JPH0281869A - Method for controlling servo - Google Patents

Abstract

PURPOSE:To improve the accuracy of stopping positions by changing the conveying speed of a paper medium by means of a microcomputer. CONSTITUTION:A sensor B6 is placed before the position reference sensor A7 of a sheet of paper 8, and the sheet of paper 8 is conveyed at a high speed until it reaches the paper sensor B6 while lowering the conveying speed by means of a microcomputer 1 at the time of detecting the sheet of paper 8 by the sensor B6. Then, at the time of detecting the sheet of paper 8 by the sensor A7, the value of a position counter 5 is read and the conveying speed is again returned to the high speed. A directing stopping position can be accurately calculated form the read value of the position counter 5. However, the speed of the sheet of paper 8 at the time of passing the sensor A7 is varied according to the requirement error in the dispersion of the stopping position. In other words, it is necessary to make the speed lower as the requirement error is smaller. That is, the speed may be lowered only between the sensor A7 and the sensor B6 out of a paper conveying length, thereby, improving the accuracy of stopping positions by slightly increasing the whole conveying time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a servo control system, and particularly to a servo control system suitable for performing position control using a microcomputer.

[Conventional technology]

As shown in Japanese Patent Application Laid-open Nos. 56-7108 and 57-109008, the servo motor is stopped when the preset amount of movement matches the actual amount of movement. A common method is to shift to control. However, when conveying a medium such as a bankbook, if the current position is unknown or the conveyance accuracy is not very good, it is necessary to stop the medium by the amount of movement from the reference position sensor. has not been done.

[Problem to be solved by the invention]

In the above-mentioned conventional technology, variations in the paper stop position occur due to variations in the time delay between when the microcomputer detects a change in the sensor output that determines the position of the paper while the paper is being conveyed, and when the position counter is read. This becomes a problem especially when the paper conveyance speed is high.

The aim of the invention is to eliminate the above-mentioned problems.

[Means to solve the problem]

The above purpose is to place sensor B in front of paper position reference sensor A, transport the paper at high speed until it reaches sensor B,
When sensor B detects paper, the conveyance speed is reduced. Next, when sensor A detects paper, the value of the position counter is read and the conveyance speed is returned to high speed. The desired stopping position can be accurately calculated from the read position counter value. However, the speed at which the paper passes through sensor A changes depending on the required error due to variation in the stop position.

In other words, the smaller the required error, the smaller the speed needs to be.

In the above method, it is only necessary to reduce the speed between the sensor A and the sensor B within the paper transport length, so the stopping position accuracy can be improved by slightly increasing the overall transport time.

[Effect]

The time from when the microcomputer detects a change in the output of the sensor that serves as the paper position reference to when the position counter is read is a finite value, so when the paper transport speed is high, the paper moves during this time. The distance also increases, and the accuracy with which the paper is stopped at the desired position deteriorates. Therefore, the problem can be solved by reducing the paper conveyance speed to a speed commensurate with the stopping accuracy in order to increase the stopping accuracy of the paper.

However, there is no need to reduce the speed during the entire paper conveyance process; by placing sensor B in front of the 1-position reference sensor A, and reducing the conveyance speed only while the paper moves from sensor B to sensor A, the overall conveyance speed can be reduced. Stopping accuracy can be improved by only slightly increasing the time.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

A position counter 5 receives pulses output from a rotary encoder 4 connected to a motor 3 that conveys a paper medium 8.
Count by Microcomputer 1 is.

By reading the value of the position counter 5 at regular intervals, the rotational speed of the motor is calculated, and the rotational speed of the motor is controlled through the driver 2.

The sensor 6.7 detects the paper medium 8 and the microcomputer 1
reads this.

When the microcomputer 1 reads that the paper medium 8 has been conveyed and the sensor 6 has detected this, the microcomputer 1 controls the driver 2 to reduce the rotational speed of the motor 3. If the speed at this time is a (m/s) and the time from when the sensor 7 detects the paper medium until the microcomputer 1 reads the value of the position counter 5 is t (s), the microcomputer 1 recognizes the The positional deviation between the paper medium and the sensor 7 is a
Xt (m). Although the transport speed a of the paper medium can be set to a roughly constant value, the time delay t varies in value, so it is impossible to make a uniform correction for the one positional deviation aXt. Therefore, in the present invention, the positional deviation is reduced by reducing the speed a. On the other hand, the microcomputer 1 returns the medium conveyance speed to the original speed after the paper medium reaches the sensor 7 and reads the value of the position counter. By calculating the stop position of the paper based on the reference and controlling the motor, positional deviation is reduced by axt.
(m) range. FIG. 2 shows the relationship between the position of the paper medium and the conveyance speed.

〔Effect of the invention〕

According to the present invention, the accuracy of the stop position can be improved by changing the transport speed of the paper medium using a microcomputer, so there is no need to increase hardware and it is economical6.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elliptical diagram of an embodiment of the present invention, and FIG. 2 is a diagram showing the relationship between the position of a paper medium and the conveyance speed in the embodiment. 1...Microcomputer, 2...Motor driver, 3...
motor. 4...Rotary encoder, 5...Position counter. 6-7 ・Paper detection sensor. 8...Paper medium. Figure microcomputer positive number? Concave

Claims (1)

[Claims] 1. In printer paper transport control, there is a motor that transports the paper, a rotary encoder connected to the motor shaft, a position counter that counts the number of output pulses of the rotary encoder, and a position counter that reads the value of the position counter to determine speed and position. In the servo control method, the sensor is composed of a microcomputer that calculates the amount of paper and controls the motor, a driver circuit that turns on/off the current flowing to the motor based on the motor control signal output by the microcomputer, and two sensors that detect the position of the paper. When the edge of the paper passes through A, the speed of the motor is reduced and the speed at which the edge of the paper passes through sensor B is slowed down. A servo control method characterized by shortening the distance that the paper travels in the time it takes to read the value.