JP2000048499A - Head positioning controller, method therefor and disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct a disturbance frequency at an operation time when the moving amount of a head is large by moving the head from a first target track to the vicinity position of a next second target track based on a prescribed position error signal and a frequency correction coefficient. SOLUTION: AFC filters 23B-23D execute AFC operation processing for an error signal S3 based on a convergent value of an AFC coefficient in a tracking mode time, and adds its result to an output of a seek control part 29 through adders 45, 43. On the other hand, the AFC filter 23A execute the AFC operation processing for the output of the seek control part 29 based on a final convergent value in the last tracking mode time just before mode switch, and adds the result to the output of the seek control part 29 with the adder 44. Thus, even in the seek mode time when the moving amounts of magnetic heads 14A-14D are large, a disk rotation synchronous disturbance according to the output of the seek control part 29 is corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head positioning control apparatus and method, and a disk apparatus, and more particularly, to a disk apparatus for recording or reproducing a disk-shaped recording medium such as a magnetic disk, a magneto-optical disk, and an optical disk. Things.

[0002]

2. Description of the Related Art Conventionally, among magnetic disk drives of this type, a magnetic material powder such as iron oxide is usually applied to one or both surfaces of a substrate made of a material such as aluminum alloy or glass. A magnetic disk is used as a recording medium.

In such a magnetic disk drive, for example, an embedded servo system is applied. After forming a plurality of servo areas on one or both sides so as to spread radially from the center of the magnetic disk, the data area is formed at an equal angle. By writing servo information between the data areas (hereinafter, this operation is called servo write)
The positioning of the magnetic head is controlled based on the servo state.

At this time, the magnetic disk device has a seek mode in which the magnetic head is moved to a position near the target position at a high speed, a settling mode in which the magnetic head is settled at the target position, and a tracking mode in which the magnetic head follows the target position. Are sequentially switched in accordance with the positioning state of the magnetic head.

In particular, in a magnetic disk device of a fixed medium type such as a Winchester disk, servo writing is often performed after the device is assembled, and a disturbance (hereinafter, referred to as a synchronous operation) generated when the disk rotates at that time. Since this is called a disk rotation synchronous disturbance, the PID (Proportional, Integrat) during tracking is not so large.
A sufficient control band is taken by a closed loop system using a compensator, an H∞ controller and the like, so that the disk rotation synchronous disturbance can be suppressed.

However, when a magnetic disk made of a resin material such as plastic is used as a substrate, unlike the magnetic disk made of an aluminum alloy or glass, the above-mentioned substrate is very soft and has an environment such as temperature and humidity. Since the weather resistance to the change is low, the rate of expansion or expansion during use or storage with the lapse of time is high.

For this reason, in a medium-fixed type magnetic disk drive using a magnetic disk whose substrate is made of a resin material such as plastic, the primary component (eccentricity) of the disk rotation synchronous disturbance may change with time. Yes, and
Depending on the rotational accuracy of the spindle motor at the time of servo writing, the second-order or higher disturbance component may increase with time.

Incidentally, the i-th (i is a natural number) order component of the disk rotation synchronous disturbance is when the magnetic disk is eccentric (i = 1) or when the track on the magnetic disk is elliptical or irregular. (I = 2), when the stamper as the manufacturer of the magnetic disk is deformed (i ≧ 3)
And the like.

Further, in such a magnetic head device using a magnetic disk whose substrate is made of a resin material such as plastic, the disk rotation synchronization is required even though the requirement for head positioning accuracy by narrowing the track pitch is becoming more severe. It is becoming difficult to secure a sufficient suppression rate of disturbance.

For this reason, it is desirable to introduce a filter that secures a suppression rate by putting a sine wave generation model in a closed loop by applying the principle of the internal model and increasing the gain at the disturbance frequency. Adaptive Feedforward Canceller (AFC: AdaptiveFe
edforward Cancellation) has been proposed.

FIG. 5 shows a control system 1 using AFC. In the control system 1, when a periodic disturbance d (t) having a predetermined frequency is input to the control target P (s), the disturbance frequency is suppressed using a digital AFC filter 2. First, when the periodic disturbance d (t) is input to the control target P (s) via the adder 3, the component of the periodic disturbance d (t) is given to the control target P (s), and the component corresponding to the component is given. The output y (t) is sent to the outside and the AFC filter 2.

Incidentally, the frequency of this periodic disturbance d (t) is denoted by ω
Assuming that _i / 2π, the periodic disturbance d (t) is given by the following equation.

[0013]

(Equation 1)

## EQU1 ## Subsequently, in the AFC filter 2, the output y (t) of the control target P (s) is given to the corresponding multipliers 4 and 5, and cos (ω _i t + Φ
_{After i)} and _{sin (ω i t + Φ i} ) are multiplied, the multiplication result is supplied to the integrator 6 and 7, respectively. The integrators 6 and 7 generate AFC coefficients a _i and b _i by integrating the multiplication results of the multipliers 4 and 5, respectively. Note that Φ _i is the AFC addition point (u
(T)) is the phase value of the frequency ω _i / 2π in the transfer function from the AFC pull-in point (y (t)).

