JPS602097A - Pulse motor control method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a control method for a pulse motor used in a type selection device of an impact printer and various other position control devices, and particularly relates to a control method for a pulse motor used in a type selection device of an impact printer and various other position control devices, and in particular, a method for constantly providing optimum reverse excitation when the motor is stopped. The present invention relates to a pulse motor control method that makes it possible to quickly and accurately stop a pulse motor at a target position by converging hunting in a short time.

BACKGROUND ART Pulse motors are widely used in various position control devices, such as type selection kW of impact printers having a type wheel, carriage drive devices of serial printers, and the like.

However, when a pulse motor is controlled in an open-loop manner, due to variations in the characteristics of the motor itself, fluctuations in drive voltage and current, and fluctuations in winding resistance due to changes in ambient temperature, etc.
Since the motor torque fluctuates and damping characteristics at stop change depending on the rotation angle, it is necessary to uniformly determine the reverse excitation timing and reverse excitation time to stop the motor at the desired target position. Therefore, it was extremely difficult to converge hunting within a certain amount of time.

Therefore, when a pulse motor is used in the type selection device of an impact printer, it becomes difficult to keep the hunting of the type wheel within the standard value within a certain period of time.
This causes inconveniences such as deterioration of print alignment and decrease in the number of prints per 7 seconds.

As one method for solving this problem, closed loop control is known in which feedback pulses are generated in accordance with the rotation of the pulse motor and these pulses are monitored.

FIG. 1 is a schematic side view showing the structure of a pulse motor equipped with feedback pulse generating means for performing closed loop control. In the drawings, / is a pulse motor, Y is its rotating shaft, 3 is an encoder, 3A is its disk, and 3B is a photo ink club.

The disk 3A coupled to the rotating shirt l-, 2 of the pulse motor has slits arranged on the circumference, and when light from the light emitting element of the photointerrupter 3B passes through the slit, the light is received. The device enters the device and an electrical pulse is generated.

In conventional closed-loop control, the seventh excitation phase switching pulse is generated to rotate the pulse motor, and after detecting the feedback pulse generated by one revolution, the seventh excitation phase switching pulse is generated. A method is used in which the rotation of the pulse motor is constantly monitored using feedback pulses.

But even with such closed-loop control.

Due to the influence of pulse motor torque fluctuations, tamping characteristics fluctuations, etc., the timing of reverse excitation may not always be optimal.
However, it is difficult to converge the hunting within a certain period of time.

Purpose Therefore, the pulse motor control method of the present invention solves these inconveniences in the conventional closed loop control method, and
To quickly and accurately stop a motor at a desired target position by constantly applying optimal reverse excitation in response to fluctuations in motor torque, damping characteristics, etc., thereby converging hunting in a short time. With the goal.

Configuration To achieve this, the pulse motor control method of the present invention includes means for generating feedback pulses in accordance with the rotation of the pulse motor, and drive control means for starting, accelerating and decelerating the pulse motor, and reverse-exciting and stopping the pulse motor immediately before stopping. 1. A pulse motor control device according to the present invention includes a memory means in which reverse excitation timing and reverse excitation time for each rotation angle of the pulse motor are stored in advance; A measuring means for measuring the pulse width of at least seven feedback pulses at the time of starting, and a correcting means for correcting the contents of the memory means based on the measurement results, and immediately before stopping the pulse motor, after detecting the last feedback pulse. , the corrected contents are read out and reverse excitation is performed.

Next, an embodiment of the pulse motor control method of the present invention will be described with reference to the drawings.

FIG. 1 is a functional block diagram showing a configuration example of a pulse motor control device used when implementing the pulse motor control method of the present invention. The symbols in the drawings are the same as in Fig. 1, and Hiroshi indicates FBP (feedback pulse).
1 is the generator, 1 is the position error counter, 2 is the FBP pulse width measurement circuit at startup, 7 is the rotation direction/pulse number/reverse excitation command circuit, g is the reverse excitation timing correction circuit, 1 is the memory, 1
0 indicates a pulse generation circuit, // indicates a driver, /, 2 indicates a load.

