JP2002251850A - Disk unit - Google Patents

Abstract

(57) [Problem] To provide a disk device capable of performing stable positioning control even when fluctuation of disturbance such as shock or vibration is large when a head follows a track. SOLUTION: An actuator 7 for positioning the magnetic head 2 with respect to the disk 1, a driving means 10 for the actuator 7, a voltage detecting means 11 for outputting a voltage signal Va generated in driving the actuator 7, a driving signal u and a voltage disturbance estimation means (12) for outputting estimates the magnitude of the disturbance load .tau.d applied from the signal Va to the magnetic head 2 disturbance estimation signal .tau.d _est, position detecting means for generating a position error signal e corresponding to the current position of the magnetic head 2 13 and a position control means 14 for generating a control signal c from the position error signal e;
And a corrector 15 for outputting a drive signal u from the disturbance estimation signal _τd est and the control signal c, stably perform head positioning to the target track with respect to impact or vibration from the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive for positioning a recording / reproducing head, such as a magnetic head, at a desired position on a target track of a disk serving as a recording medium with an actuator. The present invention relates to a disk device configured to suppress a track deviation of a head due to a disturbance such as an inertial force applied to an actuator due to an applied shock or vibration.

[0002]

2. Description of the Related Art In recent years, the size and capacity of magnetic disk drives have been rapidly increasing. As for the increase in the capacity of the magnetic disk device, the track density of the magnetic disk has been increasing, and the track pitch has been becoming narrower.
Therefore, in order to record and reproduce data on the magnetic disk,
It has become necessary to position the magnetic head with high accuracy on a target track formed with a narrow track pitch.

In a conventional magnetic disk drive, servo information is previously formed on a magnetic disk in order to position the magnetic head, and the positioning of the magnetic head is controlled in accordance with the servo information. That is, by reading the servo information with the magnetic head, an error signal indicating the position error of the magnetic head with respect to the target track is generated,
The positioning of the magnetic head is controlled so that the magnitude of the error signal is minimized.

Therefore, in order to increase the positioning accuracy of the magnetic head, the control frequency of the magnetic head positioning control system is set high, the magnetic head is quickly positioned on the target track, and the required positioning accuracy is secured. Was.

However, there are cases where a higher order natural mechanical resonance exists in the actuator itself of the positioning mechanism, and if the control frequency is increased in order to increase positioning accuracy, the positioning control system becomes unstable due to the natural mechanical resonance. Problem. Therefore, the band of the control frequency is actually limited by the inherent mechanical resonance of the actuator itself, and there is a limit to increasing the control frequency of the positioning control system.

Therefore, in order to increase the positioning accuracy of the magnetic head, it has been practiced to reduce the disturbance acting on the actuator, which is a factor that deteriorates the positioning accuracy.

With the recent increase in track density and reduction in size and weight of the actuator, the external force acting on the actuator has a great effect on the positioning control system. Moreover,
With the miniaturization and higher recording density of magnetic disk drives, the demand for high-precision positioning of magnetic heads has become more stringent,
In these magnetic disk devices, external force is compensated by feedforward control.

For example, a method has been proposed in which a head position signal is obtained from servo information recorded on a magnetic disk, and the external force is compensated by external force estimating means that receives the head position signal and a drive signal of an actuator as inputs (for example, see Japanese Patent Application Laid-Open No. H11-163873). And JP-A-9-231701.

[0009]

However, in the above prior art, the external force estimating means receives the head position signal and the drive signal of the actuator as inputs. Since the servo information recorded on the magnetic disk is recorded on the disk in a discrete state having a fixed sampling period, the head position signal is not a continuous signal. Therefore,
The control band in which the external force estimating means can estimate the external force is affected by the sampling frequency of the sector servo of the disk device, and has an upper limit depending on the sampling frequency of the sector servo. As a result, there has been a problem that the external force applied to the actuator means cannot be accurately estimated, and disturbance such as bearing friction applied to the actuator means cannot be effectively canceled. As a result, the head cannot follow the target track accurately.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides an actuator device that uses the friction of a bearing of an actuator device, the elastic force of a flexible printed circuit (FPC) for connecting the actuator device and a circuit board, or the shock or vibration applied to a disk device from the outside. It is an object of the present invention to provide a disk device capable of performing high-accuracy positioning control of a head with respect to a target track formed at a narrow track pitch by compensating for disturbance such as inertia force acting on the head.

[0011]

The magnitude of the disturbance is estimated in order to cancel the disturbance due to the bearing friction and elastic force applied to the actuator means, the inertial force received by impact and vibration, and the like. In estimating the magnitude of the disturbance, two factors are used. One is to detect a voltage generated in driving the actuator means and use a voltage signal as a result of the detection. The other is a drive signal in the drive means of the actuator means. Here, the drive signal in the drive means may be input to the drive means or may be output from the drive means. Further, instead of the driving signal in the driving means, a position control signal which is a source of generating the driving signal may be used. That is, a disturbance estimating means for estimating the magnitude of the disturbance is provided, and the disturbance estimating means uses the voltage signal detected by the voltage detecting means and the driving signal or the position control signal of the driving means as inputs to obtain the disturbance estimating signal. Generate. The disturbance estimation signal generated based on the two factors accurately estimates the magnitude of the disturbance actually applied to the head. As a result, the bearing friction of the actuator means and the F connecting the actuator means to the electronic circuit board are reduced.
It is possible to accurately estimate the magnitude of a disturbance such as an inertia force applied to the actuator means due to an elastic force of the PC or an external shock or vibration applied to the disk device. The disturbance involved in the estimation is a disturbance estimation signal.

The disturbance estimation signal is combined with the position control signal output by the position control means to generate a drive signal so that the disturbance applied to the actuator means is canceled by using the disturbance estimation signal accurately estimated as described above. By driving the actuator means of the head using the drive signal, disturbances such as bearing friction, elastic force, and inertia force applied to the actuator means can be effectively canceled.
That is, it is possible to compensate for external forces such as bearing friction, elastic force, and inertia force acting on the actuator means. Positioning control for the target track can be performed stably. That is, the positioning accuracy can be improved. As a secondary effect, the track density can be substantially improved, and the realization of a large-capacity disk device can be promoted.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be generally described.