The AFC coefficient a _i thus generated
And b _i are multiplied by cos (ω _i t) and sin (ω _i t) in the corresponding multipliers 8 and 9, respectively, and the respective multiplication results are added in the adder 10, and the addition results are controlled by the adder 10. It becomes the input u (t) of the target P (s).
This input u (t) is given by

[0016]

(Equation 2)

## EQU1 ## The input u (t) is added to the periodic disturbance d (t) in the adder 3, and a predetermined frequency component of the periodic disturbance d (t) is suppressed. Thus, by repeating such feedforward control using the AFC filter 2, the AFC coefficients a and b
Are the AFC coefficients A and B expressed in the periodic disturbance d (t).
As a result, the periodic disturbance d (t) is canceled (canceled) by the input u (t) in the adder 3.

In practice, the arithmetic processing by the AFC filter 2 (hereinafter referred to as AFC arithmetic processing) is usually performed by a digital arithmetic unit (DSP: Digital Signal Processor).
Since it is performed internally, in that case the AFC coefficients a and b are

[0019]

(Equation 3)

[0020]

(Equation 4)

Is updated according to the update rule expressed by Here, k is an integer indicating the sampling time, and T is a sampling interval. At this time, the system function (transfer function) C (t) (= u (t) / y) of the AFC filter 2
(T)) is given by

[0022]

(Equation 5)

## EQU2 ##

FIG. 6 shows a conventional magnetic disk drive 10.
A magnetic head 14A attached to each end of the head arm 13 while rotating a plurality of magnetic disks 11A and 11B whose substrates are made of a resin material such as plastic, respectively, at a high speed in accordance with the rotational drive of the spindle motor 12.
To 14D in response to the driving of the voice coil motor (VCM) 15, and the magnetic disks 11A and 11B are respectively moved.
One side 11AX, 11BX and the other side 11AY, 11BY
And the other surface 1AX, 11BX and the other surface 1 of the magnetic disks 11A, 11B are aligned.
Data is recorded or reproduced following tracks concentrically or spirally formed on 1AY and 11BY.

In the magnetic disk drive 10, the above-described embedded servo system is applied, and the servo writer 16 includes one surface 11AX of the magnetic disks 11A and 11B.
Servo information serving as a time reference is formed in each of the servo areas formed on the 11BX and the other surfaces 11AY and 11BY, thereby obtaining position information of the magnetic heads 14A to 14D.

A reproduction signal S1 obtained by reproducing the servo information in each of the servo areas on one surface 11AX, 11BX and the other surface 11AY, 11BY of the magnetic disks 11A, 11B by the magnetic heads 14A to 14D passes through a preamplifier 17 via a preamplifier 17. After being amplified, it is converted into a digital signal via an A / D (analog / digital) converter 18 and sent to the position error signal generator 19 as a reference signal S2.

The position error signal generator 19 generates a position error signal (PES) S3 indicating how much the magnetic heads 14A to 14D are displaced from the target track based on the reference signal S2. Thereafter, this is sent to the adder 21 and the switch 22 in the AFC correction control system 20.

The AFC correction control system 20 generates an error signal S
3 through the switch 22 to four AFC filters 23A
To 23D, and executes the above-described AFC operation to suppress the first to fourth order components of the disk rotation synchronous disturbance, and then adds these outputs via the adder 24. The result of this addition is sent to the adder 21 via the switch 25 as an AFC output signal S4.

The switches 22 and 25 are turned on only in the tracking mode by the mode switching signal S5 obtained from the control mode switching section 26.
In the other seek mode or settling mode, it is kept off.

Here, assuming that the rotation frequency of the magnetic disks 11A and 11B is ω / 2π, 1
AFC filter 23 for canceling the fourth order component
The system functions C ₁ (z) to C ₄ (z) of A to 23D are
Respectively

[0031]

(Equation 6)

[0032]

(Equation 7)

[0033]

(Equation 8)

[0034]

(Equation 9)

Is represented by

On the other hand, the adder 21 adds the phase error signal S3 obtained from the phase error signal generator 19 and the AFC output signal S4 obtained by adding the four AFC filters 23A to 23D. An ACF correction signal S6 is generated.

Subsequently, a pair of switches 30 and 31 having three input / output terminals are provided before and after the tracking control unit 27, the settling control unit 28, and the seek control unit 29, and are obtained from the control mode switching unit 26. On the basis of the mode switching signal S5, the switches 30 and 31 are interlocked so as to be connected to the input / output terminals at the same positions.

Thus, when the magnetic heads 14A to 14D are positioned on the target track, the AFC correction control system 20
Switches the switches 22 and 25 ON only in the tracking mode when the mode is sequentially switched to the seek mode, the settling mode and the tracking mode, and sets the switch 2 in the subsequent seek mode and the settling mode.
2 and 25 are turned off.

Thus, the AFC output signal S4 is sent to the adder 21 only in the tracking mode, and the AFC correction signal S6 obtained by adding the phase error signal S3 to the adder 21 is sent to the tracking controller 27. .

