JPH02292609A - Positioning controller - Google Patents

Abstract

PURPOSE:To eliminate an excess amount caused by a delay in the reception of a signal by detecting the rotational amount of a servo motor for a prescribed period and controlling a stop for a fixed position. CONSTITUTION:When a stop instruction signal ST occurs, the value of a counter 12 is stored in a buffer A in a micro computer 13. The value of the counter 12 goes up/down in accordance with the pulse signal of a pulse generator 5 in the servo motor 4 (in accordance with the rotational direction of the motor 4). A positioning controller 1 stores the value of the counter 12 in a buffer B in the micro computer 13 by the signal ST, subtracts buffer A from the buffer B, calculates the rotational amount C until the signal is received from the time when it is actually in putted, subtracts the amount C from stop target position data and controls the stop at the fixed position.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention receives a stop command signal output from a limit switch attached to a machine, and then stops a servo motor at a predetermined target position. The present invention relates to a positioning control device for positioning.

[Conventional technology]

Conventionally, such a positioning control device is equipped with a data processing means such as a microcomputer, which processes a stop command signal from a limit switch into two
The system accepts the data through sampling processing for each [body], and then starts position control to stop the servo motor at a fixed position.At this time, the signal is captured twice to remove noise, etc. Position control is started only when the two match.

[Problem to be solved by the invention]

However, there is a delay time due to sampling from when the stop command signal is actually generated until it is accepted by the microcomputer, and the servo motor is not controlled at all during this time. It ends up going too far past the desired position and stopping. This overshoot meter increases in proportion to the rotational speed of the servo motor. Therefore, if high-precision position control is required, first rotate the servo motor at a low speed and then stop it.
Additional measures such as providing an F command signal are required.

[Means to solve the problem]

A positioning system '41 device comprising a data processing means for sampling and receiving a stop signal from a limit switch, and stopping the servo motor at a predetermined target position after receiving the stop signal 1F, wherein the data processing means An external interrupt terminal is provided to input the stop 1F signal from the limit switch, and a counter that counts the number of pulses from the pulse generator attached to the servo motor inputs the stop signal and then inputs the stop signal to the data processing means. Find the rotation amount of the servo motor until it accepts this, and subtract this m from the stop "1 mark position?" to stop the servo motor.

[Effect]

City suspension order a. From the time the number j is input until the data processing means actually receives it, that is, the signal {.
The servo motor rotation V (overshoot star) from the time when the ls is input until it is accepted in the sampling process is detected by measuring the number of pulses output from the pulse generator, and the number is determined by subtracting that amount in advance. By controlling the vehicle to stop at the correct position, overshooting can be avoided.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a flowchart showing external interrupt processing, and FIG. 3 is a flowchart showing stop processing according to the invention.

In FIG. 1, 1 is the I/O boat i+. ．． A positioning control bag holder consisting of a counter 12, a microcomputer 13, a 1]/A converter 14, etc., 2 a limit switch, 3 a servo amplifier, 4 a servo motor, and 5 a pulse generator.

That is, in this embodiment, the I/O of the positioning control device 1 is
In addition to inputting the stop command signal ST to the O port 11 via the terminal T1 as before, it is also input to the external interrupt terminal T2 of the microcomputer 13. Although the I/O boat 11 only accepts inputs every fixed period jlJli, due to the sampling process of the microcomputer 13, it is capable of immediately accepting inputs from the external interrupt terminals 1 and 2.

Therefore, when the stop command signal ST is issued, it is input to the external interrupt Q terminal T2 of the microcomputer 13, and the processing shown in FIG. 2 is executed. In this process, microcomputer 1
The value of the counter 12 at this point in time is stored in the bus 8 in 3. This counter l2 constantly counts the pulse signal output from the pulse generator 5 attached to the servo motor 4, and if the servo motor 4 is rotating, the count value will be UP/DO depending on the direction of rotation.
WN. That is, the value stored in buffer 8 indicates the position of the servo motor shaft at the time when the stop command signal S'F was actually input.

Further, the positioning control device 1 receives the stop command signal ST after a delay of 1 to 2 samplings (t to 2 mm) through the /0 port 11 as before, and executes the process shown in FIG. 3. This process adds one step to the conventional process.

That is, in step ■, the bath sofa 1 in the microcomputer 13
3 stores the value of counter l2 at this point. In other words, this position indicates the position of the servo motor shaft at the time when the microcomputer 13 receives the signal after a delay of L~2] after the signal is actually input. Therefore, in step (2), (buffer [3 Hanwha A) is calculated, and FJ C of the servo motor rotated from the time when the signal is actually input until it is actually received is calculated. This amount C is the overshoot meter, and it would normally stop at step ■, but by subtracting this star C from the 1 mark position data and performing fixed position stop f1 2 control, overshoot will disappear and it will stop at the original stop position. be able to. In addition, microcomputer 13
The output from the servo amplifier 3 is sent via the D/A converter 14.
given to.

[Effect of the invention] The overshoot jdK is proportional to the number of revolutions N (rρm), but when expressed in terms of the number of pulses, in the conventional method, it is as follows.However, assuming that the number of pulses per revolution is 1000,
Let the delay time be t(:2+s).

N L/6 0<K<N L/3 0 For example, if the rotation fiN is 2000 (rpm),
67<K<133 (Pulse) Overshoot occurs.

However, according to the present invention, the overshoot caused by the delay in receiving the signal becomes irrelevant to the rotation speed, and l [pulse]
It can be:

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the invention, FIG. 2 is a flowchart showing external interrupt processing, and FIG. 3 is a flowchart showing city stop processing according to the invention. Symbol explanation ■...Positioning control device, 2...Limit switch, 3...Servo amplifier, 4...Servo motor, 5...
...Pulse generator, 1l...I/O port, l
2...Counter, l3...Microcomputer, 14...D
/A converter. 19th

Claims (1)

[Scope of Claims] 1) A positioning control device comprising data processing means for sampling and receiving a stop signal from a limit switch, and stopping a servo motor at a predetermined target position after receiving the stop signal, The data processing means is provided with an external interrupt terminal to which a stop signal from a limit switch is introduced, and a counter that counts the number of pulses from a pulse generator attached to the servo motor is used to input a stop signal. A positioning control device characterized in that the amount of rotation of the servo motor is determined until the data processing means accepts this information, and this amount is subtracted from the target stop position amount to stop the servo motor.