JPH0310124B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for teaching a playback type industrial robot.

When an industrial robot is combined with a machine tool, such as a bender, and the bender provides a workpiece supply service, the workpiece hits a gauge (limit switch) that determines the end of feed at the same time that the supplied workpiece is matched to the width of the bender mold. We must teach them how to do so.

Conventionally, this type of teaching work has been performed by giving a large number of teaching points according to the visual observation of a teaching operator. Therefore, many points had to be taught very carefully, which required a lot of time and effort. In addition, since it relies on visual inspection, there is a problem that a certain amount of error occurs.

The present invention is intended to improve the above-mentioned drawbacks, and aims to provide a robot teaching method capable of simplifying the teaching operation, shortening the teaching time, and improving product accuracy.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an overall view, and FIG. 2 shows a side view thereof.

This shows a robot 5 that performs a service of supplying a workpiece 3 to a machine tool 1. The robot 5 includes a rotation mechanism 7 (θ rotation) and a rotation mechanism 9.
A drive mechanism such as (α, β change) is provided and is driven by a servo mechanism 11. In the drawing, the robot 5 places the workpiece 3 on the workbench (mold) 1 of the machine tool.
3 and gripped with fingers 15.

An optical beam generator 17 is provided at the front of the machine tool 1. This is achieved by passing a light source such as an LED through an appropriate slit or the like to form a focused beam.

A light receiving sensor 19 such as a photosensor is provided on the arm or hand portion of the robot, facing the optical beam generator 17. The optical beam generator 17 and the light receiving sensor 19 are positioned on a vertical straight line connecting the machine tool 1 and the robot 5 when the robot 5 has completed setting the work 3 on the machine tool 1. In this example, the robot's hand 21 is erected vertically and is provided at a joint 23 between the hand and the arm. The light receiving sensor 19 may also be provided with a slit to narrow the light receiving width.

FIG. 3 is a block diagram showing the robot control device.

The central processing unit 25 includes a memory ROM 27 and a RAM
29 is processed, and the servo mechanism 11 is driven through the pulse distributor 31 and amplifier 33. The driving result is fed back to the pulse distributor 31.

The electric signal from the light receiving sensor is amplified by an amplifier 35 and sent to an A/D converter 37 at a threshold of a certain intensity or higher. The A/D converter digitizes this electrical signal and outputs it to the central processing unit 25. This signal allows the robot's current position to be stored as a point in the memory device RAM 29.

In the teaching work, the robot takes out the workpiece from the rack, rotates it, holds the workpiece 3 in a predetermined posture, for example, horizontally, and positions it in front of the machine tool, as shown in FIG. The process starts after the generator 17 and the light receiving sensor 19 are positioned in alignment with the optical axis. The teaching method according to the present invention is carried out from this position to the position where the workpiece is set on the machine tool.

Stand the robot's hand 21 vertically, and
and the mold 21 of the machine tool and are parallel to each other in height. At this position, the optical axis is adjusted so that the optical beam from the optical beam generator 17 can be detected by the light receiving sensor. Let the position of the tip of the workpiece be point A (see Figure 2).

The position A of the tip of the workpiece 3 when the optical axes are aligned so that the optical beam from the optical beam generator 17 can be detected by the light receiving sensor 19 as described above.
can be placed at any position regardless of the size of the workpiece 3, and the optical axis can be easily aligned without worrying about the distance from the machine tool to the workpiece 3.

A gauge (limit switch, etc.) 25 is placed at the end point B of the abutting operation. The direction in which the robot 5 is advanced with respect to the machine tool 1 is defined as x, the direction horizontal and perpendicular to the x-axis is defined as y, and the height direction is defined as z, and the explanation will be made using xyz coordinates.

The teaching method according to the present invention aims to move the robot forward along the optical axis and obtain a teaching point on a straight line.

FIG. 4 shows a flowchart of the teaching program.

The robot is located at point A at an appropriate distance from the gauge so that it can bring the workpiece into contact with the gauge simply by moving forward (step 10).
1). Move the robot at the desired speed △xmm (e.g. 10
mm) is advanced (step 102). Step 1
If the light receiving sensor detects light (turns on) in step 03, the process goes to step 104, where the seventh rotation angle θ of the rotation mechanism in the robot 5 and the rotation angles α and β of each rotation mechanism 9 at this point are memorized as points. . In step 105, the current position is
It is determined whether or not it is at the end point B where it abuts the gauge. If it is not the end point and it is determined NO, the process returns to step 102. Move forward another 10mm as above. If it is determined in step 103 that the sensor is off the optical axis and cannot detect the light, the process proceeds to step 107.

