JP3216306B2 - Rotation control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation control device for controlling a rotation speed and a rotation phase of a rotary body such as a rotary drum of a rotary magnetic head device used for a video tape recorder or the like.

[0002]

2. Description of the Related Art Conventionally, techniques for precisely controlling the rotation speed and rotation phase of a rotating body have been widely implemented in various fields. For example, in a video tape recorder employing a helical scan method in which a magnetic tape wound around a rotating drum of a rotating magnetic head device and travels and a magnetic head driven to rotate are slidably brought into contact with each other to perform recording and reproduction, the recorder is activated. When this is done, it is necessary to quickly start up the rotating drum on which the magnetic head is mounted to a state having a predetermined rotation speed and rotation phase, and a rotation control device for executing this is usually provided.

[0003] As this kind of rotation control device, one configured as shown in FIG. 3 is used. As shown in FIG. 3, the rotation control device includes a rotating drum 1 on which a magnetic head is mounted, a drum driving motor 2 for driving the rotating drum 1 to rotate, a driving power source 3 for the motor 2, The control microcomputer 5, a sensor 6 disposed in proximity to the rotary drum 1 for extracting a drum pulse S according to the rotation state of the rotary drum 1, and a rotation speed V of the rotary drum 1 based on the drum pulse S Speed detection device 7 to detect
A reference signal generator 11 that outputs a reference signal R that defines a target rotation speed and a rotation phase; and a phase difference detector 10 that detects a phase difference Φ between the drum pulse S and the reference signal R. I have.

[0004] The rotation control of the rotation control device is executed using the microcomputer 5 in accordance with the procedure shown in FIG.
In the flowchart shown in FIG. 4, when the rotation control is started by turning on the power, the microcomputer first monitors the rotation speed V detected by the speed detection device 7, and this is monitored by the target rotation speed defined by the reference signal R, for example, , 30 rpm, or 25 rpm, the magnitude of the voltage supplied from the driving power supply 3 to the motor 2 is controlled (steps ST5 and ST6 in FIG. 4).

[0005] Even when the target rotational speed is achieved in this way, generally, at this time, the phase of the drum pulse S does not match the phase of the reference signal R and has a phase difference (R and S in FIG. 5). Then, the rotation speed is finely adjusted until the phase difference falls within a sufficiently small allowable range (step ST
7 and ST8). After the phase difference falls within the allowable phase range, the rotation speed is maintained at the target rotation speed to finally obtain the rotation state of the drum whose rotation speed and rotation phase match the reference signal (step ST9 and FIG. 5). S ').

[0006]

In the control by the conventional rotation control device as described above, first, the speed is accelerated to a target speed, and then, the speed is finely adjusted in the vicinity of the target speed, whereby the rotational phase is controlled. Is adjusted to the phase of the reference signal, but the phase synchronization process is performed with almost no speed difference between the rotation speed of the drum and the speed of the reference signal, so that the phase is completely synchronized. There is a drawback in that it takes a long time until a synchronized target speed can be obtained.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned technical problems, and an object of the present invention is to provide a rotation control device capable of quickly starting the rotation state of a rotating body up to a target rotation speed and a rotation phase.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention proposes a rotating body which is driven to rotate, a rotation driving means for driving the rotating body, and a rotating state of the rotating body. , A reference signal generating means for outputting a reference signal having a fixed cycle and a phase, and a control signal to the rotation driving means based on the detection signal and the reference signal output from the rotation detecting means. Control signal generating means for generating the control signal, the control signal generating means for accelerating the rotation speed of the rotating body to match the first target speed lower by a predetermined amount than the final target speed defined by the reference signal. A rotation control device for generating a first control signal and a second control signal for accelerating the rotation speed of the rotating body from the first target speed to the final target speed and for matching the rotation phase of the rotating body to the phase of the reference signal In When the rotating body reaches the first target speed, it is checked whether the rotation phase of the rotating body is within a predetermined phase range with respect to the reference signal, and when this is confirmed, acceleration is started again. It was done.

Preferably, the first target speed lower than the final target speed by a predetermined amount is approximately 1/1 / the final target speed.
It is set to 5１ ／.

A rotation control device according to the present invention is used for rotation control of a rotary magnetic head device of a video tape recorder employing a helical scan system.
In this case, the rotating body is a rotating drum of the rotating magnetic head device.

[0011]

According to the rotation control device of the present invention, when the rotating body reaches the first target speed lower by a predetermined amount than the final target speed defined by the reference signal, the rotation phase of the rotating body becomes higher than the reference signal. Then, it is confirmed whether or not the rotation is within a predetermined phase range, and when this is confirmed, acceleration is performed again, so that the rotation speed and rotation phase of the rotating body quickly match the speed and phase of the reference signal.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a specific embodiment of a rotation control device according to the present invention will be described with reference to FIGS.

In the rotation control device according to the present invention, first, a rotation speed of a rotating body, for example, a rotating drum of a rotating magnetic head device of a video tape recorder employing a helical scan system is lower than a final target speed by a predetermined value. Start rotation up to the target speed. In the rotation state at which the first target speed has been reached, the phase of the drum pulse gradually changes with respect to the phase of the reference signal, but the phase of the drum pulse falls within a predetermined phase range with respect to the reference signal. At this time, an acceleration operation for accelerating the rotation speed of the rotating drum to the final target speed is started, and by this accelerating operation, a rotating state of the rotating drum whose rotation speed and rotation phase almost simultaneously coincide with the reference signal is obtained. Things. The control operation in this case is as shown in the flowchart of FIG.

