JPH08182364A - Position controller for microminiature motor - Google Patents

Abstract

PURPOSE: To accurately control the position of a microminiature motor based on single-phase pulse signals. CONSTITUTION: A position controller for microminiature motor is provided with a rotary encoder 13 which generates single-phase pulse signals, arithmetic section 14 which performs addition on pulses when a forward rotation command signal is given or subtraction on the pulses when a backward rotation command is given, signal switching means 21 which switches the rotation command signals to the backward rotation command signal when the count value of the arithmetic section 14 becomes equal to or larger than a set value or to the forward rotation command signal when the count value is smaller than the set value, and stop signal generating section 22 which outputs a stop command signal for a set period of time at the time of switching the rotation command signals. The arithmetic section 14 is constituted so that the section 14 can maintain the counting direction in the same direction while the stop command signal is outputted at the time of switching the rotation command signals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position control of a microminiature motor having an improved structure for detecting the rotational speed and the direction of rotation of the microminiature motor when controlling the microminiature motor to rotate normally or reversely. Regarding the device.

[0002]

2. Description of the Related Art Conventionally, when performing control for rotating a motor in a normal or reverse direction, a rotary encoder which generates a pulse according to the rotation of a rotary shaft of the motor is provided, and the motor is driven based on a pulse signal from the rotary encoder. The rotation number and the rotation direction are detected, and the motor is energized and controlled according to the detection result. An example of the rotary encoder is shown in FIGS. 4 and 5. In FIGS. 4 and 5, a disk-shaped permanent magnet 3 having two poles is attached to one end of the rotary shaft 2 of the motor 1. Two Hall elements 4 and 5 are arranged at the fixed portion on the outer peripheral side of the permanent magnet 3 so as to face the outer peripheral portion of the permanent magnet 3. These two Hall elements 4 and 5 are
The phases are arranged so as to be shifted by 90 degrees. The Hall elements 4 and 5 and the permanent magnet 3 constitute a magnetic rotary encoder 6.

In this structure, when the rotary shaft 2 of the motor 1 rotates, the permanent magnet 3 rotates, and the N pole and the S pole of the permanent magnet 3 alternately approach and separate from the Hall elements 4 and 5, respectively. As a result, the Hall elements 4 and 5 are connected to the permanent magnet 3
The detection signal that detects the magnetic pole of is output. These detection signals are sinusoidal signals that periodically change in synchronism with the rotation of the permanent magnet 3. When these sinusoidal signals are formed into a rectangular wave by a waveform shaping circuit, the waveform shown in FIG. The two-phase pulse signals A and B as shown in FIG.

In this case, the two-phase pulse signals A and B have a waveform as shown in FIG. 6 (a) when the motor 1 rotates in the normal direction and a waveform as shown in FIG. 6 (b) when the motor 1 rotates in the reverse direction. Is configured to be. Here, since the phase relationship between the pulse signals A and B is different between FIG. 6A and FIG. 6B, the rotation direction of the motor 1 can be detected by detecting the phase relationship between the pulse signals A and B. Of. Then, by counting (counting up or counting down) the pulses of the pulse signals A and B, the motor 1
It is configured to be able to detect the rotation speed of.

[0005]

In the above conventional configuration, the Hall elements 4 and 5 of the rotary encoder 6 are arranged on the outer peripheral side of the permanent magnet 3, that is, the Hall elements 4 and 5 are arranged in the radial direction of the motor 1. Therefore, the radial size of the motor 1 must be large to some extent. On the other hand, in recent years, microminiature motors (so-called millimeter size miniature motors) having a radial dimension of about 3 to 5 mm have been produced. Even if the magnetic rotary encoder is mounted in order to detect the rotation speed and the rotation direction of such a micro motor, since the radial size of the micro motor is too small, the magnetic rotary encoder is mounted. I couldn't.

Therefore, the inventor of the present invention has considered a rotary encoder having a structure that can be mounted in the axial direction of a microminiature motor. This rotary encoder is an optical rotary encoder including an optical sensor, and the optical sensor is arranged in the axial direction of the motor. Specifically, the rotary encoder is a disc having a large number of slits formed on the peripheral edge thereof, which is attached to a rotary shaft of a motor, and
The optical sensor irradiates the peripheral portion of the disk with light and receives the reflected light. In the case of this configuration, since the intensity of the reflected light is different between the slit portion and the other portion of the disc, the optical sensor generates a pulse signal according to the rotation of the motor.

