JPH02149985A - Disk device - Google Patents

Abstract

PURPOSE:To permit a head to effectively follow tracks in high density by reproducing track deviation information having intervals shorter than those of servo sectors from a part except for a data zone and adding it to a control signal obtained from a position signal as an auxiliary signal. CONSTITUTION:Track deviation information having the intervals shorter than those of the servo sectors 5 is reproduced from the part except for the data zone 2 in a disk recording medium 1, and the signal based on information is added to the control signal obtained from the position signal obtained from a servo sector 5 side as the auxiliary signal. Thus, the head can effectively follow track deviation at high density without deteriorating the storage capacity of recording/reproducing data.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a disk device such as a magnetic disk device, for example, and relates to a disk device that controls the positioning of a head using a reproduction signal from a disk recording medium. It is something.

(Prior art) As a head positioning method in a conventional disk device, for example, a servo pattern as servo information is written in advance in servo sectors provided at equal angular intervals on a disk recording medium, and the servo pattern is reproduced. There is a sector servo system in which head positioning is controlled by obtaining a position signal from a signal. This head positioning method has the advantage that it is easy to achieve high track density because the servo information is on the data surface. Therefore, in recent years, this head positioning method has come to be used in disk devices using replaceable disk recording media such as floppy disks.

However, in a disk recording medium such as a floppy disk, chucking errors during disk replacement and anisotropic expansion and contraction of the disk recording medium itself due to temperature and humidity are relatively large, and these factors tend to cause large positioning errors. It is known that in order to prevent this, the number of servo sectors can be increased, that is, the sampling frequency can be increased to increase the tracking band of the head positioning control system. However, increasing the number of servo sectors means reducing the amount of data that can be recorded and reproduced on the disk recording medium, and as mentioned above, the sector servo method is introduced to achieve higher track density and larger capacity. It contradicts that.

For this reason, conventional disk devices have attempted to cope with this by increasing the number of sectors within a range that allows the control system to maintain followability.

(Problem to be Solved by the Invention) As mentioned above, in the sector servo system, the track following performance improves as the number of servo sectors formed on a disk recording medium increases. It has the property that the area occupied by data decreases, resulting in a decrease in storage capacity.

Therefore, the number of sectors on the disk recording medium is set to 38, for example.
It is conceivable to harmonize the amount of servo information with the recorded/reproduced data by reducing the amount of information to about 100%. However, with recording media such as floppy disks, as mentioned above, the chucking error during disk replacement and the anisotropic expansion and contraction of the disk recording medium itself due to temperature and humidity are large, so the 38 or so servo sectors described above The head positioning method has a problem in that the head cannot sufficiently follow track deviations.

Further, in a general sample value control system such as that employed in the sector servo method described above, there is a phase delay due to sample and hold. In order to prevent this phase delay from affecting the control system, it is necessary to limit the servo band to 1/7 or less of the sampling frequency. Therefore, the gain in the frequency band of track runout is reduced, and there is also the problem that sufficient track following characteristics cannot be achieved.

This invention was made in consideration of these circumstances, and its purpose is to efficiently and accurately control the head against track runout without reducing the storage capacity of recorded/playback data. An object of the present invention is to provide a disk device that can follow a track.

[Structure of the Invention (Means for Solving the Problems) In order to solve the above problems, the present invention provides a method for head positioning based on servo information written in servo sectors provided at equal angular intervals on a disk recording medium. position signal reproducing means for reproducing a position signal of the disc recording medium; track runout information reproducing means for reproducing track runout information at intervals shorter than the servo sector interval from a portion other than the data zone on the disk recording medium; The gist of the present invention is to include an adding means for adding the signal as an auxiliary signal for head positioning to a control signal determined from the position signal.

(Function) In the above configuration, track runout information at intervals shorter than the servo sector interval is reproduced from a portion of the disk recording medium other than the data zone, and a signal based on this information is obtained from the servo sector side as an auxiliary signal for head positioning. The control signal is added to the control signal determined from the obtained position signal. As a result, the head can efficiently and accurately follow track wobbling without significantly increasing the number of servo sectors and therefore without causing a decrease in the storage capacity of recorded/reproduced data.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 3.