In step 107, the position of the workpiece is moved by Δymm (for example, 5 mm to the right). If the light receiving sensor detects light as determined in step 108 during the movement of Δymm, the process goes to step 105, and the rotation angle θ of the rotation mechanism 7 of the robot 5 and the rotation angles α and β of each rotation mechanism 9 at this point are calculated. Although the point is memorized, if the light cannot be sensed (off judgment), step 109 moves the work further to -Δymm (to the left).

If light cannot be detected even after moving by -Δymm, adjustments such as Δx, Δy, etc. must be made again, and the process is temporarily stopped at step 111.

In step 104, the robot moves forward from point A to point B, and at every predetermined distance, the rotation angle θ of the rotation mechanism 7 in the robot 5 and the rotation angles α and β of each rotation mechanism 9 are memorized as points, and the point B is confirmed in step 105. Then, in step 106, the process is taken over to the next process. In the next process, the robot receives a signal from the limit gauge and performs tasks such as removing the workpiece and moving backward.

Therefore, a large number of memory points can be obtained for each Δxmm, and by reproducing the memory points, the points are connected and the workpiece can be advanced in an accurate straight line.

Regarding memory playback, the forward speed between each point may be programmed separately.

Since the teaching method of the present invention is carried out based on the flowchart of FIG. 4, the teaching work is extremely simple. In other words, align the optical axis at point A, which is an arbitrary distance from the machine tool, and keep the workpiece at a constant level B.
Once the points are determined, the rest can be taught automatically.

Incidentally, in the above explanation, point storage in the lateral direction y was performed, but teaching can also be performed in the height z direction by a similar operation. In this case, the amount of movement △ in steps 107 and 109 explained in FIG.
Instead of y, Δz (movement in the height direction) may be used.

Furthermore, the optical beam generator 17 and the light receiving sensor 1
9, the optical beam generator may be provided on the robot 5 side and the light receiving sensor may be provided on the machine tool 1 side.

According to the teaching method for the industrial robot of the present invention, it is sufficient to first position the optical beam generator and the light receiving sensor so that they coincide with the optical axis, and then move the workpiece along the optical axis to a specified position until the workpiece comes into contact with the gauge. Since the robot can be moved forward for each distance and the rotation angle of the rotation mechanism and the rotation angle of each rotation mechanism in the robot can be stored as a point for each predetermined distance,
The teaching operation becomes simple, the teaching time can be shortened, and product accuracy can be improved by reproducing accurate teaching points.

[Brief explanation of the drawing]

FIG. 1 is an overall perspective view showing the relationship between a machine tool and a robot, with a part of the machine tool cut away. FIG. 2 shows a side view of FIG. 1, with parts of the machine tool shown in cross-section. FIG. 3 is a block diagram of the robot control device. FIG. 4 shows a teaching flowchart. 1... Machine tool, 5... Robot, 17... Optical beam generator, 19... Light receiving sensor.

Claims (1)

[Claims] 1. A teaching method for a playback type industrial robot that provides a workpiece supply service to a machine tool, in which the machine tool is provided with an optical beam generator 17 or a light receiving sensor 19, and the arm or hand 21 of the robot 5 is provided with a light receiving sensor 19. Alternatively, an optical beam generator 17 may be provided, and the finger 1 of the robot 5 may be
5, the arm or hand 21 of the robot 5 is positioned so that the optical beam generator 17 and the optical sensor 19 are located on a straight line while the workpiece 3 is held in a predetermined posture. The workpiece 3 is advanced a predetermined distance in the direction of the machine tool along the optical axis connecting the optical sensor 19, and the rotation angle θ of the rotation mechanism 7 in the robot 5 at that position is determined based on the ON judgment of the light receiving sensor 19 at the forward position. Each rotation angle α of each rotation mechanism 9,
β is memorized, the workpiece 3 is moved in the left-right direction or the vertical direction perpendicular to the forward direction when the off judgment is made, the on/off judgment of the light receiving sensor 19 is made on the relevant movement line, and the on judgment of the light receiving sensor 19 is made. The rotation angle θ of the rotation mechanism and the rotation angles α and β of each rotation mechanism 9 at the position at the time of the ON judgment are respectively stored, and the above-mentioned advance is performed until the workpiece 3 comes into contact with a gauge 25 provided in the machine tool. A method for teaching an industrial robot, characterized in that a large number of rotation angles and each turning angle are obtained every predetermined distance by repeating movement.