JPH0514921B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a teaching support method and apparatus for facilitating robot teaching operations.

Recently, various industrial robots have been developed, and in these robots, a task called teaching is performed in order to make the robot perform a desired operation. For example, in a welding robot, this teaching work is performed by setting multiple teaching points for a desired welding line and manually controlling each axis of the welding robot's control target area, that is, the tip of the welding torch. This is performed by moving the welding robot to a teaching point and sequentially storing the teaching point in the welding robot.

However, the teaching work described above is a very time-consuming work because the operator manually controls the movement of each axis, and the number of teaching points is large, especially in robots that perform complex movements. The teaching work of teaching the robot's position and posture at each teaching point required a very large number of steps. Furthermore, the conventional manual teaching method described above has a problem in accuracy, making it difficult to perform sufficiently accurate teaching.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a robot teaching support method and device that significantly reduces the number of steps in teaching work, and also speeds up teaching work and improves accuracy. purpose.

In order to achieve the above object, this invention first manually controls each drive axis of the robot so that the control target part of the robot is in the vicinity of a desired teaching support, and then moves the robot based on a preselected search pattern. Teaching is performed by sequentially and automatically controlling each drive shaft of the robot so that the controlled location coincides with the desired teaching point.

That is, the first invention of the present invention includes a manual movement process in which each axis of the robot is manually controlled and a controlled part of the robot is moved to the vicinity of a predetermined teaching point, and a manual movement process is selected corresponding to each teaching point. an automatic teaching process in which each axis of the robot is sequentially controlled based on a search pattern, and movement control is performed so that a controlled part of the robot matches the teaching point; and an automatic teaching process in which the controlled part of the robot matches the teaching point. Then, there is a teaching support method comprising a step of automatically storing the teaching points.

Furthermore, a second aspect of the present invention is a search pattern storage means for storing a search pattern consisting of a plurality of steps; an axis control means for controlling each axis of the robot in accordance with each step of the search pattern; Control of the robot includes a contact detection means for detecting that a control target part of the robot has contacted a workpiece, and an advancement means for advancing a predetermined step of the search pattern based on the output of the contact detection means. A teaching support device that performs automatic teaching after a subject is located near a predetermined teaching point to be taught.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an outline of a welding robot to which an embodiment of the present invention is applied. This welding robot is composed of a robot body 10, a welding robot control device 12, a teaching box 11, a welding power supply device 13, and a welding wire box 14. The robot body 10 includes a welding torch 1, a wrist 2 that controls the attitude of the welding torch 1, and an arm 3 that controls the horizontal feed X, horizontal feed Y, and vertical feed Z of this wrist 2.
The position of the torch 1 is controlled by the wrist 2 and arm 3 to weld a workpiece (not shown). In addition, the welding robot control device 12
is used to control the operation of the robot body 1, and the teaching box 11 is used during teaching work.
Something that gives drive commands to each axis of the robot.
The welding power supply device 13 is for supplying welding current to the robot body 1, and the welding wire box 14 is for supplying welding wire to the robot body 1.

When performing manual teaching work on such a welding robot, the teaching box 11
command the movement of the welding torch 1 in the X, Y, and Z axis directions by operating switches (not shown);
This is done by moving the tip of the welding torch 1 to a desired teaching point and writing the positions of the X, Y, and Z axes and the posture of the wrist 2 at this point in a memory (not shown) of the robot controller 12.

In the embodiment of the present invention, the tip of the torch 1 is first moved to the vicinity of the desired teaching point to be taught by the above-mentioned manual shaft drive, and then the shape of the joint where each teaching point exists (I type,
By automatically driving the tip of the torch 1 according to a search pattern corresponding to the shape (V-shape, U-shape, fillet, etc.), the tip of the torch 1 is moved to match a desired teaching point, and the tip of the torch 1 is moved to match the desired teaching point. The positions of the X, Y, and Z axes and the posture of the wrist 2 at this time are written in the memory of the robot control device 12.

FIG. 2 is a block diagram showing the configuration related to the above control of this embodiment. In addition, in FIG. 2, the X-axis, Y-axis, and Z-axis drive switches 21, 2
2, 23, automatic teaching switch 24 and search pattern setting switch 25 are provided in teaching box 11 shown in FIG. 1, and detect contact between automatic teaching device 20 and the tip (welding wire) 1a of torch 1 and workpiece 30. It is assumed that the torch contact detection device 26 is provided in the robot control device 12 shown in FIG.

