JPH0239803B2 - SANGYOYOROBOTSUTONOKYOJIHOHO - Google Patents

Description

[Detailed Description of the Invention] The present invention provides a playback type industrial robot (hereinafter referred to as
(abbreviated as “robot”)).

When a robot is used to supply a workpiece to a machine tool, a so-called workpiece abutting operation is involved, and the workpiece must be accurately delivered to a specified position on the machine tool. For example, when supplying a flat workpiece to a bender machine tool, hold the workpiece horizontally and place the workpiece on the limit gauge of the machine tool to determine the end point while keeping the front end of the workpiece parallel to the machining surface of the machine tool. The front end must be applied accurately. FIG. 1 shows the situation of the butting work in a plan view. As shown in the figure, it is difficult to place the installation center point R of the robot 1 on the horizontal axis X (orthogonal horizontal line) that is orthogonal to the center of the machining line 3a of the machine tool 3 (mold center), and there may be some deviation. is normal. Therefore, when the workpiece 5 is advanced from the start point A of the butting operation to the end point B, the front end surface of the workpiece is angularly displaced on the horizontal plane (hereinafter referred to as the angular displacement of the workpiece), and the front end surface of the workpiece is angularly displaced on the machine tool's machining surface. However, there is a problem that parallelism cannot be maintained. The positions of the workpiece and robot arm after movement are indicated by broken lines. When moving the workpiece forward, extend the arm 7 and move the shaft 9 at the tip of the arm to
This is the result of changing the angle between the arm 7 and the X-axis from θ ₁ to θ ₂ in order to align them on the axis.

Therefore, in the conventional teaching of workpiece butting work, in addition to manually holding the (heavy) workpiece horizontally and teaching each position, the angular displacement of the workpiece must be considered, making robot teaching work extremely difficult. There were problems in that it was troublesome, required a lot of time and effort, and had a negative effect on product accuracy.

The present invention solves the above problems, eliminates the trouble of considering the angular displacement of a workpiece in the robot teaching work in the workpiece abutment work, shortens the teaching time, reduces labor, and improves product accuracy. With the goal.

In order to achieve the above object, the teaching method for an industrial robot according to the present invention is characterized in that, in the teaching method for a working robot that provides a workpiece supply service to a machine tool, a method for teaching a work robot that provides a workpiece supply service to a machine tool includes the following: A light emitting device that generates parallel optical beams forward is provided at a fixed position on the machine tool, and a hand portion that is rotatable in a horizontal plane via a rotation axis perpendicular to the arm is provided at the tip of the robot arm,
A central light-receiving sensor is provided on the robot hand portion to receive the optical beam at a starting point of the workpiece abutment work, and light-receiving sensors are also provided to the left and right of the light-receiving sensor, and the workpiece is advanced a small amount at a time toward the machine tool. , determine whether each of the light receiving sensors is on or off at each forward position, and if the left or right light receiving sensor is on, the workpiece is corrected to the left or right by rotation of the rotating shaft and the center sensor is turned on. , memorize the rotation angle of the rotation axis as a teaching point at the position where the center sensor is turned on;
The object is to move forward to the end point of the abutting operation while repeating the forward movement, correction movement, and memorization of the teaching point to obtain the teaching point.

Therefore, according to this teaching method, it is possible to automatically obtain the optimal teaching point regarding the angular displacement of the workpiece, shortening the working time and labor, and
Product accuracy can be improved.

Examples will be described below.

FIG. 2 is a front view showing an example in which the robot 1 provides a work supply service to the vendor 3. The robot is not limited to the robot shown in the drawings, but may be any of the rectangular coordinate type, cylindrical coordinate type, polar coordinate type, and multi-joint type, in which the tip of the arm can move in three dimensions.

