JPS61273607A - Continuous route control method for robot - Google Patents

Abstract

PURPOSE:To attain the selection of robot actions with much account made of the smoothness or reproducibility of the route in response to the robot working, by selecting the route data processing mode in a play-back state. CONSTITUTION:A robot operator delivers the flag data 22 showing a processing mode A, B or C to a data storage means 20 via a route data processing mode input means 21 before a play-back action. In a play-back action mode a position command arithmetic means 23 supplies successively the route data on the tip part of a robot arm. Then the input route data is turned into a motor revolving angle through the coordinate conversion and a position command 24 is delivered in a route data processing mode A. In a route data processing mode B the command 24 is delivered after the input route data is interpolated for a fixed period of time by an interpolation method. While the input route data is approximated by a fixed approximation method and the command 24 is delivered in a route data processing mode C. A speed command arithmetic means 25 delivers a speed command 27 which drives a robot arm 16 based on the command 24.

Description

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

2. Description of the Related Art An example of a conventional continuous path control method for a robot will be described with reference to FIGS. 5 and 6.

FIG. 5 is a schematic explanatory diagram of a control device that performs a conventional continuous path control method for a robot. That is, during direct teaching, no drive voltage is applied to the motor 2 that is the drive source of the robot arm 1, and the teaching operator draws a target path by directly operating the robot arm 1 with his/her hand, and the motor at this time The rotation angle of the motor 2 is detected by the position detection means 3, and the route data writing means 4 inputs the rotation angle of the motor 2 detected by the position detection means 3 at regular intervals and writes it into the data storage means 6. During playbank, the position command output means 6 is connected to the data storage means 5.
The time-series rotation angle data 7 of the motor 2 stored in the memory are sequentially read out and outputted as a position command 8, and the speed command calculation means 9 uses the position command 8 and the position of the motor 2 detected by the position detection means. The speed control means 12 calculates the deviation between the speed command 11 and the speed feedback signal 14 of the motor 2 detected by the speed detection means 13, and outputs the speed command 11 by calculating the deviation from the feedback signal 1o and adding compensation to it. is compensated and further amplified to apply a voltage to the motor 2, and the motor 2 is connected to the power transmission means 1.
5 to drive the robot arm 4.

Still, FIG. 6 shows the procedure by which the position command output means 6 outputs the position command 8.

That is, the position command output means 6 reads out the time-series rotation angle data 7 of the motor 2 from the data storage means 5, outputs this as a position command 8 to the speed command calculation means 9, and this procedure is performed as the rotation angle data 7. This is repeated until the process is completed.

5 Problems to be Solved by the Peno Invention However, with this method, the vibration of the teaching operator's arm or hand during direct teaching is reflected in the robot's movement, and even if the target path of the tip of the robot arm is smooth, the robot arm However, there is a problem in that the movement of the robot causes path deviation or vibration of the robot arm.

-1. During direct teaching, the teaching operator holds the robot arm 1 directly in his hand and draws the target path, so the time-series rotation angle data of the motor 2 always includes vibrations in the teaching operator's arm or hand. Includes
This rotation angle data becomes the position command 8 during playback operation, and since the robot arm 1 operates based on the position command 8, the target path may be smooth due to vibrations of the teaching operator's arm or hand during direct teaching. Also, path deviation or vibration of the robot arm occurs in the movement of the robot arm.

When the target path of the robot arm is smooth, the present invention provides a means for significantly reducing the influence of chatter of the teaching operator's arm or hand on the robot operation during direct teaching. This allows selection at playback based on judgment.

Means for Solving the Problems FIG. 1 is an explanatory diagram showing the steps of a playback method for robot continuous path motion according to the present invention. As shown in FIG. 1, the continuous path control method for a robot according to the present invention is performed when the robot performs a playbank operation based on the path data of the tip of the robot arm stored in the storage means of the robot control device by direct teaching. , a route data processing mode flag that determines a method of processing the route data until obtaining a position command value for the robot controller from the route data is stored in the storage means of the robot controller by manual input by the robot operator; During the playback operation, the robot control device judges the path data processing mode flag and converts the path data of robot 7...-7 obtained by direct teaching from the orthogonal coordinate system to the motor rotation angle or robot arm rotation angle. Route data processing mode A emphasizes reproducibility of the route during direct teaching, where the coordinates are transformed and used as position commands for a robot control device such as a play bank. (b) Time-series route data of the robot obtained by direct teaching is The thinned out path data is thinned out using a certain method, the thinned out path data is smoothly interpolated using a certain interpolation method, and this interpolated path data is converted from the orthogonal coordinate system to the motor rotation angle or robot arm rotation angle for playback. Path data processing mode B smoothes the path of the tip of the robot arm by using the position command of the robot control device.

