JPS60178509A - Teaching system of robot - Google Patents

Abstract

PURPOSE:To improve the efficiency of teaching operation by calculating the attitude that the robot takes as teaching data, and substituting it with on-line teaching data in a specific operation period. CONSTITUTION:The robot teaching system consists of an input device 1 for indicating an operation command, etc., angle arithmetic unit 2 for each articulation of the robot, etc., and further memory 9 for storing time-series data on each directly taught articulation angle and an editing device 10 for replacing on- line and off-line teaching data with each other are provided. Then, the off-line teaching data is sent from memory 3 to a robot controller 6 to put the robot 7 in assembling operation. In this case, when part of teaching data is corrected on on-line basis, correction start and end signals are inputted over a look at a correction part on a screen 5 and the part between them is corrected by a direct teaching device 8 and stored in said memory 9. Then, said editing device 10 is started and part of data in said memory 3 is replaced.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a teaching method for automatic machines (hereinafter referred to as robots), and in particular, a method suitable for using online teaching data to determine the conditions of offline teaching results. Regarding robot teaching methods.

[Background of the invention]

Currently, robots (particularly articulated robots) do not necessarily have sufficient absolute accuracy for one positioning due to mechanical errors such as backlash, and there are variations in the absolute accuracy of each robot. For this reason, the robot cannot perform positioning as specified by offline teaching, resulting in an error. This error varies from robot to robot, and is a major reason why it is not possible to make the robot perform the desired work with offline teaching alone.

Conventionally, the following methods have been used to counter the above-mentioned errors.

(1) Parameter adjustment method The positioning error of the robot is treated as a parameter, and the parameter adjustment is performed using error data of each robot measured off-line.

(2) Sensor usage: A sensor is attached to the robot, and feedback is given to the robot based on the difference between the position determined by the sensor signal and the taught position. There are various types of sensors, but a visual sensor is a typical one.

(3) Representative point teaching method This is a method in which several representative points are retaught by direct teaching (online teaching), and using this data, all the previously taught data is corrected by interpolation calculations and the like.

However, in advanced tasks that require human senses, the method of reteaching several representative points and interpolating between the representative points often does not work. Therefore, it is necessary to modify the teaching data in a certain continuous section.

[Purpose of the invention]

The purpose of the present invention is to correct offline teaching data by:
To provide an easy-to-use numerical method that allows online teaching data, which humans perform using their senses, to be used not only discretely at several points but also continuously over a certain section.

[Summary of the invention]

In both online and offline teaching, the data sent to the robot controller is time-series data of each joint angle. In online teaching, it is difficult to match the robot's movements with time-series data, so reteaching and replacing a portion of the data is virtually never done.

On the other hand, in offline teaching, since time-series data of joint angles is calculated based on the robot's motion, it is possible to establish a correspondence between the robot posture and the time-series data. The present invention is characterized in that by utilizing this correspondence relationship, data in a certain motion section can be completely replaced with data obtained through online teaching.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. 1st
The pot teaching system shown in the figure is based on the robot's environment (
an input device 1 for the operator to instruct the robot's movement commands (work objects and peripheral devices); an angle calculation device 2 for calculating the angle that each joint of the robot should take in order to realize the instructed movement; A memory for storing angles in time series; a coordinate transformation calculation device 4 for displaying the three-dimensional robot posture on a two-dimensional screen; a robot movement display device 5 for checking off-line teaching results; a robot controller 6 for operating the robot 7 based on the robot 7, a direct teaching device 8 for teaching the robot 7 online, a memory 9 for storing time series data of each joint angle as a result of direct teaching, online teaching data and offline teaching. and an editing device 110 for exchanging data.

Now, as shown in FIG. 2, in offline teaching to explain this teaching method by taking as an example the work of assembling a round bar 11 on a stand 12, the operator uses the input device 1 to specify the point marked with an X in the same figure. do. The joint angles of the robot at each point on the trajectory indicated by dotted lines are calculated by the angle calculation device 2 and stored in the memory 3 as time series data. The offline teaching result is displayed on the operation display device f! after calculation by the coordinate transformation calculation device 4.
5, it will be displayed in a moving image and will be confirmed by the operator.

The offline teaching data after confirmation is sent from the memory 3 to the robot controller 6, and the robot 7 performs assembly work. At this time, due to backlash of the robot 7, etc., the central axes of the round bar 11 and the hole 13 of the stand 12 may be misaligned, causing "snapping" as shown in FIG. 3, and the round bar 11 may not move. In the robot re-teaching process, the operator performs the following operations in order to modify part of the teaching data online.