The robot 1 has a rotating shaft 9, an arm 7 that extends upward and downward, and a hand 11, and the hand is provided with a finger 13 for gripping a workpiece. The hand 11 is provided via a rotating shaft 15 perpendicular to the arm 7 so as to be able to swing relative to the arm 7 in a horizontal plane. This shows a situation in which a workpiece 5 is gripped by fingers 13 and pressed against a machine tool 3. The robot control device 17 has a CPU 19 and a memory
Pulse interpolation unit 21 according to the contents of ROM and RAM;
Pulses are sent from each amplifier 25 to each servo motor M through the pulse distribution section 23 to operate each of the axes. The operation results of each axis are sent to the distribution unit 2 using pulse signals.
3 and is subjected to feedback control.

The machine tool 3 is controlled by a control device 27, which controls a positioning motor M ₁ of a limit gauge 29 that determines the end position of the workpiece 5 and a bending motor M ₂ that moves the bender upper die. Robot control devices and machine tool control devices are interface DI,
Contacted via DO.

A light emitter 31, such as a semiconductor laser or a light emitting diode, which emits an optical beam forward in parallel with a horizontal line perpendicular to the processing line of the machine tool is attached to a fixed position of the machine tool, that is, to the machine tool itself, a mold, or the like. This example shows an example in which it is attached to a mold 33. Alternatively, it is possible to attach it to the rear of the machine tool and project the optical beam forward by passing through the gap in the machine tool, but the function and effect are no different from those provided in the machine tool itself. In addition, a center light receiving sensor S _O that receives the optical beam is provided on the robot hand 11 (finger 13) at point A where the work of abutting the workpiece against the machine tool starts, and light receiving sensors are also installed to the left and right of the center light receiving sensor. Provide S _L and S _R. The optical axis 35 does not necessarily need to connect the centers of the mold or the workpiece, and may be parallel to the X axis described in the prior art. A light receiving sensor is provided facing the light emitter, which is the origin of this optical axis. The light receiving sensor is, for example, a photodiode, a phototransistor, a light emitting diode, a silicon semiconductor element, etc., and is selected depending on the light source of the optical beam, response time conditions, etc.

3 is an enlarged view of the robot finger 13 portion of FIG. 2, and FIG. 4 is a right side view of FIG. 3 as seen from the machine tool side. Below the finger 13 that grips the workpiece 5, a central light receiving sensor S0 is provided facing the optical axis 35 of the optical beam, and S _{L and} S _R are provided on the left and right sides (FIG. 4) of the central light receiving sensor S0. Between the light receiving sensor S _O and S _L , S _R is the fourth
They must be installed without any gaps in the left and right direction as shown in the figure. The width of the light-receiving sensor S _O affects accuracy and must be made small, but S _L and S _R may be long in the left-right direction. Sensing signals from each light receiving sensor are sent to the robot control device. Although the light receiving sensor is provided on the robot finger in this example, it may be provided on the hand portion as long as it is a member fixed to the workpiece 15 during the abutting operation. As described above, the condition is that the center light receiving sensor receives the optical beam and turns on at the start point of the abutting operation.

FIG. 5 is an explanatory diagram showing a method of processing signals from a light receiving sensor. The light receiving signals from each light receiving sensor S _O , S _L , S _R pass through amplifiers A _L , A _O , AR and are outputted from comparators C L , C O , _CR as voltage signals of a certain value or higher, and then are outputted from comparators C _L , C _O , _CR to a level converter L. It is converted into a desired voltage or current format by _L , L _O and L _R and input to the interface DI of the robot control device 17. A current is applied to the optical beam generator 31 during the abutment teaching operation to generate an optical beam. In this example, light is emitted from the interface DO of the control device 17 via the level converter L and amplifier A.

FIG. 6 shows a control flowchart. FIG. 7 is an explanatory diagram of the light receiving sensor provided on the robot finger, viewed from the machine tool side. The symbol α in the drawings indicates the rotation of the rotating shaft 15 (see FIG. 2).

It is assumed that the abutting work start point A, the end point B, and the workpiece horizontality have already been given by other teachings.