According to a first aspect of the present invention, there is provided a disk drive comprising: an actuator for positioning a head with respect to a disk; a driving unit for the actuator; and a voltage signal generated by driving the actuator and outputting a voltage signal. Voltage detecting means, a disturbance estimating means for estimating a magnitude of a disturbance applied to the head from the drive signal and the voltage signal, and outputting a disturbance estimation signal, and servo information pre-recorded on the disk and detected by the head. And a position control means for generating and outputting an error signal corresponding to the current position of the head from the head, and a position control means for generating and outputting a position control signal corresponding to the error signal, wherein the drive signal is the position control signal. It is configured to be obtained by synthesizing a signal and the disturbance estimation signal. In this configuration, the drive signal in the drive unit may be input to the drive unit or output from the drive unit, and the same applies to the following.

The operation of the first invention is as follows. The disturbance estimating means determines the bearing friction of the actuator means and the elasticity of the FPC connecting the actuator means and the electronic circuit board based on the drive signal given to the driving means for driving the actuator means and the voltage signal detected from the actuator means. It is possible to accurately estimate the magnitude of a disturbance such as a force or the inertial force received by the actuator means due to an external shock or vibration applied to the disk device. The disturbance relating to the estimation is a disturbance estimation signal. Here, it is particularly important to be able to accurately estimate the magnitude of disturbance loads such as bearing friction, elastic force, and inertia force applied to the actuator means from the drive signal and the voltage signal during the following operation in which the head follows the target track. It is.

The disturbance estimation signal is combined with the position control signal output by the position control means to generate a drive signal so that the disturbance applied to the actuator means is canceled by using the disturbance estimation signal accurately estimated as described above. If the actuator means of the head is driven by the drive signal, disturbance applied to the actuator means can be canceled well. In other words, since it is possible to compensate for external forces such as bearing friction, elastic force and inertia force acting on the actuator means, even if the fluctuation of the disturbance is large at the time of the following operation toward the target track, the positioning of the head to the target track is performed. Control can be performed stably.
That is, the positioning accuracy can be improved.

According to a second aspect of the present invention, in the disk device according to the first aspect, the disturbance estimating means includes a comparing means to which a voltage signal detected by the voltage detecting means is input, and a first driving signal, First multiplying means for multiplying the coefficient of
Second multiplying means for multiplying the output of the comparing means by a second coefficient, first integrating means for integrating the output of the comparing means, and second multiplying means from the output of the first multiplying means A second integration means for integrating a value obtained by subtracting an added value of the output of the first integration means and the output of the first integration means, wherein the comparison means compares the voltage signal and the output of the second integration means with each other. It is configured to compare and output the result to the second multiplying means and the first integrating means.

The operation of the second invention is as follows. The output of the first multiplying means for inputting the drive signal becomes a drive torque estimation signal corresponding to the drive torque acting on the actuator means. The output of the second integrating means serves as a feedback element for the voltage signal input from the voltage detecting means. The output of the comparison means for calculating the difference between the voltage signal and the feedback element from the second integration means is provided to the first integration means and the second multiplication means. The output of the first integrating means for integrating the difference is a disturbance estimation signal corresponding to a disturbance such as a friction received from the bearing by the actuator means, an elastic force received from the FPC, or an inertial force received by the actuator means due to shock or vibration. . The output of the second multiplying means, which is obtained by multiplying the difference by a predetermined coefficient, is added to the disturbance estimation signal. Then, a difference from the added value is obtained from the drive torque estimation signal, and is provided to the second integration means.

As a result of the above, the disturbance estimation signal output from the first integrator means that the actuator means uses the bearing or FP
This corresponds to an accurate estimation of a disturbance such as an inertia force received by the actuator means due to an elastic force received from C, impact or vibration. Then, since the feedforward control is performed so as to cancel the disturbance applied to the actuator means with the disturbance estimation signal accurately determined as described above, it is possible to compensate for the disturbance acting on the actuator means in the following operation, and to perform the compensation during the following operation. Even if the fluctuation of the disturbance in the actuator means is large, the positioning control of the head with respect to the target track can be stably performed, and the positioning accuracy can be improved.

According to a third aspect of the present invention, there is provided a disk drive comprising: an actuator for positioning a head with respect to a disk; a driving unit for the actuator; and a voltage signal generated by driving the actuator and outputting a voltage signal. Voltage detecting means, a position detecting means for generating and outputting an error signal corresponding to the current position of the head from servo information previously recorded on the disk and detected by the head, and a position control signal corresponding to the error signal Position control means for generating and outputting, and disturbance estimation means for estimating the magnitude of disturbance applied to the head from the voltage signal and the position control signal and outputting a disturbance estimation signal,
The drive signal is configured to be obtained by combining the position control signal and the disturbance estimation signal.

The operation of the third invention is as follows. The disturbance estimating unit is configured to output the bearing friction of the actuator unit and the electronic control unit based on a position control signal output from the position control unit and a voltage signal detected from the actuator unit to drive the actuator unit to drive the actuator unit. It is possible to accurately estimate the magnitude of a disturbance such as an inertial force received by the actuator means due to an elastic force of the FPC connecting to the circuit board, or an external impact or vibration. Here, it is particularly important to be able to accurately estimate the magnitude of disturbance such as bearing friction, elastic force, and inertia force applied to the actuator means from the position control signal and the voltage signal during the following operation in which the head follows the target track. It is.

The disturbance estimation signal is combined with the position control signal output by the position control means so as to cancel the disturbance applied to the actuator means using the disturbance estimation signal accurately estimated as described above to generate a drive signal. If the actuator means of the head is driven by the drive signal, disturbances such as bearing friction, elastic force, and inertia force applied to the actuator means can be canceled well. That is, since it is possible to compensate for disturbances such as bearing friction, elastic force, and inertia force acting on the actuator means, the head can be positioned on the target track even when the fluctuation of the disturbance is large during the following operation toward the target track. Control can be performed stably. That is, the positioning accuracy can be improved.