In this embodiment, an example will be described in which track runout information is obtained in advance from a specific track provided on the outer periphery of a disk recording medium and is stored in the control system.

First, the configuration of the disk recording medium will be explained using FIGS. 1 and 2.

FIG. 1 schematically shows recording patterns such as servo sectors on a disk recording medium.

Each track on the disk recording medium surface 1 is divided into a plurality of sectors provided at equal angular intervals, as described below. That is, on one or both sides of the disk recording medium 1,
A data zone 2 is formed on the inner circumference, and a guard zone 3 is formed on the outer circumference.

The data zone 2 is divided into 38 sectors 4, and each sector 4 includes a servo sector 5 containing a servo pattern 12 as servo information and a data sector for recording/reproducing data, as shown in FIG. 2(A). It consists of 6.

On the other hand, the guard zone 3 is provided at the outer periphery of the disk recording medium 1 with a width of about 10 tracks in order to detect the outermost track in the data zone 2. This area is divided into the same number of sectors or more than the data zone 2, and a servo pattern similar to the servo pattern 12 shown in FIG. 2(A) is formed in each sector.

Servo information read from the sector on the guard zone 3 is used as track runout information, and a signal obtained based on this information is used for head positioning and as an auxiliary signal.

As shown in FIG. 2(A), the servo sector 5 includes an erase section 7 for detecting a servo sector, an AGC section 8 for obtaining an AGC signal, a zone section 9 for identifying guard zones and data zones, and a servo pattern 12. It consists of a position part 11 in which a is formed. And, Figure 2 (A
), when the magnetic head 13 is positioned over each half of the servo track, the magnetic head 13 is positioned in the middle of the data track.

FIG. 2(B) shows the signal reproduced by the magnetic herad 13. As described later, A%B of this reproduced signal
, C, and D are peak-held to obtain A-B and CD, which becomes a position signal for head positioning.

Next, FIG. 3 shows the configuration of the head positioning control system. As described above, the position signal and track runout information are reproduced from the disk recording medium 1 on which the servo pattern 12 as servo information is formed, and the track runout information is taken in and stored in the μCPU, and then the two are added. The process of positioning the head will be explained, and the configuration of the head positioning control system will also be explained.

When the disk recording medium 1 is set in the floppy disk device, the μCPU 30 switches the servo system to speed control and at the same time switches the analog switch 35 to control the D/A.
A control signal for moving the actuator 15 toward the outer periphery of the disk recording medium 1 is applied to the voice coil motor 17 via the converter 31, analog switch 35, and amplifier 36.

As a result, the magnetic head 13 fixed to the actuator 15 moves from the inner circumferential side to the outer circumferential side of the disk recording medium 1. Then, the actuator 15 comes into contact with the stopper 16 and stops. At this time, the magnetic head 13 is located above the guard zone 3 of the disk recording medium 1. magnetic head 1
3 is fixed at this position, reads servo information from the servo sector on the guard zone 3 with one revolution of the disk recording medium 1, and uses this as a trunk shake signal to be sent to the μCPU 30.
will be stored in the memory of. At this time, an index signal generated once per rotation of the disk recording medium 1 is used as a reference point for track runout.

The number of samples of the track shake signal obtained in this manner is greater than the number of samples of the position signal obtained from the servo sector 5 in the data zone 2. In this way, the magnetic head 13 of this embodiment also has a function as track runout information reproducing means.

Next, head positioning control is performed as follows.

A signal as shown in FIG. 2(B) reproduced from the disk recording medium 1 by the magnetic head 13 is supplied to the AGC amplifier 18 via the preamplifier 14.
8 adjusts the playback level.

One side of the level-adjusted playback signal is sent to the binarization circuit 1.
9, and the other is input to each peak hold circuit 22.2.
Entered on 3.24.25.

A binarized signal is obtained in the binarization circuit 19, and the binarized signal is input to the erase detection circuit 20, where the erase portion 7 indicating the beginning of the servo sector 5 is detected.