However, in an optical rotary encoder, if an attempt is made to output two-phase pulse signals A and B, a considerably complicated structure is required as compared with the magnetic type encoder. This is not possible with a configuration that can be arranged in the axial direction of a small motor. Therefore, the optical rotary encoder mounted on the microminiature motor has to be configured to generate only a single-phase pulse signal. However, since the rotation direction of the motor cannot be known only by the single-phase pulse signal, the position of the motor cannot be accurately controlled.

On the other hand, the inventor of the present invention, when the normal rotation command for normal rotation of the motor is issued from the control circuit,
A configuration is considered in which the pulse of the single-phase pulse signal is counted up and the pulse of the single-phase pulse signal is counted down when a reverse rotation command for rotating the motor in reverse is issued. According to this structure, the position of the motor can be controlled without knowing the rotation direction of the motor. However, in the above configuration, when the operation of continuously rotating the motor in the forward and reverse directions is continuously repeated, the motor may rotate in the normal rotation direction due to inertia even if the normal rotation command is switched to the reverse rotation command. Yes, this also occurs when switching the reverse command. For this reason, in the above configuration, there is a high possibility that an error will be included in the pulse count value at the time of switching the command, so that it cannot be actually used.

Therefore, an object of the present invention is to provide a microminiature motor capable of accurately controlling the position of the motor on the basis of the single-phase pulse signal in a configuration for generating a single-phase pulse signal in response to the rotation of the microminiature motor. To provide a position control device.

[0010]

A position control device for a microminiature motor according to the present invention comprises a drive circuit for rotationally driving the microminiature motor, and a pulse generating means for generating a pulse according to the rotation of the microminiature motor. A pulse signal from the pulse generating means is added when a forward rotation command signal for rotating the microminiature motor in the normal direction is given, and a reverse rotation command signal for reversing the microminiature motor is given. Pulse counting means for counting the pulse from the pulse generating means so that the pulse value from the pulse generating means is subtracted, and when the count value of the pulse counting means matches or exceeds the set value, the reverse rotation command signal is output from the forward rotation command signal. Signal switching means for switching so as to output a forward rotation command signal from the reverse rotation command signal when the count value matches or falls below the initial value. And a stop signal generating means for outputting a stop command signal for stopping the microminiature motor for a set time when the signal is switched by the signal switching means, and the pulse counting means is a forward rotation command signal or a reverse rotation command signal. It is characterized in that the pulse counting direction is maintained in the same direction as before until the stop command signal is output from the stop signal generating means even when is switched.

In the case of the above structure, it is preferable that the pulse generating means is composed of an optical rotary encoder having an optical sensor. Further, the pulse generating means may be composed of a magnetic rotary encoder including a permanent magnet and a magnetic sensor. Further, it is preferable that the stop signal generating means is configured so that the set time for outputting the stop command signal can be changed.

Furthermore, it is also preferable that the signal switching means is constructed so that the set value can be changed. In this case, it is preferable that the setting value of the signal switching unit is stored in the storage unit that retains the stored contents even when the power is turned off. Further, it is preferable that the microminiature motor is composed of a brushless motor. Further, it is conceivable to provide the motor stop means for holding the stopped state of the microminiature motor.

[0013]

According to the above means, even when the rotation command signal is switched from the forward rotation command signal to the reverse rotation command signal or vice versa, during the set time during which the stop command generation means outputs the stop command signal. The pulse count direction is kept in the same direction as before. As a result, in the case where the operation of continuously rotating the motor in the forward and reverse directions is continuously performed, even if the motor may rotate in the direction up to then due to inertia when the rotation command is switched, Since the pulse count direction is maintained in the same direction as before until is stopped, the pulse count value does not include an error when the rotation command is switched. Therefore, even in a configuration in which a single-phase pulse signal is generated according to the rotation of the microminiature motor, the position of the motor can be accurately controlled based on the single-phase pulse signal.