According to a fourth aspect of the present invention, in the disk apparatus according to the third aspect, the disturbance estimating means includes a comparing means to which the voltage signal detected by the voltage detecting means is input, A first multiplying means for multiplying the output of the comparing means by a second coefficient; a first integrating means for integrating an output of the comparing means; A second integration means for integrating a value obtained by subtracting an output of the second multiplication means from an output of the first multiplication means, wherein the comparison means converts the voltage signal and an output of the second integration means. It is configured to compare and output the result to the second multiplying means and the first integrating means.

The operation of the fourth invention is as follows. First input of a position control signal from the position control means
The output of the multiplication means becomes a drive torque estimation signal corresponding to the drive torque acting on the actuator means. The output of the second integrating means serves as a feedback element for the voltage signal input from the voltage detecting means. Voltage signal and second
The output of the comparing means for calculating the difference from the feedback element from the integrating means is supplied to the first integrating means and the second multiplying means. The output of the first integrating means for integrating the difference is the friction which the actuator means receives from the bearing or the FPC
A disturbance estimation signal corresponding to a disturbance such as an inertia force received by the actuator means due to an elastic force received from the actuator, impact or vibration. The difference from the output of the second multiplication means, which is obtained by multiplying the difference by a predetermined coefficient from the drive torque estimation signal, is provided to the second integration means.

As a result of the above, the disturbance estimation signal output from the first integrator is output from the actuator means to the bearing or the FP.
This corresponds to an accurate estimation of the inertial force received by the actuator means due to the disturbance received from C and the impact or vibration. Then, the feedforward control is performed so as to cancel the disturbance applied to the actuator means by using the disturbance estimation signal accurately estimated as described above, so that the disturbance acting on the actuator means can be compensated in the following operation, and the following operation can be performed. Even if the fluctuation of disturbance by the actuator means is sometimes large, the positioning control of the head with respect to the target track can be stably performed, and the positioning accuracy can be improved. Further, it is not necessary to perform the addition of the first integration means and the second multiplication means required in the second invention, and the means for the addition can be omitted, and the configuration is simplified. Can be brought.

In the disk device according to a fifth aspect of the present invention, in the first to fourth aspects, a control band of the disturbance estimating means is set to be larger than a control band of the position control means.

The operation of the fifth invention is as follows. To extend the control band of the positioning control system is to increase the proportional gain, but there is an upper limit depending on the sampling frequency of the sector servo of the disk drive and the natural mechanical resonance frequency of the actuator means. On the other hand, the disturbance estimating means is not affected by the sampling frequency of the sector servo of the disk device.
Therefore, in the disturbance estimating means, the control band can be set higher than the control band of the positioning control system. As a result, over a higher control band,
The head can accurately follow the target track.

According to a sixth aspect of the present invention, in the disk apparatus according to the first to fifth aspects, the actuator means is provided on at least one yoke side of the pair of yokes opposed to each other with a gap therebetween. A circuit comprising a fixed permanent magnet and a drive coil disposed in a magnetic gap formed by the permanent magnet and the yoke, wherein a circuit in which a capacitor and a resistor are connected in series with the drive coil is connected. ing.

The operation of the sixth invention is as follows. In general, a drive coil constituting an actuator has not only a resistance component but also an inductance component. As a result, if the control band of the disturbance estimating means is increased, the control system becomes unstable due to the influence of the inductance, and there is a limit to increasing the control band of the disturbance estimating means. Therefore, by connecting a circuit in which a capacitor and a resistor are connected in series in parallel with the drive coil, the influence of the inductance of the drive coil can be removed, and the control band can be set higher than the control band of the positioning control system. . As a result, the head can accurately follow the target track over a higher control band.

The present invention operates most advantageously when applied to a magnetic disk drive, but is not necessarily limited to a magnetic disk drive.

(Specific Embodiment) Hereinafter, a specific embodiment of a disk drive according to the present invention will be described in detail with reference to the drawings. Note that components having similar functions are described with the same reference numerals.

(First Embodiment) FIG. 1 is a block diagram showing a configuration of a magnetic disk drive according to a first embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a magnetic disk which is rotated by a spindle motor (not shown).
Reference numeral 2 denotes a magnetic head for recording and reproducing data on and from the magnetic disk 1. Reference numeral 3 denotes an arm, and a magnetic head 2 mounted at one end.
Is rotated around the bearing 4 so that the magnetic head 2
Is moved to a target track on the magnetic disk 1.
Reference numeral 5 denotes a drive coil provided at the rear end of the arm 3, and reference numeral 6 denotes a stator (yoke). A magnet (permanent magnet; not shown) is disposed on a surface facing the drive coil 5. The stator 6 is composed of a pair of yokes facing each other via a gap, and the magnet is fixed to at least one of the yokes in the gap. The arm 3 receives a rotational force due to the interaction between the magnetic flux generated by the magnet disposed on the stator 6 and the magnetic field generated by the current supplied to the drive coil 5.
An actuator 7 is configured by the magnetic head 2, the arm 3, the bearing 4, the drive coil 5, and the stator 6.

Reference numeral 10 denotes a driver, and reference numeral 11 denotes a voltage detector included in the driver 10, which detects a voltage generated at both ends of the drive coil 5 and outputs a voltage signal Va. Reference numeral 12 denotes a disturbance estimator, which outputs a voltage signal Va output from the voltage detector 11 and the driver 1.
And a input is the drive signal u 0 estimates a disturbance torque acting on the arm 3, and outputs a disturbance estimation signal .tau.d _est.

A track position signal is recorded in advance in each sector of the magnetic disk 1 as servo information, and this position signal is read by the magnetic head 2. The position detector 13 detects the current position of the magnetic head 2 based on the position signal read by the magnetic head 2, and generates a position error signal e indicating a difference from the target position r of the target track. The position controller 14 receives the position error signal e generated by the position detector 14, performs amplification and phase compensation, and generates a position control signal c. 15 is a corrector, is input to the position control signal c and the disturbance estimation signal of the disturbance estimator 12 .tau.d _est of the position controller 14, after performing correction calculation by the correction circuit 15, the drive signal u to the driver 10 input. Driver 10
Supplies a drive current Ia to the drive coil 5 in response to the input drive signal u, rotates the arm 3 around the bearing 4, and rotates and moves the magnetic head 2 attached to the tip of the arm 3. In order to record / reproduce data on / from the magnetic disk 1, the magnetic head 2 is configured to be positioned with high accuracy on a target track formed with a narrow track pitch.

Here, in contrast to the description in the claims, the driver 10 corresponds to the driving means and the voltage detector 1
1 corresponds to a voltage detecting means, the disturbance estimator 12 corresponds to a disturbance estimating means, the position detector 13 corresponds to a position detecting means, and the position controller 14 corresponds to a position controlling means.

Next, the operation of the positioning control system of the magnetic disk drive according to the first embodiment will be described with reference to FIG.
FIG. 2 is a block diagram showing the overall configuration of the position control system in the magnetic disk drive of the first embodiment.

A portion 30 surrounded by a chain line in the figure is a block of the disturbance estimator 12. Similarly, a portion 47 surrounded by an alternate long and short dash line is a block of the compensator 15. In FIG. 2, s represents the Laplace operator. Further, in FIG. 2, the hold element by sampling the sector servo is omitted for simplicity of description.

In FIG. 2, if the current track position detected by the magnetic head 2 is x, the position error signal e with respect to the target track position r is represented by (Equation 1). Is obtained.

[0040]

(Equation 1) The position controller 14 represented by the block 21 in FIG. 2 adds the transfer function Gx to the position error signal e output from the comparator 20.
The digital filter processing of (z) is performed to generate a position control signal c, which is output to the corrector 15 represented by a block 47. The ordinary PID control is applied to the positioning control system, and the transfer function of the position controller 14 can be expressed by (Equation 2).

[0041]

(Equation 2)Where z^-1Indicates one sample delay, and Kx is the positioning
This shows the proportional gain of the control system. Coefficient a_d,a_iIs the frequency characteristic
And a coefficient a_dIs the derivative, the coefficient a _iIs the integral
It is a coefficient. The position control signal c is driven via the adder 46.
It becomes a motion signal u. The drive signal u is supplied to the block 22 (transmission
The number is gm times the voltage signal in the driver 10 of gm).
It is converted into a current signal and outputs a drive current Ia. Block
In the actuator 7 represented by the link 23, the drive coil
The drive current Ia applied to the coil 5 depends on the magnetic field generated by
Interaction with the magnetic flux of the magnet of the stator 6 described above
It is converted into a driving torque τ by the transfer function Kt. Where
The arrival function Kt is a torque constant of the actuator 7. B
The transfer function (Lb / Js) of the lock 24 is
From the acting drive torque τ to the moving speed v of the magnetic head 2
Represents the transfer characteristics of Here, J is the inertia mode of arm 3.
Lb is the magnetic head from the bearing 4 of the arm 3
The distance to 2 is shown. Block 25 is an integrator,
The transfer function is represented by 1 / s, and the moving speed v of the magnetic head 2
Is converted to the current track position x.

In the voltage detector 11 represented by the blocks 26 and 27, the block 26 outputs an induced voltage Ea generated at both ends of the drive coil 5 when the actuator 7 rotates, and the block 27 outputs the induced voltage Ea. Then, a voltage drop (Ra + La · s) · Ia generated when the drive current Ia is supplied to the controller 7 is output, and the adder 28 adds them to output the terminal voltage of the actuator 7 as a voltage signal Va. That is,

[0043]

(Equation 3) There is a relationship. Here, Ra indicates the coil resistance of the drive coil 5, and La indicates the inductance of the drive coil 5.

A disturbance τd acting on the arm 3 such as a bearing friction of the actuator 7, an elastic force of an FPC connecting the actuator 7 to the electronic circuit board, and an inertial force received by the actuator 7 due to an external shock or vibration applied to the magnetic disk drive. Can be expressed by the adder 29 as being input to the stage preceding the block 24.

Block 3 in a portion surrounded by a dashed line in FIG.
Numeral 0 denotes a block diagram of the disturbance estimator 12. This block 30 includes a block 32 having the same transfer function as the transfer function of the block 22, which is the driver 10, and a transfer function of the block 23, which is the actuator 7. , A block having the same transfer function as the transfer function of the block, a block having the same transfer function as the transfer function of the block, and a transfer of the block A block 39 having the same transfer function as the function is included. Block 32 and Block 3
3 is the first multiplier, and block 44 is the second multiplier.
, The first integrator, block 34
The combination of the block and the block 35 constitutes a second integrator. Here, the suffix “n” of each constant in the block 30 indicates a nominal value, and the variable with “est” indicates an estimated value. Here, in contrast to the description in the claims, the first multiplier corresponds to the first multiplying means, the second multiplier corresponds to the second multiplying means, and the first integral The integrator corresponds to the first integrating means, the second integrator corresponds to the second integrating means, and the comparator 37 corresponds to the comparing means.

The drive signal u input to the block 22 is
It is also input to the block 32 constituting the disturbance estimator 12,
By multiplying (gmn · Ktn) by the blocks 32 and 33, a drive torque estimation signal τ _est that is the same as the drive torque τ acting on the arm 3 is obtained.

In FIG. 2, the block 34 outputs a speed estimation signal v _est . In block 35, the induced voltage estimation signal Ea _est obtained by multiplying Kvn velocity estimation signal v _est, the voltage drop of the estimated current Ia _est to the actuator 7 is generated by being energized (Ran + Lan
S) · I _est is added by the adder 36, and the adder 36
From the voltage estimation signal Va _est is outputted. The voltage estimation signal Va _est is input to the comparator 37 and compared with the actually detected voltage signal Va, and the resulting error signal α (= Va
−V a _est ) is input to the first integrator represented by the block 43 and the second multiplier represented by the block 44. The first integrator 43 integrates the error signal alpha, and outputs a disturbance estimation signal .tau.d _est for disturbance. The error signal α is input to the second multiplier represented by the block 44, multiplied by g 1 and added to the adder 38. The output of the adder 38 is input to the subtractor 31, and the result γ of the output of the adder 38 subtracted from the drive torque estimation signal τ _est output from the block 33
Is output to the block 34.

