JPH05336782A - Motor control equipment - Google Patents

Abstract

PURPOSE:To enable proper control of rotation even when a motor load changes, by changing a gain of a rotation control loop, or a gain of the rotation control and the content of phase compensation of a phase loop, in accordance with the motor load. CONSTITUTION:In a digital computing unit 2, a control value is compared with a prescribed reference value so as to detect a load of a spindle motor 1, the amount of slippage is determined thereby, a phase compensation table is selected on the basis of this amount of slippage and a correction corresponding to the load of the spindle motor 1 is made for a gain obtained by synthesizing a speed error amount with a phase error amount. In other words, a variable NS1 is compared with a count value obtained from a V sync and is subjected to scaling and then a value thus obtained is substituted for a variable ES. Then, one of digital filters in a plurality is selected in accordance with the load of the spindle motor 1, the NS1 is passed through the selected digital filter and the result is substituted for a phase error value ESOUT and used for a PWM output processing. In this way, responsiveness to a change in the load of the motor is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device for feedback controlling the rotation speed and phase of a motor for rotating a flexible disk or the like. For example, an image of a subject received by a light receiving element is used as an image signal. The present invention relates to a motor control device suitable for use as a spindle motor for rotating a disc in a still video device for recording on or reproducing from a flexible disc.

[0002]

2. Description of the Related Art Recently, a flexible disk (hereinafter, referred to as FD in this specification) is used to capture an image taken in the same manner as an ordinary camera.
Is abbreviated. A still video system for magnetically recording and reproducing an image by using a still video camera for recording in (1) and a device for reproducing the image from the FD has been developed and commercialized.

The FD in such a still video system is usually divided into 52 tracks, and the screen and audio data are recorded on each of the first to 50th tracks. The 51st track is an empty track, and the 52nd track is an optional Kyo track. Set this FD in a still video camera or playback device, and in the case of NTSC system, 3
The magnetic head is made to access a desired track by constant rotation at 600 rpm to actually record and reproduce an image.

Here, the phase of the FD as described above must be always matched with the image signal when the image is recorded, for example. Conventionally, the speed is obtained by comparing the FG pulse detected several times in one rotation with a reference clock with marks provided on the FD rotary table at equal intervals in the circumferential direction, and a specific position near the center of the FD. PG obtained by detecting one PG yoke provided in
The phase is obtained by comparing the pulse and the vertical synchronizing signal (V sync) obtained from the image signal, and the motor is feedback-controlled from these data.

[0005]

However, for example, when vibration or impact is applied to a still video camera equipped with the above-described structure during shooting, the load on the spindle motor fluctuates temporarily. Then, there is a problem that the proper rotation control cannot be performed temporarily, the rotation itself fluctuates, the image cannot be recorded correctly, and it takes time to restore the image. Further, in the above structure, the sliding resistance caused by the contact of the magnetic head with each track of the FD is different between the outer peripheral side and the inner peripheral side of the FD, the external environment is changed, or the device is aged over time. Since the load of the spindle motor fluctuates, there is also a problem that it is difficult to perform rotation control that absorbs all the fluctuation of the load.

In view of the problems of the prior art as described above, a main object of the present invention is to provide a motor control device capable of controlling the rotation of the motor with good responsiveness even when a load change occurs. is there.

[0007]

According to the present invention, there is provided a motor control device for feedback controlling the rotation speed and phase of a motor for rotating a flexible disk or the like. It has a means for detecting a rotation load and a means for changing the gain of the rotation control, or the gain of the rotation control loop and the phase compensation content of the phase loop according to the rotation load detected by the detection means. It is achieved by providing a motor controller. Here, although only the gain of the rotation control loop may be changed, for example, if the gain is increased too much under the same phase compensation, oscillation may occur. Therefore, if the phase compensation is also changed at the same time as the gain is increased. A sufficient gain can be secured when the load changes.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the configuration of a motor control device in a still video device to which the present invention is applied.

A spindle motor 1 for driving an FD (not shown) is PWM-processed via a drive circuit 3 by a digital arithmetic unit 2 as a motor control device composed of a microcomputer.
The drive is controlled by the control. An FG sensor 7 is connected to the digital arithmetic unit 2 via a comparator 4 and an amplifier 6 to which a reference voltage is supplied, and a PG sensor 11 via a comparator 9 and an amplifier 10 to which a reference voltage is also supplied. Are connected. Further, the digital computing unit 2 is connected via a drive circuit 14 to a step motor 13 for driving the magnetic head 12 for accessing the FD to record and reproduce an image in the tracking direction.

In the digital arithmetic unit 2, the speed is detected by the FG pulse input from the FG sensor 7 through the amplifier 6 and the comparator 4, and after comparing with the reference timer, scaling is performed to obtain the speed error amount. I do. In parallel with this operation, the PG sensor 11 to the amplifier 10 and the comparator 9
The phase is detected by the PG pulse input via
After the comparison with the V sync, scaling is performed, a phase compensation table is selected from the track position information described later, and a work for obtaining a phase error amount is performed based on this phase compensation table.
The speed error amount and the phase error amount obtained by these operations are combined to obtain the gain, and after gain control, the control value is actually PWM-outputted to the spindle motor 1 via the drive circuit 3.

