JPH0456714B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the drive of a welding torch in a welding robot.

Conventional welding robots are configured to stop the welding operation when the welding torch collides with the workpiece to be welded during welding, and to notify the operator of the abnormality using a warning light, buzzer, or the like. Therefore, when the operator is notified of the above abnormality, he or she manually moves the welding torch out of the stopped position, checks the welding torch for bending, etc.
If the welding torch was normal, the cause of the collision was removed and the torch was restarted.

In other words, with conventional welding robots, when the above-mentioned abnormality occurs, it is up to the operator to decide how to escape the welding torch, and the welding torch is also visually checked by the operator.
It was not possible to save labor.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a welding torch drive control method that makes a welding robot unmanned and saves labor.

According to the present invention, when the welding torch collides with the workpiece to be welded during welding, the welding operation is stopped and the welding torch is automatically escaped from the collision location, and the welding torch quality determination means is disposed at a predetermined location. If the welding torch is determined to be normal, the welding torch is automatically moved to the starting end position of the next welding line, and welding work is automatically restarted here.

The present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 illustrates the operating mode of a welding torch according to the present invention. In the figure, a workpiece 1 to be welded has three welding lines 2, 3, and 4. In addition, the teaching points at the starting end position of each welding line are respectively P1, P3, and P5,
When the teaching points at the end positions are respectively P2, P4, and P6, welding line 2 can be represented by line segment 1P2, welding line 3 can be represented by line segment 34, and welding line 4 can be represented by line segment 56.

Point ABCDEFGH surrounding this workpiece 1 to be welded
For convenience, the area indicated by is designated as the work area WA, and the other area in which the welding torch 5 can be moved is designated as the safety area SA. In addition, Safety Area SA
At the check point C1, there is a welding torch quality determining means 10 for determining the quality of the welding torch.
(Fig. 2) is provided. Here, the safety area SA includes safety points S1, S2, S3 and check point C2 within the area SA.
This is an area where the welding torch 5 and the workpiece 1 will not collide when the welding torch 5 moves at high speed between the two. In addition, safety points S1, S2,
S3 is a point in the safety area SA provided corresponding to teaching points P1, P3, and P5 of welding lines 2, 3, and 4, respectively, and these points S1, S2, and S3 are points that the welding torch 5 Teaching is performed so as not to collide with the workpiece 1 when moving between the point and the above-mentioned teaching point.

In the control method according to the present invention, a program according to the flowchart shown in FIG. 4 is created in advance, and this program is executed when the torch 5 collides with the work 1.

A specific example of executing this program will be explained below.

Now, for example, if the welding torch 5 collides with the workpiece 1 due to a setting error or tacking error of the workpiece 1 while welding the welding line 3, immediately stop the welding operation and move the welding torch 5 away from the collision. It is moved along the welding line 3 in the opposite direction to the welding direction from the hot spot. When the welding torch 5 reaches the starting end position P3 of the welding line 3, the welding torch 5 is moved from this position P3 to a safety point S2 taught in advance in correspondence with the position P3. Note that as the control method for the welding torch 5 up to this point, a continuous path control method using interpolation is adopted.

When the welding torch 5 reaches the safety point S2, it moves point-to-point (TPT) from the safety point S2 to the check point C2.
The welding torch 5 is moved at high speed by control. Incidentally, during this movement, the attitude of the welding torch 5 is also controlled so as to be in the attitude when checking the welding torch. Welding torch 5 is check point C
2, the welding torch 5 is further moved to the check point C1, and the welding torch quality determining means 10 disposed at the check point C1
Determine the quality of the product.

When the welding torch 5 is determined to be normal by the welding torch quality determining means 10, the welding torch 5 is moved to the check point C2, and then the welding line 4 next to the welding line 3 where the collision occurred is moved. The welding torch 5 is moved at high speed to the taught safety point S3 corresponding to the starting position P5 while appropriately changing the attitude thereof (FIG. 1).

When the welding torch 5 reaches the safety point S3, it is moved to the starting end position P5 of the welding line 4, and the welding operation is restarted from this position P5.

By creating such a program, if the welding torch collides with the workpiece with sufficient force to avoid damage, the welding operation can be automatically resumed from the next welding line.

In addition, when moving the welding torch 5 to the starting end position P5, as shown in FIG. 3, the welding torch 5 is moved to a position P5' near the position P5, and the starting end detection operation is executed from this position P5'. It is preferable to move the welding torch 5 to the starting end position P5 while doing so. The start end detection operation shown in FIG.
5', the welding torch 5 is searched in the horizontal direction, and after the workpiece and welding wire come into contact, it is returned by a predetermined amount, and then it is searched in the vertical direction, and after the workpiece and welding wire are in contact, it is moved in a predetermined direction by a predetermined amount. move the welding torch by
I'm trying to move it to 5.

