JPS61231606A - Controller of robot - Google Patents

Abstract

PURPOSE:To attain acceleration/deceleration control in an optional form in an optional time without addition of a complicated external circuit by providing a pulse number display table to an arithmetic control means. CONSTITUTION:The pulse number display table 7 displaying a pulse number at each address counter No. corresponding to the speed step of a robot arm is stored in a memory of a CPU 6 in advance. When a robot arm moves from a point to another, the speed change of start acceleration full speed deceleration stop is caused. The CPU 6 compares the present pulse number counted by the counter 3 with the pulse number of a corresponding address counter displayed in the table 7, reads the speed stage of the robot arm to be in response to the actual change in the pulse number from the table 7 to output a command speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a robot control device, and particularly to a robot control device suitable for performing arbitrary acceleration/deceleration control.

[Background of the invention]

Conventional acceleration/deceleration control, that is, slow-up and slow-down control, is described in Japanese Patent Publication No. 59-32802.According to this publication, the period between each pulse of the distribution Hals whose period changes gradually is determined by a storage means for storing data in the order of transmission; an address counter for specifying the address of the storage means and reading out the inter-pulse period stored in the storage means; A pulse distribution device is described that includes a preset counter that outputs a distribution pulse when the speed has elapsed, and a control circuit that increments the address counter forward or backward using the distribution pulse output from the preset counter when the speed changes, but it is extremely complicated. In addition, in the method of controlling the period of the distribution pulse by changing the charging potential due to charging and discharging of the capacitor, the slow-up and slow-down characteristics were adjusted by the time constant of the capacitor and the charging/discharging resistor. .

The slow-up and slow-down characteristics obtained by such a method are not appropriate for the torque characteristics of the servo motor and the response characteristics of the controlled object, and there is a problem in that arbitrary acceleration and deceleration is difficult.

The speed data corresponding to the position of the controlled object is stored in the storage device inside the controller, and this speed data is read out every time the controlled object moves a predetermined amount to perform slow-up and slow-down control. Although such a method has been proposed, there is a problem in that an area for storing speed data in a constant speed state is required and a large capacity memory is required.

[Purpose of the invention]

The present invention has been made in view of the problems of the prior art described above, and can be realized without adding any particularly complicated external circuits.
To provide a robot control device that can achieve smooth operation of a robot arm by realizing acceleration/deceleration control in any form and for any time simply by providing a small amount of pulse number display table in the arithmetic control means. That is the purpose.

[Summary of the invention]

The configuration of the robot control device according to the present invention includes: a motor for controlling the position and speed of the robot arm; a means for counting the number of pulses generated by the pulse generating means;
and an arithmetic and control device that controls these, and the arithmetic and control device has the following functions in advance.

A pulse number display table containing the number of pulses for each address counter corresponding to the speed stage of the robot arm is stored, and the current number of pulses counted by the means for counting the number of pulses and the number of pulses in the pulse number display table are stored. The speed step of the robot arm that should correspond to the change in the current pulse number is read from the pulse number display table by comparing the number of pulses, and a command speed for the middle motor is output.

It should be noted that the number of pulses in the pulse number display table provided for the present invention is to be read as a number of movement pulses that is considerably larger than the movement of the robot arm when the motor is accelerated, and when the motor is decelerated, Time is read as the number of remaining pulses corresponding to the time remaining until the pot arm reaches the target position. Then, by changing it based on the total number of pulses calculation formula, which can also be called speed data to be input into the tape no. Achieving arbitrary acceleration/deceleration By using the same table for heel acceleration and deceleration, the amount of tables is halved, realizing acceleration/deceleration control with a small memory capacity4.

51. .

[Embodiments of the invention]

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 6.
I will explain.

FIG. 1 is a schematic configuration diagram of a robot control device according to an embodiment of the present invention, and FIG. 2 is a diagram showing the operation of the device shown in FIG.
i: A flowchart showing a method of referring to the pulse number display table when performing mp speed. FIG. 3 is a diagram illustrating an example of an acceleration/deceleration curve.

Referring to FIG. 1, 1 is a servo motor for controlling the position and speed of the robot arm, 2 is a rotary encoder related to the rotation of the motor (pulse generation means that outputs square wave pulses in response to A counter for counting the number of generated pulses; 4 is a servo circuit; 5 is a motor drive circuit; 6 is a CPU for an arithmetic and control unit; these form a closed loop as shown by the arrow line. The servo circuit 4 drives the servo motor 1 at a desired rotational speed to move the robot arm to a predetermined position, and therefore feeds back rotation information of the servo motor 1 using the number of pulses counted by the counter 5. However, it has a function of operating the motor drive circuit 5 based on the command speed output from the CPU 6 accordingly.

In the memory of the CPU 6, a pulse number display table 7 as shown in Table 1 is stored in advance, which displays the number of pulses for each address counter order corresponding to the speed stage of the robot arm.
to remember.

Table 1 Table 1 is an example of a pulse number display table.

That is, in this example, there are 127 speed steps until the robot arm reaches a predetermined movement speed, in other words, there are 127 speed command steps output by the CPU 6, and the corresponding number of pulses according to the rotation of the servo motor 1 is 0. ~126 of 12
This is what is displayed at each seven-level address counter.

The number of pulses displayed in the pulse number display table in Table 1 is less than or equal to the number of pulses c corresponding to the amount of movement of the robot arm when the servo motor 1 is accelerated, that is, when the robot arm movement speed is accelerated, and is referred to as the number of movement pulses) When the servo motor 1 decelerates, that is, when the robot arm [tl speed] ).

Next, the operation of the robot control device of this embodiment will be explained.

When moving the robot arm from one point to another,
The speed changes from starting to increasing speed to full speed to decelerating to stopping.