After calculating the head position information of the magnetic heads 14A to 14D based on the AFC correction signal S6, the tracking control unit 27 uses this as a head drive signal S7 via a D / A (digital / analog) conversion unit 32. After that, it is sent to the voice coil motor driver 33. As a result, the voice coil motor driver 33
Is the voice coil motor 1 based on the head drive signal S7.
5 by driving the magnetic heads 14A to 14D to the respective surfaces 1 of the corresponding magnetic disks 11A and 11B.
The target tracks formed on the 1AX, 11BX and the other surfaces 11AY, 11BY can be tracked.

On the other hand, in the seek mode or the settling mode, the error signal S3 obtained from the position error signal generating section 19 is supplied directly to the settling control section 28 or the seek control section 29, and the settling control section 28 or the seek control After calculating the head position information, the unit 29 calculates the head drive signal S8 or S
9 is transmitted to the voice coil motor driver 33 via the D / A converter 32.

Thus, the voice coil motor driver 33
Drives the voice coil motor 15 on the basis of the head drive signal S8 or S9, so that the magnetic head 14A
To 14D respectively correspond to the magnetic disks 11A and 11A.
One side 11AX, 11BX and the other side 11AY, 11B of B
The target track formed on Y can be sought or settled.

The magnetic disk device 10 is provided with a recording / reproducing section 34, and a predetermined recording signal S supplied from the outside is provided.
10 through the magnetic heads 14A to 14D, one surface 11AX, 11BX and the other surface 11 of the magnetic disks 11A, 11B.
While recording on a target track formed on AY and 11BY, a reproduction signal S11 read from the target track is recorded.
Is sent to a subsequent signal processing unit (not shown).

[0044]

By the way, in the magnetic disk device 10 having such a configuration, the magnetic disks 11A,
1B based on an error signal S3 obtained by reproducing
The filters 23A to 23D execute the above-described AFC operation processing, and add the AFC output signal S4 as the operation result to the error signal S3 to synchronize with the rotation frequencies of the magnetic disks 11A and 11B obtained from the error signal S3. Thus, the disturbance frequency generated due to the disturbance can be sufficiently suppressed.

When positioning the magnetic heads 14A to 14D from the track currently in the tracking control state to a desired target track, the mode is switched from the tracking control unit 27 to the seek control unit 29, so that the currently positioned track is The magnetic heads 14A to 14D are caused to seek to the target track. At this time, A as an AFC calculation processing result by the AFC filters 23A to 23D.
The FC coefficient is a convergence value obtained when tracking control is performed, and an AFC correction signal S6 in which a disk rotation synchronous disturbance is corrected based on the convergence value is input to the seek control unit 29.

Therefore, the seek control unit 29 seeks the magnetic heads 14A to 14D with respect to the target track in a state where the disk rotation synchronous disturbance is not completely corrected. There is a possibility that the magnetic heads 14A to 14D cannot be settled (settled). Therefore, in the seek mode, there is a problem that it is very difficult to perform feedforward control using the convergence value of the AFC coefficient in the tracking mode.

On the other hand, a resin material such as plastic is very soft and has a high rate of expansion or contraction due to a change in environment such as temperature or humidity, as compared with a conventional aluminum or glass substrate. Therefore, even if a magnetic disk whose substrate is made of a resin material such as plastic is mounted on a medium-fixed magnetic disk device and then servo-written, relatively large eccentricity and track deformation may occur with time. There is.

For this reason, in the magnetic head device 10 using a magnetic disk whose substrate is made of a resin material such as plastic, very large eccentricity may occur, and it is desired to compensate for disturbance of a specific frequency component even in the seek mode. There is a request.

In the seek mode, however, the magnetic heads 14A to 14D rotate at high speed with the magnetic disk 11A,
AFC filter 23 moves in the radial direction of 11B.
A to 23D cannot update the value of the AFC coefficient by executing the above-described AFC operation based on the error signal S3, and as a result, compensate for the disturbance frequency synchronized with the rotation frequency of the magnetic disks 11A and 11B. Had a problem that would be very difficult.

Further, the disturbance frequency that could not be compensated in the seek mode may have a further adverse effect in the settling mode. At this time, the magnetic heads 14A to 14D cannot be positioned at desired target tracks on the magnetic disks 11A and 11B. There was a problem.

The present invention has been made in view of the above points, and a head positioning control apparatus and method and a disk control method capable of significantly improving the head positioning accuracy with a simple structure regardless of the type of disk-shaped recording medium. It is intended to propose a device.

[0052]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, a position error signal representing the amount of head displacement relative to a first target track on a disk-shaped recording medium whose substrate is made of a resin material is generated. Position error signal generating means, and a frequency correction coefficient for correcting a disturbance frequency generated in synchronization with the rotation frequency of the disk-shaped recording medium,
Frequency correction means for generating a tracking control based on the position error signal; and a head for moving the head from the first target track on the disk-shaped recording medium on which tracking control is performed, based on the position error signal and the frequency correction coefficient. And a head moving means for moving to a position near the second target track.

As a result, based on the frequency correction coefficient obtained from the frequency correcting means when the tracking control is performed based on the position error signal, the head moving means moves the head to the first target on the disk-shaped recording medium which is subjected to tracking control. By moving from the track to a position near the next second target track, the disturbance frequency is synchronized with the rotation frequency of the disk-shaped recording medium because the disk-shaped recording medium made of a resin material is deformed with time. Even if it occurs, the disturbance frequency can be corrected during the operation in which the moving amount of the head is large.