The circuit shown in Fig. 2 consists of a startup FBP pulse width measurement circuit (B), a reverse excitation timing correction circuit (g), and a memo (IJ?). It is basically the same as the conventional control device except that

The memory 9 contains information about the motor with standard torque.
Reverse excitation timing for each rotation angle 1. and reverse excitation time t
2 is stored in advance, and the pulse width t of the feedback pulse at startup when the torque is also standard
o is also memorized.

The startup FBP pulse width measurement circuit g is a measuring means that measures the pulse width of at least one feedback pulse when the motor is started.

The reverse excitation timing correction circuit g uses the pulse width measurement result by the pulse width measurement circuit g and the pulse width t stored in the memorizo. and based on the comparison results, the reverse excitation timing 1. for each motor rotation angle stored in the memory 9 is determined. and correct the reverse excitation time t2. and,
The correction results are stored again in the memory 9, for example.

FIG. 3 is a time chart showing the relationship between each pulse at the time of starting the pulse motor. t in the drawing indicates the pulse width of the seven feedback pulses at startup.

The time chart in FIG. 3 is the same as in the case of the conventional closed loop control system.

The following FIG. 7 is a time chart showing the relationship between each pulse at the time of deceleration and stop using the pulse motor control method of the present invention. tI in the drawing is the corrected reverse excitation timing, t2'
indicates the similarly corrected reverse excitation time m.

Further, FIG. 5 is a flowchart explaining the control operation in the pulse motor control method of the present invention, and FIG.
4 is a flowchart illustrating a reverse excitation timing correcting operation in the pulse motor control system of the present invention, which is a detailed development of a part of FIG. 3; FIG.

The operation of the pulse motor control system of the present invention is as shown in the flowchart of FIG. 5. When the motor starts rotating, lζ, as shown in detail in the flow of FIG.
The pulse width of the feedback pulse generated at startup is measured by the startup pulse width measurement circuit B shown in FIG. In comparison, the reverse excitation timing for each rotation angle stored in the memory 9 in advance is 1. is changed to N, and reverse excitation time t2 is corrected to tI by 111. The corrected reverse excitation timing curve and reverse excitation time 12' are stored again in the memory t.

With this operation, the correction of the reverse excitation timing shown in FIG. 6 is completed.

Thereafter, the pulse motor is controlled by the flow shown in FIG. This flow is similar to that of conventional closed loop control.

At the time of stopping, as shown in FIG. 7, after detecting the final feedback pulse, the corrected reverse excitation timing N and reverse excitation time 1; t5 are read out from the memory 9, and reverse excitation is performed.

That is, after a time tI from the rise of the final feedback pulse in FIG. 7, the phase immediately before the last excited phase is reversely excited for the time tl.

In addition, in the above embodiment, the case was explained in which only seven pulse widths were measured for the feedback pulse at startup, but two or more pulses were each measured, and the average value was calculated as follows: By correcting the reverse excitation timing t1 and the reverse excitation time t2, it becomes possible to perform more accurate correction.

Also, in the case of standard torque, reverse excitation for each rotation angle of the motor - timing 1. And the reverse excitation time is 12% and the pulse width t0 of the feedback pulse is.

The reverse excitation timing, timing B, and reverse excitation time tI for each rotation angle are stored in the memory 9 in FIG. We have explained the case where

However, the reverse excitation timing t in the case of standard torque,
Since the reverse excitation time hJ and the pulse width to of the feedback pulse are determined at the time of manufacture, these data are stored in advance in the fixed storage means of %ROM%, and the reverse excitation timing i for each corrected rotation angle is determined. Is it possible to store / and rBJt2' during reverse excitation in a storage means such as RAM and read it out when stopped? You can also strain it. In other words, when setting the rotation direction and number of pulses to the rotation direction/pulse number/reverse excitation command circuit 7 in Fig. 2 by command from the CPU, etc., the reverse excitation timing for each rotation angle in the case of standard torque t
, the reverse excitation time t2, and the feedback pulse pulse width joG memory 9 are set, and the pulse width t at startup is set.
It is also possible to make corrections corresponding to the above and rewrite the contents set in the memorizo into reverse excitation timing B and reverse excitation time tI for each rotation angle.