(1) Reproduce the video screen display of robot motion using offline teaching data.

(2) When you want to switch to online teaching while looking at the screen, for example, when the round bar comes close to the hole, the screen also stops,
Input device 1 for starting correction signal based on online teaching data
Enter from.

(3) When you want to move the screen again and finish the correction using the online teaching data, for example, when the round rod is inserted into the hole and the robot releases its hand from the round rod, stop the screen and use the online teaching data to make the correction. Input the end signal from the input device [1.

(4) Move the robot 7 from the initial position using the offline teaching data to the correction start point using the online teaching data, and stop the robot 7 at that point.

(5) For the online teaching section, use the direct teaching device 8 to make small corrections to the posture and position of the robot.

This teaching data is stored in the memory 9.

(6) Start up the editing device 10 in order to modify the offline teaching data using the teaching data.

As a result, part of the data in the memory 3 is completely replaced, making it possible for the robot 7 to perform the desired work.

FIG. 4 shows the flow of data in the above embodiment.

Of the above-mentioned embodiments, the offline teaching section (devices 1 to 5)
There are known examples regarding this (for example, [Autome John J, May 1983 issue, P2O3).

In addition, the online teaching section (devices 16 to 9) has already been commercialized and is clearly a known fact. 1 Features of the present invention are 1 The editing device 10 replaces a part of the offline teaching data with online teaching data. The point is that it has realized the functions that can be done, and has organically linked the teaching methods of two different approaches.

In order to realize the above replacement function, it is necessary to solve the following technical problems.

(a) I! Recognition of the data interval to be replaced (b) Regarding the replacement of data in the interval (a), it is necessary to recognize the start and end points of the replacement. In the embodiment, by utilizing the fact that the time-series data in the memory 3 and the display screen of the robot motion display device 5 correspond in l to l, the start and end points of replacement can be determined by the operator instructing the screen. The method is to recognize points.

As a modification of the embodiment, for example, a robot motion display device lf
In a teaching system that does not have 5, it is sufficient to adopt a method in which the start and end points of data replacement are determined in advance based on past experience and knowledge. It is also possible to synchronize the movements of the robot 7 and to indicate the replacement start point using the input device 1 while observing the movement of the robot 7. In this way, step (1) "reproduction of video screen display" in the above embodiment becomes unnecessary.

Regarding (b), it is a function of the editing device IO itself, but it can be easily realized by using, for example, a microcomputer.

In addition, the robot's position at the end of online teaching!
A is slightly shifted from the robot position B, which is the previously specified replacement end point. Therefore, when switching from online teaching to offline teaching, the robot may move suddenly from position A to position B. This movement can be made smoother by adding a function to interpolate between the current position A and the offline teaching position 1iB.

〔Effect of the invention〕

According to the present invention, there is a first-order effect.

(1) Most of the offline teaching data (approximately 60% or more) can be used even for robots with poor absolute positioning accuracy due to backlash (for example, articulated robots), so the efficiency of teaching work is improved.

(2) Since no visual or tactile sensors are used, the teaching system is inexpensive.

(3) Since the operator only needs to teach online about advanced tasks that require human senses, the operator's expert skills can be demonstrated and a highly efficient man-machine system can be constructed.

(4) By switching the mode from offline teaching to online teaching, the operator can safely teach the robot without being in danger of the robot running out of control due to programming errors.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of the robot teaching system, Fig. 2 is an explanatory diagram showing the work object of the robot, Fig. 3 is a longitudinal cross-sectional view of the work object shown in Fig. 2, and Fig. 4 is a diagram showing the working object of the robot. It is a flowchart of a processing procedure. 1: Input device for operation commands, etc. Figure 1 *Figure 2 ￥13 Figure Liu 41 Continued from page 1 0 Inventor Sadanori Arata Inside Ozenjimu Development Research Institute, Asao Ward, Kawasaki City

Claims (1)

[Claims] an input means for inputting the robot's working environment and operation commands;
a first calculation means for calculating the posture that the robot should take in order to perform the movement instructed by the input movement command; a storage means for storing the calculation results in chronological order as offline teaching data; In a robot offline teaching system comprising a second calculation means for converting the robot posture to display it on a two-dimensional screen, and a display means for continuously displaying the calculation results on a video screen, the offline teaching data and the robot A robot teaching method characterized in that offline teaching data in a predetermined motion section is replaced with online teaching data based on a correspondence relationship with motion.