Further, in the present invention, after generating a position error signal indicating the amount of displacement of the head with respect to the first target track on the disk-shaped recording medium whose substrate is made of a resin material, the rotation frequency of the disk-shaped recording medium is changed to A frequency correction coefficient for correcting a disturbance frequency generated in synchronization is generated when tracking control is performed based on the position error signal. Subsequently, based on the position error signal and the frequency correction coefficient, the head is moved from the tracking-controlled first target track on the disk-shaped recording medium to a position near the next second target track.

As a result, based on the frequency correction coefficient obtained when the tracking control is performed based on the position error signal, the head is moved from the first target track on the disk-shaped recording medium whose tracking is controlled to the next second target track. By moving to a position near the track, even when a disturbance frequency occurs in synchronization with the rotation frequency of the disk-shaped recording medium because the substrate has been deformed with time due to the disk-shaped recording medium made of a resin material, The disturbance frequency can be corrected during the operation in which the moving amount of the head is large.

Further, in the present invention, a disk-shaped recording medium whose substrate is made of a resin material, and a position error signal for generating a position error signal indicating a positional deviation amount of the head with respect to a first target track on the disk-shaped recording medium. Generating means;
A frequency correction means for generating a frequency correction coefficient for correcting a disturbance frequency generated in synchronization with the rotation frequency of the disk-shaped recording medium when tracking control is performed based on the position error signal; and a position error signal and a frequency correction coefficient. Head moving means for moving the head from a tracking-controlled first target track on the disk-shaped recording medium to a position near the next second target track on the basis of Recording / reproducing means for recording or reproducing predetermined information on two target tracks is provided.

As a result, based on the frequency correction coefficient obtained from the frequency correcting means when the tracking control is performed based on the position error signal, the head moving means moves the head to the first target on the disk-shaped recording medium, which is subjected to tracking control. By moving from the track to a position near the next second target track, the disturbance frequency is synchronized with the rotation frequency of the disk-shaped recording medium because the disk-shaped recording medium made of a resin material is deformed with time. Even if it occurs, the disturbance frequency can be corrected during the operation in which the moving amount of the head is large, thus preventing the recording / reproducing characteristics from deteriorating.

[0058]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

(1) Configuration of the Magnetic Disk Drive According to the Present Embodiment In FIG. 1 in which the same reference numerals are assigned to parts corresponding to those in FIG. 6, reference numeral 40 denotes a medium-fixed magnetic disk drive according to the present embodiment as a whole. The configuration is the same as that of the conventional magnetic disk device 10 except that the configuration of the AFC correction control system 41 is different.

As shown in FIG. 2, the magnetic disk device 40 includes a plurality of magnetic disks 11A and 11B which are driven to rotate about an output shaft 12A of a spindle motor 12.
The magnetic heads 14A to 14D attached to the tips of the head arm 13 rotatably mounted on a fixed shaft 42 provided near the position of the head arm 13 are driven by push pins (not shown). Are moved by a minute distance.

In the magnetic disk device 40, the one surface 11AX, 11BX and the other surface 1 of the magnetic disks 11A, 11B whose substrates are made of a resin material such as plastic are used at the time of servo writing by the end-bed servo method described above.
In each of the servo areas formed in 1AY and 11BY, servo information serving as a time reference is written to the magnetic heads 14A to 14A.
Writing is performed along the trajectory T _SV of D.

As shown in FIG. 1, in the magnetic disk device 40, a plurality of magnetic disks 11A and 11B are
The magnetic heads 14A to 14A attached to each end of the head arm 13 are rotated at a high speed in accordance with the rotation
D is moved in accordance with the driving of the voice coil motor (VCM) 15 and is aligned with the one surface 11AX, 11BX and the other surface 11AY, 11BY of the magnetic disks 11A, 11B, respectively, so that the magnetic disk 11
A, 11B, one side 11AX, 11BX and the other side 11A
Video and audio data are recorded or reproduced, respectively, following tracks concentrically or spirally formed on Y and 11BY.

At this time, the magnetic disk device 40 converts the position information of the magnetic heads 14A to 14D based on the servo information formed in the servo areas of the one surface 11AX, 11BX and the other surface 11AY, 11BY of the magnetic disks 11A, 11B. Have been made to gain.

As described above, the surfaces 11AX and 11AX of the magnetic disks 11A and 11B are controlled by the magnetic heads 14A to 14D.
The reproduced signal S1 obtained by reproducing the servo information in the servo areas of the BX and the other surfaces 11AY and 11BY is amplified via the preamplifier 17, and is then digitally converted via the A / D converter 18. This is sent to the position error signal generator 19 as a reference signal S2.

The position error signal generator 19 generates a position error signal (PES: Position Error Signal) S3 indicating how much the magnetic heads 14A to 14D are displaced from the target track based on the reference signal S2. Thereafter, this is sent to the switch 22 and the adder 43 in the AFC correction control system 41.

In the AFC correction control system 41, the error signal S3 obtained from the position error signal generator 18 is supplied to the AFC filters 23A to 23D via the switch 22 and also to the adder 43 as it is.

