state due to contact with is detected by energization detection means (not shown) in the robot control panel 3.

Note that the workpiece 7 is moved to the welding robot 1 by the positioner 8.
Attitude is controlled against. Further, as shown in FIGS. 2(a) and 2(b), the workpiece 7 of this embodiment has at least a lower plate 11 and a standing plate 12 stacked on the lower plate 11. The method of the present invention is applied when welding the lap fillet weld joint 13 between the lower plate 11 and the upright plate 12.

Incidentally, when the arc welding robot 1 performs a welding operation on the workpiece 7, the content of the welding operation is taught in advance, and the replay operation is performed according to a program stored in the storage device of the robot control panel 3. The teaching is performed by manually operating the welding torch 2 using the teaching box 4.
The position of the workpiece 7 and the workpiece 7 are controlled relative to each other, for example, according to the following procedures <a) to (g).

(a) Retreat position 1! The welding torch 2 is moved to P, (see FIGS. 2(a) and 2(b)) and the position P0 is memorized.

(b) Appropriate welding start position pc (Fig. 2 (a), (b)
[Reference] 2. A position PC3 that is far away from the upright board 12 and at an appropriate height and distance from the lower board 11.
is stored as a reference position for welding start position detection.

(C) At this position PC5, a start command for sensing the welding start position of the lap fillet weld joint 13 based on the method of the present invention is set.

(d) Move the tip of the wire that protrudes a predetermined length from the welding torch 2 to the welding start position pc of the welding line (lap fillet weld joint 13 between the lower plate 11 and the upright plate 12) on the workpiece 7, and move it to this position. Memorize your PC.

(e) Set welding conditions, etc. at this position PC.

(f) Subsequently, if necessary, the welding intermediate position of the welding line is memorized, and finally the welding end position is memorized to set the grater processing conditions.

(g) After that, the retracted position of the welding torch 2 after welding is completed is memorized, and if there is another weld line on the workpiece 7, teaching is performed according to the type of joint.

Next, a method for detecting a welding start position as an embodiment of the present invention will be explained with reference to FIGS. 1 to 3.

As shown in FIGS. 2(a) and 2(b), the lap fillet weld joint 13 to which the method of the present invention is applied consists of a lower plate 11 and a vertical plate 12 stacked on the lower plate 11. Become. In addition, the lap fillet weld joint 13A indicated by the broken line is in the teaching position,
Figure 2 (a) shows the lap fillet weld joint 13 of the next workpiece.
FIG. 2 is a diagram for explaining an example of the movement state of the welding torch 2 when the welding torch 2 is shifted in the −Y direction as shown by the solid line, and FIG.
b) is a diagram for explaining an example of the movement state of the welding torch 2 when the lap fillet weld joint m13 of the next workpiece is shifted in the +Y force direction as shown by the solid line.

(1) First, based on the teaching data, the welding torch 2 is positioned at the taught retreat position P (step Sl), and then the welding start position detection reference position PC
8 (step S2).

(2) Once positioned at the reference position PC5, a sensing voltage is applied to the welding torch 2 according to the taught sensing start command, and the welding torch 2 is moved in a predetermined angle extension direction (for example, welding start at the time of teaching) from the reference position PC5. 45° diagonally downward) toward position pc (step S3).

(3) During this movement in the predetermined angle extension direction, it is determined whether or not there is a high force detected by the energization inspection means (step S4
). The movement in step S3 is continued until there is a high force detected as energization. In this way, when the output is obtained, the position P1 on the lower plate 1 or the vertical plate 12 is detected.

(4) After detecting the position P1, move the welding torch 2 by a second predetermined distance Ω in the +Z force direction (in the order of the number C) (upward) and place it at the position P2 (step S5), this position P, In this step, it is determined whether or not there is a high force detected by the energization detection means (step S6). If it is determined that there is no energization detection output, as shown in FIG. 2(a), it is recognized that the lower plate 11 has been detected and the process proceeds to step S7, whereas if it is determined that there is a power supply, the process proceeds to step S7. , as shown in FIG. 2(b), it is recognized that the standing board 12 has been detected and the process proceeds to step SIO. However, the second predetermined distance Q is set to be smaller than the thickness t of the standing board 12.

(5) If it is determined in step S6 that there is no high force in the energization detection, as shown in FIG. That is, it is horizontally moved in the direction of the upright board 12 (step S7), and the upright board 12 is detected (step S8). Then, move the welding torch 2 to the standing plate 12 detection position MP okara - Z force direction Mar lower plate 1
Vertical movement (down) by the second predetermined distance Q2 in one direction
(Step S9). As a result, the welding torch 2 moves to the current workpiece 7 corresponding to the taught welding start position PC.
The welding start position P4 of the lap fillet weld joint 13 is reached.

(6) On the other hand, if it is determined in step S6 that there is an energization detection output, as shown in FIG. That is, it is horizontally moved a third predetermined distance Q (about several square meters) away from the standing board 12 and placed at the position P (step 5IO). Thereafter, the welding torch 2 is vertically moved (pulled down) in the -Z direction, that is, in the direction of the lower plate 11 (step 5ll).
), the lower plate 11 is detected (step 512). and,
The welding torch 2 is horizontally moved from the detection position P of the lower plate 11 in the Y direction, that is, in the direction of the vertical plate 12, by the third predetermined distance Q (step 513).