At step 101, the tip of the workpiece is at point A. The workpiece is advanced by Δlmm, for example 2 mm, from point A (steps 102 and 103). At this advanced position, it is determined whether each light receiving sensor is on or off (step 104). If the central light receiving sensor S _O is on in this judgment, it indicates that the workpiece is parallel to the machining surface of the machine tool, so the angle of the rotation axis 15 at this time is stored in the robot memory along with the position information. (Step 105)
Proceed to step 106. If it is determined in step 104 that the left light receiving sensor S _L is on, the process proceeds to step 108.
Then, the rotary shaft 15 is rotated until the _SO is at this position as seen from the machine tool (steps 108 and 109).
+α rotation in step 108 means rotating the rotating shaft 15 in this manner. step
109 confirms that the light receiving sensor S _O is on,
Proceeding to step 105, the angle of the rotation axis at this time is stored in the robot memory. In step 104, the light receiving sensor
When S _R is confirmed, the rotating shaft 15 is rotated -α, contrary to the case where S _L is on (steps 110 and 111).
If the center sensor _SO is turned on again in step 111, the process moves to step 105, and the angle of the rotation axis at this time is stored. In step 106, it is determined whether or not the terminal point B has been reached, and until the terminal point B is reached, the above-mentioned advance by Δlmm, light receiving sensor ON determination, + or -α rotation, and memory storage are repeated. △
Every time the workpiece moves forward by lmm, the angle of the rotation axis at which the workpiece and machine tool become parallel is stored in memory, and the step
After confirming point B in step 106, the process ends in step 107.

Since the angle values are stored together with the coordinate values of each forward position, when storing and reproducing each position, it is possible to move forward by storing and reproducing each position, and to adjust the angle of the rotating shaft in accordance with the forward movement.

If the robot is taught based on the flowchart of FIG. 6, it will be freed from complications caused by angular displacement of the workpiece, and teaching related to the abutment work will be facilitated. In addition, all kinds of work such as changing robot positions, converting workpiece types, and replacing machine tools can be handled immediately.

Therefore, according to the teaching method of the industrial robot of the present invention, which maintains parallelism between the machined surface and the front end of the workpiece using an optical beam emitted perpendicularly from the machined surface of the machine tool, and memorizes and reproduces the parallelism, the workpiece and the machine tool It is possible to easily and accurately determine the parallelism with
It is possible to shorten teaching time and save labor.
Changes in work content can be dealt with immediately, and product accuracy can be improved.

[Brief explanation of drawings]

Figure 1 is a schematic plan view showing the positional relationship between the robot and machine tool, Figure 2 is a schematic front view of the robot and machine tool, Figure 3 is an enlarged front view of the robot finger, and Figure 4 is a view from the machine tool side. FIG. 5 is an explanatory diagram of the relationship between the robot control device and the light receiving sensor, FIG. 6 is a control flowchart, and FIG. 7 is an explanatory diagram schematically showing the light receiving sensor of FIG. 4. . 1...Robot, 3...Machine tool, 5...Workpiece, 15...Rotating axis, 31...Light emitter, S _O , S _L ,
S _R ...Light receiving sensor.

Claims (1)

[Claims] 1. A teaching method for an industrial robot that provides a workpiece supply service to a machine tool, comprising: providing a light emitting device at a fixed position on the machine tool that projects an optical beam forward in parallel with a horizontal line perpendicular to the processing line of the machine tool; A hand section is provided at the tip of the robot arm that can freely rotate in a horizontal plane via a rotation axis perpendicular to the arm, and a center light receiving sensor is provided on the robot hand section to receive the optical beam at the starting point of the workpiece abutting operation. Light receiving sensors are also provided to the left and right of the light receiving sensor, and the workpiece is advanced a small amount toward the machine tool, and each of the light receiving sensors is judged to be on or off at each forward position, and the left or right light receiving sensor is turned on. In this case, the workpiece is corrected to the left or right by rotation of the rotary shaft, the center sensor is turned on, the rotation angle of the rotary shaft is stored as a teaching point at the position where the center sensor is turned on, and the forward movement and A teaching method for an industrial robot, characterized in that the robot moves forward to the end point of an abutting operation while repeating corrective movement and memorizing the teaching point to obtain the teaching point.