Further, if the set time for outputting the stop command signal is made variable in the stop signal generating means, various motors having different times until stopping can be controlled by the same structure by changing the set time. It is possible. Further, if the set value is variable in the signal switching means, the operation time for rotating the motor in the forward and reverse directions can be set to a desired time. In this case, if the setting value changed by the signal switching means is stored in the storage means that retains the stored contents even when the power is turned off,
It is not necessary to reset the setting value when the power is turned on again after the power is turned off. If the motor stop means (for example, an electromagnetic brake or a mechanical brake) that holds the stopped state of the microminiature motor is provided, the motor can be used for stopping the motor midway.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. First, FIG. 1 shows an electrical configuration of a position control device for a micro motor by combining functional blocks. In FIG. 1, the microminiature motor 11 is composed of, for example, a DC brushless motor, and has a substantially cylindrical shape. The radial size of the micro motor 11 is about 2 to 5 mm. The right end of the rotary shaft (output shaft) 12 of the microminiature motor 11 is projected rightward from the right end of the microminiature motor 11.

At the right end of the rotary shaft 12, there is provided, for example, a rotary encoder 13 which is a pulse generating means. The rotary encoder 13 is composed of an optical rotary encoder including an optical sensor (not shown), and the optical sensor is arranged in the axial direction of the motor 11. Specifically, the rotary encoder 13 is a disc (not shown) attached to the rotary shaft 12 of the motor 11 and having a number of slits formed on the peripheral edge thereof, and the disc provided at a fixed portion in the axial direction. And a reflection type optical sensor that receives the reflected light. In this case, since the intensity of the reflected light is different between the slit portion of the disk and the other portion, the optical sensor outputs a pulse signal according to the rotation of the motor 11,
In this case, a single-phase pulse signal is generated. It is preferable that the light from the light emitting element of the optical sensor is applied to the disc through the optical fiber and the reflected light reflected by the disc is received by the light receiving element of the optical sensor through the optical fiber. If this optical fiber is used, the rotary encoder 13
The configuration of can be further simplified.

The pulse signal output from the rotary encoder 13 is applied to the pulse counting means, for example, the arithmetic section 14. The calculator 14 counts up (adds) the pulses from the rotary encoder 13 when a forward rotation command signal for rotating the microminiature motor 11 in the normal direction is given, and reverses the microminiature motor 11. It is configured to count down (subtract) the pulse from the rotary encoder 13 when the reverse rotation command signal is given. Further, the arithmetic unit 14 is configured to reset (clear to zero) the count value when a reset signal is given from the reset switch 15.

Then, the arithmetic unit 14 is configured to output a count value signal indicating the count value and to provide it to the first comparator 16 and the second comparator 17. First
The comparator 16 of the
In response to a signal indicating the set value from the set value holding unit 18 that stores and holds the set value, a high level signal is issued when the count value matches or exceeds the set value, and a low level signal is issued to the motor inversion command when the count value is not. It is configured to output to the unit 19. In addition, the second comparator 17 includes an arithmetic unit 14
When the count value is equal to or lower than the set value, the high level signal, If it is not, a low level signal is output to the motor reversal command unit 19.
The set value holding unit 18 receives the count value signal from the calculation unit 14 as described later in detail, and
By receiving a setting signal from the outside, the set value to be stored can be changed.

Further, the motor reversal command section 19 is a signal for commanding the rotation direction of the microminiature motor 11 based on the signals from the first and second comparators 16 and 17, that is, a forward rotation command signal or a reverse rotation command. It has a function of outputting a signal.
Specifically, the motor reversal command unit 19 receives the high level signal from the first comparator 16 in this state, assuming that the normal rotation command signal (specifically, the high level signal) is first output. When the count value coincides with the set value, the reverse rotation command signal (specifically, low level signal) is switched and output at that time (signal switching time). Further, when the motor inversion command unit 19 receives a high level signal from the second comparator 17 while outputting the reverse rotation command signal, that is, when the count value matches the initial value, the time (signal It is configured to switch and output the forward rotation command signal at the time of switching. The command signal output from the motor reversal command unit 19 is shown in FIG.
In this case, the motor reversal command unit 19, the first comparator 16,
The second comparator 17, the set value holding unit 18, and the initial value holding unit 20 constitute a signal switching unit 21.