FIG. 2 shows a signal waveform in the control of the rotary drum performed in the procedure shown in FIG. In FIG. 2, the final target speed is 25 revolutions / second, and the reference signal R has a period of 40 ms as shown in the signal waveform R of FIG.
As a pulse.

The first target speed lower than the final target speed by a predetermined value is set to 4/5 of the final target speed, and the loop consisting of steps ST1 and ST2 in FIG. 1 is repeatedly executed. Realizes this speed. The period of the drum pulse S ₀ when the speed reaches this speed is 50 ms as shown in the signal waveform S ₀ of FIG.
Becomes The transition state of the drum pulse when the drum pulse S ₀ is obtained and the drum drum is accelerated to the final target speed of 25 revolutions / sec during the acceleration period of 5 revolutions of the rotating drum is shown in a simplified manner. This is the signal waveform S 'in FIG.

In this signal waveform, in step ST3 of FIG. 1, it is checked whether or not the phase of the drum pulse is near 180 degrees with respect to the reference signal R. When this is confirmed, in FIG. s' _{when 3} occurs, starts the acceleration operation of the next step ST4. In this acceleration operation, as shown in FIG. 2, during the acceleration period of 5 rotations, acceleration is performed so that the period of the drum pulse is shortened by 2 ms per rotation, and the last pulse s ′ of this acceleration period _From the time point when ₈ is obtained, drum pulses whose rotation speed and rotation phase completely match the reference signal R are obtained. It should be noted that the end of the acceleration operation in step ST4 is performed when the phase of the drum pulse reaches a state in which the phase of the drum pulse coincides with the phase of the reference signal for a predetermined number of times.

The embodiment of the present invention described with reference to FIGS. 1 and 2 is merely an idealized example. Actually, various embodiments are possible within the technical idea of the present invention. Configuration changes are possible. For example, in the example described above,
Although the value of the first target speed is set to 4/5 of the final target speed, it is not always necessary to limit to this ratio.
It is appropriate to set about / 5 to 5/6.

Further, the first target speed lower than the final target speed by a predetermined value is 6/5 to 7/7 of the final target speed.
/ 6 may be set.
The value of the target speed is almost 1/5 to 1/1 / the value of the final target speed.
It is sufficient that the speed is lower than the final target speed by six. In this case, the acceleration operation in step ST4 in FIG. 1 executes a deceleration operation from the first target speed to the final target speed. In view of these points, the term "acceleration" in this specification and the drawings is defined to be used not only in the case of increasing speed but also in the case of deceleration.

Further, in the embodiment of the present invention described with reference to FIGS. 1 and 2, when the phase difference Φ becomes close to 180 degrees, the acceleration operation toward the final target speed is started. The range of the phase difference Φ when starting this acceleration operation is
In short, it is necessary that the rotational phase coincides with the phase of the reference signal at the same time when the final target speed is reached by this acceleration operation, which is equivalent to the value of the final target speed and the value of the first target speed. , Step ST4 in FIG.
Is determined by the length of the acceleration period during which the acceleration operation is performed, the speed response characteristics of the motor / drum system when the drive voltage is changed, and the like, and the optimum range of the phase difference can be experimentally obtained.

The above-described embodiment shows an example in which the present invention is applied to a rotary magnetic head device of a video tape recorder. However, the present invention is not limited to this.
Other than this, the present invention can be applied to, for example, the rotation control of a disk in a video disk player, the control of a rotary head in a DAT (Digital Audio Tape Recorder), and the like. Design changes are possible.

[0021]

As described above, the rotation control device according to the present invention is designed such that when the rotating body reaches the first target speed lower by a predetermined amount than the final target speed specified by the reference signal,
It is checked whether the rotation phase of the rotating body is within a predetermined phase range with respect to the reference signal, and when this is confirmed, the acceleration is performed again. Therefore, when the apparatus equipped with the rotating body is activated, the time required for the activation can be reduced.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an operation of a rotation control device according to the present invention.

FIG. 2 is a signal waveform diagram and a timing chart showing a control state of the rotation control device.

FIG. 3 is a block diagram showing a conventional rotation control device.

FIG. 4 is a flowchart showing an operation of a conventional rotation control device.

FIG. 5 is a signal waveform diagram showing a control state of a conventional rotation control device.

[Explanation of symbols]

1 rotating drum, 2 drive motor, 3 drive power supply,
5 microcomputer for speed control, 6 sensor, 7 speed detector, 10 phase difference detector, 11 reference signal generator

Continuation of front page (56) References JP-A-4-193086 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02P 5/00 301 G11B 15/467 G11B 15/473 G11B 15/48 G11B 19/247

Claims (3)

(57) [Claims] A rotating body driven to rotate; a rotation driving means for driving the rotating body; a rotation detecting means for detecting a rotation state of the rotating body; and a reference signal having a constant cycle and phase. Reference signal generating means, and control signal generating means for generating a control signal to the rotation driving means based on the detection signal output from the rotation detecting means and the reference signal , wherein the control signal generating means Accelerate the rotation speed of the rotating body
A first control signal for matching a first target speed lower by a predetermined amount than a final target speed defined by the reference signal, and a rotation speed of the rotating body from the first target speed to the final target speed. a rotation control device for generating a second control signal for accelerating and matching the rotational phases of the rotary member to the phase of the reference signal to when said rotating member reaches a first target speed, the Rotating body rotation
Whether the inverted phase is within a predetermined phase range with respect to the reference signal
Confirm that when this is confirmed you will start accelerating again
A rotation control device characterized in that it is configured as follows . 2. The system according to claim 1, wherein the first target speed is approximately 1/5 to 1/6 of the final target speed.
The rotation control device as described in the above. 3. The rotation control device according to claim 1, wherein the rotating body is a rotating drum of a rotating magnetic head device.