The teaching worker first specifies the number of the teaching point to be taught using the teaching point number designation switch (not shown) in the teaching box 11, and then
By operating the Y-axis and Z-axis drive switches 21, 22, and 23, X-axis, Y-axis, and Z-axis drive commands are transmitted from the teaching box 11 to the robot control device 1.
2, the robot control device 12 also controls the
The axis control mechanism 4 of the welding robot is driven in response to the axis and Z-axis drive commands, and the tip 1a of the torch 1 is moved to the vicinity of a desired teaching point. The control up to this point is similar to the shaft drive operation in conventional teaching work.

Then, by turning on the automatic teaching switch 24 and selecting a predetermined search pattern using the search pattern setting switch 25, an automatic teaching operation is performed based on the selected predetermined search pattern. The automatic teaching operation based on this search pattern is performed by sequentially executing each step of the search pattern by the automatic teaching device 20. When executing each step, the tip (welding wire) 1a of the torch 1 and the workpiece 30 are The contact is used as a step transition condition. Various methods can be used to detect the contact between the tip 1a of the torch 1 and the workpiece 30, but in this embodiment, the contact between the tip 1a of the torch 1 and the workpiece 30 is utilized to detect the contact between the torch 1 and the workpiece 30. Contact between the tip 1a and the workpiece 30 is detected. Specifically, a predetermined voltage is applied between the tip 1a of the torch 1 and the workpiece 30 using a predetermined contact power source, and a change in the current flowing between the tip 1a of the torch 1 and the workpiece 30 is detected. Contact between the tip 1a and the workpiece 30 is detected.
In FIG. 2, contact between the tip 1a of the torch 1 and the workpiece 30 is detected by a torch contact detection device 26. In FIG. That is, the torch contact detection device 26
is composed of a contact detection power supply 28 that applies a predetermined voltage for detection between the tip 1a of the torch 1 and the workpiece 30, and a contact detection section 27 that detects changes in the current flowing through the torch 1. The tip 1a of the torch 1 and the workpiece 30 are spaced apart, and a contact signal TS is generated which becomes "0" when the current flowing through the torch 1 is below a predetermined threshold value and "1" when it exceeds the predetermined threshold value. Occur. This contact signal TS is applied to the automatic teaching device 20.

As the automatic teaching device 20 executes each step of the selected search pattern, the robot controller 12 gives a drive command for each axis, and when the desired axis movement operation is completed, the robot controller 12
Point teaching signal PT is output to. When the robot control device 12 receives this point teaching signal PT, it stores the X-axis, Y-axis, Z-axis positions and wrist posture of the robot at this time in a memory (not shown) in the robot control device 12, and thereby this teaching The teaching work at the point ends. Each search pattern is programmed in a memory (not shown) provided in the automatic teaching device 20, and a predetermined program among the above programs is selected in response to selection of a search pattern by the search pattern setting switch 25 of the teaching box 11. executed.

Next, an example of the operation of the automatic teaching device 20 based on each search pattern will be explained.

First, as shown in FIG. 3, a case will be described in which a unidirectional search pattern is selected by the search pattern setting switch 25 in which the work 1 is driven in the minus Y direction and the teaching point is a location where the work 1 comes into contact with the work 30. The operation of the automatic teaching device 20 in this case is shown in a flowchart as shown in FIG. That is, first, it is detected whether the automatic teaching switch 24 is on or not, and if it is on, a drive command to move the Y-axis in the negative direction is applied to the robot control device 12, and the axis control mechanism 4 of the welding robot moves the Y-axis in the negative direction. move in the direction. This Y-axis movement continues until the tip 1a of the torch 1 and the workpiece 30 come into contact with each other by the torch contact detection device 26, that is, until the contact signal TS generated from the contact detection section 27 of the torch contact detection device 26 becomes “1”. I can continue. When the contact signal TS becomes “1”, Y is sent to the robot control device 12.
Generates an axis stop command, then a point teaching signal
The teaching operation is completed by adding PT to the robot control device 12 and storing the X-, Y-, and Z-axis positions of the robot and the posture of the wrist in a memory (not shown) as teaching point data.