The normal rotation or reverse rotation command signal output from the motor reversal command unit 19 is provided to the stop signal generation unit 22 and the count direction command unit 23. The stop signal generating unit 22 constitutes a stop signal generating means, and as shown in FIGS. 2A and 2B, the normal rotation command signal from the motor reversal command unit 19 is switched to the reverse rotation command signal. Or when the reverse rotation command signal is switched to the forward rotation command signal (when switching each signal), the stop command signal (specifically, a high level signal) for stopping the microminiature motor 11 is set for a set time. It is configured to output only t1. The stop command signal output from the stop signal generation unit 22 is provided to the count direction command unit 23 and the motor drive circuit 24.

Further, the count direction command section 23 receives a forward rotation or reverse rotation command signal from the motor reversal command section 19,
In response to the stop command signal from the stop signal generator 22, the count direction signal is output as shown in FIG. 2 (c). Specifically, the count direction command unit 23 outputs a normal rotation direction signal (high level signal) when the normal rotation command signal is received from the motor reversal command unit 19, and the normal rotation command signal becomes a reverse rotation command signal. Even if you switch
While receiving the stop command signal from the stop signal generator 22, the forward rotation direction signal (high level signal) is continuously output. Then, the count direction command unit 23 outputs a reverse rotation direction signal (low level signal) at the time when the stop direction signal is not received from the stop signal generation unit 22.

Further, the count direction command unit 23 outputs a reverse rotation direction signal (low level signal) while receiving the reverse rotation command signal from the motor reverse command unit 19, and the reverse rotation command signal is switched to the normal rotation command signal. Also, the stop signal creation unit 22
The reverse rotation direction signal (low level signal) is continuously output while the stop command signal is received from. Then, when the count direction command unit 23 stops receiving the stop command signal from the stop signal generation unit 22, the normal direction signal (high level signal)
Is output. Hereinafter, the count direction command unit 23 is configured to repeatedly execute the same operation as the above-described operation. Further, the forward rotation or reverse rotation direction signal output from the count direction command unit 23 is given to the calculation unit 14 and at the same time the motor drive circuit 24 via the changeover switch 25.
It is given to.

Here, the arithmetic unit 14 adds (counts up) the pulse when it receives the forward direction signal from the count direction command unit 23, and subtracts the pulse (when it receives the reverse direction signal). Countdown) is configured to count. In addition, the changeover switch 25
Is a switch that is switched by the user, and when the contact (c-a) is on, an off signal for turning off the motor 11 is given to the motor drive circuit 24. Then, when the contact (c-b) of the changeover switch 25 is on, an on signal for turning on the motor 11 (for example, energizing in the forward direction) is given to the motor drive circuit 24. Furthermore, when the contact points (cd) of the changeover switch 25 are on, the forward rotation or reverse rotation direction signal output from the count direction command unit 23 is given to the motor drive circuit 24.

Further, the motor drive circuit 24 receives the stop signal from the stop signal generator 22 when the contact between the contacts (c-a) of the changeover switch 25 is turned on and the off signal is received. 11 is turned off and stopped. The motor drive circuit 24 is configured to energize (turn on) the motor 11 to rotate it in the forward direction when the contact (c-b) of the changeover switch 25 is turned on and receives an on signal. ing. Further, the motor drive circuit 24 energizes the motor 11 when the forward direction signal is received from the count direction command unit 23 in a state where the contacts (cd) of the changeover switch 25 are turned on, and the forward direction is turned on. On the other hand, when the reverse rotation direction signal is received from the count direction command unit 23, the motor 11 is energized to rotate in the reverse rotation direction.

Next, the operation of the above configuration will be described with reference to FIG. The flow chart of FIG. 3 schematically shows the contents of control (operation) of the position control device for the micro motor 11 described above. First, the case of performing the process of setting the set value of the set value holding unit 18 will be described. in this case,
As shown in FIG. 3, when the reset switch 15 is first operated, the process proceeds to “YES” in step S1 and the calculation unit 1
The count value of 4 is reset (step S2). Then, when an operation of turning on the contacts (c-b) of the changeover switch 25 is performed, the process proceeds to “YES” at step S3, and the microminiature motor 11 is turned on to rotate in the forward rotation direction (step S4). ), The count-up operation of the calculation unit 14 is started (step S5).