These AFC filters 23A to 23D are:
The first to fourth order components of the disk rotation synchronous disturbance are suppressed by executing the above-described AFC operation based on the error signal S3.
The output of 3A is the AFC output signal S15 as switch 31
The output of the ACF filters 23B to 23D is added via an adder 45, and then sent as an AFC output signal S16 to an adder 43 via a switch 46.

After the error signal S3 and the AFC output signal S16 are added in the adder 43, the A
The FC addition signal S17 is alternatively supplied to one of the tracking control unit 26, the settling control unit 27, and the seek control unit 28 via the switch 30. Thus, the AFC addition signal S17 sent to the tracking control unit 27, the settling control unit 28, or the seek control unit 29 is
After a predetermined head control process is performed in the corresponding control units 27 to 29, the head control process is given to the adder 44 via the switch 31.

In this case, the switches 30 and 31 are operated in order of the control movement amount of the magnetic heads 14A to 14D based on the mode switching signal S18 obtained from the control mode switching unit 47, that is, the seek control unit 29 and the settling control unit 2
8 and the tracking control unit 27 are switched at a predetermined timing.

At the same time, the switches 22 and 46 are switched on based on the mode switching signal S18 obtained from the control mode switching section 47 after a lapse of a predetermined time in the settling mode until the tracking mode. The switch is turned off from the seek mode until after a predetermined time has elapsed in the settling mode.

The adder 44 adds the AFC output signal S15 to the outputs of the control units 27 to 29 selected from the tracking control unit 27, the settling control unit 28 or the seek control unit 29, and then adds the AFC correction signal to the AFC correction signal. D as S19
Voice coil motor driver 3 via a / A converter 32
3

The voice coil motor driver 33 has an AF
By driving the voice coil motor 15 on the basis of the C correction signal S19, the magnetic heads 14A to 14D can be moved to the corresponding surfaces 11A and 11B of one surface 11A, respectively.
It can be positioned on target tracks formed on X, 11BX and other surfaces 11AY, 11BY.

The magnetic disk device 40 is provided with a recording / reproducing section 34, and a predetermined recording signal S supplied from the outside is provided.
10 through the magnetic heads 14A to 14D, one surface 11AX, 11BX and the other surface 11 of the magnetic disks 11A, 11B.
While recording on a target track formed on AY and 11BY, a reproduction signal S11 read from the target track is recorded.
Is sent to a subsequent signal processing unit (not shown).

(2) Arithmetic Processing Procedure Using AFC Filter Here, FIG. 3 shows each of the AFC filters 23A to 23A from a predetermined time in the settling mode to the tracking mode.
7 shows a calculation processing procedure RT1 of D. I-th (i = 1 to 4: i
Represents the order of the disk rotation synchronous disturbance) AFC filters 23A to 23D corresponding to the next disk rotation synchronous disturbance
Enters the arithmetic processing procedure RT1 from step SP1. When the error signal S3 is input in step SP2, the process proceeds to the next step SP3, where each AFC filter 23
After clearing the set values in A to 23D (i = 1), the process proceeds to step SP4.

In step SP4, first, the AFC
The filter 23A calculates (updates) the AFC coefficients a _i (kT) and b _i (kT) from the above equations (3) and (4) based on the error signal S3 represented by y (t). .
The AFC coefficients a _i (kT) and b _i (kT) are expressed by the following equations, respectively.

[0076]

(Equation 10)

[0077]

[Equation 11]

Is represented by

Subsequently, in step SP5, the AFC filter 23A sets the AFC coefficients a _i (kT) and b _i (k
T) is multiplied by cos (ω _i t) and sin (ω _i t). Thus, the AFC filter 23A can generate the input u _i (kt) by cumulatively adding the multiplication results for the disturbance order (i = 1) to be compensated. Incidentally, this u _i (kT) is given by the following equation.

[0080]

(Equation 12)

Is represented as

Thereafter, the process proceeds to step SP6 to increase the order of the disturbance, and then in step 7, the i-th (i = 2 to i)
4) Steps SP4 and SP5 described above for the AFC filter 23B corresponding to the next disk rotation synchronous disturbance.
By performing the same processing as the above, the input u _i (kt) (i
= 2-4) respectively.

Thus, in steps SP8 and SP9, the input u _i (k) obtained from the AFC filter 23A
t) (i = 1) as the AFC output signal S15 and the adder 4
Sends out a 4, after sending the AFC output signal S16 obtained by adding the input u _i obtained from AFC filter 23B~23D (kt) (i = 2~4 ) to the adder 43,
In step SP10, the arithmetic processing procedure RT1 ends. Incidentally, the AFC output signal S16 is represented by the following equation as u (kt).

[0084]

(Equation 13)

Is represented by This means that the AFC filter 23 corresponding to the second to fourth order disk rotation synchronous disturbances
B to 23D indicate that the convergence value of the AFC coefficient at the time of tracking control can be applied also in the seek mode or the settling mode.

Thus, for example, the magnetic head 14A
When the tracking control is performed at predetermined outer peripheral positions of the magnetic disks 11A and 11B on the magnetic disks 11A and 11B, the eccentric amounts of the magnetic disks 11A and 11B are usually constant.
In the C filters 23A to 23D, the AFC coefficients converge to a predetermined value.

