JPS6039207A - Automatic teaching method of industrial robot - Google Patents

Abstract

PURPOSE:To attain teaching work with high accuracy, safety and in a short time by outputting a command value of each operating axis of a robot from a detected value of a sensor and a present value of a position of a hand of the robot and attitude and inducing automatically the hand of the robot. CONSTITUTION:An industrial robot 1 grips a tool 8 by its hand 6 at the reproducing operation, controls the position and the attitude of the hand 6 according to the indication of a controller 10 and conducts a prescribed work to a processing object 2. In case of the teaching work, a sensor 7 is gripped by the hand 6. The sensor 7 consists of a distance/attitude detecting section and a ridge line position detecting section so as to detect the distance to the surface of the processing object 2, the attitude and the position of a ridge line 5 of the object 2. Then the command value of each operating axis of the robot is outputted depending on the detected value of the sensor 7 and the present value of the position and attitude of the hand 6 of the robot 1 so as to guide automatically the hand 6 of the robot 1 thereby obtaining a teaching data.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method for automatically performing a teaching operation to an industrial robot 1 of a storage/reproduction type.

[Prior art]

As is well known, in an industrial robot using a memory replay method, it is necessary to memorize (memorize) by guiding the robot's hand to the position and posture to be controlled one by one in advance. This is called teaching work. By performing this teaching work, the robot can repeat the work learned through the teaching work any number of times. This is the playback operation. By the way, conventional teaching operations use a so-called teach box in which a plurality of switches are arranged, and the operator turns on and off the desired switch of the C-teach box to "instruct the robot 1-1 with one look."
This was done by guiding the child's hand.

However, in this method, the operator manually guides the robot 1- by manipulating the switches one by one, which requires skill in operation and also requires a long teaching process. Furthermore, this method requires the operator to enter the robot's operating area as necessary in order to visually confirm the relative position and orientation of the workpiece and the tool gripped by the robot. However, it has the disadvantage that it poses a danger to the operator.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the drawbacks of the conventional methods described above, it is an object of the present invention to provide an automatic teaching method that is highly accurate, has a short teaching time, and is safe.

[Summary of the invention]

The gist of the present invention is to attach a sensor to the wrist of the robot that detects the distance and orientation to the surface of the workpiece and the position of the ridgeline of the workpiece, and to compare the detected values of the sensor with the current position and orientation of the robot's hand. This system automatically teaches the robot based on the values and automatically generates teaching data.

[Embodiments of the invention]

FIG. 1 is an overall configuration diagram for explaining one embodiment of the present invention. In FIG. 1, 1 is an industrial robot,
During the playback operation, the tool is held in the hand 6 and the control device 10
The workpiece (
A predetermined operation is performed on 2 (hereinafter referred to as a work). 7 is a sensor that is held in the hand 6 of the robot 1 during teaching work, and 8 is a sensor that is used while being held in the hand 6 of the robot 1 during playback operations.
These sensors 7 and tools 8 are normally housed in a standby stand 9. Here, the sensor 7 consists of a distance/orientation detection section and an edge line position detection section, and detects the distance and attitude with respect to the surface of the workpiece 2 and the position of the ridgeline 5 of the workpiece 2 by photoelectric means. , the distance/posture detection unit is configured to sequentially irradiate the surface of the workpiece 2 with light from three or more point light sources and receive the reflected light with a two-dimensional photodetector, thereby detecting the surface of the workpiece 2 ( In addition, the ridgeline position detection unit irradiates Surin 1 light from diagonally above the ridgeline 5 so as to cross the ridgeline 5, and the reflected light is detected by a one-dimensional detector. By adopting a configuration in which light is received at , the position of the ridge line 5 of the workpiece 2 can be detected. In addition, the Kashiru sensor was filed by the present applicant in a patent application filed in 1988-11! Since it has already been proposed as JI No. 9, further explanation of its physical structure will be omitted.

Hereinafter, in this embodiment, the work of the industrial robots 1 to 1 is to weld along the ridgeline 5 from point 3 of the workpiece 2 (hereinafter referred to as the starting point) to another point 4 (hereinafter referred to as the end point). shall be carried out. Therefore, the tool 8 will be described below as a torch. FIG. 2 is a diagram illustrating the procedure of the teaching work according to the present invention in this case, in which (a) is a plan view of the relationship between the workpiece 2 and the sensor 7, and (b) is a side view of the same. Automatic teaching according to the present invention is performed in the following steps.

(1) Under the control of the control bag [1110, the hand 6 of the robot I-1 grasps the sensor 7 from the standby stand 9.

(2) Point 11 where the sensor 7 is set in advance (When installing the workpiece 2, even if the workpiece 2 deviates from the reference position,
The sensor 7 is located above the workpiece 2 and is close to the starting point 3).

(3) The distance and attitude of the sensor 7 relative to the surface of the workpiece 2 are controlled so that the output of the distance/attitude detection unit [5 becomes a predetermined value, and the sensor 7 is moved to the point 12 (distance/attitude). attitude control mode).

(4) While controlling the distance and attitude, move the sensor 7 in a preset direction (the direction in which the ridgeline 5 exists) and search for a point 13 where the output of the ridgeline position detection unit 16 of the sensor 7 becomes a predetermined value. (Ridge line search mode 1~).

