JPH0421268B2 - - Google Patents

Description

Detailed Description of the Invention <<Field of Application of the Invention>> The present invention relates to a head capable of at least reading recorded information out of recording information on a disc-shaped recording medium and reading recorded information from the recording medium. The present invention relates to a head control device for a disk device that controls the positioning of a recording medium in the radial direction.

<<Background of the Invention>> Magnetic disks are well known as disk-shaped recording media, and floppy disks in particular are widely used in personal computers and the like because of their ease of use.

However, the capacity of floppy disks is relatively small and the data transfer rate is limited, which may be inconvenient for some applications.

For this reason, in systems used for this type of application, so-called Wenchiester type fixed hard disks are used, and floppy disks are used to back up important information stored on these fixed hard disks. It is used as a medium.

However, this type of system requires disk devices for both the fixed hard disk and the floppy disk, which poses a problem in that the system price becomes high.

Therefore, cartridge-type hard disks (removable disks) are used in this type of system because they are easy to handle, have a large capacity, and have a high data transfer rate.

In this disk device, when a cartridge containing a hard disk is loaded, the hard disk is rotated at high speed, and after a short period of time, the magnetic head is levitated by the dynamic pressure generated by the rotation of the disk. The head records information on the hard disk and reads it.

Here, improvements are being made to further increase the recording capacity while ensuring device reliability by preventing dust from entering the space mentioned above, preventing scratches on the disk surface and head caused by the dust, and improving head positioning accuracy. The system is designed for use in disk devices.

However, it is difficult to align the recording track center of a loaded hard disk with its rotation center, and the hard disk rotates eccentrically. It is impossible to accurately position the head relative to the disk drive, and this can cause problems when trying to increase the recording capacity, or it may be necessary to exchange disks on which information is recorded between different disk devices of the same type. There were drawbacks such as reduced reliability in terms of being able to read and write information (interchangeability).

[Object of the Invention] The present invention has been made in view of the above-mentioned conventional problems, and its object is to accurately position and control the head with respect to the track regardless of the eccentric rotation of the disk-shaped recording medium. An object of the present invention is to provide a head control device for a disk device.

<<Structure of the Invention>> In order to achieve the above object, the present invention comprises a head 2 for reading recorded information from a disk-shaped recording medium 1 which is rotationally driven, and a reading head 2 arranged in the radial direction of the recording medium 1 in FIG. The head positioning control device 3 includes: a head drive system 4 for driving the reading head 2; a head control system 5 for controlling the head drive system 4; The drive system 5 includes a rotation angle detection means 6 for detecting the rotation angle of the recording medium 1, a position detection means 7 for detecting the track position from the read head output, and a detection position of the positioning reference track 9 at the reference rotation angle 8. The pitch calculation means 13 calculates the pitch 12 of each data track 11 between the two reference tracks 9 and 10 based on the detected position of the positioning reference track 10 and the detected position of the positioning reference track 9 at a plurality of set rotation angles 14. Positioning reference track 9 in which the rotation angle of the recording medium 1 is a variable
an eccentricity calculation means 16 for determining the eccentricity 15 of the reading head 2; a target position calculation means 17 for determining the position of the data track 11, which is the positioning target of the reading head 2, based on the track pitch 12; A target position correction means 19 for correcting the target position 18 at the rotation angle using the eccentricity 15 of the positioning reference track 9, and control for applying the corrected target position 20 to the drive system 4 as a positioning control target value 21 for the reading head 2. It is characterized by including a target value output means 22.

<<Embodiments of the Invention>> Hereinafter, preferred embodiments of the apparatus according to the present invention will be described based on the drawings.

In FIG. 2, a hard disk 30 is rotationally driven by a spindle motor 32 consisting of a DC brushless motor, and a magnetic head 34 records information on the disk 30 and reads the recorded information.

The disk 30 is housed in a cartridge (not shown), and is set in the apparatus as shown in FIG. Note that the cartridge is inserted into the interior through the door 36 and is inserted into the disk 3.
The disk 30 and the spindle are connected by the armature 42 shown in FIG. 2 which is integrated with the spindle being attracted to a magnet (not shown) which is integrated with the spindle.

Further, the head 34 is attached to an arm 38 shown in FIG. 3, and the arm 38 is supported by a movable table 40.

This movable table 40 can move forward and backward with respect to the center of rotation of the disk 30, and its forward and backward movement is performed by a step motor 44. The driving force of the step motor 44 is transmitted to the movable table 40 in FIG. 3 via a power transmission mechanism 46 in FIG. 2 including a pulley, a belt, etc.

Here, the step motor 44 constituting the head drive system 4 is controlled by the head control system 5 described below.

In FIG. 2, an index signal detection mark 42a attached to the armature 42 is detected by an index signal detection sensor 48 as an index signal. The rotation angle of the disk 30 is generated by time control from the index signal, and each angle obtained by dividing the disk 30 into several parts is thereby obtained.

Further, drive control pulses (control signals) for the step motor 44 are counted by a head position detection circuit 50, and the position of the reading head 34 is estimated by the counting operation of the head position detection circuit 50.

These detection signals are supplied to a motor control circuit 52, and the output voltage of the head 34 is supplied to this motor control circuit 52.

This motor control circuit 52 is mainly composed of a microcomputer, and its control signals are supplied to a driver 54 that drives the spindle motor 32 and a driver 56 that drives the step motor 44.

This embodiment has the above configuration, and its operation will be explained below.

In FIG. 4, the disk 30 has a data area 10 in which a large number of data tracks 100 are formed.
2, a reference track 104 used as a positioning reference track 9 is formed on the outside thereof, and a reference track 106 used as a reference track 10 for pitch calculation is formed on the inside thereof.

An index area 108 is provided in a narrow rotation angle range, and its left boundary angle (θ=0) in the figure is the aforementioned reference rotation angle 8.

FIG. 5 shows an example of the recorded contents in the index area 108, and the area 1
On the outside of the reference track 104 where the 08 portion has been subjected to DC erasure, there is provided an identification track area 110 where similar erasure has been performed.

Further, a DC erasure area 112 is provided inside the reference track 104 and outside the data area 102.
02, DC erasure areas 114 and 116 are provided inside this reference track 106, respectively.

Further, servo information, which will be described later, is recorded in a data area 102 within this area 108, and a gap area 120 is formed in the radial direction at one end of the data area 102.

As understood from FIG. 6, the above servo information consists of information A and information B, and information A is area 10.
Information B is recorded in the left half area of 8, and information B is recorded in the right half area.

And the width of information A and B is the same and is track 100.
The information A and B are shifted from the track 100 by half the pitch and arranged alternately in the radial direction.

FIG. 7 shows the identification track area 110 of FIG.
In this area 110, identification tracks 122 and DC erasure areas 124 are alternately formed in the radial direction.

The innermost identification track 122i is provided adjacent to the reference track 104 via two DC-cancelled tracks.

FIG. 8 shows the motor control circuit 52 in FIG.
The control procedure carried out is shown, and in step 200, rotation of the disk 30 is started.

Then, in step 202, the reference track 104 is searched in accordance with the procedure shown in FIG.

At step 304 in FIG. 9, the head 34 is moved from the peripheral edge of the disk 30 to the identification track area 110, and then the head 34 is driven intermittently by 1/4 track width (step 306).

At step 300, the head 34 rotates at the rotation angle θ=0.
When it is confirmed from the index signal that it has moved to the position, in step 302, this angle θ = 0
The following processing is performed based on this synchronization.

Furthermore, the above-mentioned absent driving is continued until the head output V becomes equal to or higher than the value V ^* shown in FIG. 10 (step 308).

Note that the horizontal axis in FIG. 10 represents the head movement position X, and the value V ^* is set to half the peak output Vp when the head 34 reaches the track center Xp.

The fact that the head output V has exceeded the value V ^* means that the identification track 122 has been detected, and when that detection is performed, the head 34 is further intermittently driven by 1/16 track width, and the drive head output V is This is done until it begins to drop (step 310,
312).

This decrease in the head output V is due to the identification track 122.
This means that the head 34 has been moved near the peak position Xp, and then the head 34 is controlled to move toward the center of rotation by two tracks (step 314).

Thereafter, it is monitored whether the head output V exceeds the value V ^* (step 316), and if the head output V does not exceed the value V ^* , the head 34 is output from the identification track 122.
The control proceeds further by the distance of 2 tracks minus the width of
Return to

Also, when the head output V exceeds the value V ^* ,
A track search flag indicating detection of reference track 104 is set (step 320).

As can be understood from the above description, during the initial low speed drive of the head 34, the outermost identification track 1
22 is detected, the head 34 is driven at a slow speed.

When the center of the track 122 is detected during the slow speed drive, the head 34 moves to the area 122.
are jumped one after another until the reference track 104 is searched.

By providing the identification track 122 in this manner, the search for the reference track 104 is facilitated.

In FIG. 8, this search process (step
202), the eccentricity characteristic of the reference track 104 is determined in step 204 as follows.

FIG. 11 shows the processing procedure of step 204. First, the center position of reference track 104 is detected (step 400).

The processing procedure for detecting the center position is shown in FIG. 12, in which the head 34 is intermittently advanced by a minute amount ΔX until its output V becomes equal to or greater than the value V ^* (steps 500, 502).

When the output V becomes equal to or greater than the value V ^* , the position Xi in FIG. 13 at that time is stored (step 504).

Furthermore, the head 34 is intermittently fed by a minute amount ΔX until its output V becomes equal to or less than the A value V ^* (step
506, 508), and when the output V becomes less than or equal to the value V ^* , the position Xj at that time is stored (step 510).

Finally, the value obtained by subtracting the quantity ΔX and the position Xi from the position Xj is divided by 2 to obtain the center position Xc shown in FIG. 13 (step 512).

When the track center position Xc is thus detected at step 400 in FIG. 11, it is stored (step 402), and then these processes (steps 400, 402) are performed at a plurality of different rotation angles. It is determined whether or not (step 404).

When these processes (steps 400, 402) are performed for each set rotation angle, the eccentricity of the reference track 104 at each set rotation angle is determined with the position θ=0 as a reference (step 408).

Furthermore, from these eccentricities, eccentricities for more rotation angles and for all rotation angles are estimated (step 410).

These eccentricities are obtained by subtracting the center position at angle θ=0 from the center position at each rotation angle, and are stored as characteristics at step 206 in FIG.

In the next step 208, the head 34 is driven to search for the reference track 104, and in step 210
Then, the center position of the track 104 at the angle θ=0 is stored.

In this step 212, the reference track 10 is
The distance between 4 and 106 is determined from their center positions, and the distance is divided by the total number of tracks between them, and the resulting data track pitch is stored as a coefficient.

Thereafter, the motor control circuit 52 enters a standby state for command input (step 214).

Here, when a movement command for the head 34 is input and the number of tracks from the reference track 104 to the moving target data track 100 is specified, in step 216, the number of tracks is multiplied by the data track pitch. Reference track 10
The position of the data track 100, which is the moving target, is determined by adding the center positions of the data track 100.

The head 34 is then moved to the target position (step 218), at which time the head 34 is at an angle θ=
If it is confirmed that it is in the 0 position (step
220), the radial positioning error at that position is detected using the servo information A and B shown in FIG. 6 (step 222).

Further, in step 224, the target position is corrected based on the detection error, and in step 226, the head 34 is slightly moved to the corrected target position.

Also, in step 228, the target data track 10 is
The rotation angle indicating the indicated position at 0 is set, and it is confirmed in step 230 that the angle θ is not 0. In step 232, the amount of eccentricity at that angle is determined from the above characteristics, and correction is made using this amount of eccentricity. The head 34 is positioned to the determined target position.

As explained above, according to this embodiment, even if the head 34 rotates eccentrically with respect to the center of rotation, the head 34 can be accurately positioned at a specified angular position on the specified data track 104 of the disk 30, so that the spacing between those tracks can be adjusted. This makes it possible to increase the recording capacity of the disk 30.

Furthermore, since the head 34 can be positioned with high precision using the servo information A and B, the disk 34 can be positioned with high accuracy.
It becomes possible to increase the recording capacity of.

Furthermore, since the identification track 122 is provided outside the reference track 104, the identification track 122
It is possible to facilitate the search of 4.

<<Effects of the Invention>> As explained above, according to the present invention, the positioning target value at a specified rotation angle is corrected based on the eccentricity of the recording medium that has been investigated in advance, so that the target track can be achieved despite eccentric rotation of the recording medium. It becomes possible to accurately position the head relative to the head.

As a result, it becomes possible to significantly increase the recording density of a removable disk, and interchangeability between disk devices becomes possible without reducing reliability.

[Brief explanation of drawings]

Fig. 1 is a diagram corresponding to claims, Fig. 2 is a block diagram showing a preferred embodiment of the device according to the present invention, Fig. 3 is an explanatory diagram of the internal structure of the disk device, Fig. 4 is an explanatory diagram of recorded contents of the disk, Fig. 5 is an explanatory diagram of the index area, Fig. 6 is an explanatory diagram of servo information, Fig. 7 is an explanatory diagram of the identification track area, Figs. 8 and 9 are flowcharts, and Fig. 10 is a head output characteristic diagram.
11 and 12 are flowcharts, and FIG. 13 is a head output characteristic diagram. DESCRIPTION OF SYMBOLS 1... Recording medium, 2... Reading head, 3... Head positioning control device, 4... Head drive system, 5
...Head control system, 6...Rotation angle detection means, 7...
... position detection means, 13 ... track pitch calculation means, 16 ... eccentricity calculation means, 17 ... target value calculation means, 19 ... target value correction means, 22 ... control target value output means.

Claims (1)

[Scope of Claims] 1. A head positioning control device comprising: a reading head for reading recorded information from a rotationally driven disk-shaped recording medium; and a head positioning control device for positioning and controlling the reading head in the radial direction of the recording medium. The head control system includes a head drive system that drives the reading head and a head control system that controls the head drive system. position detection means for detecting the track position; track pitch calculation means for calculating the pitch of each data track between the two reference tracks based on the detected position of the positioning reference track at the reference rotation angle and the detected position of the pitch calculation reference track; Eccentricity calculation means for calculating the eccentricity of the positioning reference track with the rotation angle of the recording medium as a variable from the detected position of the positioning reference track at a plurality of set rotation angles, and a track pitch for determining the position of the data track that is the positioning target of the reading head. a target position calculation means for calculating the target position based on the rotation angle of the recording medium, a target position correction means for correcting the target position at the rotation angle using the eccentricity of the positioning reference track determined based on the rotation angle of the recording medium, and a reading head for the corrected target position. 1. A head control device for a disk drive, comprising: control target value output means for providing a positioning control target value to a head drive system.