JPS60193176A - Head positioning system - Google Patents

Abstract

PURPOSE:To attain tracking performance with fidelity to track deflection in a data sector by obtaining not only servo information obtained only from a face where a track to be accessed for data write/read exists but also servo information on an opposite face from the position of the accessed track in the data sector. CONSTITUTION:Each track on sides A22 and B23 of a disc is divided into 32 sectors provided at a special angular interval and the relation of position of the sector 14 on each side is arranged so that the phase in the circumferential direction is different by nu/2 sector. A signal to read a track accessed for data write/ read from the existing side is fetched to a servo signal detection circuit by an analog switch 32 at first and an erasure section 18 having the maximum erasure section on one track and positioned at the head of each sector is detected by an erasure detecting circuit 30. In extracting each signal from the data side, the analog switch 32 is switched immediately by a CPU47, the signal read from the other side is fetched to the servo signal detection circuit and each signal of AGC, zone and position section is extracted by the similar process.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention efficiently and accurately positions a head in accordance with a servo signal on a recording medium in which a servo signal is embedded in a predetermined area of a data surface. The present invention relates to a head positioning system that allows for head positioning.

[Technical background of the invention]

In recent years, so-called floppy disk devices that use flexible magnetic disk recording media (hereinafter referred to as ``floppy disks'') that are inexpensive and easy to handle have become widespread. Positioning is generally performed by an oven loop method using a stepping motor.

However, with recent advances in high-density technology for recording media, conventional head positioning methods have been subject to problems such as chucking errors when replacing disks, anisotropic expansion and contraction of the disk itself due to temperature and humidity, and mechanical errors in the stepping motor. A new problem has arisen in that it is not possible to avoid off-track events caused by. For this reason, it has become necessary to apply tracking servo to this type of floppy disk device as well, similar to that of a so-called hard disk.

Incidentally, for an 8-inch floppy disk device, a tracking method has been proposed in which positioning is performed using an optical interference grating. This method embeds servo information on the inner and outer circumferences of the disk, and the radial runout (
Eccentricity) is measured in advance and the track position is determined by interpolation. However, with this method, the servo 1W signal is only on the inner and outer peripheries of the disk, so it is not possible to accurately obtain the track position on the disk plate, which expands and contracts anisotropically. It was difficult to obtain detention.

On the other hand, the present inventors previously proposed a system using a so-called embedded servo system. In this method, a data surface is divided into a plurality of sectors, a servo sector cover for controlling the head position is provided at an index portion for detecting each sector, and servo information is embedded in the servo sector in advance.

In this method, for example, as shown in FIG. 1, a servo sector 2 provided between data sectors 1 is connected to an erase section 3. AG
It is composed of a C section 4 and a position section 5. The erase section 3 has a maximum erasure period of one track, and is a section that detects the beginning of each sector. Also, A.G.
Cg34 is used as a signal when adjusting the signal level between tracks and between sectors. And position part 5
is a part that detects the position in the radial direction of the recording medium, and a two-phase servo signal 6, which is usually called a two-phase dipit pattern, is used.
is written. Note that writing by the head is prohibited in this servo sector 2.

For such a disk, if the head 8 is currently on-tracking on the 4N+4 track as shown in FIG. 1, the signal detected on the servo sector 2 will be the signal shown in FIG. 2. Here, the signals detected by the position section 5 are sequentially referred to as a position signal A.

B, C, and D, head position control is performed as follows. ' That is, the position signals A, B, C, and D are set as the first signal group, and the difference signals between AB and CD of the respective peter-held values X=A-B Y=C-D are defined as the first signal group. Let the phase signal and difference signal U=X+'Yv,=x−y of the first signal group be a second signal group. These signals X, Y,
U.

The relationship between the size of (2) and the position of the head is as shown in FIG.

When performing a seek operation, if the maximum movement speed of the head is less than 4 tracks per sector, as is clear from Figure 3, the section where the head is located can be determined by determining the magnitude of X and Y. . .

L□, L2. L, can be determined, and furthermore, by using U and V that show linear changes within this determined section, the accurate position of the head can be determined.

In other words, interval. , L, , L, , L3 is determined by first obtaining the signals X and Y, L,; X〉O, Y) O L,; ; By determining X<0, Y>0, the head existence section L0~Ls
can be known.

On the other hand, the position of the head within the track is as follows using U and ■: 1) o=V/a+〇, 5;L.

D', = 0.5- U/a; LID, = 0.5-
V/a: Lt D 3= U/a +〇, 5; It can be determined by LH (however, a is the amplitude value of X and Y shown in FIG. 3).

In this way, if the section LB where the head was located in the previous sector and the position DB within that section Ln are stored in the memory, the section Lp where the head is currently located and the position Dp within that section Lp can be stored in the memory. Accordingly, the current position p
p can be calculated. At the same time, the head movement speed V per sector can also be determined by v=pp-p13.

Therefore, by using such information, first, according to a preset speed table, roughly control the movement of the head by speed control (1), and then,
When the head approaches the target position l\i&, it becomes possible to effectively perform the seek operation of the head by controlling the position. In other words, even when the disk itself expands and contracts anisotropically, it is possible to position the head at 1 m f.

Here, the above positioning method is performed using servo information obtained from only one surface of the disk.

[Problems with background technology]

By the way, in such an embedded servo system, the more servo sectors formed on the disk surface, the better the track following performance and the higher the seek speed, but on the other hand, the number of servo sectors increases. If it increases, the area occupied by the data sector decreases, and the storage capacity decreases. Therefore, the inventors of the present invention considered achieving a balance between the two by limiting the number of disk divisions to about 32 and forming 32 servo sectors.

However, in a floppy disk device, the steady and thermal dimensional errors mentioned above are more pronounced than in a two-dimensional disk device. We have discovered a problem in that the head cannot sufficiently follow the resulting track deviation.

Furthermore, in a sample value control system, there is generally a phase delay due to sample and hold. Since this delay becomes more noticeable as the servo band is closer to the sampling frequency, the servo band is normally controlled to about 177 of the sampling frequency. However, with a floppy disk device,
Since the disk rotation speed is 36 rpm and the number of sectors is about 32, the sampling frequency is 192 Hz.

Therefore, the servo band is about 27 Hz, and the gain of the servo system at 6H2, which is the fundamental frequency of track runout, is about 10-odd dB at most, causing the problem that sufficient servo is not applied.

Furthermore, during a seek operation, the maximum moving speed of the platform and head using two-phase rotary signals is less than 4 tracks per sector, and the higher the rotation speed and the greater the number of sectors, the faster the seek speed becomes. However, when a floppy disk is loaded, which has a lower rotational speed than a hard disk drive, not only does the seek speed become slower, but if the seek speed is slow, it is easily affected by external forces such as friction, making it impossible to perform a smooth seek. also occurred.

[Purpose of the invention]

The present invention has been made in view of the above problems, and its purpose is to provide a head positioning method that can perform high-speed, high-sensitivity tracking without causing a decrease in data storage capacity. There is a particular thing.

[Summary of the invention]

The present invention provides a system in which the same number of sectors are provided at equal angular intervals on each data surface of a disk recording medium that defines a recording area on each of the opposing surfaces, and the sectors are arranged at positions whose phases in the circumferential direction differ by 1/2 sector. Servo sectors are taken out alternately from the sectors of each data surface arranged in this way according to the rotation of the disk, and the servo information of each data surface is read out, as well as the relative position in the radial direction of the servo information pattern embedded in each data surface. The mounting of the head on the data surface is caused by differences in position, etc. □ The phase difference between the position signals obtained from each surface is detected in advance, and the track is accessed for writing/reading data. The servo information obtained from the surface opposite to the surface where the track exists is corrected according to the above phase difference, and used in addition to the servo information obtained from the surface where the track to be accessed exists during position control or speed control. It is characterized by:

〔Effect of the invention〕

According to the present invention, not only the servo information obtained from the surface where the track accessed for writing/reading data exists, but also the servo information of the surface opposite to it,
By determining the position of the track to be accessed within the data sector, it is possible to more faithfully follow track wobbling within the data sector.

Also, by obtaining servo information by sampling alternately from sectors of each data surface whose phase in the circumferential direction differs by 172 sectors, the sampling frequency is twice that of obtaining servo information from one side. Therefore, the servo band is 2
As a result, the gain of the servo system at the fundamental frequency of track runout can be increased four times.

Furthermore, since the period of the detected sector is equivalent to 1
This is equivalent to doubling the number of sectors when obtaining servo information from only one side, and the seek speed can be doubled. [Embodiments of the Invention] The details of the present invention will be described below with reference to the illustrated embodiments. This will be explained based on an example.

FIG. 4 schematically shows a recording pattern of a floppy disk according to an embodiment of the present invention. In the figure, tracks on each surface of the disk, that is, Am22 and 8th surface 23, are arranged at equal angular intervals. The sectors 14 on each surface are arranged so that the relative positions of the sectors 14 are different from each other by 1/2 sectors in the circumferential direction. Each sector 14 also includes an erase section 18, an AGC section 19, a zone section 20, and a position $21 as shown in FIG.
The servo sector 15, 17 is formed of an embedded servo information pattern consisting of four parts, and a data sector 16 for writing/reading data. Note that servo sectors 15 and 17 are prohibited from being read by the head.

Next, the process of extracting servo information from a disk in which servo information is embedded on each surface as described above will be explained with reference to FIGS. 1, 2, 5, and 7.

First, data is written/written using the analog switch 32.
The signal read from the side where the track to be accessed for continuous output is present is passed to the servo signal detection circuit, and 1
The erase detection circuit 3o erases the erase section 18, which has the largest erase section in the track and is located at the beginning of each sector.
Just detect it. Then, in synchronization with this erase, the gate generation circuit 38 generates a gate with a predetermined time width at each position of the AGO zone and position section (A, B, C, D), and each signal is extracted. It will be done. In addition, Ueda Hi position signal person, B, C.

D is sequentially held at its peak value by the peak hold circuits 39, 41, 43.45 during the period when the gate is open, and is sent to the CPU 47 via the A/D converter 40, 42, 44, 46, I10 port 50. If necessary, the first signal group X, Y and the second signal group U, V are transferred to the CP.
Created by U47.

Further, when each number i is taken out, a signal having a time width of a data sector is generated by a gate generation circuit. This section is a section in which data is written/read, and writing by the head is prohibited in other sections. Immediately after the above-mentioned signals are output from this data side, the analog switch 32 is switched by the CPU 47, and the signals read from the other side are taken into the servo signal detection circuit, and the AGC, Each signal in the zone and the front section is cleared. And again, when each of the above signals is taken in, the analog switch is switched, but the timing at this time is
As soon as the CPU detects the end of the gate signal ``, which has the width of the data sector, generated in the sector of the surface where the track to be accessed for writing/reading data exists, it is switched. By repeating the above process as the disk rotates, servo information is alternately extracted from each data surface.

However, as mentioned above, the position signal groups X, Y, U, and V, which are more detailed from each surface, are caused by the deviation of the relative position in the radial direction of the servo information pattern embedded in each surface and the head position of each surface. Attachment produces a phase difference P due to differences in position and the like. Here, the position signal group has a 4-track period,
The phase difference is less than 4 tracks. Therefore, in order to use these position signal groups with different phases, the phase difference must be detected in advance and the position signal obtained from the surface opposite to the surface on which the track to be accessed for writing/reading data exists is corrected. The method for doing so will now be described with reference to FIGS. 6 and 7.

In FIG. 7, a disk 11 is placed in the floppy disk device.
When inserted, the CPU 47 switches the servo system to speed control and at the same time switches the analog switch 53 via the I10 boat 48 to control the I10 boat 50 and D/A.
Converter 51. A negative speed control signal is given to the voice coil motor 29 via the analog switch 53 and the amplifier 54 (the direction of the current is positive when going from the outer circumference to the inner circumference of the disk). As a result, the heads 24 and 25 fixed to the carriage 55 are moved from the inner circumference to the outer circumference of the disk 11, and eventually come into contact with the stopper 28, and the heads are fixed at this position.

First, on the A side 22 of the disc,
Servo information is sent to CPU4 from 32 servo sectors by rotation.
7 and store the X and Y signals in the memory 49.

The information obtained at this time is a track deviation signal caused by errors such as disk eccentricity and temperature/humidity. In the tree example,
The amplitude of track runout is suppressed to within l track.

Next, as described above (from the track runout obtained in each sector of side A, the center position LA of track runout within the section L0 to L1 is determined).
C is calculated by the CPU 47. Furthermore, the same process is performed on the B side to find the center position LBC of the track runout within the section L0 to L.

There is one section here. ~L, the position within is expressed as L" DOp "OL = 1 + Dt p LI L = 2 + D t z L t L-3 + Ds; L3 (0<D(1, DI-Dt, Ds<1) (1) The phase shift PA of the B plane relative to the A plane in the inner circumferential direction.
B is when LAC>LBC and @PAn-Lac-LBc When track LAC<LBC, PAB=4-(LBC-LAC
) Track 1ii Phase deviation of the A surface relative to the B surface in the inner circumferential direction PB
A is, when LBC>L, AC, PBA=LBC-LAC track LBC (when LAC, PBA=4-(LAC-Lnc)
) Track (iii) When LBC=LAC PAB=PBA=
Obtained as 0. (0≦PA) (, PBA<4) Then, the section L0 to L is obtained from the obtained track runout.

A specific method for determining the center position of track runout in the following is shown below.

Since the amplitude of the track runout is within one track, the position signal obtained in each sector is obtained within one section or over two sections L0 to L3.

When the tracker and deflection signal force S is obtained within a certain section, its center position is also within that section, and the center position DC within that section is DC = (Dk, +Dk, 10...・・・・・・・・・
+Dks)/S. Here, k is the interval (
0≦to≦3) S is the number of sectors (S-32), Dks
is the position within the interval obtained by Sefta S (Q(
Dks〈1).

Furthermore, when the track runout signal is obtained over two sections, the section where the center position exists and the position D within the section
C is D'C=([)k, +Dkl +-・・・・-+DkL
+(1+D(k+1)(L+1))+(1+D,(k+
1)(,L+2))10・・・・・・・・・+(1+D(
k+1)8))/8 D'c (When 1, exists in Lk section Dc=D'cD'
When C>1, it exists in the Lk+1 interval and is obtained by DC=D'C-1. Here, k and S are the same as above,
L is "", an arbitrary value of 0<L<8. Also, k=4
=o when .

Now, when a single track is being sought, the speed of the head is first controlled according to a preset speed table until the head is within a predetermined distance, for example, 0.3 tracks, from the target track. In detecting the head position at this time, the position obtained from the surface opposite to the surface where the target track exists is determined by the phase difference PAB or PBA.
Corrected and used.

On the other hand, when the target track reaches a predetermined distance and shifts to position control, the CPU 47 determines that the target track is between 4N and 4N.
+3, and depending on the track, the I10 boat 50. D/A
In the position signal obtained from the plane where the target track exists, the following signal is outputted to the compensation circuit 52 via the converter 51.

X; 4Nl-Rack-Y; 4N+1 Track-X; 4N+21-Rack Y; 4N+3 Track T In other words, when the head on the surface where the target track exists is on-track on the target track, the center of the positive slope is always This is because position control is performed using a signal such that . Therefore, it is necessary to output a signal having a similar slope from the position signal obtained from the surface opposite to the surface where the target track exists, and the CPU outputs a signal that has been corrected as follows using the above phase difference. .

(i) To obtain the slope of When 4, ゛ y − - 1 When -y-+X 3≦P(When 4 -U-Black+X (Mountain) - To obtain the slope of -10 -+X 1≦P (when 2 -U-black tenx
When PA'B exists on the B side, p=pBA is used. Moreover, X is a value below the decimal point of PAB and PBA.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the servo sector recording pattern of a conventional embedded servo system, FIG. 2 is a waveform diagram showing an example of a signal that the head reads through the recording pattern, and FIG. , Y, 'U, V signals and the head position. FIG. 4 is a diagram schematically showing the recording pattern of a floppy disk according to an embodiment of the present invention. FIG. FIG. 6 is a diagram showing the details of the servo sector portion of the pattern, FIG. 6 is a diagram showing the relationship between track runout and position signals of each surface according to the same embodiment, and FIG. 7 is a diagram showing the electrical configuration of the floppy disk device according to the same embodiment. FIG. 1.16...Data sector, 2,15.17...Servo sector, 3.18...Erase section, 4.19...
・AGO section, 5.21...Position section, 8, 24
. 25.33...head, 11...floppy disk. 12...Data zone, 13...Guard zone, 1
4... Sector, 20... Zone part, 35... Stopper. Representative patent attorney Noriyuki Chika (and 1 other person) Figure 1 Figure 2 Figure 3 Figure 4 Figure 5/ Figure 6 External causes Internal causes Figure 7

Claims (1)

[Claims] (1) A recording area is provided on each of the opposing surfaces, and a plurality of concentric annular tracks are defined on each surface, and each of these tracks is divided into a plurality of sectors provided at equal angular intervals. In a disk, the valley sector is composed of a servo sector in which servo information for head positioning is embedded in advance and a data sector for writing/reading data.The above sectors have the same number on each data surface, and each data The relative positional relationship of the sectors on the surface is such that the phase in the circumferential direction is different by 1/2 sector, that is, the center position of two adjacent sectors on one surface is located at the center of the sector on the other surface, The servo information embedded in the sectors of each data surface whose phase in the circumferential direction differs by 1/2 sector is detected alternately as the disk rotates, the servo information is read from each surface, and the servo information embedded in each data surface is Data is written/read by detecting the phase difference in the position signal obtained from the valley surface, which is caused by the relative positional deviation of the pattern in the radial direction and the positioning of the head on each data surface. Therefore, the servo information obtained from the surface opposite to the surface where the track to be accessed exists is extracted according to the detected phase difference, and it is determined that the track to be accessed exists (2
) Servo information is obtained from the two-phase dibit pattern.