JPS61153886A - Head control device of disk device - Google Patents

Abstract

PURPOSE:To position correctly a head regardless of an eccentric rotation of the recording medium by obtaining a data track position, which goes to be the positioning target of a reading head, based upon a track pitch and correcting a target position based upon the eccentric quantity of a reference track determined by the rotational angle of the recording medium. CONSTITUTION:A rotational angle from a reference position of recording medium 1 during the rotation is determined by a rotational angle detecting means 6, the position of a positioning track 9 and a reference track 10 for counting a pitch in a reference rotational angle 8 is counted by a position detecting means 7 from the output of a reading head 2, and the pitch of respective data tracks 11 is obtained at a track pitch calculating means 13. The eccentric quantity of the track 9 as a function of the rotational angle is obtained by an eccentric quantity calculation means 16 from the position of a reference track 9 in plural set rotational angles 14. To a target position of the data track obtained based upon a track pitch 12 at a target position setting means 17, the correction of an eccentric quantity 15 is added by a target position correcting means 19, and the head 2 is positioned through a control target value output means 22 and a head driving system 4.

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 positioning in the radial direction of a recording medium.

(Background of the Invention) Magnetic disks are well known as disc-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 speed is limited, which may cause problems depending on the application.

For this reason, systems used for this type of purpose use so-called Wenchester-type fixed hard disks, and floppy disks are used as recording media to back up important information stored on these fixed hard disks. It's being used.

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

Therefore, a cartridge-type hard disk (removable disk) is used in this type of system because it is easy to handle, has a large capacity, and has a high data transfer rate.

In such a disk drive, when a cartridge containing a hard disk is loaded, the hard disk rotates at high speed, and a magnetic head is levitated through a small gap by the dynamic pressure generated by the rotation of the disk. Information is recorded on and read from the hard disk.

Here, improvements can be made to further increase the recording capacity while ensuring device reliability by preventing dust from entering the gap, preventing scratches on the disk surface and head caused by the dust, and improving head positioning accuracy. This type of disk device is designed.

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 using the same type of disk drive, and this may cause problems in increasing the recording capacity, or may cause discs on which information is recorded to be exchanged between different disk drives of the same type. It had drawbacks such as lowering the reliability of being able to read and write (interchangeability).

(Object of the Invention) The present invention has been made in view of the above-mentioned conventional problems, and its object is to be able to accurately position and control the head with respect to the track regardless of the eccentric rotation of the disc-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 includes a reading head 2 that reads recorded information from a disk-shaped recording medium 1 that is rotationally driven; Head positioning control device 3 that performs positioning control in the radial direction
The head positioning control device 3 includes: a head drive system 4 that drives the reading head 2; and a head control system 5 that controls the head drive system 4; a rotation angle detection means 6 for detecting the rotation angle of the reading head, a position detection means 7 for detecting the track position from the output of the reading head, a detection position of the positioning reference track 9 at the reference rotation angle 8, and a detection of the pitch reference track 10. track pitch calculation means 13 that calculates the pitch 12 of each data track 11 between both reference tracks 9 and 10 based on the position, and the rotation angle of the recording medium 1 from the detected position of the positioning reference track 9 at a plurality of set rotation angles 14. Eccentricity 1 of the positioning reference track 9 where is taken as a variable
5, a target position calculating means 17 that calculates the position of the data track 11, which is the positioning target of the reading head 2, based on the track pitch 12, and a positioning standard determined based on the rotation angle of the recording medium 1. A target position β king means 19 corrects the target position 18 at the rotation angle using the eccentricity @15 of the track 9, and a positioning control target value 21 for reading the corrected target position 20 and the positioning control target value 21 for the navels 1 and 2.
control target value output means 22 to give to the head drive system 4 as
It is characterized by including and.

(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. The cartridge is inserted into the interior from the static 36, and the armature 42 shown in FIG. connected.

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 moving 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 controlled by a step motor 44.
It is carried out by The driving force of the step motor 44 is transmitted through the power transmission mechanism 4 in FIG. 2, which includes a belt and the like.
6 to the moving table 40 in FIG.

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

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 head position detection circuit 50 estimates and detects the position of the reading head 34 by the counting operation.

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 provided.

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

In FIG. 4, the disk 30 is provided with a data area 102 in which a large number of data tracks 100 are formed, and a reference track 104 used as a positioning reference track 9 is located outside the data area 102, and a reference track for pitch ejection is located outside the data area 102. A reference track 106, used as 10, is formed inside each of them.

and index area 1 in a narrow rotation angle range.
08 is provided, and the 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 outside the reference track 104 where the area 108 portion has been DC erased, there is an identification track area 110 where similar erasure has been performed. It is being

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

Furthermore, data area 102 within this area 108
Servo information, which will be described later, is recorded therein, 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 servo information consists of information A and information B, with information A being recorded in the left half of area 108 and information B being recorded in the right half of the area.