On the other hand, the digital computing unit 2 compares the control value with a predetermined reference value to detect the load of the spindle motor 1 to obtain the deviation amount, and selects the phase compensation table based on the deviation amount. The gain obtained by combining the speed error amount and the phase error amount is corrected according to the load of the spindle motor 1.

The main part of the above procedure will be described with reference to the flow charts shown in FIGS. First, it is determined in step 1 of FIG. 2 that the disk has been set, and when it is set, the magnetic head 12 is moved to a vacant track in step 2 and waits until an actual image is taken (step 3). Then, when the image is taken, the spindle motor 1
Drive the FG pulse to the digital calculator 2 (FIG. 3),
The interrupt input of the PG pulse (FIG. 4) is permitted and the PWM output from the digital computing unit 2 to the spindle motor 1 is permitted (step 4). After that, when the spindle motor 1 steadily rotates and the rotation is locked (step 5),
In step 6, the image is recorded on the disk and the spindle motor 1 is stopped.

On the other hand, when the FG pulse is input, the free running counter value is substituted into the variable NF1 in step 11 as shown in FIG. The maximum value of this free running counter is added, and the process proceeds to step 14. Here, the free-running counter is an 18-bit counter that counts with a reference clock having a predetermined frequency (for example, 6.0 MHz).
F1 is the value when the FG pulse is input this time.

In step 14, the value NF2 at the previous FG pulse input is subtracted from the current value NF1 to obtain the cycle of the FG pulse, which is subtracted from the reference cycle of the FG pulse.
The velocity error value EVOUT is obtained by multiplying the coefficient KV obtained as an approximately constant by the number of teeth of FG. Then, in step 15, NF1 is set as the next previous value N
Substituting it into F2, the PWM output process of step 16 is performed.

When the PG pulse is input, the counter value of the timer is substituted into the variable NS1 in step 21, as shown in FIG. Here, this timer is, for example, 7
Approximately 000 by a reference clock with a predetermined frequency of 50 kHz
Counting from 0H to 30D4H is performed, and each time the FD makes one rotation, it is cleared by the V sync that is issued 7H behind the PG pulse (2F87H). The PG pulse used here is a so-called delay PG or shift PG signal from which mechanical attachment errors have been removed in advance. Next, NS1 is compared with the count value obtained by the V sync, and after scaling, substituted into the variable ES (step 22). Then, in step 23, one of the plurality of digital filters is selected according to the load of the spindle motor 1, and in step 24, the result is substituted into the phase error value ESOUT through the digital filter NS1. It is used for the PWM output processing in step 16 of FIG.

Next, the PWM output processing in step 16 of FIG. 3 will be described with reference to FIG. First, step 31
Then, the speed error value EVOUT obtained in step 14 of FIG. 3 and the phase error value ESOUT obtained in step 23 of FIG. 4 are added to obtain the error value EOUT.
To calculate. Needless to say, the speed error value EVOUT occurs, for example, 16 times each time the FD makes one revolution, while the phase error value ESOUT occurs once every revolution. Then, in step 32, the compensation coefficient K is obtained according to the load of the spindle motor 1, the PWM output value OUT is calculated (step 33), and the PWM output is actually performed. Here, in this embodiment, the load of the spindle motor 1 is obtained from its control value. In practice, it may be directly calculated from the speed of the spindle motor 1, that is, the FD.

Actually, the PWM output is compensated according to the load of the spindle motor without replacing the digital filter used for the phase error value (phase compensation),
It may be done only by changing the compensation coefficient (gain adjustment) for the output value, but if the gain is increased too much under the same phase compensation, oscillation may occur, so it is recommended to change the phase compensation at the same time as the gain is increased. In this case, a sufficient gain can be secured when the load changes, and the response can be improved, so that problems such as recording errors can be prevented.

[0019]

As is apparent from the above description, according to the motor control device of the present invention, the load of the motor is detected, and the gain of the rotation control loop or the gain and the phase loop of the rotation control is detected according to the detected load. By changing the content of the phase compensation, it is possible to respond to the load variation with good responsiveness, so that the proper rotation control of the motor can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram of a main part of a video still camera to which the present invention is applied.

FIG. 2 is a flowchart showing an operating procedure of an embodiment according to the present invention.

FIG. 3 is a flowchart showing an operating procedure of an embodiment according to the present invention.

FIG. 4 is a flowchart showing an operating procedure of an embodiment according to the present invention.

FIG. 5 is a flowchart showing an operating procedure of an embodiment according to the present invention.

[Explanation of symbols]

 1 Spindle Motor 2 Digital Operator 3 Drive Circuit 4 Comparator 6 Amplifier 7 FG Sensor 9 Comparator 10 Amplifier 11 PG Sensor

Claims (2)

[Claims] 1. A motor control device for feedback-controlling the rotational speed and phase of a motor for rotating a flexible disk or the like, comprising means for detecting the rotational load of the motor, and means for detecting the rotational load of the motor. A motor control device comprising: a gain of the rotation control loop, or a means for changing the gain of the rotation control and the phase compensation content of the phase loop according to a rotation load. 2. The spindle motor for rotating the disk in a still video device for recording or reproducing an image of an object received by a light receiving element as an image signal on a flexible disk, the motor comprising a spindle motor. The motor control device according to claim 1, wherein: