JPH0739182A - Motor rotating speed controller, rotating information isolating circuit and rotating information detector - Google Patents

Abstract

PURPOSE:To detect rotating information such as a motor rotating speed signal, a rotating phase reference signal, etc., by a detector of one system. CONSTITUTION:Rotating information detected by a detector 2 from a motor 1 is isolated by an isolating circuit 4 to a rotating speed signal (FG) and a rotating phase reference signal (PG). Number of revolutions of a motor is controlled and a motor torque ripple, etc., is corrected according to the signals to stabilize rotation of the motor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor rotation speed control device, a rotation information separation circuit and a rotation information detector used therein.

[0002]

2. Description of the Related Art Motor rotation speed control using a rotation phase reference signal and a rotation speed signal of a motor is disclosed, for example, in the specification of Japanese Patent Application No. 4-199723 by the present applicant.

FIG. 7 is a block diagram of the motor rotation speed control device described therein. The rotation speed signal (hereinafter referred to as FG) of the motor 1 and the rotation phase reference signal (hereinafter referred to as PG) are respectively detected by the rotation speed detector 30 and the rotation position detector 31, and after passing through the amplification circuits 32 and 33, rotation is performed. It is input to the speed control unit 5. In the rotation speed control unit 5, F
G and PG are respectively compared with target values, a speed error is obtained from FG, a phase error is obtained from PG, and both errors are added to generate a speed command signal D. Further, FG and PG are input to the FG address circuit 6 which is a motor torque ripple correction unit, are set by the start address 7 by using PG as a trigger, and generate an FG address signal that counts up for each FG input. With respect to the FG address signal, the correction data corresponding to the FG address signal is read from the memory circuit 8, and the ripple correction signal C amplified by the gain circuit 9 based on the gain setting value 10 is generated. The speed command signal D and the ripple correction signal C are added to the adder 1
1 is added, and the output E is input to the drive circuit 12,
By driving the motor 1, rotation speed control and torque ripple correction are performed.

FIGS. 8 (a) and 8 (b) are a side view and a plan view of a slit plate of a PG and FG detector used in such an apparatus, respectively. As shown in these drawings, on the circumference of the slit plate 36 centering on the motor rotation shaft 13, there are light-transmitting slits 34, 34 ... For detecting the rotation speed at a constant pitch p, and the rotation speed detection thereof. To a position where it does not optically interfere with the transparent slit 34 for
A translucent slit 35 for detecting the rotational position is arranged.
The slit plate 36 is attached to the motor rotary shaft 13, and the light-transmitting slits 34 and 34 are sandwiched between the light-emitting element 30-.
1, 31-1 and the light receiving element 30 so as to face them.
And 31 are arranged, and the translucent slits 34 and 35 are arranged.
FG and PG are detected based on the light passing through.

[0005]

However, according to the above configuration, there are two detection units for FG and PG detection,
That is, each requires a dedicated light-transmitting slit, a light-emitting element, a light-receiving element, and an amplifier circuit, which causes an increase in the volume of the mechanism section and the cost of parts, and troublesome position adjustment.

[0006]

In order to solve the above-mentioned problems, the present invention surely uses a single-system detecting section and a circuit for separating the rotation information obtained thereby, so that the FG and the PG can be reliably operated.
Was detected.

[0007]

According to the present invention, the rotation information of the rotating body can be separated into FG and PG by the one-system detecting section and the simple separating circuit. As a result, it becomes possible to control the rotation speed of the motor and correct the torque ripple. Further, by using the rotation information as the separation control signal of the separation circuit, even if the rotation speed of the rotating body changes, FG
And PG can be reliably separated.

[0008]

FIG. 1 is a block diagram of an embodiment of the present invention. The difference between the device of the embodiment of FIG. 1 and the device of the conventional example of FIG. 7 is that the detector and amplifier circuit for PG and FG are one system, and then PG and FG are separated by a separation circuit.

In the block diagram of FIG. 1, the rotation information detected by a detector 2 described later is waveform-shaped by an amplifier circuit 3, and then a separation circuit 4 described later detects FG and PG. The subsequent operation is the same as in the case of FIG.

FIG. 2A is a side view of the detector, and FIG. 2B is a plan view of a slit plate used for the detector. As shown in these figures, in the slit plate 14 fixed to the motor rotating shaft 13 and rotating with the rotation of the motor, the light transmitting slits 15 and 15 are arranged at a constant pitch p on the circumference of the motor rotating shaft 13. ... is arranged. The slit width of the translucent slit 15 is a constant width w except for the slit s0, and the slit width of the slit s0 is longer than w. A light emitting element 2-1 and a light receiving element 2-2 facing the light emitting element 2-1 are arranged with the light transmitting slit 15 interposed therebetween, and the light passing through the light transmitting slit 15 is detected as rotation information.

FIG. 3A is a block diagram of the separation circuit 4, and FIG. 3B is a waveform diagram of each part of this circuit. The rotation information A is an input to the separation circuit 4 whose waveform has been shaped. If the rotation information A has a constant rotation speed and becomes high level when passing light is detected, the translucent slits 15 have intervals of a constant pitch p, and the slit widths other than the slit s0 are w. It rises every fixed time t, and becomes a waveform of high level pulse width t ₁ . At the slit s0,
The high level pulse width becomes longer than t ₁ .

The separation circuit 4 is composed of a sawtooth wave generation circuit 16, a comparator 17 and an edge detection section 18. First, paying attention only to the rising portion of the rotation information A, the edge detection unit 18 detects an edge to generate an FG, that is, a rotation speed signal. The output of the sawtooth wave generation circuit 16 is charged up only during the high level period of the rotation information A, and is reset at the low level. The sawtooth wave B generated in this way is input to the comparator 17 where it is compared with the comparison voltage B'and P
A G or rotational phase reference signal is generated.

Returning to FIG. 1, the detected FG and PG
Is input to the rotation speed control unit 5. Rotation speed controller 5
Entered in. In the rotation speed control unit 5, FG and PG are respectively compared with a target value, and a speed error is calculated from FG as PG.
The phase error is calculated from the above, and both errors are added to generate the speed command signal D. Further, the FG and PG signals are input to the FG address circuit 6 which is a motor torque ripple correction unit, and are set by the start address 7 by using PG as a trigger, and an FG address signal that counts up each time the FG is input is generated. With respect to the FG address signal, the correction data corresponding to the FG address signal is read from the storage circuit 8, and the ripple correction signal C amplified by the gain circuit 9 based on the gain setting value 10 is generated. The speed command signal D and the ripple correction signal C are added by the adder 11, and the output E is input to the drive circuit 12 to drive the motor 1 to perform the rotation speed control and the torque ripple correction.

As described above, since the FG and PG can be detected by the one-system detecting section, the apparatus can be downsized, the cost can be reduced, and the adjustment time can be reduced.

The slit width of the slit plate 14 is 1
You may use the thing narrowed only in one place.

Further, as shown in FIG. 4A, the slits s0 may be different in the interval of the light transmitting slits 15. In this case, the separation circuit 4 is shown in FIG. 5A. Use something like this.

FIG. 5A is a block diagram of the separation circuit 4 when the slit plate of FIG. 4A is used, and FIG.
[Fig. 4] is a waveform diagram of each part in (a). This separation circuit is shown in FIG.
As shown in (a), it is composed of a frequency-voltage conversion circuit 19, a comparator 17, and a low-pass filter 20. The rotation information A is input to the low pass filter 20 to generate an FG having a waveform in which a portion of s0 having a narrow slit interval and a high frequency is cut. Further, the rotation information A is input to the frequency-voltage conversion circuit 19,
The output waveform B is input to the comparator 17 and compared with the comparison voltage B'to generate PG.

Further, a fixed slit pitch p as shown in FIG. 4B is used, a slit plate 14 in which the width w of the slit 15 is gradually changed is used, and FG is a rising edge of the rotation information A in the separation circuit. Alternatively, the PG may be detected, and the PG may be detected by inputting the rotation information waveform to a low-pass filter and comparing the output with a comparison voltage by a comparator.

In the aforementioned separation circuit, the comparison voltage B '
Was constant. If the motor rotation speed is used at a substantially constant value in the above-described embodiment, FG and P
For the separation of G, the above method is very effective. But,
If the motor speed is changed and used, it may cause trouble. That is, when the motor rotation speed is fast, the pulse width of the slit s0 portion and the pulse widths of the other slits become short, so the comparison voltage B'must be set low, and conversely when the motor rotation speed is slow. ,
The pulse width of the slit at the s0 portion and the pulse width of the other portions become long, and the comparison voltage B ′ must be set high. Therefore, when the rotation speed of the motor is changed and used, if the comparison voltage B'is a constant voltage, PG may be erroneously detected.

In the following embodiment of the separation circuit, the comparison voltage B'is tracked according to the change of the rotation speed of the rotating body including the motor.
Even if the number of rotations of the rotating body changes, F
It is possible to reliably detect G and PG.

FIG. 6A is a block diagram of an example of such a separation circuit, and FIG. 6B is a waveform diagram of each part thereof.
In FIG. 6A, this separation circuit is provided in parallel with the sawtooth wave generation circuit 16 of the circuit of FIG. 3A, and a comparison voltage generation circuit 21 including a frequency-voltage converter 22, a low-pass filter 23, and an amplifier 24. Is provided. Those having the same symbols as those of the separation circuit 4 in FIG. 3A have the same functions, and the description thereof will be omitted. In FIG. 6A, rotation information A which is rotation information of a rotating body such as a motor or a rotating roller is
The separated control signal is input to the frequency-voltage converter 22 of the comparison voltage generation circuit 21 for conversion and passed through the low-pass filter 23 to remove noise and minute fluctuations, and the amplifier 2
By setting the gain and the offset at 4, the comparison voltage B'is output.

By providing the comparison voltage generating circuit 21, the comparison voltage B'becomes a value following the rotation information and changes following the rotation speed of the rotating body.
When the rotation speed is high as in (b) (1), the comparison voltage B'is low, and when the rotation speed is low as shown in FIG. 6 (b) (2), the comparison voltage B'is It becomes higher, and FG and PG can be reliably separated.

It is not necessary to use the rotation information A as the separation control signal, and a signal proportional to the rotation speed of the rotating body may be used. For example, a rotation speed signal, that is, FG may be used as the separation control signal. At this time, when the speed error is obtained inside the rotation speed control unit 5 in FIG. 1, if the FG is subjected to frequency-voltage conversion, the conversion output is taken into the comparison voltage generation circuit 21, thereby reducing the circuit scale. It is possible to

In this embodiment, FIG.
The rotation detector using the separation circuit of the method shown in FIG. 6A has been described in the detection units shown in FIGS.
The slit plate of (a) can be applied to all the rotation detectors such as the rotation detector of the separation circuit of the method of FIG. 5 (a) and the slit plate of FIG. 4 (b). Further, although the comparison voltage B'is controlled in this embodiment, the present invention is not limited to this, and the charge-up amount of the sawtooth wave B may be controlled without changing the comparison voltage B ', for example.

The block diagram of the entire apparatus is shown in FIG. 1 even if any of the separation circuits shown in FIGS. 3 (a), 5 (a) and 6 (a) is used.
Will be similar to.

In a small-sized magnetic recording / reproducing apparatus, a motor controls the tape speed to be constant by directly or indirectly driving the take-up reel by a motor without using a capstan or a pinch roller. Although the number depends on the type of tape, it is known that the number of tapes changes about 2.5 times from the beginning to the end of winding. Figure 6
The separation circuit for changing the comparison voltage as shown in (a) is particularly effective when used in a state in which the motor rotation speed greatly changes, such as a magnetic recording / reproducing device driven by a reel. Since it operates so as to change the comparison voltage B ′ following the change, FG and PG can be reliably detected even if the motor rotation speed changes, and motor rotation speed control and torque ripple correction are possible.

In the above embodiment, the rotation information detector is of a type that receives the passing light from the light emitting element 2-1 arranged oppositely through the slit plate 14, but the light emitting element and the light receiving element are integrated into a reflection. Type detectors and baffles may be used. Furthermore, the detection unit does not have to be of an optical type, and a unit that electrostatically or magnetically detects can be used.

[0028]

By using the present invention, the FG and PG of the motor can be detected by only one detecting section and a simple separation circuit, and the rotation speed control of the rotating body and the torque ripple correction can be easily performed. The rotation can be stabilized. Further, the signal can always be detected by the saturated signal, and PG and FG are not separated by the signal level, so it is not necessary to pay attention to the difference in the output level due to the individual difference of the detection element such as the light receiving element. There is no need to adjust the threshold level. Further, even if the speed of the rotating body changes, FG and PG can be reliably detected. Further, even when the motor rotational speed is changed and used, for example, when the magnetic recording / reproducing apparatus is driven by a reel, the FG and PG of the motor can be accurately detected. Therefore, it is possible to reduce the number of parts of the detection unit, and it is possible to realize the downsizing of the mechanism, the cost of the parts, and the adjustment of the position of the parts of the detection unit.

[Brief description of drawings]

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

FIG. 2A is a side view of a detection unit, and FIG. 2B is a plan view of a slit plate used for the detection unit.

FIG. 3A is a block diagram of an example of a separation circuit,
(B) is a waveform diagram of each part.

4A and 4B are plan views of another example of the slit plate.

5A is a block diagram of an example of another separation circuit, and FIG. 5B is a waveform diagram of each part thereof.

6A is a block diagram of still another example of the separation circuit, and FIG. 6B is a waveform diagram of each part thereof.

FIG. 7 is a block diagram of a conventional example.

FIG. 8A is a side view of a conventional detection unit, and FIG.
[Fig. 4] is a plan view of the slit plate.

[Explanation of symbols]

 1 Motor 2 Detector 3 Amplifying Circuit 4 Separation Circuit 5 Rotation Speed Control Section 6 FG Address Circuit 7 Start Address 8 Storage Circuit 9 Gain Circuit 10 Gain Setting Value 11 Adder 12 Drive Circuit 13 Motor Rotating Shaft 14 Slit Plate 15 Transparent Slit 16 sawtooth wave generation circuit 17 comparator 18 edge detection unit 19 frequency-voltage conversion circuit 20 low-pass filter 21 comparison voltage generation circuit 22 frequency-voltage converter 23 low-pass filter 24 amplifier

Claims (4)

[Claims] 1. A detector for simultaneously detecting rotation information including a rotation phase reference signal and a rotation speed signal, a separation circuit for separating the rotation phase reference signal and the rotation speed signal from the output of the detector, and a rotation phase reference signal. A means for controlling the rotation speed of the motor according to the rotation speed signal, and a motor rotation speed control device. 2. A rotation information separating circuit, comprising means for separating the simultaneously detected rotation phase reference signal and rotation speed signal, and the comparison voltage of the means for separating the rotation phase reference signal is constant. . 3. The rotating phase reference signal and the rotating speed signal, which are simultaneously detected, are separated from each other, and the comparison voltage of the rotating phase reference signal separating means is a voltage proportional to the rotating speed. Rotation information separation circuit. 4. A rotation information detector comprising patterns of different shapes provided on the circumference at equal pitches, and means for simultaneously detecting a rotation phase reference signal and a rotation speed signal from the pattern.