Then, after this, when the operating time desired by the user has elapsed (that is, when the microminiature motor 11 has rotated by the desired rotational speed), the contact points (c-a) of the changeover switch 25 are changed. When you turn it on, step S
In step 6, the process proceeds to "YES" to turn off the microminiature motor 11 to stop it (step S7), and stop the count-up operation of the arithmetic unit 14 (step S8). Subsequently, when the user operates a setting switch (not shown) to give a setting signal to the set value holding unit 18, the process proceeds to “YES” in step S9, and the set value holding unit 18 causes the set value holding unit 18 to calculate the count value. Upon receiving the signal, the count value counted by the calculation unit 14 is stored and held as a set value (step S10). Thus, the set value held in the set value holding unit 18 can be changed to a desired value by appropriately changing the time when the microminiature motor 11 is turned off, in other words, the time when the contact between the contacts (ca) of the changeover switch 25 is turned on. It has a configuration that can be set to a value.

Next, a case will be described in which the operation of rotating the microminiature motor 11 in the normal direction and the operation of rotating it in the reverse direction are alternately repeated. In this case, if the user performs an operation of turning on the contacts (cd) of the changeover switch 25 without operating the reset switch 15, the process proceeds to “NO” in step S1 and “YE” in step S11.
S "to execute the forward / reverse continuous operation (step S
12).

Here, first, the operation of reversing the micro motor 11 is performed. Specifically, at first, since the count value of the calculation unit 14 and the set value of the set value holding unit 18 match, a high level signal is given from the first comparator 16 to the motor inversion command unit 19. There is. Then, a reverse rotation instruction signal is given from the motor reverse instruction portion 19 to the count direction instruction portion 23, and further, a reverse rotation direction signal is given from the count direction instruction portion 23 to the motor drive circuit 24 and the calculation portion 14. . Therefore, when the contact points (c-d) of the changeover switch 25 are turned on, the micro drive motor 24 is turned on by the motor drive circuit 24 to be rotationally driven in the reverse rotation direction, and the calculation unit 14 starts the countdown operation. .

After that, when the count value of the arithmetic unit 14 reaches the initial value (zero), the count value of the arithmetic unit 14 and the set value of the initial value holding unit 20 match, so that the second comparator A high-level signal is given from 17 to the motor reversal command unit 19. As a result, the motor reversal command unit 19 switches from the reverse rotation command signal to the normal rotation command signal and gives the normal rotation command signal to the count direction command unit 23 and the stop signal generation unit 22. Then, when the reverse rotation command signal is switched to the normal rotation command signal (during signal switching), the stop signal generation unit 22 counts the stop command signal for stopping the microminiature motor 11 for the set time t1. And to the motor drive circuit 24.

As a result, while the motor drive circuit 24 is receiving the stop command signal (set time t1), the microminiature motor 1
Turn off (cut off) 1 and stop. At the same time, the count direction command unit 23 continues to output the reverse direction signal to the calculation unit 14 while receiving the stop command signal (setting time t1). As a result, the arithmetic unit 14 holds the pulse counting direction in the direction up to then (countdown direction in this case) during the set time t1.

After that, when the set time t1 elapses,
Since the stop signal generation unit 22 stops outputting the stop command signal, the count direction command unit 23 switches from the reverse rotation direction signal to the normal rotation direction signal and outputs it. As a result, the motor drive circuit 24 turns on (energizes) the microminiature motor 11 to rotate it in the forward direction. At the same time, the arithmetic unit 14 switches the counting direction of the pulse to the counting up direction, and thereafter performs the counting up operation. As a result, the operation of rotating the microminiature motor 11 in the normal direction is performed.

After that, when the count value of the arithmetic unit 14 reaches the set value, the count value of the arithmetic unit 14 and the set value of the set value holding unit 18 match, so that the first comparator 1
A high level signal from 6 is given to the motor reversal command unit 19. As a result, the motor reversal command unit 19 switches from the normal rotation command signal to the reverse rotation command signal, and gives the reverse rotation command signal to the count direction command unit 23 and the stop signal generation unit 22. Then, when the forward rotation command signal is switched to the reverse rotation command signal (during signal switching), the stop signal generation unit 22 counts the stop command signal for stopping the microminiature motor 11 for the set time t1. And to the motor drive circuit 24.

As a result, the motor drive circuit 24 receives the stop command signal (set time t1) and the microminiature motor 1
Turn off 1 and stop. At the same time, the count direction command unit 23 receives the stop command signal (set time t
1) The normal rotation direction signal is continuously output to the calculation unit 14. As a result, the arithmetic unit 14 holds the pulse counting direction in the direction up to then (count-up direction in this case) during the set time t1.

After that, when the set time t1 elapses,
Since the stop signal generation unit 22 does not output the stop command signal, the count direction command unit 23 switches from the normal rotation direction signal to the reverse rotation direction signal and outputs it. As a result, the motor drive circuit 24 turns on the micro motor 11 to rotate it in the reverse direction. At the same time, the arithmetic unit 14 switches the pulse count direction to the countdown direction, and thereafter performs the countdown operation. As a result, the micro motor 11
The operation to reverse is performed. Below, the micro motor 11
The normal rotation operation and the reverse rotation operation are alternately and continuously repeated (see FIG. 2 (e)).

When the continuous operation is stopped, an operation of turning on the contact (ca) of the changeover switch 25 is performed.
Then, in step S13, the process proceeds to “YES”, the motor drive circuit 24 turns off (cuts off the electric power) the microminiature motor 11 and stops it (step S14), and the arithmetic unit 14 stops the counting operation (step S15). .

According to this embodiment having such a configuration, even when the rotation command signal is switched from the forward rotation command signal to the reverse rotation command signal or vice versa, the stop signal generation unit 22 outputs the stop command signal. During the set time t1, the pulse counting direction of the arithmetic unit 14 is kept in the same direction as before, so that the operation of rotating the microminiature motor 11 in the forward and reverse directions is continuously repeated. In this case, even if the microminiature motor 11 rotates in the previous direction due to inertia when the rotation command is switched, until the microminiature motor 11 stops, the counting direction of the pulse is until then. Will be held in the same direction as. Therefore, when the rotation command is switched, the count value of the pulse of the calculation unit 14 does not include an error. Therefore, the microminiature motor 1
In the configuration using the rotary encoder 13 that generates a single-phase pulse signal in response to one rotation, the position of the microminiature motor 11 can be accurately controlled based on the single-phase pulse signal.

Further, in the above embodiment, the set value holding unit 18
Since the setting value is variable in the above, it is possible to set each operation time for rotating the microminiature motor 11 in the normal rotation and the reverse rotation to a desired time. In this case, the configuration for changing the set value is not limited to the above-described embodiment, and for example, a configuration such as a dip switch for changing the set value may be provided.

A backup power source may be provided so that the set value stored in the set value holding section 18 can be stored and held even when the power is turned off. In this case, it is not necessary to reset the set value when the power is turned on again after the power is turned off, and the usability is improved. In the above-mentioned configuration, the backup power supply and the set value holding unit 18 constitute a storage unit that holds the stored contents even when the power is turned off. Further, instead of the backup power source, a non-volatile memory (for example, EEPROM or the like) may be used. Furthermore, if the backup power supply is used to store the count value of the calculation unit 14 even when the power supply is turned off, the position control and maintenance of the microminiature motor 11 can be performed more easily.

On the other hand, the stop signal generating section 22 may be configured so that the set time t1 for outputting the stop command signal can be varied. With such a configuration, it is possible for various motors with different time until stop. It is possible to control operation with the same configuration by changing the set time. It is also preferable that an electromagnetic brake, a mechanical brake, or the like is provided as the motor stopping means for holding the stopped state of the microminiature motor 11. Further, in the case of this configuration, when the motor is stopped, the motor does not rotate due to an external force, and therefore, it can be used for a purpose of stopping the motor on the way.

In the above embodiment, the rotary encoder 13 is composed of an optical rotary encoder.
Instead of this, a magnetic rotary encoder including a permanent magnet and a magnetic sensor may be used. Also in the case of this configuration, it is possible to obtain substantially the same operational effects as those of the above embodiment.

[0041]

As is apparent from the above description, the present invention generates a single-phase pulse signal according to the rotation of a microminiature motor, and controls the motor position based on the single-phase pulse signal. In this configuration, even when the forward rotation command signal or the reverse rotation command signal is switched, the pulse counting direction is maintained in the same direction as before during the set time during which the stop command generating unit outputs the stop command signal. Since the configuration is adopted, even if the operation of continuously rotating the motor in the forward direction and the reverse direction is continuously repeated, the pulse count value of the pulse counting means does not include an error when the rotation command is switched, and a single-phase pulse signal is generated. It has an excellent effect that it can be controlled accurately based on the above.

Further, since the set time for outputting the stop command signal is variable in the stop signal generating means, the same structure can be controlled by changing the set time even for various motors having different times until the stop. It is possible to Further, since the set value is variable in the signal switching means, the operation time for rotating the motor in the forward and reverse directions can be set to a desired time. In this case, if the set value changed by the signal switching means is stored in the storage means that retains the stored contents even when the power is turned off, the set value is set when the power is turned on again after the power is turned off. There is no need to reconfigure. If the motor stop means (for example, an electromagnetic brake or a mechanical brake) for holding the stopped state of the microminiature motor is provided, the motor can be used for stopping the motor midway.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

[Figure 2] Time chart

FIG. 3 Flow chart

FIG. 4 is a front view showing a conventional microminiature motor and a rotary encoder.

FIG. 5 is a side view showing a micro motor and a rotary encoder.

FIG. 6 Time chart

[Explanation of symbols]

11 is a micro motor, 12 is a rotary shaft, 13 is a rotary encoder (pulse generating means), 14 is a computing unit (pulse counting means), 16 is a first comparator, 17 is a second comparator, and 18 is a setting. Value holding unit, 19 is a motor reversal command unit, 2
Reference numeral 0 is an initial value holding unit, 21 is a signal switching unit, 22 is a stop signal creating unit (stop signal creating unit), 23 is a count direction command unit, 24 is a motor drive circuit, and 25 is a changeover switch.

Claims (8)

[Claims] 1. A drive circuit for rotationally driving a microminiature motor, pulse generating means for generating a pulse in response to rotation of the microminiature motor, and a normal rotation command signal for normal rotation of the microminiature motor. Pulse to count the pulse from the pulse generating means when the reverse rotation command signal for reversing the microminiature motor is given. Switching between the counting means and the forward rotation command signal to output the reverse rotation command signal when the count value of the pulse counting means matches or exceeds the set value, and reverses when the count value matches or falls below the initial value. A signal switching means for switching the command signal to output a normal rotation command signal, and the microminiature motor is stopped when the signal is switched by the signal switching means. Stop signal generating means for outputting a stop command signal for a set time, the pulse counting means, even when the forward rotation command signal or the reverse rotation command signal is switched, the stop command signal from the stop signal generating means A position control device for a microminiature motor that keeps the pulse counting direction in the same direction as before while it is being output. 2. The position control device for a microminiature motor according to claim 1, wherein the pulse generating means is composed of an optical rotary encoder including an optical sensor. 3. The position control device for a microminiature motor according to claim 1, wherein the pulse generating means is composed of a magnetic rotary encoder including a permanent magnet and a magnetic sensor. 4. The position control of the microminiature motor according to claim 1, wherein the stop signal generating means is configured to be able to vary a set time for outputting a stop command signal. apparatus. 5. The position control device for a microminiature motor according to claim 1, wherein the signal switching means is configured to be able to change a set value. 6. The position control of a microminiature motor according to claim 5, wherein the set value of the signal switching means is stored in a storage means that retains stored contents even when power is turned off. apparatus. 7. The microminiature motor comprises a brushless motor.
2. A position control device for a microminiature motor according to any one of 1. 8. The position control device for a microminiature motor according to claim 1, further comprising a motor stopping means for holding the stopped state of the microminiature motor.