As a result, the welding torch 2 moves to the indicated welding start position P.
Lap fillet weld joint 13 of the current workpiece 7 corresponding to c
The welding start position P4 is reached.

(7) After guiding the welding torch 2 to the actual proper welding start position P in this manner, in this embodiment, the welding torch 2 is directed upward at an angle of 45° and 2M
(Step $14). Then, the position P of the tip of the wire at this pulling position. is taken as the welding start position and memorized (step 515), and this position P
The difference Δ between the data No. 6 and the teaching data Pc is calculated and stored (step 816).

(8) The above operations move the welding torch 2 to position P.

After moving to , based on the calculated and stored difference Δ,
Correct the subsequent teaching data (step S1
7) Welding is performed along the weld line of the lap fillet weld joint portion 13.

2, according to the welding start position detection method of this embodiment, the lower plate 11. By detecting the workpiece 7 made of the standing plate 12, the position above the workpiece 7 near the standing plate 12 can be reliably detected.
If there is a limit to the distance between the lower plates [see Figure 5 (a) 1,
Even if the lower plate 11 is curved [see Fig. 5(b)], the appropriate welding start position of the lap fillet weld joint 13 can be determined without measuring the lower plate distance to select the distance Qx. It can be detected extremely easily and reliably.

Further, in this embodiment, step S14. In S15, the welding torch 2 guided to the welding start position P4 is pulled up by 2 mm in the pointing direction, and that position is set as the actual welding start position, so that the distance between the tip of the wire and the workpiece 7 is
A good predetermined spacing is provided when starting the arc. The welding robot l, which performs memory replay operation, uses the tip of the wire that protrudes a predetermined length from the welding torch 2 as a position control point, keeps the protruding length of the wire constant during welding, and welds under the set welding conditions. However, due to the wire protrusion length constant control by the welding power source 6, after welding is completed, the wire protrudes by 13M, which is about 2M shorter. For this reason,
As described above, the position P5, where the welding torch 2 is raised by two strokes after reaching the welding start position P, is substantially the proper welding start position after sensing. Furthermore, since the positional information of the wire tip at the raised position P6 of the welding torch 2 is taken in as the welding start position in step S15, the detection accuracy due to the bending V (bending) of the wire is not ordered.

[Effects of the Invention] As detailed above, according to the welding start position detection method of the automatic welding device of the present invention, the first welding start position is
Detects the workpiece on a predetermined angular extension line from a reference position that is a predetermined distance away from the vertical plate, determines whether it has contacted the vertical plate or the lower plate, and then selects an appropriate action to perform proper welding. Since the start position is detected, the position on the workpiece near the vertical plate can be reliably detected, and even if there is a limit to the distance between the lower plate of the lap fillet weld joint, the appropriate welding start position of the lap fillet weld joint can be determined. This has the effect of making it possible to detect extremely easily and reliably.

[Brief explanation of drawings]

1 to 3 show a welding start position detection method of an automatic welding device as an embodiment of the present invention, and FIG. 1 is a flow chart for explaining the procedure, and FIG.
b) is a diagram for explaining an example of the movement state of the welding torch according to the procedure of FIG. 1, and FIG. 3 is a perspective view showing the overall configuration of an arc welding robot to which the method of the present invention is applied; FIG. 4 is a diagram for explaining a welding start position detection means in a conventional lap fillet weld joint, and FIGS. 5(a) and (b).
) are diagrams showing examples in which the bottom plate of a lap fillet weld joint is short and curved, respectively. In the figure, 1- arc welding robot (automatic welding device)
, 1a-wrist part, 2-welding torch, 30-bot control panel,
4-teaching box, 6 welding power source, 7-work,
8-positioner, 11-lower plate, 12-vertical plate, 13.13
A - Lap fillet weld joint. Patent Rogandai Kobe Steel, Ltd.

Claims (1)

[Scope of Claims] Automatic welding in which a welding voltage and a sensing voltage are selectively applied to a welding torch, and a workpiece component is detected from the energization state between a consumable electrode protruding from the welding torch and the workpiece when the sensing voltage is applied. A method for detecting a welding start position of an apparatus, which comprises: detecting a welding start position of a lap fillet weld joint between a lower plate and a vertical plate stacked on the lower plate; A position separated from the vertical plate by a predetermined distance is taught in advance as a reference position for detecting a welding start position, and after detecting a workpiece on a line extending at a predetermined angle from the reference position with the welding torch, the welding torch is moved to a second welding torch.
If the welding torch is not energized in the raised state, the welding torch is moved in the direction of the standing plate, detects the standing plate, and then lowered by the second predetermined distance. while detecting an appropriate welding start position, if the welding torch is energized in the raised state, move the welding torch to a third position in a direction away from the standing plate.
The automatic welding device is characterized in that the automatic welding device detects the lower plate by moving it a predetermined distance and then lowering it, and then moves it a third predetermined distance in the direction of the upright plate to detect an appropriate welding start position. Welding start position detection method.