The widths of the information A and B are the same and set approximately equal to the pitch of the track 100, and the information A and B are shifted from the track 100 by half the pitch and are alternately arranged in the radial direction.

FIG. 7 shows the identification track area 110 of FIG. 5, and in this area 110, the identification trough 9-1
22 and DC erasure areas 124 are formed alternately in the radial direction.

The innermost identification track 1221 is provided adjacent to the reference 1 to rack 104 via two DC-erased tracks.

FIG. 8 shows a control procedure performed by the motor control circuit 52 in FIG. 2, and in step 200, rotation of the disk 30 is started.

Then, in step 202, references 1 to 104 are searched according to the procedure shown in FIG.

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

In step 300, when it is confirmed from the index signal that the head 34 has moved to the position where the rotation angle θ=O, in step 302, synchronization is established with this angle θ=O,
The following processing is performed based on this synchronization.

Roughly speaking, in the above intermittent drive, the head output V is the value 78 in Fig. 10.
This is continued until the above is reached (step 308).

The horizontal axis of FIG. 10 shows the head movement position X, and the value 8 is set to half the peak output Vp when the head 34 reaches the track center χp.

When the head output V exceeds the value 78, it 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 this driving is performed as the head output V increases. This is done until it starts to drop (steps 310, 312>).

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

Thereafter, it is monitored whether the head output ■ exceeds the value ■8 (step 316), and if the head output ■ does not exceed the value ■8, the head 34 outputs an amount corresponding to the distance between the identification tracks 122 minus the width of two tracks. Further control is performed (step 318), and the process returns to step 308.

Further, when the head output ■ exceeds the value V8, a track search flag indicating the detection of the reference track 104 is set (step 320).

As can be understood from the above description, when the outermost identification track 122 is detected during the initial low speed drive of the head 34, the head 34 is driven at a slow speed.

When the center of the track 122 is detected during the slow drive, the head 34 jumps areas 124 one after another and is moved 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, when this search process (step 202>) is performed, in step 204, the reference track 104 is
The eccentricity characteristic of is obtained as follows.

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

The processing procedure for detecting the center position is shown in FIG.
It is intermittently fed by Δχ (steps 500, 502>).

Then, when the output V becomes greater than or equal to the value v8, the 13th
The position Xi in the diagram is stored (step 504).

Furthermore, the head 34 is intermittently fed by a minute amount Δχ until its output V becomes less than the value ■8 (steps 506 and 508>
, the position X when the output V becomes less than or equal to the value V8
j is stored (step 510).

Finally, the value obtained by subtracting the amount Δχ and the position χi from the position Xj is divided by 2 to obtain the center position χG shown in FIG. 13 (step 512).

When the track center position χC is detected in step 400 of FIG. 11 in this way, 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 and 402) are performed for each set rotation angle, the position θ=07!
As the i-reference, the amount of eccentricity of the reference track 104 at each set rotation angle is determined (step 408).

Further, from these eccentricities, the eccentricity for a large number of rotation angles or for all rotation angles is estimated (step 410).

The amount of eccentricity is the angle θ from the center position at each rotation angle.
= The center position when O is subtracted,
It is stored as a characteristic in step 206 of FIG.

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

And in this step 212, the reference track 104.1
The distance between 06 and 06 is calculated from their center positions, and the distance is divided by the total number of tracks between them, and the data track pitch obtained thereby 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 a number of tracks from 1 to 100 from the reference 1 track 104 to the moving target data track 100 is specified, the number of tracks is multiplied by the data track pitch in step 216km. The center position of the reference 1-rack 104 is added to the calculated value to determine the position of the data track 100, which is the moving target.

Next, the head 34 is moved to the target position (step 218>, and when it is confirmed that the head 34 is at the angle θ=O (step 220>), the servo information A and B in FIG. is used to detect the radial positioning error at that position (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.

Further, in step 228, the rotation angle indicating the indicated position on the target data track 100 is set to zero, and when it is confirmed in step 230 that the angle 0 is not 0, the eccentricity at that angle is determined from the above characteristics. The amount of eccentricity is determined, and the head 34 is positioned to a target position corrected by this amount of eccentricity.

As explained above, according to this embodiment, even if the head 34 rotates eccentrically with respect to the rotation center, 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 track interval can be adjusted. This makes it possible to increase the recording capacity of the disk 30. - Also, since the head 34 can be positioned with high precision using the servo information A and B, it is possible to roughly increase the recording capacity of the disk 30.

Furthermore, an identification track 12 is provided outside the reference track 104.
2, it is possible to facilitate the search for the track 104.

(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 checked in advance, so that the target position can be tracked even if the recording medium is eccentrically rotated. 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 the interchangeability of disks 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, and 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, and Fig. 8 is an explanatory diagram of the identification track area.
9 is a flow chart, FIG. 10 is a head output characteristic diagram, FIGS. 11 and 12 are flow charts, and FIG. 13 is a head output characteristic diagram. 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)

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