FIG. 5 shows an example of automatic teaching operation when welding a V-shaped groove. First, it is assumed that the torch 1 is manually controlled to move to the position shown by the solid line in FIG. At this position, the search pattern setting switch 25 is set to a search pattern corresponding to the V-shaped groove (Y, Z2 direction search pattern).
It is assumed that the automatic teaching switch 24 is turned on. The automatic teaching device 20 first gives a command to the robot control device 12 to move the Z-axis in the plus direction, as shown in the flowchart of FIG. 6, and moves the Z-axis in the plus direction (downward in the paper). This movement continues until the contact signal TS generated from the torch contact detection device 26 becomes "1". When the contact signal TS becomes “1”,
The automatic teaching device 20 is the robot control device 1
2 is given a command to move the Z-axis by _-Z1 , and the Z-axis is moved by _Z1 in the negative direction (upward on the paper). Here, the value Z ₁ is the distance a between the tip 1a of the torch 1 and the top of the V-shaped groove at the final teaching position.
Any larger value may be used. Next, the automatic teaching device 20 gives a command to the robot control device 12 to move the Y-axis in the plus direction. This Y-axis movement continues until the contact signal TS generated from the torch contact detection device 26 becomes "1". When the contact signal TS becomes "1", a command is given to the robot control device to move the Y-axis by _Y1 in the negative direction. Here, the value Y ₁ is twice the distance a between the tip 1a of the torch 1 and the top of the V-shaped groove at the final teaching position (Y ₁
= 2a). After the Y-axis is moved by _-Y1 , a command is subsequently applied to the robot control device 12 to simultaneously move the Y-axis in the minus direction and the Z-axis in the plus direction. As a result, the tip 1a of the torch 1 moves toward the top of the V-shaped groove while maintaining a distance _Y1 along one side of the groove. This movement continues until the contact signal TS generated from the torch contact detection device 26 becomes "1". When the contact signal TS becomes "1", a command is given to the robot control device 12 to move the Y axis by Y ₁ /2 (=a) in the positive direction. This allows torch 1
will reach the position shown by the imaginary line in Figure 5, and will stop at this position. This position is the teaching point of the V-shaped groove. Therefore, at this position, the automatic teaching device 20 outputs the point teaching signal PT to the robot control device 12, and the robot control device 12 outputs the point teaching signal PT.
In response to this, the robot's X-axis, Y-axis, Z-axis positions and wrist posture are memorized, thereby completing the teaching operation at this teaching point.

Next, the automatic teaching operation when performing fillet welding will be explained according to FIGS. 7 and 8. The position of the torch 1 indicated by the solid line in FIG. 7 is the starting position of the automatic teaching operation. In this position, it is assumed that the torch 1 is set at an angle of 45° with respect to the workpiece 30 to be fillet welded by controlling the wrist (not shown). At this position, the search pattern setting switch 25 selects the search pattern (Y, Z2 direction search pattern) corresponding to fillet welding, and the automatic teaching switch 2
4 is turned on, as shown in FIG. 8, the automatic teaching device 20 first gives a command to the robot controller 12 to move the Y-axis in the plus direction, and the Y-axis is controlled to move in the plus direction. This Y-axis movement continues until the contact signal TS generated from the torch contact detection device 26 becomes "1". When the contact signal TS becomes "1", a command is given to the robot control device 12 to move the Y-axis by _Y2 in the negative direction. Here, the value Y ₂ is the tip 1a of the torch 1 at the final teaching position.
Letting a be the distance between and the top of the fillet weld, any value may be used as long as it is larger than √2. Next, a command to move the Z-axis in the plus direction is given to the robot control device 12, and the tip 1a of the torch 1 moves in the plus Z direction (downward in the paper). This movement is caused by a contact signal output from the torch contact detection device 26.
This continues until TS becomes "1". Contact signal TS
becomes “1”, the automatic teaching device 20 instructs the robot controller 12 in the Y-axis direction (Y ₂ −
a/√2) and a signal to simultaneously move (a/√2) in the Z-axis direction. This causes the torch 1 to move to the position shown by the imaginary line in FIG. This position is the desired teaching point for fillet welding. Therefore, at this position, the automatic teaching device 20 outputs a point teaching signal PT to the robot control device 12, and the robot control device 12 responds to this point teaching signal PT by adjusting the X-, Y-, and Z-axis positions of the robot. By memorizing the posture of the wrist, the teaching operation at this teaching point is completed.