The coefficient g1 of the block 44 and the coefficient g2 of the block 43 are constants for stabilizing the operation of the disturbance estimator 12, and the details will be described later.

In FIG. 2, a block 47 surrounded by a chain line is a block diagram of the compensator 15. A block 45 included in the corrector 15 includes a disturbance estimation signal τ
By multiplying d _est by 1 / (gmn · Ktn), arm 3
Generating a correction signal β to the driver 10 required to generate the driving force of the magnitude corresponding to the disturbance estimation signal .tau.d _est to. The correction signal β is added to the position control signal c in the adder 46.

Next, the operation of the disturbance estimator 12 in the block 30 will be described in detail with reference to FIG.

[0051] FIGS. 3 (a) is a block diagram rewritten block 30 of FIG. 2 shows the transfer from the input of the drive signal u to the output of the disturbance estimation signal .tau.d _est. FIG. 3B is a block diagram of FIG. 3A in which the input position (comparator 37) of the voltage signal Va is equivalently converted and moved based on (Equation 3). It is a block diagram which transformed the block diagram of a). Here, for the sake of simplicity, the value of gm in block 22 in FIG.

[0052]

(Equation 4) , The drive current Ia (= gmu) and the estimated current Ia _est
(= Gmn · u).

Focusing on the first and second terms of (Equation 3), Ea of the first term can be obtained by multiplying the magnitude by (Jn · s) / (Lbn · Kvn) as shown in FIG. The input position of the comparator 37 of FIG.
It can be equivalently moved to the input position of the subtractor 48 shown in FIG. Also, (Ra + La ·) in the second term of (Equation 2)
s) · Ia can be included as a block 39 in FIG. 3A and expressed as a block 49 in FIG. 3B.

Focusing on the subtractor 48 in FIG. 3B, δ, which is the output of the subtractor 48, is expressed as (Equation 5).

[0055]

(Equation 5) Next, focusing on the comparator 25 and the blocks 24 and 26 in FIG.

[0056]

(Equation 6) Here, for simplicity,

[0057]

(Equation 7)

[0058]

(Equation 8) Assuming that (Equation 6) is substituted into (Equation 5), (Equation 5)
Is transformed as shown in (Equation 9).

[0059]

(Equation 9) That is, the output δ of the subtractor 48 is equal to the disturbance τd applied to the arm 3.

Therefore, from the block diagram of FIG. 3B, the disturbance estimation signal τd _{est is obtained} from the disturbance τd applied to the arm 3.
When the transfer function up to is obtained, it becomes as shown in (Equation 10).

[0061]

(Equation 10) From (Equation 10), it can be seen that the disturbance estimator 12 can estimate the actual disturbance τd from the drive signal u and the voltage signal Va by the second-order delay system by the loop in the block 30 surrounded by the dashed line in FIG. .

Here, if the natural angular frequency (estimated angular frequency) of the second-order delay system is ωo and the damping factor is ζo,
The constants g1 and g2 for stabilizing the operation of the disturbance estimator 12 are expressed by the following (Equation 11) and (Equation 12), respectively.

[0063]

[Equation 11]

[0064]

(Equation 12) Here, if the estimated angular frequency ωo is set sufficiently higher than the position control band fc and the damping factor ζo is selected to be 0.7 to 1, the disturbance estimator 12 can accurately determine the disturbance τd such as bearing friction, elastic force and inertia force. Can be estimated.

By transforming (Equation 10) using (Equation 11) and (Equation 12),

[0066]

(Equation 13) Becomes That is, the block diagram of the disturbance estimator 12 in FIG. 3A can be simplified as shown by a block 52 in FIG. 3C.

Next, the operation of the corrector 15 indicated by the block 47 will be described in detail with reference to FIG.

Block 4 surrounded by the dashed line in FIG.
7 shows a block diagram of the corrector 15. Block 45
Outputs a disturbance estimation signal _{τd est 1 / (gmn · Ktn} ) multiplied by the correction signal β to the adder 46. That is, by multiplying the disturbance estimation signal τd _est by 1 / (gmn · Ktn), the adder 46 adds the correction signal β necessary for causing the actuator 7 to generate a driving force having a magnitude corresponding to the disturbance estimation signal τd _est.
Output to Further correction signal beta, from being gmn · Ktn times by the block 22 and the block 23, advance in order to adjust the size of the disturbance estimation signal _τd est 1
/ (Gmn · Ktn) times.

To summarize the above, the magnetic disk drive of the first embodiment is characterized in that the bearing friction of the actuator 7, the elastic force of the flexible printed circuit board connecting the actuator 7 and the electronic circuit board, the impact applied to the magnetic disk drive from the outside, and the like. so as to cancel the disturbances .tau.d due inertial force experienced by the actuator 7 by the vibration, the disturbance estimation signal .tau.d _{es t}
Is made to act on the actuator 7.

FIG. 4A is a block diagram of the block diagram of FIG. 2, in which the parts from the adder 46 to the comparator 25 and the block 24 related to the operation of the corrector 15 are extracted. FIG. 4B shows a disturbance τd applied to the comparator 25.
FIG. 7 is a block diagram in which a disturbance τd applied to a block 52 is combined into one τd. Components having the same functions as those in the block diagram of FIG. 2 are denoted by the same reference numerals, and redundant description will be omitted.

In the block diagram of FIG. 4A, the block 52 corresponds to the block 52 of FIG.
0).

Therefore, from FIG. 4B, it can be considered that the disturbance τd externally applied to the arm 3 is applied to the head position control system through the filter represented by the transfer function of (Expression 14).

[0073]

[Equation 14] FIG. 5 shows the frequency characteristic of the transfer function Gd (s) represented by (Equation 14) by a polygonal line approximation. From the frequency characteristics of the transfer function Gd (s) shown in FIG. 5, at an angular frequency lower than the angular frequency ωo, the gain is 0 dB or less, and as the angular frequency ω falls, the attenuation ratio becomes −20 dB / dec (decade). It is declining. dec means 10 times. That is, as shown in FIG. 5, the transfer function Gd (s) has a low-frequency cutoff filter characteristic capable of suppressing frequencies lower than the angular frequency ωo.