The following FIG. 7 is a circuit diagram showing an example of the configuration of a driver used in a constant voltage, constant current and power type of a phase pulse motor. In the drawing, / is a single pulse generator, LA to LD are its excitation coils, φA to φD are phase excitation signals, Q/ to Q4 are transistors, U/ and U, 2 are, for example, FT37A; 3M
Type-like IC, U3 is for example HA/7'l! rg type operational amplifier, Ug-US is an operational amplifier such as HA/7de03 type, U4 and U7 are inverters, Ug-U/
/ indicates an amplifier.

Moreover, FIG. 3 shows the circuit configuration of the IC shown in FIG. /~/Y in the drawings are terminal numbers.

This third figure shows FT! ;7 On the left is a circuit example of a 3M type IC,
A Darlington transistor array is shown.

As explained in detail above, the pulse motor fttll bias type of the present invention includes a means for generating feedback pulses according to the rotation of the pulse motor, and a means for starting, accelerating and decelerating the pulse motor, and back-exciting the pulse motor immediately before stopping. In the pulse motor control device, the pulse motor control device includes a memory means in which reverse excitation timing and reverse excitation time are stored in advance for each rotation angle of the pulse motor, and at least seven feedback pulses at the time of startup. A measuring means for measuring the width and a correcting means for correcting the contents of the memory means based on the measurement results are provided, and immediately before the pulse motor stops, after detecting the final feedback pulse, the corrected contents are read out and reverse excitation is performed. I try to do that.

Effects Therefore, depending on the pulse motor control method of the present invention, fluctuations in drive voltage/current and temperature of winding resistance, fluctuations in torque due to fluctuations in the characteristics of the motor itself, fluctuations in damping characteristics due to differences in rotation angle, etc. Accordingly, it is possible to always perform optimum reverse excitation, and one inch can be converged in a short time, and the motor can be quickly and accurately stopped at the target position.

Therefore, if the present invention is applied to a character selection device of an impact printer, for example, it becomes possible to obtain a print with good character alignment without reducing the printing speed.

[Brief explanation of drawings]

Fig. 1 is a schematic side view showing the structure of a pulse motor equipped with feed pulse generation means for closed loop control, and Fig. 2 is a pulse motor control used when implementing the pulse motor control method of the present invention. FIG. 3 is a time chart showing the relationship between each pulse when starting the pulse motor; FIG. FIG. 6 is a flowchart explaining the control operation in the pulse motor control method of the present invention, and FIG. 7th flowchart explaining the corrective operation of
The figure is a circuit diagram showing an example of the configuration of a driver used in a constant-voltage, constant-current drive system for a gray-phase pulse motor, and FIG. 3 is an example of the circuit of the IC shown in FIG. 7. In the drawing, / is the pulse motor, 3 is the encoder, Da is the FBP generator, left is the position error counter, O is the startup FBP pulse width measurement circuit, 7 is the rotation direction, pulse number, reverse excitation command circuit, and the opposite side. Excitation timing correction circuit, wo is memory, 10 is pulse generation circuit, // is driver, /2
indicates load. Patent applicant Ricoh Co., Ltd. - ;+ 1 Figure piece 2 Figure 3 Figure square 4 Figure O 5 Figure 6 Figure O 8 Figure

Claims (1)

[Claims] In a pulse motor control device equipped with means for generating feedback pulses according to the rotation of the pulse motor, and drive control means for starting, accelerating and decelerating the pulse motor, and reverse excitation to stop the pulse motor just before stopping, a memory means in which a reverse excitation timing and a reverse excitation time are stored in advance; a measuring means for measuring the pulse width of at least one feedback pulse at startup; and a correcting means for correcting the contents of the memory means based on the measurement result. 1. A pulse motor control method, comprising: detecting the final feedback pulse immediately before stopping the pulse motor, reading out the corrected content, and performing reverse excitation.