FIG. 4 shows an arithmetic processing procedure RT2 of the AFC filter 23A when the AFC coefficient is not updated within a predetermined time after the start of the settling mode or in the seek mode.

First, the AFC filters 23A to 23D corresponding to the i-th (i = 1) -order disk rotation synchronous disturbance enter the arithmetic processing procedure from step SP20, and execute step S20.
Since the switches 22 and 46 (FIG. 1) are turned off at P21, the error signal S3 is not input, that is, y (kT) = 0. Subsequently, after the set value in the AFC filter 23A is cleared (i = 1) in step SP22, the process proceeds to step SP23.

In step SP23, the AFC filter 23A is fixed to the AFC coefficients a _i (kT) and b _i (kT) obtained immediately before the seek control, that is, the AFC coefficients obtained when the tracking control is performed. At this time, the AFC coefficients a _i (kT) and b _i (kT) are expressed by the following equations, respectively.

[0090]

[Equation 14]

[0091]

(Equation 15)

The coefficient value is expressed as cos (ωt)
And sin (ωt) are multiplied by
The AFC coefficient continues to be output.

Subsequently, at step SP24, the AFC
The filter 23A has AFC coefficients a _i (kT) and b
against _{i (kT) cos (ω i} t) and sin (ω _i
t). Thus, the AFC filter 23A can generate the input u _i (kt) by cumulatively adding the multiplication results for the disturbance order (i = 1) to be compensated.

Thereafter, the flow advances to step SP25 to go to the i-th (i
= 1) input u _i (kt output for AFC filter 23A corresponding to the next disc rotation synchronizing disturbance) (i =
After sending 1) to the adder 44, the operation processing procedure RT2 is ended in step SP26.

By the way, in the AFC correction control system 41, the error signal S3 is not input to the AFC filters 23A to 23D until a predetermined time from the seek mode to the settling mode has elapsed. The AFC calculation process performed after the elapse of the predetermined time until the tracking mode is continued. Thus, for example, the magnetic heads 14A to 14D are
When seeking from a predetermined disk outer peripheral position to a predetermined inner peripheral position on the 1A and 11B, the AFC filter 23A uses an AFC which is a convergence value during tracking at the outer peripheral position.
The coefficients can also be applied at the inner circumference position.

(3) Operation and effect of the present embodiment In the above configuration, in the magnetic disk device 40,
Due to the high speed rotation of the magnetic disks 11A and 11B, the first
When the next to fourth disk rotation synchronous disturbances occur, the reference signal S2 obtained from the servo area on the disk surface includes the magnetic disks 11A,
A disturbance frequency synchronized with the rotation frequency of 1B is generated.

The error signal S3 generated on the basis of the reference signal S2 is the second to fourth signals in the tracking mode.
AFC filter 2 for the next disk rotation synchronous disturbance
3B to 23D and the AF described above sequentially through the adder 45.
After the C calculation process is performed, the adder 43 adds the error signal S3 to the original error signal S3 and inputs the result to the tracking control unit 27.

At the same time, the error signal S3 is processed by the AFC filter 23A corresponding to the first-order disk rotation synchronous disturbance, and the above-described AFC operation is executed.
A is added to the output of the tracking control unit 27 at A
This is output as the FC correction signal S19.

By performing feedback control of the AFC correction signal S19 in a tracking servo loop including the tracking control section 27, the AFC filter 23A
The AFC coefficient obtained by each AFC operation process of 23D is sequentially updated and converges to a predetermined value. Thus, the tracking of the magnetic heads 14A to 14D is accurately controlled in accordance with the AFC correction signal S19 in which the disk rotation synchronous disturbance has been corrected.

Here, the magnetic heads 14A to 14A are moved from the track currently under tracking control (first target track) to the next target track (second target track).
When positioning D, the magnetic heads 14A to 14D are sought from the currently positioned track to the next target track by switching the mode from the tracking mode to the seek mode.

At this time, the convergence value obtained when the tracking control is performed is applied to the AFC coefficient obtained by each of the AFC calculation processes of the AFC filters 23B to 23D, whereas the AFC calculation process of the AFC filter 23A is used. As the AFC coefficient, the final convergence value in the previous tracking mode immediately before the mode switching is applied.

That is, the AFC filters 23B to 23D execute the AFC operation on the error signal S3 based on the convergence value of the AFC coefficient in the tracking mode, and seek the result of the operation through the adders 45 and 43. The output is added to the output of the control unit 29. On the other hand, AFC filter 2
3A executes an AFC calculation process on the output of the seek control unit 29 based on the final convergence value in the previous tracking mode immediately before the mode switching, and then adds the calculation processing result in the adder 44 to the seek control unit 29. And the output of

Thus, in the seek mode, the magnetic head 1
Since the 4A to 14D move in the radial direction of the magnetic disks 11A and 11B, it is very difficult to measure a disturbance frequency generated in synchronization with the rotation frequency of the magnetic disks 11A and 11B. Even in the seek mode in which the moving amount of 14D is large, it is possible to correct the disk rotation synchronous disturbance corresponding to the output of the seek control unit 29 based on the AFC coefficient obtained by the AFC operation processing in the tracking mode. Further, the current AFC coefficient used in the seek mode is used to obtain a convergence value of the AFC coefficient in the next tracking mode.

Accordingly, in the case of the magnetic disks 11A and 11B whose substrates are made of a resin material such as plastic, for example, very large eccentricity and track deformation may occur with the passage of time. Using the method described above, it is possible to correct the disk rotation synchronous disturbance.

According to the above configuration, the magnetic disk drive 4
0, the magnetic disks 11A, 1A, and 1B in the seek mode based on the AFC coefficient obtained by the AFC operation when the tracking control is performed based on the error signal S3.
By correcting the disturbance frequency synchronized with the rotation frequency of 1B, even if the substrate uses the magnetic disks 11A and 11B made of a resin material such as plastic, the magnetic head in the seek mode is used. 14A ~
To realize a magnetic disk drive 40 capable of correcting a disk rotation synchronous disturbance during an operation with a large moving amount of 14D and thus significantly improving the magnetic head positioning accuracy with a simple configuration regardless of the type of magnetic disk. Can be.

(5) Other Embodiments In the first embodiment, when tracking control is performed, it is obtained by AFC calculation processing (14).
AFC coefficients a _i (kT) and b in equations (15) and (15)
_The case where seek control or settling control is performed on the next target track on one surface 11AX, 11BX and the other surface 11AY, 11BY of the magnetic disks 11A, 11B based on _i (kT) has been described. Is not limited to this, one surface 11 of the magnetic disks 11A and 11B
The AFC coefficients _ai obtained by dividing the AX, 11BX and the other surfaces 11AY, 11BY into a plurality of regions in the radial direction and performing tracking control for each region are expressed by the AFC coefficients _{ai in the} expressions (14) and (15). (KT) and b _i (kT)
May be assigned and stored in a storage means (not shown) such as a RAM (Random Access Memory) or a memory.

In this case, the control mode switching unit 47 switches the switches 30 and 31 to the settling control unit 2 within a predetermined time after the start of the settling mode or during the seek mode.
8 or the AFC coefficients a _i (kT) and b _i (kT) stored in the storage means are read out in synchronization with the timing of switching to the seek control section 29 and transmitted to the corresponding settling control section 28 or seek control section 29. Then, the same effect as described above can be obtained.

In the above embodiment, an AFC (adaptive feedforward canceller) is used as a frequency correcting means for correcting a disturbance frequency generated in synchronization with the rotation frequency of the magnetic disks 11A and 11B based on the error signal S3. Although the case where the filters 23A to 23D are applied has been described, the present invention is not limited to this, and other various characteristic frequency disturbance elimination filters may be applied. In short, various frequency correction means can be widely applied as long as they can suppress a disturbance frequency generated in synchronization with the rotation frequencies of the magnetic disks 11A and 11B.

Further, in the above embodiment, the magnetic heads 14A to 14D are connected to the magnetic disks 11A and 11D based on the error signal S3 and the frequency correction coefficient (AFC coefficient).
A case in which the head moving means for moving to a position near the next target track (second target track) on B mainly includes the seek control unit 29, the voice coil motor driver 33, and the voice coil motor 15 As described above, the present invention is not limited to this, and the settling control unit 28,
The voice coil motor driver 33 and the voice coil motor 15 may be used. Also, a single control unit may be provided as a series of continuous operations of the seek control and the settling control, and the control unit, the voice coil motor driver 33, and the voice coil motor 15 may be configured.

Further, in the above-described embodiment, the case where the end-bed servo system is applied as the servo system of the magnetic disk device 40 has been described. However, the present invention is not limited to this. Type magnetic disk drive, a servo surface servo system in which one surface of one of the magnetic disks is dedicated to servo information and servo information is written on the one surface may be applied. Can be widely applied to.

Further, in the above embodiment, the i-th
The case where the first to fourth order disk rotation synchronous disturbances occur in synchronization with the rotation of the magnetic disks 11A and 11B as the next disk rotation synchronous disturbance has been described, but the present invention is not limited to this, and the disk rotation synchronous disturbance is not limited thereto. Fifth according to the degree of
The disk rotation synchronous disturbance of the next level or more may be corrected by the frequency correction means.

Further, in the above-described embodiment, the case where the magnetic disks 11A and 11B are made of a resin material made of plastic as the substrate has been described.
The present invention is not limited to this, and various resins other than plastic may be used as the resin material forming the substrate. In short, the present invention can be widely applied to a conventional magnetic disk having a substrate made of an aluminum alloy or a glass material, which is very soft and has low weather resistance to environmental changes such as temperature and humidity.

Further, in the above-described embodiment, the case where the present invention is applied to the fixed medium type magnetic disk device 40 for recording or reproducing the magnetic disks 11A and 11B has been described, but the present invention is not limited to this. For example, the present invention may be applied to a medium exchange type magnetic disk device such as a disk pack. In short, it can be widely applied to a device which requires suppression of a disk rotation synchronous disturbance when recording or reproducing a disk-shaped recording medium. it can. In this case, an optical head, an optical pickup, or the like can be widely used as a head other than the magnetic heads 14A to 14D. Discs and optical discs can be widely applied.

[0114]

As described above, according to the present invention, a position error signal representing the amount of displacement of a head with respect to a first target track on a disk-shaped recording medium whose substrate is made of a resin material;
Based on the frequency correction coefficient obtained from the frequency correction means when the tracking control is performed in accordance with the position error signal, the head moving means moves the head from the first target track on the disk-shaped recording medium on which tracking control has been performed to the next. Is moved to a position in the vicinity of the second target track, the disturbance frequency is synchronized with the rotation frequency of the disk-shaped recording medium because the disk-shaped recording medium made of a resin material is deformed with time. Even if it occurs, the disturbance frequency can be corrected at the time of operation in which the moving amount of the head is large, and thus the positioning accuracy of the head can be remarkably improved with a simple configuration regardless of the type of the disk-shaped recording medium. A head positioning control device and method and a disk device can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a magnetic disk device according to an embodiment.

FIG. 2 is a schematic diagram illustrating a configuration of a magnetic disk device in the present embodiment.

FIG. 3 is a flowchart illustrating an AFC calculation processing procedure in a tracking mode.

FIG. 4 is a flowchart illustrating an AFC calculation processing procedure in a seek mode.

FIG. 5 is a block diagram for explaining the principle of the AFC control system;

FIG. 6 is a block diagram illustrating a configuration of a conventional magnetic disk drive.

[Explanation of symbols]

2, 23A to 23D: AFC filter, 10, 40 ...
... Magnetic disk device, 11A, 11B ... Magnetic disk, 14A-14D ... Magnetic head, 15 ... Voice coil motor, 16 ... Servo writer, 19 ... Position error signal generator, 20, 41 ... AFC correction Control system, 21,
24, 43 to 45... Adders, 22, 25, 30, 3
1, 46 switches, 26, 47 control mode switching unit, 27 tracking control unit, 28 settling control unit, 29 seek control unit, 33 voice coil motor driver, 34 recording Playback section.

Claims (9)

[Claims] 1. A position error signal generating means for generating a position error signal indicating an amount of positional deviation of a head with respect to a first target track on a disk-shaped recording medium whose substrate is made of a resin material, and rotation of the disk-shaped recording medium. Frequency correction means for generating a frequency correction coefficient for correcting a disturbance frequency generated in synchronization with the frequency when tracking control is performed based on the position error signal, based on the position error signal and the frequency correction coefficient ,
Head positioning means for moving the head from the tracking-controlled first target track on the disk-shaped recording medium to a position near the next second target track. apparatus. 2. The frequency correction means divides the disturbance frequency into a plurality of frequency components for each predetermined level, and generates the frequency correction coefficient for correcting a predetermined number of frequency components among the plurality of frequency components. The head positioning control device according to claim 1, wherein 3. The frequency correction means divides the disk-shaped recording medium into a plurality of regions in a radial direction, and allocates and stores the frequency correction coefficient obtained when the tracking control is performed for each of the regions. When the head moving means moves the head to a position near the second target track,
2. The head positioning control device according to claim 1, wherein the frequency correction coefficient corresponding to the area where the second target track is located is read from the storage means and output. 4. A first step of generating a position error signal representing an amount of positional deviation of a head with respect to a first target track on a disk-shaped recording medium whose substrate is made of a resin material, and a rotation frequency of the disk-shaped recording medium. A second step of generating a frequency correction coefficient for correcting a disturbance frequency generated in synchronization with the position error signal when tracking control is performed based on the position error signal, based on the position error signal and the frequency correction coefficient ,
Moving the head from the tracking-controlled first target track on the disk-shaped recording medium to a position near the next second target track. Control method. 5. In the second step, the disturbance frequency is divided into a plurality of frequency components for each predetermined level, and a predetermined number of frequency components among the plurality of frequency components are corrected based on the frequency correction coefficient. 5. The head positioning control method according to claim 4, wherein: 6. In the second step, the disk-shaped recording medium is divided into a plurality of regions in a radial direction, and the frequency correction coefficient obtained when the tracking control is performed is assigned to each of the regions. In the third step, when the head is moved to a position near the second target track, the frequency correction coefficient corresponding to the area where the second target track is located is read out. The head positioning control method according to claim 4, wherein the head position is output. 7. A disk-shaped recording medium whose substrate is made of a resin material, a position error signal generating means for generating a position error signal indicating a positional deviation amount of a head with respect to a first target track on the disk-shaped recording medium, Frequency correction means for generating a frequency correction coefficient for correcting a disturbance frequency generated in synchronization with the rotation frequency of the disk-shaped recording medium when tracking control is performed based on the position error signal; and Based on the frequency correction coefficient,
Head moving means for moving the head from the tracking-controlled first target track on the disk-shaped recording medium to a position near a next second target track; and the head moving means for positioning the head. And a recording / reproducing means for recording or reproducing predetermined information on the second target track. 8. The frequency correction means divides the disturbance frequency into a plurality of frequency components for each predetermined level, and generates the frequency correction coefficient for correcting a predetermined number of frequency components among the plurality of frequency components. The disk drive according to claim 7, wherein 9. The frequency correction means divides the disk-shaped recording medium into a plurality of regions in a radial direction and allocates and stores the frequency correction coefficient obtained when the tracking control is performed for each of the regions. When the head moving means moves the head to a position near the second target track,
8. The disk device according to claim 7, wherein the frequency correction coefficient corresponding to the area where the second target track is located is read from the storage means and output.