(C) Thinning out the robot's time-series route data obtained through direct teaching in a certain way,
By smoothly approximating the thinned out route data using a certain approximation method, and converting the approximated route data from the Cartesian coordinate system to the motor rotation angle or robot arm rotation angle, the robot position command is used during playback. One of the three route data processing modes is selected: route data processing mode C1, which places more emphasis on the smoothness of the route of the tip of the robot arm than the route data processing mode B.

Operation If the target path of the robot arm is smooth, select path data processing mode B that emphasizes the smoothness of the path, and ensure that the desired target path of the robot arm is clean and does not necessarily pass through the thinned out path data points. If there is no need to do so, route data processing mode C, which emphasizes the smoothness of the route even more than route data processing mode B, can be selected. can significantly reduce the impact on Depending on the robot work, the target route may be a route with many bending points, and in this case, if you select route data processing mode A, which emphasizes route reproducibility, playback operation along the target route can be performed on page 9. can be realized.

Embodiment Hereinafter, one embodiment of the present invention will be described based on the accompanying drawings.

FIG. 2 shows an embodiment of the present invention.

That is, during direct teaching, no drive voltage is applied to the motor 17 that is the drive source of the robot arm 16, and the teaching operator draws a target path by directly operating the robot arm 16 with the child, and the motor 17 at this time The rotation angle of the motor 17 is detected by the position detection means 18, and the path data writing means 19 inputs the rotation angle of the motor 17 detected by the position detection means 18 at regular intervals, and calculates the orthogonal angle of the tip of the robot arm 16 from the rotation angle. The coordinates are converted to the coordinate system position and written into the data storage means 2o as route data of the robot arm, and at the same time, detection time data corresponding to this route data is also written into the data storage means 2o. Before the playback operation, the robot operator uses the route data processing mode input means 21 to output flag data 22 indicating the route data processing mode A or 1 or B or C to the data storage means 2o. The position command calculation means 23 inputs the 7 lag 22 of the route data processing mode from the data storage means 20 as an initialization calculation for the robot playback operation, and when the route data processing mode is B or C, it is stored in the data storage means 20. The time-series route data of the tip of the robot arm that has been used is thinned out and output as new route data to the data storage means 2o. During the playbank operation, the position command calculating means 23 sequentially inputs time-series route data of the tip of the robot arm from the data storage means 2o, and when the route data processing mode is A, the input route data is used as the motor rotation angle. When the route data processing mode is B, the input route data is interpolated using a certain interpolation method, the coordinates are transformed to a motor rotation angle, and the position command 24 is output. When the data processing mode is C, the input route data is approximated by a certain approximation method, the coordinates are converted into a motor rotation angle, and the position command 24 is output, and the speed command calculation means 26 The deviation between the command 24 and the position feedback signal 26 of the motor 17 detected by the position detecting means 18 is taken, compensation is added to the deviation, and a speed command 27 is output. Speed feedback signal 3o of the motor 2 detected by 29
A voltage is applied to the motor 17 after compensating for and further amplifying the deviation, and the motor 17 drives the robot arm 16 via the power transmission means 31.

Further, FIG. 3 shows the procedure by which the position command calculation means 23 outputs the position command 24. Before the play bank operation of the robot, the robot operator inputs the flag 22 indicating the route data processing mode A, B, or C to the data storage means 2 using the route data processing mode input means 21.
Write to o.

When the route data processing mode is B or C, the time-series route data of the tip of the robot arm is stored as a gator for a certain number of data, and the data 23 is stored as a time-series of the tip of the robot arm from the data storage means 2o. When the route data processing mode is A, the input route data is coordinate-transformed into a motor rotation angle and a position command 24 is output, and when the route data processing mode is B, the input route data is output. The route data is interpolated using a certain interpolation method, the coordinates are converted to a motor rotation angle, and the position command 24 is output. When the route data processing mode is C, the input route data is approximated using a certain approximation method to obtain the motor rotation angle. The coordinates are transformed into , and a position command 24 is output. Examples of interpolation and approximation methods in this procedure will be described with reference to FIG. FIG. 4 shows a series of route data stored in the data storage means 2Q.

The route data expressed in the orthogonal coordinate system is expressed as (ti) along with the detection time of each route data during direct teaching.
+”i *’!□, 2.) is stored,
Interpolation and approximation are (ti, x□) (i=1...n)
(t i, yi) (i=1...n
) 13 pages (t4.zi) (i=1...n). Akima's method is still used as an interpolation method, and a method using a B-spline curve is used as an approximation method.

As a result, if the desired robot arm's target path is smooth, path data processing mode B that emphasizes the smoothness of the path is selected, and the desired robot arm's target path is smooth and the thinned out path data points are selected. If it is not necessary to pass, route data processing mode C, which emphasizes the smoothness of the trajectory even more than route data processing mode B, can be selected. The influence of chatter on robot operation can be significantly reduced. In addition, depending on the robot work, the target route may be a route with many bending points, and in this case, if route data processing mode A, which emphasizes route reproducibility, is selected, playback operation along the target route can be realized. can.

Effects of the Invention 14"-/' As described above, the present invention provides a route data processing mode A that obtains a position command by coordinately converting route data into a motor rotation angle by direct teaching, and a route data processing mode A that obtains a position command by thinning the route data and smoothing the coordinates. A route data processing mode B that interpolates the data and converts the coordinates to a motor rotation angle to obtain a position command, and a route data processing mode C that thins out the route data, smoothly approximates it, and transforms the coordinates to a motor rotation angle to obtain a position command. The robot operator can select the playback motion in advance, and depending on the robot's work, the robot operator can select a robot motion that emphasizes the smoothness of the path or a robot motion that emphasizes the reproducibility of the path during direct teaching. be able to.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a continuous path control method for a robot according to the present invention, FIG. 2 is a schematic explanatory diagram of a robot control device according to an embodiment of the present invention, and FIG. 3 is a position command diagram according to an embodiment of the present invention. FIG. 4 is an explanatory diagram showing the calculation procedure; FIG. 4 is an explanatory diagram of route data stored in the data memory means in an embodiment of the present invention; FIG. An explanatory diagram, FIG. 6, is an explanatory diagram showing the procedure of conventional position command calculation. 16...Robot arm, 17...Motor, 19...Route data writing means, 2o...
... Data storage means, 21 ... Route data processing mode input means, 22 ... Route data processing mode flag, 23 ... Position command calculation means, 24
...Position command. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (1)

[Claims] When the robot performs a playback operation based on the path data of the tip of the robot arm stored in the storage means of the robot control device by direct teaching, the position command value of the robot control device is determined from the path data. A path data processing mode flag that determines how to process the path data until the path data is obtained is stored in the storage means of the robot control device by manual input by the robot operator, and the robot control device processes the path data during the playback operation of the robot. Determine the mode flag, and (a) convert the robot path data obtained by direct teaching from the orthogonal coordinate system to a motor rotation angle or robot arm rotation angle and use it as a position command for the robot control device during playback. Path data processing mode A emphasizes the reproducibility of the path during teaching; (b) thins out the robot's time-series path data obtained by direct teaching in a certain way;
The thinned out route data is smoothly interpolated using a certain interpolation method, and the interpolated route data is converted from the orthogonal coordinate system to a motor rotation angle or robot arm rotation angle, and is used as a position command for the robot control device during playback. Path data processing mode B that smooths the path of the tip of the robot arm by (c) thinning out the robot's time-series path data obtained by direct teaching in a certain way,
By smoothly approximating the thinned out route data using a certain approximation method, and converting the approximated route data from the orthogonal coordinate system to the motor rotation angle or robot arm rotation angle, it is used as the robot position command during playback. It is possible to select at least two of the following three route data processing modes: a route data processing mode C that puts more emphasis on the smoothness of the route of the tip of the robot arm than the route data processing mode B, and one type of processing is selected from these at the time of execution. A continuous path control method for a robot characterized by selecting and executing a mode.