FIGS. 9 and 10 show the automatic teaching operation when welding a rectangular groove. 9th
The position of the torch 1 indicated by a solid line in the figure is the starting position of automatic teaching. In this position, the torch 1 is controlled by a wrist (not shown) at a 1/2 angle of the V-shaped groove (in this case, 22.5 degrees to the slope of the V-shaped groove).
angle). Assuming that the search pattern setting switch 25 selects the search pattern corresponding to the rectangular bevel at this position, and the automatic teaching switch 24 is turned on.
The movement locus of the tip 1a of the torch 1 based on commands from the automatic teaching device 20 is controlled as follows.

The torch 1 is moved in the plus Z direction until the contact detection signal TS generated from the torch contact detection device 26 becomes "1".

Move torch 1 by Z ₂ in the minus Z direction.

Move torch 1 by _Y3 in the minus Y direction.

The torch 1 is moved in the plus Z direction until the contact detection signal TS generated from the torch contact detection device 26 becomes "1".

Move torch 1 in the ZY axis direction (b-c+Z ₂ )-
a cos θ and simultaneously move by (b−c+Z ₂ )−asin θ (however, θ=22.5°) in the Z-axis direction.

Incidentally, when the automatic teaching starting position of the torch 1 is on the flat part of the workpiece 30 in the example of the slope formation, the torch 1 may be moved in the plus Y direction in the step. In any case, it is sufficient that the tip 1a of the torch 1 is positioned above the groove of the rectangular groove in the step, and the value _Y3 is determined to control the movement to such a position.

At the end of the step, the torch 1 will be in the position shown in phantom in FIG. At this position, the automatic teaching device 20 outputs a point teaching signal PT to the robot control device 12, and the robot control device 12 responds to this point teaching signal PT by controlling the robot's X-, Y-, and Z-axis positions and wrist posture. By storing this, the teaching operation at this teaching point is completed.

Although control using a unidirectional search pattern and control using search patterns corresponding to a V-shaped groove, a fillet joint, and a rectangular groove have been described above, search patterns can be similarly set for other joints.

Furthermore, although the above embodiments have been described with reference to the case in which the present invention is applied to a welding robot, it goes without saying that the present invention can be similarly applied to other industrial robots.

As explained above, according to the present invention, the teaching process can be dramatically shortened and teaching can be performed with high precision, so that the teaching work can be performed at high speed and with high precision. Furthermore, automatic teaching at any teaching point is possible by setting an appropriate search pattern.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an outline of a welding robot to which an embodiment of the present invention is applied, Fig. 2 is a block diagram showing an embodiment of the invention, and Fig. 3 is an automatic teaching based on a unidirectional search pattern. FIG. 4 is a flowchart showing an example of controlling the automatic teaching operation shown in FIG. 3, FIG. 5 is a diagram explaining the automatic teaching operation for a V-shaped groove, and FIG. 6 is a diagram showing the operation control. A flowchart showing an example; FIG. 7 is a diagram explaining the automatic teaching operation for a fillet joint; FIG. 8 is a flowchart showing an example of the operation control; FIG. 9 is a diagram explaining the automatic teaching operation for a rectangular bevel. 10 are flowcharts showing examples of the operation control. 1...Torch, 2...Wrist, 3...Arm, 4...
Welding robot axis control mechanism, 10... robot main body, 11... teaching box, 12... robot control device, 13... welding power supply device, 14...
...Welding wire box, 20...Automatic teaching device, 21...X-axis drive switch, 22...Y
Axis drive switch, 23... Z-axis drive switch, 2
4...Automatic teaching switch, 25...Search pattern setting switch, 26...Torch contact detection device, 30...Work.

Claims (1)

[Claims] 1. Based on a manual movement process in which each axis of the robot is manually controlled to move the controlled part of the robot to the vicinity of a predetermined teaching point, and a search pattern selected corresponding to each teaching point. an automatic teaching process in which each axis of the robot is sequentially controlled so that the controlled part of the robot is moved so as to match the teaching point; and when the controlled part of the robot matches the teaching point, the teaching point is moved. A teaching support method comprising a process of automatically memorizing. 2. The robot is a welding robot, the control target location is the tip of a welding torch, and the search pattern is selected in accordance with a joint shape in which a teaching point to be taught exists. teaching support methods. 3 search pattern storage means for storing a search pattern consisting of a plurality of steps; axis control means for controlling each axis of the robot in accordance with each step of the search pattern; a contact detection means for detecting that the robot is in the vicinity of a predetermined teaching point to be taught by the object to be controlled by the robot; A teaching support device that performs automatic teaching after locating the robot.