Then, the sample pulse generator 21 is operated based on the erase detection signal, and the peak hold circuits 22, 23, 24, 25 are operated by the sample signals sequentially output from the sample pulse generator 21 in the position section 11.
is activated and the servo signal is sampled. In this way, the servo signals A and BSC are written in the position section 11 by the peak hold circuits 22, 23, 24, and 25.
.

D is detected. Next, the reproduced servo signals A, B,
Difference signals (A-B) and (C-D) between C and D, that is, position signals, are obtained by subtracters 26 and 27. In this way, sample pulse generator 21 and peak hold circuit 22.2
3.24.25, position signals (A-B), (C-) for head positioning are obtained from servo information ASBSC,,D.
A position signal reproducing means for reproducing D) is configured.

The above position signal is sent to the μCPU through the A/D converter 29.
Incorporated into 30. The μCPU 30 executes a predetermined calculation based on the above position signal to determine the track position of the magnetic head 13 with respect to the disk recording medium 1. Then, a positioning control signal for the magnetic head 13 is issued via the D/A converter 31 in accordance with the position signal.

This control signal is inputted to the amplifier 36 via the compensator 32 to drive the actuator 15. The compensator 32 includes an integrator, a phase lag/lead compensator, a low-pass filter, and the like.

However, with only the control mode described above, sector 4
Since the number of samples from the track is small, sufficient tracking performance against track shake cannot be achieved.

Therefore, in this embodiment, the aforementioned track runout signal stored in the μCPU 30 is generated via the D/A converter 33. The generation time interval of this track runout signal is less than the sampling interval from sector 4, that is, less than the generation time interval of the position signal. This track shake reproduced signal is subjected to differential processing via a differentiator 34 for phase adjustment, and then is passed through a compensator 3 in an adder 40 serving as an adding means.
It is added with the signal from 2. The actuator 15 is driven via the amplifier 36 using this added signal. Due to this control operation, the magnetic head 13 accurately and stably follows the track runout even though the number of sectors 4 is small.

Note that this invention is not limited to the embodiments described above. In the above embodiment, the track runout information is stored in μCP in advance.
Although the method of storing the track runout information in U30 has been described, a separate fixed magnetic head may be provided in the guard zone section 3 at the outer periphery as a means for reproducing track runout information, and the track runout information may be obtained from there.

Furthermore, the track deviation information may be obtained not only from the outer circumference of the disc recording medium but also from the inner circumference outside the data zone.

In short, this invention can be implemented with various modifications without departing from its gist.

[Effects of the Invention] As explained above, according to the present invention, track runout information at intervals shorter than the servo sector interval is reproduced from a portion other than the data zone on a disk recording medium, and a signal based on this information is used for head positioning. Since the auxiliary signal is added to the control signal determined from the position signal obtained from the servo sector side, there is no need to significantly increase the number of servo sectors, and therefore no reduction in the storage capacity of recorded/playback data. , the head can be made to follow the track efficiently and with high precision against track runout, and its practical effects are extremely large.

[Brief explanation of the drawing]

1 to 3 show an embodiment of a disk device according to the present invention, in which FIG. 1 is a plan view showing the configuration of servo sectors, etc. on a disk recording medium, and FIG. FIG. 3 is a block diagram showing the configuration of a head positioning control system. 1: Disk recording medium, 2: Data zone, 3: Guard zone, 4: Sector, 5: Servo sector,
12: servo pattern; 13: magnetic head functioning as Ni-track deflection information reproducing means; 21: sample pulse generator; 22-25: peak hold circuit constituting position signal reproducing means together with the sample pulse generator; 30: μCPU. 40: Adder (addition means).

Claims (1)

[Claims] position signal reproducing means for reproducing a position signal for head positioning from servo information written in servo sectors provided at equal angular intervals on a disk recording medium; track runout information reproducing means for reproducing track runout information at intervals shorter than the interval; and addition means for adding a signal based on the track runout information to a control signal determined from the position signal as an auxiliary signal for head positioning. A disk device characterized by: