JPS6258308A - Play-back type robot - Google Patents

Abstract

PURPOSE:To simplify the teaching jobs and to shorten the teaching time by calculating the teaching intervals from the requested locus accuracy and speed and storing them automatically. CONSTITUTION:A body 3 to be driven is moved manually and the pulses produced from a pulse generator 7 are counted. Then the moving speed of the body 3 is calculated by a moving speed calculating means 14. An interval calculating means 16 calculates the teaching point intervals based on the reference moving speed of the body 3 stored in a reference speed/accuracy storing means 15, the stored data on the following accuracy of the working locus and the calculated moving speed of the body 3. The result of calculation of the means 16 is automatically stored in a teaching data storing means 10 in the form of the coordinates on the working locus of the body 3.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a playback type industrial robot that achieves a given work objective by reproducing a work previously taught by a human.

(Conventional technology) In recent years, in the industry, industrial robots have been installed in each part of the production line for the purpose of improving product quality, reducing product costs, and improving production efficiency. are being processed and assembled.

There are various types of industrial robots, and indirect type robots are mainly used for automatic product assembly work, spot welding work, painting work, etc. When positioning the robot arm in the above-mentioned work, the trajectory, speed, and acceleration/deceleration characteristics of the tip become a problem.
One way to give position commands for this positioning is to memorize the coordinates of the points to pass one after another (teaching) while actually moving the operating tip with a joystick, and to continuously pass through these points. There is a teaching playback method that reproduces the motion by positioning (playback).

FIG. 4 shows an external view of an indirect robot having a teaching playback system.

This indirect type robot body has an arm 2 and an arm 3 attached to a swivel base 1 that is attached to a base B so as to be pivotable in the direction shown by the arrow in the figure.
The arm 3 is provided with a working tip A that actually performs work. This swivel base 1, arm 2, and arm 3 are
It is generally driven by an electric or hydraulic motor based on commands from the operation panel 4. The operation panel 4 displays the coordinates of the swivel base 1, arm 2, and arm 3 of the indirect robot.
A teaching pendant 5 is connected to which data is stored in a computer provided in the operation panel 4 during teaching.

A block diagram of an operating device for an indirect robot having such a teaching playback method is shown in FIG.

As shown in the figure, this operating device includes a motor 6 that drives the arm 3, an encoder 7 that is fixed to the shaft of the motor 6 and generates a pulse train according to the rotation angle of the shaft, and a pulse train generated by the encoder 7. A pulse counter 8 that counts the number of pulses in a pulse train, a ROM 9 that stores the robot work program, and a RAM 1 that operates the arm 3 during teaching and stores its coordinates (teaching points).
0, a CPU 12 that calculates the operating speed, stop position, etc. of the arm 3 based on instructions from the teaching pendant 5 and ROM 9, and data from the pulse counter 8 and RAM 10.
The D/A converter 11 converts the digital signal output from the D/A converter 12 into an analog signal, and the amplifier 13 amplifies the analog signal output from the D/A converter 11 and drives the motor 6. There is. In this figure, in order to facilitate understanding of the configuration of the operating device, a configuration diagram for one arm is shown, but in reality, the configuration includes a motor 6, an encoder 7, a pulse counter 8, and so on. The same number of D/A converters 11 and amplifiers 13 as the number of swivel tables and arms constituting the robot body are provided.

Next, a flowchart of a program for teaching the trajectory of the tip of the arm using the operating device having such a configuration is shown in FIG. 6. This will be explained in detail with reference to the following.

TEP1 When a command to enter the teaching mode is issued by the operation button of the teaching pendant 5, the CPLJ12 cancels the normal servo control operation and prepares to store information on the position and movement speed of each arm of the robot body in the RAM10. do.

TEP2 The movement speed designation button for the movement tip part provided on the teaching pendant 5 specifies the movement #J speed of the movement tip part A. This instruction is temporarily stored in the accumulator of CPU 12.

TEP3 Use the joystick provided on the teaching pendant 5 to move the operating tip A of the arm 3 to the desired position (teaching point) to be memorized.

In this case, the signal output by the simulator is C
It is calculated by the PU 12, and the arm 3 is moved by the motor 6 via the D/A converter 11 and amplifier 13.

TEP4 When the operating tip of arm 3 reaches the teaching point, stop operating the joystick and stop the operation of each arm.

TEP5 The moving speed of the operation tip A specified in STEP2 and the coordinates of each arm at the teaching point are stored in the RAM 10 by pressing the memory button set on the teaching pendant 5.

The coordinates of each arm at the teaching point are stored in the RAM 10 as the cumulative number of pulses of the encoder 7 counted by the pulse counter 8.

TEP6 0 Processes from 5TEP2 to 5TEP5 are performed until the work (teaching work) of storing all the teaching points necessary for the bot to perform the work in the RAM 10 is completed, and when the teaching work is completed, 8TEP7
Proceed to.

TEP7 When the teaching work is completed, press the button provided on the teaching pendant 5 that outputs the end of teaching work, and return the operating device to normal control.

As explained above, the playback type robot can determine the coordinates of any point on the trajectory that the operating tip A passes during work,
A desired work is performed by sampling the data of the moving speed between two arbitrary points at an arbitrary number of points, and operating the operating tip A based on this stored data during playback.

(Problems to be Solved by the Invention) However, in the conventional playback robot as described above, as shown in FIG. The moving speed is such that the moving tip A can be moved within the required trajectory accuracy range during playback (
The surface IQ +
In the curved portions a-b-c, etc., the teaching point interval is narrowed, and the moving speed of the operating tip portion A is also slowed down, such as between the curved portions c-d, which are close to the straight line of the curve I, and the straight-line portions d-.
For example, between teaching points a, b, and c, the interval between the teaching points is widened and the moving speed of the operating tip A is set to be fast.

d, e and the speed between each teaching point had to be stored in the computer.

Furthermore, since the teaching point, the teaching point 1 interval, and the moving speed of the operating tip △ between the teaching points had to be determined based on human feeling, considerable skill was required for the teaching work. Furthermore, when the working trajectory of the operating tip A has many curved parts, a large amount of time is required for the teaching work, resulting in high costs.

Furthermore, the working trajectory of the operating tip A during playback after the teaching task is completed is expressed as a multi-core approximate curve ■, but if there is a problem with the accuracy of this trajectory, the teaching task must be performed again. This poses many problems, such as the fact that it takes a lot of time to make the corrections.

The present invention was made to solve these conventional problems, and calculates a teaching interval from the required trajectory accuracy and speed, and automatically transmits the teaching data obtained based on this teaching interval. The purpose of the present invention is to provide a playback type robot that has the function of storing data.

(Means for Solving the Problems) In order to achieve the above-mentioned objects, the present invention provides a driving means for driving a driven body, and a control system for instructing the driving means to move the driven body at a moving speed and direction. a pulse generator connected to the drive means to generate a pulse train proportional to the rotation angle of the driven body; a pulse counter that counts the number of pulses in the pulse train output from the pulse generator; a moving speed calculating means for calculating the moving speed of the driven body based on an output signal of the driven body; and a reference speed/accuracy storage means storing basic data for storing coordinates on the moving trajectory of the driven body. and a teaching point interval calculating means for calculating the storage interval of the coordinates based on the signals of the moving speed general calculating means and the reference speed/accuracy storing means, and when a signal is output from the teaching point interval calculating means. The present invention is characterized by further comprising teaching data storage means for storing data output from the pulse counter and the movement speed calculation means.

(Operation) The operation of the present invention will be explained below based on FIG. 1. When the arm 3, which is the driven body, is manually moved by the teaching pendant 5, which is the control means, and the working trajectory is drawn, the arm 3 is moved from the pulse generator 7.
A pulse is generated every unit rotation angle. This pulse is counted by a pulse counter 8, and the moving speed calculation means 1
4, the moving speed of the arm 3 is determined by detecting the pulse count value per unit time.

Next, the reference value of the moving speed of the arm 3 stored in the reference 'a degree/accuracy storage means 15 and the storage data of the tracking accuracy of the work trajectory and the moving speed of the arm 3 calculated by the moving speed calculation means 14 are used. Based on this, the teaching point interval calculation means 16 calculates a teaching point interval that maintains the tracking accuracy.

Then, from the teaching point interval calculation means 16,
When a signal for storing the coordinates of the teaching point is output, the moving speed of the arm 3 and the pulse count value are stored in the teaching data storage means 10. In this way, the coordinates on the work trajectory of the arm 3 are automatically stored one after another at appropriate intervals to maintain tracking accuracy.

(Example) Next, an example of the present invention will be described in detail based on FIGS. 2 and 3.

FIG. 2 is a flowchart of a teaching program according to the present invention. The general device configuration of the playback robot according to the present invention is the same as that shown in FIG. 5, so the program shown in FIG. 2 will be explained with reference to that diagram.

STEP10 When the teaching mode is specified by the operation button of the teaching pendant 5, the CPU 12 shifts from the normal servo control operation to the teaching operation, and prepares to store information on the position and movement speed of each arm of the robot body in the RAM 10. is done.

5TEP11 From the teaching pendant 5, input the basic speed vO of the operating tip A and the trajectory accuracy magnification (coefficient) R during playback operation. The basic speed VO and coefficient R input here are stored at a predetermined location in the RAM 10.

5TEP12 STEPl Calculate the basic teaching point interval based on the data input in 1. This basic teaching point interval can be calculated by calculating OtR, where t is the reference time.

STEP13 Operate the joystick provided on the teaching pendant 5 to draw a working trajectory on the operating tip A of the arm 3. The moving speed of the arm 3 at this time can be arbitrarily selected by the operator.

5TEP1 4 Calculate the current moving speed V to the operating tip from the number of pulses counted by the pulse counter 8 during the reference time.

5TEP15 Calculate the current teaching point interval from the speed V calculated in STEP14. This teaching point interval is expressed as Vt/VotR-V/VoR.

5TEP16 ST[EPl Based on the teaching point interval calculated in 5, it is determined whether the operating tip A has reached the teaching point. When the teaching point is reached, proceed to 5TEPI 7.

5TEPI 7 When the tip of the operation reaches the teaching point, the swivel base 1. The pulse count values of arms 2 and 3 and the movement speed between the teaching points are output to the CPU 12, and each data is stored in a predetermined location of the RAM 10.

5TEPI 8 It is determined whether the teaching work is completed. If the teaching work is not completed, the process returns to S-lower EP13, the above-mentioned 5TEP13 to 5TEP17 are processed, and when the teaching work is completed, the process advances to 5TEP19.

TEP19 When the teaching work is completed, press the teaching end button provided on the teaching pendant 5, without returning the operating device to normal control.

In this way, according to this program, by simply moving the operating tip using the teaching pendant 5 as shown in the curve ■ in Figure 3, the teaching point that satisfies the preset trajectory accuracy is automatically determined. You will be able to remember it.

Furthermore, the basic speed V input at 5TEPI 1.

If either or both of and accuracy magnification R are increased,
Since the interval between teaching points on the working trajectory of the operating tip A becomes smaller, the accuracy of the trajectory during playback can be improved.

(Effects of the Invention) As explained above, the playback robot according to the present invention automatically stores teaching data in the process of continuously performing actual playback operations during teaching work. This solves the problem of conventional teaching work that required skill and a large amount of time.Furthermore, the basic speed and accuracy multiplier set during teaching can be set arbitrarily, making it easier for the robot to operate. The accuracy of the trajectory can be set arbitrarily, which brings about excellent effects such as expanding the range of work applicable to the robot.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a playback robot according to the present invention, FIG. 2 is a flowchart of a teaching program for a playback robot according to the present invention, and FIG. 3 is a reference diagram of the effect of the program shown in FIG. Figure 4 is an external view of the condylar tract of a general playback type robot, and Figure 5 is the 4th condylar tract.
FIG. 6 is a flowchart of a teaching program for a conventional playback robot, and FIG. 7 is a reference diagram for explaining the operation of the program shown in FIG. 6. . 1... Swivel base, 2, 3... Arm, A...
Operating tip, B...base. Patent Applicant: Nissan Motor Co., Ltd. Figure 2 0: Run 1 Zuto) c ~ Decito Figure 5 Figure 6 Figure 7 R int

Claims (1)

[Claims] a driving means for driving a driven body; a control means for instructing the driving means to move the driven body; and a control means connected to the driving means to generate a pulse train proportional to the rotation angle of the driven body. a pulse generator that generates a pulse, a pulse counter that counts the number of pulses in a pulse train output from the pulse generator, a moving speed calculation means that calculates the moving speed of the driven object based on an output signal of the pulse counter, and A reference speed/accuracy storage means in which basic data for storing coordinates on the movement trajectory of the body is stored, and a storage of the coordinates based on signals from the movement speed calculation means and the reference speed/accuracy storage means. A teaching point interval calculation means for calculating the interval, and a teaching data storage means for storing data output from the pulse counter and the movement speed calculation means when a signal is output from the teaching point interval calculation means. A playback robot featuring: