JP3499347B2 - Welding robot control method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding robot control method, and more particularly to a welding robot control method capable of automatically tacking a workpiece which is a pre-process of welding.

[0002]

2. Description of the Related Art Conventionally, as a method of performing automatic welding after teaching by a welding robot, it is general to perform the procedure as shown in FIG.

That is, the teaching mode is set (step S101) and teaching is performed (step S10).
2), but in the teaching at this time, 2 for a straight line
For points and arcs, teaching is performed on three teaching points to determine each block as a straight line or an arc.

Next, the automatic operation is started (step S1
03), it is determined whether or not the continuous operation is performed (step S1
04), when continuous operation is selected (step S10)
5), automatically perform continuous operation from the start point to the end point of the welding line obtained by teaching (step S106),
It ends (step SE).

When the operation for each single block such as a straight line or a circle is selected (step S107), the operation is stopped at each teaching point TP (step S10).
8), it is common to output a signal (step S109) and end the operation (step SE).

[0006]

However, such a conventional technique has a problem that a signal cannot be output at any desired position during automatic operation. Further, even when the single block feed is selected, there is a problem that the teaching point can be stopped or the signal can be issued.

For this reason, in the welding process, when the workpieces to be joined are temporarily fixed to each other as a previous step, they cannot be automatically performed based on the result of the teaching of the welding line previously performed. was there.

The object of the present invention has been made by paying attention to the above-mentioned conventional technique, and to treat an arbitrary point in the same manner as a teaching point by using an interpolating locus line obtained by a small number of teaching points. Is to provide a welding robot control method capable of issuing a signal and temporarily attaching a work.

[0009]

In order to achieve the above-mentioned object, a welding robot control method of the invention according to claim 1 comprises:
A welding robot that automatically welds a work along a welding line after teaching the welding line, teaches about the number of points corresponding to the shape of the welding line, and calculates by using the coordinate value of the teaching point. The interpolation locus line for displaying the welding line is obtained, the interpolation locus line is divided at a predetermined number or at predetermined intervals to obtain the coordinate values of the division points, and part or all of the obtained division points are used as temporary positions. It is characterized by performing temporary tacking.

Therefore, in the case of a straight line, two points, an arc and two
3 points for a quadratic curve, N + for an Nth-order curve in general
Find the interpolation locus line by teaching one point,
By treating the intermediate point of the teaching points in the same way as the teaching point based on this interpolation trajectory line,
It is possible to issue a signal at a desired position or temporarily attach a work.

Further, in the welding robot control method of the invention according to claim 2, a signal is issued at the division point of claim 1, and if the tacking step is selected at the position where this signal is issued, the tacking is performed. It is characterized by controlling.

Therefore, when a signal is emitted at each division point and the temporary attachment is selected at the division point, the workpiece is temporarily attached at the division point.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the flow of the teaching operation in the welding robot.

First, when teaching is started (step S1), it is judged whether the linear element of the block to be welded is a straight line (step S2), and if it is a straight line (step S).
In 3), two teaching points PT that determine this straight line are taught (step S4).

If it is not a straight line, it is judged whether or not it is a circular arc (step S5), and if it is a circular arc (step S6), teaching is carried out for the three teaching points PT (step S7).

Further, if it is not an arc (step S8), it is regarded as an arbitrary curve (hereinafter referred to as "spline") and a predetermined number of teaching points P of 4 or more.
Teaching is performed on T (step S9).

The interpolation locus line L is calculated from the coordinates of the points taught in this way (step S1).
0), create a regular program. That is, the straight line is 2
It is determined from the points, and the arc and the quadratic curve are determined from the three points.

In the case of the spline, a cubic curve can be approximated from the coordinates of four points, a quartic curve can be approximated from the coordinates of five points, that is, an N−1th order curve can be approximated from the coordinates of N points in general. Therefore, the number of teaching points TP is determined by the shape of the welding line WL. This teaching point TP
The interpolation locus line L is determined according to the number of, and a regular program is created.

Next, in order to obtain the coordinates of the points on the obtained interpolation locus line L, the division number or pitch in the interpolated block is input (step S11), and the coordinates for the division points SP are obtained by calculation ( Step S12).

The coordinates of each division point SP obtained by the above calculation are stored as additional teaching points (step S13) and written in the memory as a back program (step S14).

Next, it is judged whether or not the work is temporarily attached as a pre-welding process, that is, whether the back program is used (step S15). Temporary attachment is performed (step S16).