At each speed stage of the robot arm, the CPU 6 compares the current number of pulses counted by the counter 6 with the pulse number of the corresponding address counter displayed in the pulse number display table 7 in Table 1, and determines the actual pulse number. The speed step of the robot arm that should correspond to the change in the number of pulses is read from the pulse number display table 7 and the command speed is output.

The pulse number display table 7 (for example, Table 1) displays the number of movement pulses at which the speed will be increased by one step after moving this many pulses during acceleration, and is stored in the memory of the CPU 6 for 127 speed steps. .

During deceleration, the table 7 is read in the opposite direction and the speed is successively reduced, so that the same pulse number display table 7 can be used.

That is, the pulse number display table 7 as shown in Table 1
The table is read in opposite directions when the servo motor accelerates and decelerates. Now, the second method of referring to table 7 (Table 1) when the robot arm moves to the target position is as follows. The flowchart shown in Figure.

8.

The motion of moving from point to point can be broadly divided into two: acceleration and deceleration. It is divided into two by half the number of moving pulses, and the first half is considered to be acceleration and the second half is deceleration.

The robot arm first starts moving at speed stage 1. Then, read the data C pulse number of address counter floor 0 of the pulse number display table in Table 1, and when the current number of pulses counted by counter 3 moves more than the number of pulses in the pulse number display table, change the speed by 1. It only increases by stages. The address counter of the pulse number display table is N11.
Refer to the data of 1. When the current number of pulses moves more than the number of pulses of 1, the speed is increased by one step and the same operation is repeated to continue accelerating (7) When the maximum speed is reached, continue at that speed.

Then, when half of the pulses to be moved have been moved, deceleration is started.

When decelerating, when the remaining number of pulses, which corresponds to the number of pulses remaining until the robot arm reaches the target position, is smaller than the address counter data in the table being referenced, the speed is decreased by one step, and the pulse number display table is The address counter order of is also decreased by 1. Thereafter, similar operations are repeated to continue decelerating, and when the speed reaches 0, the acceleration/deceleration operation is terminated and position servo operation is performed.

By changing the contents of the pulse number display table 7, a smooth acceleration/deceleration curve such as a cycloid curve or an exponential curve can be realized, and the acceleration/deceleration time can also be easily changed.

The number of data items in the pulse number display table 7 is adjusted to the number of speed stages, and has the advantage that it can be as small as 127 items here, for example.

Next, a method of calculating the pulse number display table will be described. Now, suppose we want to realize a curve of acceleration (C, deceleration) as shown in Figure 3. 2 to servo circuit 4 Speed command stage is 7
It is assumed that there are 127 bits, that is, 127 steps. The speed is maximum. The number of pulses moving in 1 second at vO is Pma
If we set it as x, the acceleration will be ・ 11 ・ .

Therefore, in order to realize acceleration/deceleration as shown in Fig. 6, f(
t) no reverse gawo f-' (t),! -L, te, speed iv
All you have to do is issue the command at the pulse point calculated by . Therefore, velocity V=1.2. . . . up to 127, calculate the number of pulses Pv at each speed step, and store them in order in the pulse number display table.

As described above, according to this embodiment, acceleration/deceleration control in any form and at any time can be performed at low cost without adding any external circuits such as a particularly complicated pulse distribution device by using a small number of pulse display table. In addition, in the above embodiment, an example of a servo motor employing a rotary encoder was explained as a drive motor, but other motors that can be digitally controlled such as a step motor may also be used.
good.

In addition, the pulse number display table shown in Table 1, No. 12
.

In the flowchart shown in FIG. 2, an example in which the speed stage of the robot arm is 127 has been explained, but this is just an example, and it goes without saying that other speed stages can be set depending on the moving distance of the robot arm and the characteristics of the servo motor.

Furthermore, if you want to reduce the maximum speed, you can perform acceleration/deceleration to any 9 maximum speeds by multiplying all speed command values during acceleration/deceleration by a positive decimal whose absolute value is less than 1. I can do it.

〔Effect of the invention〕

- As described above, according to the present invention, the calculation and control means can be equipped with only a small number of pulse number display tables without the need for a particularly complicated external circuit.
It is possible to provide a robot arm and a robot control device that can achieve smooth operation by realizing acceleration/deceleration control in any form and for any time.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a robot control device according to an embodiment of the present invention, and FIG. m2 is a method for referring to a pulse number display table when operating the device in FIG. FIG. 6 is a diagram illustrating an example of an acceleration/deceleration curve. 1 River servo motor, 2... rotary encoder, 6...
...Counter, 4...Servo circuit, 5...Motor drive circuit%6...CPU%7...Pulse number display table.

Claims (1)

[Claims] 1. A motor for controlling the position and speed of the robot arm, a means for counting the number of pulses generated by the pulse generating means, and an arithmetic control device for controlling these; The device stores in advance a pulse number display table that displays the number of pulses for each address counter corresponding to the speed stage of the robot arm, and displays the current number of pulses counted by the means for counting the number of pulses and the number of pulses. The present invention is characterized in that the speed step of the robot arm that should correspond to the change in the current pulse number is read out from the pulse number display table by comparing the number of pulses with the number of pulses on the display table, and a command speed for the motor is output. robot control device. 2. In the device described in claim 1, the number of pulses in the pulse number display table is read as the number of movement pulses corresponding to the movement of the robot arm when the motor is accelerated; A robot control device that reads the number of pulses remaining during deceleration, which corresponds to the number of pulses remaining until the robot arm reaches its target position. 3. In either of claims 1 or 2, the pulse number display table is configured to read the table in opposite directions when the motor is accelerating and decelerating. Device.