That is, in the magnetic disk drive according to the first embodiment of the present invention, even when a disturbance τd due to bearing friction, elastic force, inertia force or the like acts on the arm 3, the disturbance τd is estimated by the disturbance estimator 12. The disturbance estimation signal τd _est is used to cancel the externally applied disturbance τd. Therefore, the externally applied disturbance τ
d acts as if it were added to the head positioning control system through the filter having the cut-off frequency characteristic of (Equation 14) and FIG.

Therefore, in the magnetic disk drive according to the first embodiment of the present invention, the bearing friction of the actuator 7 and the connection between the actuator 7 and the electronic circuit board are achieved with the first-order low-frequency cutoff characteristic at a frequency lower than the angular frequency ωo. FPC
It is possible to suppress disturbance due to the inertia force received by the actuator 7 due to the elastic force of the magnetic disk device or the shock or vibration applied to the magnetic disk device from the outside.

That is, in the magnetic disk drive according to the first embodiment of the present invention, even if vibration or shock is applied from the outside and disturbance τd acts on the actuator 7, the disturbance τd is estimated by the disturbance estimator 12 and externally. Since the control is performed so as to cancel the added disturbance τd, there is an effect as if a mechanical vibration isolating mechanism is applied to the magnetic disk device.

FIG. 6 is a time response waveform diagram for explaining in more detail the disturbance suppressing effect of the disturbance estimator 12 of the magnetic disk drive according to the first embodiment of the present invention.

FIG. 6A shows the maximum angular acceleration (d
ωo / dt) is 1000 rad / s ² (radian / second ² )
Half sinusoidal rotating impact when applied to a magnetic disk apparatus, the waveform 61 of the disturbance .tau.d inertial force actuator 7 is subjected (indicated by dashed lines), the disturbance estimation signal .tau.d _est of waveform disturbance estimator 12 outputs the 62 is shown. Assuming that the moment of inertia J around the bearing 4 of the actuator 7 is 1 g · cm ² , the maximum value of the disturbance τd is

[0079]

(Equation 15) Becomes

Here, the estimated frequency fo (ωo = 2πf) for determining the control parameters of (Equation 11) and (Equation 12)
o) and the value of the damping factor ζo are each 3 kHz
The simulation was performed by setting the control band of the position control system to 400 Hz.

The disturbance estimator 12 includes a drive signal u input to the driver 10 and a voltage signal Va output from the voltage detector 11.
Estimating a disturbance torque .tau.d acting on the actuator 7, although slight time delay exists, and outputs an actual estimated disturbance signal .tau.d _est substantially similar disturbance .tau.d.

FIG. 6B shows that the disturbance estimation signal τd _est output from the disturbance estimator 12 is input to the corrector 15 and the disturbance estimation signal τd _{est is applied} to the actuator 7 so as to cancel the fluctuation due to the disturbance τ d. Waveform 64 of Drive Current Ia in Case
When shows the simulation result of the drive current Ia of the waveform 63 in the case you do not enter a disturbance estimation signal .tau.d _est in corrector 15. The torque constant Kt of the actuator 7 is 23d
yn · cm / mA.

The servo information recorded on the magnetic disk is
The head position signal is not a continuous signal because it is recorded on the disc in a discrete state having a fixed sampling period. Therefore, the control signal c of the position controller 14 where the digital processing is performed changes stepwise. as a result,
The waveform of the drive current Ia of the actuator 7 when no disturbance estimation signal .tau.d _est input to the corrector 15, the same as the waveform of the control signal c, changes stepwise as shown by the waveform 63 shown in FIG. 6 (b) (Ia = gm.c = gm.u). Waveform 64 of the drive current Ia of the actuator 7 when the disturbance estimation signal .tau.d _est inputted to the correction circuit 15, adds the corrector 15 the estimated disturbance signal .tau.d _est of the disturbance estimator 12 to the control signal c of the position controller 14 Therefore, the time delay from the time (t = 0) when a rotational shock is applied to the magnetic disk device is smaller than the waveform 63 in FIG. 6B.

[0084] FIG. 6 (c), when the disturbance estimation signal .tau.d _est allowed to act on the actuator 7 so as to cancel the fluctuation of the disturbance estimated disturbance signal .tau.d _est outputted by the disturbance estimator 12 input to the corrector 15 7 shows a simulation result of a waveform 66 of the position error signal e of FIG. 7 and a waveform 65 of the position error signal e when the disturbance estimator 12 is not applied. If the disturbance estimator 12 is applied even when a half-sine-wave-shaped rotational shock is applied to the magnetic disk drive from the outside, the position error signal e does not fluctuate greatly like the waveform 66, and the case where the disturbance estimator 12 is not applied. The disturbance suppression effect is improved as compared with the waveform 65.

As a result, in the magnetic disk drive of the first embodiment of the present invention, the disturbance estimator 12 can accurately detect the disturbance due to the inertia force applied to the actuator 7 by the shock or vibration applied from the outside. Track deviation due to disturbance can be suppressed, and the positioning of the magnetic head 2 on the target track is controlled with high accuracy. Therefore,
The magnetic disk device according to the first embodiment of the present invention can perform stable tracking control with respect to shock and vibration, and can improve the reliability of the magnetic disk device.

FIG. 7 is a block diagram of a positioning control system in the magnetic disk drive according to the first embodiment shown in FIG.
FIG. 4 is an open-loop frequency characteristic diagram showing transmission up to FIG.
According to the gain characteristic diagram of FIG. 7, the gain intersection frequency fc at which the open loop gain becomes zero is 400 Hz. Further, from the phase characteristic diagram of FIG. 7, at the gain intersection frequency fc, the phase margin θm at that time is 60 degrees, and a stable head positioning control system is configured. This is because in the block 30 of the disturbance estimator 12 surrounded by the dashed line in FIG. 2, the voltage drop of the coil resistance Ran and the coil inductance Lan generated by the drive current I _est flowing through the drive coil is calculated by (Ran + Lan This is because the block 39 of s) is faithfully represented. Actually, since the coil inductance Lan is smaller than the coil resistance Ran, it is difficult to form a circuit with high accuracy. Also, since Lan · s is a differential element, it is particularly susceptible to noise, and special care must be taken when constructing a circuit.