After making the tacking, or step 15
If the temporary attachment is not performed in step 1, the regular program is executed by automatic operation to perform continuous welding (step S1
7) The welding process is completed (step SE).

Generally, in the welding process, the teaching point TP of the welding line WL and the temporary attachment point KP, which is the previous process for fixing the workpiece, often do not coincide. Therefore, when it is selected to perform tacking, the back program obtained by teaching the welding line WL is used to output a signal at the additional teaching point (that is, the division point SP) registered as the back program. The temporary attachment is performed by outputting the temporary attachment, or the temporary attachment is performed by appropriately inputting the instruction for performing the temporary attachment only at a necessary portion.

With reference to FIGS. 2 to 6 as well, a case where continuous welding is performed after temporary attachment along, for example, an arcuate welding line WL will be specifically described.

First, teaching is performed on three arbitrary teaching points TP (see FIG. 2). This 3
The arc equation is determined from the coordinates of the points, and the arc equation that is the welding line locus L is stored in the memory as a regular program (see FIG. 4 (A)).

On the other hand, the space between the teaching points is automatically divided to obtain coordinate values for a predetermined interval or a predetermined number of division points SP (see FIG. 3). Register these points as additional teaching points and create a back program,
It is stored in the memory together with the above-mentioned regular program (see FIG. 4B).

In the case of temporary tacking, a signal is output at the teaching point TP and the additional teaching point SP using the back program created as described above, and the workpiece is tacked at a desired position. (See Figure 5).

Here, the temporary tacking is performed at all the division points SP, but it is also possible to select the temporary tacking only at a necessary portion.

After the tacking is completed, or when the tacking is not performed in step S15, the regular program is executed to perform the welding by the automatic operation (see FIG. 6).

From the above results, the work can be temporarily attached at a desired position without being limited to the teaching point TP position of the welding line WL and without separately performing the teaching for the temporary attachment position.

The present invention is not limited to the above-described embodiment, but can be implemented in other modes by making appropriate changes. That is, in the above-described embodiment, as a back program for obtaining the coordinates of the temporary attachment position, the coordinates of the division points SP such as a predetermined interval are obtained from the interpolation locus line L obtained from the teaching point TP, and the coordinates of the points are arranged. Although the back program is created more, the back program may be composed of two programs, a program expressing the equation of the interpolation locus line L and another program displaying the temporary fixing position. Further, the temporary fixing may be performed by inputting the temporary fixing position at any time.

[0033]

As described above, in the welding robot control method according to the invention of claim 1, in the case of a straight line, two points,
By teaching 3 points for arcs and quadratic curves, and generally N + 1 points for N-order curves, the interpolation locus line is obtained, and the intermediate point of the teaching points is handled in the same way as the teaching point Since the temporary attachment can be performed at any position, the temporary attachment can be performed even at a position different from the teaching point. Further, since the interpolating locus line obtained by teaching the welding line is used as the dividing point to be the tacking position, it is not necessary to separately perform teaching for tacking, and even if the welding line is changed. Temporary attachment can be performed in the same manner without modification.

In the welding robot control method according to the second aspect of the present invention, when a signal is issued at each division point and the temporary attachment is selected at the division point, the workpiece is temporarily attached at the division point. Therefore, temporary attachment can be performed only at necessary division points.

[Brief description of drawings]

FIG. 1 is a flowchart showing a procedure of a welding robot control method according to the present invention.

FIG. 2 is a diagram showing teaching points of arcuate welding lines.

FIG. 3 is a diagram showing division points obtained by dividing teaching points.

FIG. 4 is an explanatory diagram showing a regular program and a back program.

FIG. 5 is an explanatory diagram showing a state in which a part of division points is temporarily attached.

FIG. 6 is an explanatory diagram showing a state in which continuous welding is performed according to a regular program.

FIG. 7 is a flowchart showing a procedure of a conventional welding robot control method.

[Explanation of symbols]

WL welding line L interpolation locus line SP division point

Claims (2)

(57) [Claims] 1. A welding robot that automatically welds a workpiece along a welding line after teaching the welding line, teaching the points corresponding to the shape of the welding line, and determining the coordinate values of the teaching points. Obtain an interpolation trajectory line that displays the welding line by calculation using
Welding characterized in that the interpolation locus line is divided at a predetermined number or at predetermined intervals to obtain the coordinate values of the division points, and part or all of the obtained division points are used as the provisional positions to temporarily tack the work. Robot control method. 2. The welding robot control according to claim 1, wherein a signal is issued at the division point, and when the tacking step is selected at the position where the signal is issued, the tacking is controlled to perform tacking. Method.