JPH03228103A - Route control system for multi-joint type robot - Google Patents

Abstract

PURPOSE:To reduce calculation required for correction and to enable smooth route preparation in a short time by executing the correction of position data only to a position, where the change of acceleration is large, at the tip of an arm. CONSTITUTION:An analog value to be detected by an acceleration sensor 33 provided at the tip of the arm is passed through an amplifier 34 and an A/D converter 35 and held in a data storing means 36 together with the position data. When a series of reproducing operations are finished, the position with the large acceleration change in the data held in the data storing means 36 is found out and concerning the position data, the correction to calculate the position from the position data adjacent to the data is executed to all the route data. The correction are executed by a data comparing/correcting means 37. Thus, since the position data is corrected only at the position where the acceleration change is large, the smooth route preparation can be executed with the small amount of calculation.

Description

[Detailed description of the invention] b) Industrial application field The present invention relates to a continuous path control method for a robot.

BACKGROUND OF THE INVENTION In recent years, various methods of teaching motion of articulated robots have been considered. One of them is the direct teaching method. In this method, the operator draws a target path by directly manipulating the arm without applying a drive voltage to the motor that is the drive source of the robot arm, and the rotation angle of the motor is sequentially detected by the position detection means. , this is stored in a storage means or the like. Then, during playback, the robot arm is operated by driving a motor based on the data thus stored.

However, with this method, the vibration of the teaching operator's bowl or hand during direct teaching is reflected in the robot's playback motion, and even if the target path at the tip of the robot arm is smooth, the movement of the robot arm may be affected by vibrations in the path or the robot's hand. There is a problem in that the arm vibrates.

In other words, during direct teaching, the teaching operator holds the robot arm directly and draws the target path, so the time-series rotation angle data of the motor always includes vibrations of the teaching operator's bowl or hand, and this rotation angle The data becomes a position command during playback operation, and the robot arm operates based on the position command. Therefore, even if the target path is smooth due to vibration of the teaching operator's bowl or hand during direct teaching, the robot arm will move. Movement path fluctuations or robot arm vibrations occur.

For this reason, in Japanese Patent Laid-Open No. 61-273609, etc., it has been proposed to sample rough route data during teaching and to approximate the route data smoothly during playback.

C) Problems to be solved by the invention However, in order to obtain smooth trajectory data using this method, a large amount of calculation is required for numerical analysis, and a fairly high-speed processing unit is required, making it difficult for the robot itself. It will be quite expensive.

Additionally, it is difficult to ensure real-time performance of the robot's movements due to the large amount of calculations involved.

2) Means for Solving the Problems The present invention has been made in view of the above points, and is directed to an articulated robot in which the tip of the arm is moved by an external force and the movement path is taught by changing the position data. , an acceleration sensor that converts the acceleration level into a signal level is provided at the tip of the arm, and for position data on a route where the acceleration change detected by this acceleration sensor changes by a certain amount or more when reproducing teaching data, a position near the position data is The location data is determined from the data.

e) Since the position data is corrected only in areas where the change in action acceleration is large, a smooth route can be created with a small amount of calculation.

f) Embodiment Figure 2 shows a robot in which the control method of the present invention is used.
During direct teaching, position data regarding each joint of the robot arm (32) output from the position detecting means (30) is detected at regular intervals by the sampling generating means, and is read into the minimum trajectory movement amount determining means (22). The distance traveled within the sampling interval is calculated based on this detection data, and when this value becomes greater than the value set by the minimum travel amount setting input means (20), the minimum trajectory travel amount determination means (22) ) gives a signal to the locus data writing means (23), whereby the locus data writing means (23) writes the position data from the position detecting means (30) into the data storage means (24). Such operations are performed every time each sampling signal arrives.

On the other hand, during playback, when the mode input means (33) is used to select the processing mode, either as is (A), interpolation (B), or approximation (C), and the speed parameter for moving across the wheel is determined, the speed is detected. means (29), position detection means (30
), operate the motor (28) by the position command calculation means (25), speed command calculation means (26), and speed control means (27) according to the position data in the data storage means (24), Articulated robot arm (32)
operate at constant speed.

On the other hand, FIG. 1 shows the construction method of the present invention. This will be explained below.

If the ti and if data taught by direct teaching and stored in the data storage means (24 months) are played back as they are, the robot (32) will operate according to the values of the taught data, so at the position where a lot of chatter occurs, the robot (32) will The value detected by the provided acceleration sensor (33) consisting of a gyro, piezoelectric element, etc. increases.

The analog value of the acceleration sensor (33) is amplified by the amplifier (30), passed through the A/D conversion 11 (35), and is stored in the data storage means (36) as position data at each sampling period. When the operation is completed, a position with a large change in acceleration is found among the data stored in the data storage means, and the data at that position is determined from the position data adjacent to that data. This is done using the data comparison/correction means (3).
7). This situation is shown in FIGS. 3 and 4. Figure 3 shows that the acceleration change was large at the S8 position, and Figure 4 shows that S, was corrected to S,', so that S,'=f(S,,S,)
It can be shown in the form (S!' is the two of S, and S,
[meaning a function of two values].

If the position data corrected by the data comparison/correction means (37) is used as the motion data for the next playback and the same procedure is repeated, by repeating this process, the taught raw data will be able to match the taught trajectory without limit. It becomes possible to obtain a smooth trajectory.

In this embodiment, chatter is detected using the acceleration sensor (33), but a vibration sensor that detects the vibration level at the tip of the arm may also be used.

g) Effects of the invention As mentioned above, the path of the chaotic articulated robot lH
In the n method, position data is corrected only for positions where the acceleration change of the arm tip is large, so less calculations are required for correction, and a smooth route can be created in a short time.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of the path control system of the articulated robot of the present invention, Fig. 2 is a schematic diagram of the articulated robot to which the present invention is applied, and Fig. 3 is a diagram showing the role of data storage. Schematic diagram of the state of
FIG. 4 is an explanatory diagram showing the path locus of the tip of the arm. (211)...minimum movement amount setting input means, (21).
. . . Sampling J signal generation means, (22) . . . Minimum locus movement amount judgment 1 stage, (25) . . . Position command calculation means,
(28)...Motor, (30)...Position detection means,
(36)...Data storage means, (37)...Data comparison/correction means.

Claims (1)

[Claims] 1) In an articulated robot that teaches the movement path by moving the tip of the arm using an external force and giving position data,
An acceleration sensor that converts the acceleration level into a signal level is installed at the tip of the arm, and for position data on a route where the acceleration change detected by this acceleration sensor changes more than a certain level when reproducing teaching data, position data adjacent to the position data is A path control method for articulated robots characterized by determining their position data.