FIG. 2 is a schematic configuration diagram showing an example of the welding torch quality determining means 10. This welding torch quality determination means 10 includes light sources 11x, 11y, 11z, lenses 12x, 12y, 12z, and slits 13x, 1
3y, 13z, photo sensor 14xa, 14xb,
It consists of three optical sensors 15, 16, 17 consisting of 14ya, 14yb, 14za, 14zb and a welding torch quality determination circuit 20.

The optical sensors 15, 16, and 17 check the bending or deviation of the welding torch 5 in the X, Y, and Z directions, respectively. When the welding torch 5 is normal, the photo sensors 14xa,
14ya and 14za do not receive light, photo sensor 14
xb, 14yb, and 14zb receive light. It is assumed that the photo sensor outputs a high level signal H when receiving light, and outputs a low level signal L when not receiving light.

The welding torch quality determination circuit 20 includes an OR circuit 21 that takes OR conditions for the outputs of the photo sensors 14xa, 14ya, and 14za, an inverter 22 that inverts the output of the OR circuit 21, photo sensors 14xb, 14yb,
AND circuit 2 that takes the AND condition for the output of 14zb
3, an AND circuit 24 that takes an AND condition for the outputs of an inverter 22 and an AND circuit 23. Therefore, the inverter 22 outputs a high level signal only when the photo sensors 14xa, 14ya, and 14za are all outputting the low level signal L, and the AND circuit 23 outputs the high level signal
A high level signal H is output only when 4xb, 14yb, and 14zb are all outputting a high level signal H. When the two input signals are both high level signals H, the AND circuit 24 determines that the welding torch 5 is normal and outputs a high level signal to a controller (not shown).

Although the present embodiment describes the case where the workpiece to be welded has a plurality of welding lines, the present invention can also be applied to the case where a plurality of workpieces to be welded are sequentially automatically welded, and in this case, the welding torch collides with the workpiece. , and if the welding torch is normal, skip that workpiece (welding line) and move on to the next workpiece (welding line).
Simply move the welding torch to Further, the welding torch quality determination means is not limited to one using an optical sensor as in this embodiment, but can also be realized by, for example, a combination of a dial gauge.

As explained above, according to the present invention, by providing a safety point for each welding line, when the welding torch collides with the workpiece to be welded, it is possible to safely and quickly escape the welding torch.
In addition, if the welding torch is normal, it can be safely and quickly moved to the next welding line after the welding line where there was a collision, so even if the welding torch collides with the workpiece to be welded, it can be moved to the appropriate position. The welding torch quality determination means automatically checks the welding torch for bending, etc., and if the welding torch is determined to be normal, welding starts from the welding line next to the welding line where the collision occurred. can be restarted. Thereby, it is possible to save labor when the welding torch collides with the welding torch, and it is also possible to improve the operating rate of the welding robot.

[Brief explanation of the drawing]

FIG. 1 is a welding torch operation diagram showing an example of the operation of the welding torch according to the present invention, FIG. 2 is a schematic configuration diagram showing an example of the welding torch quality determination means according to the present invention, and FIG. 3 is a welding line diagram. FIG. 4 is a flowchart showing an embodiment of the welding torch drive control method according to the present invention. 1... Work to be welded, 2, 3, 4... Welding line, 5... Welding torch, 10... Welding torch quality determination means, 15, 16, 17... Optical sensor, 2
0...Welding torch quality judgment circuit, S1, S2, S
3... Safety point, C1, C2... Check point.

Claims (1)

[Scope of Claims] 1. In a welding robot that automatically welds a plurality of welding lines in sequence, a welding torch quality determination means for determining the quality of the welding torch is disposed at a suitable location in a movable area of the welding torch, and If it is detected that the welding torch has collided with the workpiece to be welded while welding any welding line among the welding lines, the welding operation is stopped and the welding torch is moved in the opposite direction to the starting position of the welding line. moving the welding torch, and then passing the welding torch from the starting end position to a safety point taught corresponding to the starting end position,
The welding torch is moved to the determination position of the welding torch quality determination means, and then the welding torch quality determination optional means determines whether the welding torch is normal or not. A program is created in which the welding line is moved to the starting end position of the next welding line via a safety point that is taught corresponding to the starting end position, and the welding work is restarted at this point. During the teaching, the safety point for retracting the welding torch from the starting end position of each welding line is taught, and when the welding torch collides with the workpiece to be welded, the welding torch is drive-controlled according to the program. A welding torch drive control method characterized by: 2. The welding torch drive control method according to claim 1, wherein the welding torch quality determining means determines that the welding torch is a normal welding torch if the amount of bending of the welding torch is within a predetermined range.