JPS6277096A - Pulse motor control system - Google Patents

Abstract

PURPOSE:To effectively suppress the speed vibration of a pulse motor by forming a rising curve in a curve for generating two speed vibration components of substantially reverse phase in the motor. CONSTITUTION:A ROM 12 stores a driving frequency curve. Output information of the ROM 12 is converted by a digital/analog converter 14 to an analog voltage signal, which is input to a voltage control oscillator 16 as a control voltage. The oscillating frequency of the oscillator 16 alters according to the control voltage, its output pulse is shaped to a drive pulse of 50% duty by a duty controller 18, and then applied to the motor 10. The rising curve of the driving frequency is set to a curve for generating the two speed vibration components of substantially reverse phases in the motor to effectively suppress the speed vibration of the motor.

Description

[Detailed Description of the Invention] [Field of Application in Industry-1-] The present invention relates to a control method for a pulse motor, and more specifically, to a method for suppressing vibration of a pulse motor at the time of starting the Q and stabilizing the operation. Regarding the control method.

[Prior Art] For example, in the sorting feed mechanism of an OCR (optical code reader), if the sorting can be carried out stably and at a constant speed, it takes only 1 minute, which is a certain amount of time. The variation in i[+ separation is 1
'1 volume is possible. Therefore, the feed pulse motor of the sort feed mechanism is driven by open loop control. The driving frequency of the pulse motor is set to increase at a constant slope of 1γ.

[Problem to be solved] Now, in such a conventional pulse motor control method, depending on the load characteristics of the pulse motor, the pulse motor may generate severe vibration at startup, or it may take a long time to settle the vibration. In the worst case scenario, tax adjustment for pulse motors could occur.

Generally, the design is such that such vibration problems do not occur at room temperature. However, when the ambient temperature becomes extremely low, for example to about O'C, the load f on the rotating parts becomes large, and the constant of the transmission member increases (changes), making it easy for the above-mentioned vibration problem to occur. Ta.

[Object of the Invention] An object of the present invention is to provide a new pulse motor control method that can effectively solve the vibration problem of the pulse motor.

[F stage for solving the problem] In order to achieve this object, the present invention provides a drive frequency of \r1. The curve is such that the pulse motor generates two velocity vibration components having substantially opposite phases.

[Effect: Due to the canceling effect of the speed vibration components having substantially opposite phases, the speed vibration of the pulse motor is effectively suppressed, the convergence time is significantly shortened, and the tax adjustment of the pulse motor is also prevented.

Such a drive frequency q-increase curve can be realized relatively easily as will be explained in connection with the embodiments below.

[Example 1] An example of the present invention will be described below with reference to the drawings.

FIG. 2 is a schematic block diagram of a pulse motor control system according to the present invention. In this figure, 10 is a pulse motor, for example, the pulse motor of the OCR sheet feeding mechanism as described above. 12f-! It is a ROM (read Φ only memory) and stores information on the drive frequency curve of the pulse motor 10.

The output information (digital signal) of ROM12 is digital/
It is converted into an analog voltage signal by an analog converter 14, and this analog voltage signal is inputted to a voltage controlled oscillator 16 as a control voltage. The oscillation frequency of this voltage controlled oscillator 16 changes according to its control voltage, and its output pulse is shaped into a 50% duty drive pulse by a duty control circuit 18 and then applied to the pulse motor 10.

A counter 20 is counted up by a clock pulse CLK of a constant period and reset by a reset pulse R8T. The output signal of this counter 20 is supplied to the ROM 12 as an address signal.

FIG. 1 shows each drive hJl stored in the ROM 12.
The n-curve and the speed response of the pulse motor 10 to it are each reduced. However, the time axis has been partially expanded or contracted. Hereinafter, the operation of this embodiment will be explained with reference to this figure.

After the counter 20 is reset by the reset pulse R8T, the clock pulse CLK is input and the counter 20 starts counting up, and the information of the drive frequency curve L1 shown in FIG. 1 is sequentially read from the ROM 12.
A drive pulse having a frequency corresponding to the information is supplied to the pulse motor 10.