FIG. 8 is a block diagram of the positioning control system shown in FIG.
Thus, a track error (position error signal) when the voltage drop of the coil inductance Lan is ignored and the voltage drop of the coil inductance Lan is ignored among the voltage drops generated by the drive current I _est flowing through the drive coil. FIG. 6 is an open-loop frequency characteristic diagram showing transmission from e) to a head position x. As is clear from the gain characteristic diagram and the phase characteristic diagram of FIG.
If the coil inductance Lan of the drive coil is omitted for simplification, the head positioning control system including the disturbance estimator 12 becomes unstable. That is, according to the gain characteristic diagram of FIG. 8, the gain intersection frequency fc at which the open loop gain becomes zero is 200 Hz, and the phase at that time is further delayed than -180 degrees, so that the control system is unstable. Coil inductance Lan included in drive coil
Is smaller than the voltage drop due to the coil resistance Ran, but is included in the block 30 (Lan.
The term s) is an important element for stabilizing the positioning control system shown in FIG.

If the term (Lan · s) included in the block 30 is omitted, the positioning control system shown in FIG. 2 becomes unstable because the actual drive coil 5 uses components of the coil resistance Ra and the coil inductance La. This is because the component of the coil inductance Lan was not included in the disturbance estimator 12 in spite of having. Therefore, in order to stabilize the positioning control system, it is considered that the coil inductance of the drive coil 5 is equivalently reduced to zero.

FIG. 9 is a circuit diagram for stabilizing the positioning control system. A circuit in which a capacitor C and a resistor r are connected in series is connected in parallel to the drive coil 5. In FIG. 9, a combined impedance Za when a circuit in which a capacitor C and a resistor r are connected in series to the drive coil 5 is connected in parallel is represented by (Equation 16).

[0090]

(Equation 16) In (Equation 16), the values of the resistor r and the capacitor C are

[0091]

[Equation 17]

[0092]

(Equation 18) , Za in (Equation 16) can be expressed as (Equation 19).

[0093]

[Equation 19] That is, when the values of the resistor r and the capacitor C constituting the circuit shown in FIG. 9 are set as (Equation 17) and (Equation 18), respectively, the combined impedance Z at both ends of the drive coil 5 is obtained.
a becomes equal to the resistance Ra according to (Equation 19), and the drive coil 5 does not equivalently include the coil inductance La. Therefore, as shown in FIG. 9, if a circuit formed by connecting a resistor r and a capacitor C in series is connected in parallel to the drive coil 5, it is included in the disturbance estimator 12 in the block diagram of the positioning control system in FIG. In block 30, only the voltage drop of the coil resistance Ran caused by the drive current I _est flowing through the drive coil needs to be considered, and instead of the block 39 included in the disturbance estimator 12 of FIG.
A block 49 of 0 may be used. As a result, the disturbance estimator 12 can be configured more easily.

The waveform shown by the dotted line in FIG. 8 is a block diagram of the positioning control system in the magnetic disk drive of the first embodiment shown in FIG. 2, in which block 39 is replaced with block 49 in FIG. The transmission from the track error (position error signal) e to the head position x when a circuit formed by connecting a resistor r and a capacitor C represented by (Equation 17) and (Equation 18) in series at both ends is connected in parallel. 6 is an open loop frequency characteristic shown in FIG. It can be seen that almost the same characteristics as the open loop frequency characteristics of FIG. 7 can be obtained.

In the above-described magnetic disk drive according to the first embodiment of the present invention, the drive signal u output from the block 47 is input as one input signal to the disturbance estimator 12. It goes without saying that the same effect can be obtained by using the drive current Ia output from the driver 10 output from the block 22 instead of u.

(Embodiment 2) FIG. 11 is a block diagram showing a configuration of a magnetic disk drive according to Embodiment 2 of the present invention. FIG. 12 is a block diagram showing an overall configuration of a head positioning control system in the magnetic disk drive of the second embodiment. Note that components having the same functions as those of the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.

The magnetic disk drive of the second embodiment shown in FIG. 11 is different from the first embodiment of FIG.
This is a signal input to the disturbance estimator. That is, in the first embodiment of FIG. 1, the voltage signal Va generated by the voltage detector 11 and the drive signal u are input to the disturbance estimator 12, but in the second embodiment of FIG. Voltage detector 1
1 and a position control signal c generated by the position controller 14 are input to the disturbance estimator 16.

The disturbance estimation signal τd _est generated by the disturbance estimator 16 shown in FIG. Corrector 15, the position the position control signal c output from the controller 14 and the disturbance estimation signal .tau.d _est of the disturbance estimator 16 is input, after performing correction calculation by the correction circuit 15, a drive signal u driver 1
To output to 0.

FIG. 12 is a block diagram of the disturbance estimator 16 in a block 60 surrounded by a dashed line. The disturbance estimator 16 receives as input the voltage signal Va generated by the voltage detector 11 and the position control signal c generated by the position controller 14 represented by the block 21.

In the disturbance estimator 12 according to the first embodiment, the following is performed. First integrator block 43
The signal obtained by multiplying the signal obtained by multiplying the coefficient (g2 / s) by the coefficient (g1) of the block 44 of the second multiplier is added by the adder 38. The signal obtained as a result of the addition and the coefficient (gmn ·
Ktn) a drive torque estimation signal tau _est obtained by multiplying is input to the subtracter 31. The signal γ obtained by the subtractor 31 was input to the block 42 of the second integrator. That is, since the drive signal u to which the correction signal β is added is input to the disturbance estimator 12, the adder 38 shown in FIG.
Needed.

However, the disturbance estimator 16 of the second embodiment is configured to input the position control signal c before the correction signal β is added, so that the adder 38 as shown in FIG. 2 is unnecessary. .