(5) While keeping the output value of the distance/attitude detection unit 15 of the sensor 7 at a predetermined value, move the sensor 7 along the line 14 in a preset direction (the direction where the starting point 3 exists) to detect the ridge line position. The point where the detected value of the section 16 suddenly changes is regarded as the starting point 3 (starting point search mode).

(6) Move the sensor 7 in a preset direction from the starting point 3 (
(in the direction in which the end point 4 exists) along the line 14 while keeping the output value of the distance/posture detection unit 15 at a predetermined value.

At this time, teaching data is generated at regular time intervals using a method described later, and is sequentially stored in the storage unit in the control device 10 (guidance/teaching mode).

(7) The point where the detection value of the ridgeline position detection unit 16 of the sensor 7 suddenly changes is regarded as the end point 4, and the guidance/teaching mode is ended.

After the automatic teaching work is completed as described above, the industrial robot 1 returns the sensor 7 to the standby stand 9 and grasps the torch 8 instead, thereby reading out the teaching data stored in the control device 10. perform the actual work (playback operation).

FIG. 3 shows a block diagram of the control system of the industrial robot, and a method of controlling the robot and a method of generating teaching data will be explained using this block diagram. Note that the I" box 1-1 includes a positioning control system for each operating axis.

It is omitted in FIG.

During teaching work, the sensor 7 held by the hand 6 of the industrial robot 1 calculates the deviation Δy of the position of the ridgeline in the coordinate system fixed to the sensor 7 (sensor coordinate system x5-y5-z).
5 and the distance deviation ΔZ from the workpiece 2, and the posture deviation Δα9. 8β5 (respectively X6.■, rotation angle around the axis) is output. These sensor output values are converted into values ΔX of a coordinate system fixed in space (absolute coordinate system X, −Y −Z) by a coordinate conversion calculator 17. In addition to the value, sensor 7
No. 48 Δ for moving in the X5 axis direction of the sensor coordinate system
X5 is input. This signal ΔX5 is 'o' in the range/attitude control mode and the ridge line search mode.

In the starting point search mode 1-, the predetermined value -ΔX5 is set, and in the guidance/teaching mode, the predetermined value ΔX5 is set. Further, in the ridgeline search mode, a predetermined value Δy5 is inputted to the calculator 17 instead of Δy5 until the ridgeline 5 is within the detection range of the sensor 7, and the sensor 7 is moved in the direction of the ridgeline 5.

The output value ΔX of coordinate transformation operation nH:+] 7 is the coefficient unit 18
The absolute value is inputted to the adder 19 after being multiplied by a predetermined coefficient by It is added to the current value χ of the position and orientation of the sensor 7 in the coordinate system, and a command value 7 is output. Command value,
is input to the coordinate transformation calculator 21 in a mode other than the reproduction mode, and the position command value (0, In teaching mode, Δa and X/.

are added by the adder 22, and the added value is stored in the storage unit 23 at regular time intervals as teaching data. In the reproduction mode, the image 1α stored in the storage unit 23 is
are sequentially input to the interpolation calculator 24, and the command value at the time of reproduction)
? 1 is created, and the position command value (0.

becomes.

Note that the coordinate transformation calculator 17, coefficient unit 18, adder 19, coordinate transformation calculators 20, 21° adder 22, storage section 23, supplementary law calculator 24, etc. in FIG. 3 are included in the control device 10 in FIG. It shall be provided. In that case, each part may be configured individually using hard logic, or the entire part may be replaced by a computer.

In the explanation of the second embodiment, the teaching data is stored in the memory sequentially at fixed time intervals, but in order to save memory, as shown in FIG.
．． 26 while taking turns, the teacher-evening editorial department 27
For the parts that can be interpolated with straight lines or circular arcs, edit the straight parts to only 2 points and the circular arc parts to about 3 points, and store them in the storage section 2.
3 may be stored.

In addition, in FIG. 3, data for reproduction (teaching data) is stored by adding X4 and Δy, but 8y
is generally small, and the value of Xl or only X may be used as a child value for reproduction.

The above has been explained using the teaching of arc welding work as an example.
It goes without saying that the present invention can be applied to teaching sealing operations in which fillers are applied to gaps between works, and other applications.

〔Effect of the invention〕

As described above, according to the present invention, there is an advantage that the teaching work of the industrial Kawaguchi boy 1- of the storage/reproduction method can be performed automatically with high precision, safely, and in a short time.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention, FIG. 2 is an explanation of the automatic teaching procedure according to the present invention, FIG. 3 is a block diagram of the control system of industrial robots 1 to 4, and FIG. 1 describes another embodiment of the teaching arc storage method. 1 Roposo 1~. 2. Object to be processed (work), 6.
-Hand, 7...Sensor, 81--Chi, 1°...Control device. Figure 1 Figure 2 (Inlet C)

Claims (1)

[Claims] In the memory replay type industrial robot, a sensor is attached to the wrist of the robot 1- for detecting the distance and orientation of the workpiece to the surface and the position of the ridgeline of the workpiece,
The robot is characterized by outputting a command value for each motion axis of the robot based on the detected value of the sensor and the current value of the position and posture of the robot's hand, automatically guiding the robot's hand, and obtaining teaching data. Automatic teaching method for industrial robots.