In this example, the driving frequency curve L1 is ramped up at a constant slope to a speed of 90% of the maximum frequency Fm, then maintained at that speed for a certain period of time T1, and then again at a constant slope to the maximum speed. M is incremented by 1γ up to several Fm, and thereafter held at the highest frequency for a certain period of time.

Here, +]ij'! of the start-up curve. The pulse motor 10 generates speed vibrations as shown by the curve RLa. The period and amplitude of this vibration, as well as its attenuation, are determined by the negative 6; pulse motor 10
A tax adjustment will occur.

However, when a rising curve like Ll is used, the pulse motor 10 also generates speed vibrations like curve R1b in the latter half thereof. This velocity vibration R1b is the velocity vibration R
The period, amplitude, and 1jtif rate (these are approximately determined by the load of the pulse motor 10) are almost the same as those of 1a, but the phase is shifted by approximately 180 degrees. In other words, by appropriately selecting the time T1 etc. with respect to the vibration period (for example, a fraction of the vibration period), two such velocity vibration components of opposite phase are generated.

As a result, the two speed vibration components of opposite phases cancel each other out, and the response of the pulse motor 10 becomes like a kerf R1.
The vibration amplitude is significantly reduced, the settling time is shortened, and the voltage margin for rainproofing the pulse motor 10 is increased, making it difficult for the pulse motor 10 to occur. Comparing the case where the drive frequency is continuously increased by \y1.at a constant slope up to the highest frequency Fm, the voltage margin can be relatively easily set to several fractions of 10%.

Up to this point, the pulse motor 10 has been
I explained. Regarding the start-down of the pulse motor 10, the drive frequency curve and the response of the pulse motor 10 are as shown in FIG.

Although eleven embodiments have been described above, the present invention is not limited thereto, and can be implemented with appropriate modifications.

For example, in the embodiment described in Flif, information on the entire drive frequency curve is stored in the ROM 12, but q [;
Only the information of the rising part and the falling part is stored in the ROM 12, the highest frequency information is held separately, and the counter 20 is stored during the constant speed period.
It is also possible to stop counting up and input separately held highest frequency information to the digital/analog converter 14 during that time.

The drive frequency curve can also be modified as appropriate.

If the fi4:f characteristic of a pulse motor changes significantly depending on temperature, information on multiple drive frequency curves is stored in memory, an appropriate drive frequency curve is selected according to the ambient temperature, and the selected curve is The pulse motor may be controlled according to the information.

The driving frequency curve information may be stored in a rewritable memory such as RAM or EPROM.

Further, the present invention can be similarly applied to control of pulse motors used for purposes other than pulse motors of OCR sheet feeding mechanisms.

[Effect of the invention] Here it is! - As explained above, according to the present invention, the drive frequency start-up curve is a curve that causes the pulse motor to generate two speed vibration components with almost opposite phases, so that the speed vibration has a proper phase. Due to the canceling effect of the components, the speed vibration of the pulse motor is effectively suppressed, the convergence time is significantly shortened, and the tax adjustment of the pulse motor is also prevented.
You can achieve effects such as:

[Brief explanation of drawings]

FIG. 1 is a graph showing a drive frequency curve and the frequency response of a pulse motor in an embodiment of the present invention, and FIG. 2 is a schematic block diagram of the same embodiment. 10...Pulse motor, 12...ROM, 14...
- Digital/analog converter, 16... Voltage controlled oscillator, 20... Counter, Ll... Driving frequency curve, R1... Response curve, Rla, Rlb... Velocity vibration components of opposite phase.

Claims (2)

[Claims] (1) A pulse motor control method characterized in that the drive frequency rise curve is such that the pulse motor generates two velocity vibration components with substantially opposite phases. (2) The drive frequency is raised to a predetermined frequency lower than the highest frequency, maintained at that frequency for a predetermined time, and then raised to the highest frequency. pulse motor control method.