In FIG. 12, a block 41 combining the blocks 32 and 33 constitutes a first multiplier, a block 44 constitutes a second multiplier, a block 43 constitutes a first integrator, and a block 34 constitutes a first multiplier. A block 42 including the block 35 constitutes a second integrator.

The operation of the disturbance estimator 16 in the magnetic disk drive of Embodiment 2 configured as described above will be described.
The operation of the disturbance estimator 12 according to the first embodiment will be described with reference to FIGS.

First, in FIG. 2, if the input of the second integrator 42 constituting the disturbance estimator 12 of the first embodiment is assumed to be γ, the signal γ is focused on the subtractor 31 and

[0105]

(Equation 20) However, the drive signal u is represented by (Equation 21) focusing on the adder 46 of FIG.

[0106]

(Equation 21) Therefore, according to (Equation 20) and (Equation 21), the signal γ
Can be represented by (Equation 22).

[0107]

(Equation 22) Rewriting the block diagram 30 of the disturbance estimator 12 of the first embodiment shown in FIG. 2 based on (Equation 22), FIG.
A block diagram 60 of the disturbance estimator 16 shown in FIG. As shown in FIG. 12, the position controller 14 (block 2)
The position control signal c generated in 1) is input to the multiplier of the block 32, and the output of the block 32 is input to the multiplier of the block 33. Therefore, it is possible to obtain the drive torque estimation signal tau _est by multiplying the coefficient (gmn · Ktn) the position control signal c.

[0108] On the other hand, the disturbance estimation signal τd _est is, block 4
7 is input to the corrector 15. Therefore, the magnetic disk device of the second embodiment is operated by the disturbance estimator 16 similarly to the first embodiment.
Estimating a disturbance torque acting from the position control signal c to the arm 3 for generating the voltage signal Va and the position controller 14 to generate the outputs a disturbance estimation signal .tau.d _est. Disturbance estimation signal τ
d _est is input to the corrector 15 so as to cancel the disturbance τd acting on the arm 3 such as bearing friction, elastic force, and inertia force.

As a result, in the magnetic disk drive of the second embodiment of the present invention, the disturbance estimator 16 can accurately detect the disturbance due to the inertial force applied to the actuator 7 due to the shock or vibration applied from the outside. Even when a disturbance τd due to the inertia force applied to the actuator 7 due to the bearing friction applied to the actuator 7, the elastic force of the FPC, or an externally applied impact or vibration acts, the disturbance τd is estimated by the disturbance estimator 16. Disturbance estimation signal τd _est
, So as to cancel the externally applied disturbance τd. Therefore, similarly to the first embodiment, the externally applied disturbance τd acts as if it were added to the positioning control system through the filter having the cut-off frequency characteristic of (Equation 14) and FIG. Therefore, in the magnetic disk device according to the second embodiment of the present invention, disturbance can be suppressed by the first-order low-frequency cutoff characteristic at a frequency equal to or lower than the angular frequency ωo. Track deviation due to disturbance can be suppressed, and the positioning of the magnetic head 2 on the target track is controlled with high accuracy. Therefore, stable tracking control against shocks and vibrations is possible, and the reliability of the magnetic disk drive can be improved.

As described above, according to the magnetic disk drive of the second embodiment, the number of adders required for the configuration of the disturbance estimator 16 and the corrector 15 is reduced as compared with the magnetic disk drive of the first embodiment. be able to. Therefore, Embodiment 2
The magnetic disk drive of the first embodiment estimates a disturbance τd acting on the arm 3 such as a bearing friction, an elastic force, and an inertia force acting as a disturbance on the head positioning control system with a simpler configuration as compared with the first embodiment. The head positioning control can be stably performed, and the magnetic head 2 can be positioned with high accuracy on a target track formed with a narrow track pitch.

Further, in the magnetic disk drive according to the second embodiment, when the position control system is realized by hardware such as an analog circuit, the adjustment of the circuit can be simplified by reducing the number of adders. . Further, when the position control system is realized by software, it is possible to reduce a calculation time delay due to the calculation processing.

The disturbance estimator 12 configured in the same manner as the block 30 in FIG. 2 is not affected by the sampling frequency of the sector servo of the magnetic disk drive. Therefore, the control band of the disturbance estimator 12 can be set higher than the control band of the positioning control system.

Further, in the magnetic disk drive of the second embodiment, the number of adders forming the disturbance estimator 16 and the compensator 15 can be reduced, so that the control system is realized by hardware such as an analog circuit. Can simplify the adjustment of the circuit. Further, when the control system is realized by software, it is possible to reduce the operation time delay due to the operation processing, and it is possible to further increase the control band.

In each of the embodiments described above, the multiplier and the integrator are described as being constituted by analog filters. However, the multipliers and integrators may be constituted by digital filters. Further, each unit constituting the position control system of each embodiment may be realized by software by a microcomputer.

In each of the embodiments described above, the magnetic disk device has been described, but the present invention is not limited to this.

[0116]

As described above, according to the disk drive of the present invention, the FPC for connecting the bearing means of the actuator means and the actuator means to the circuit board by the disturbance estimating means.
It is possible to accurately detect disturbances such as inertia force acting on the actuator means due to the elastic force of the disk drive or the external impact or vibration applied to the disk drive, and the fluctuation of the disturbance acting on the actuator means during the following operation toward the target track. Even if it is large, fluctuation of disturbance can be compensated, so that the positioning accuracy of the head with respect to the target track can be improved. At the same time, by canceling the inertial force applied to the actuator means by an external impact or vibration applied to the disk device, the shock resistance of the disk device can be improved, and the positioning control of the head can be stably performed.

Therefore, according to the disk apparatus of the present invention, when the disturbance acting on the actuator means has a large influence on the positioning control system due to the reduction in size and weight of the actuator means, the head positioning accuracy can be improved. Since the track density can be increased as compared with the related art, a large-capacity disk device can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a magnetic disk drive according to a first embodiment of the present invention;

FIG. 2 is a block diagram showing an overall configuration of a positioning control system according to the first embodiment of the present invention.

FIGS. 3A and 3B are block diagrams for explaining a disturbance estimating operation of the disturbance estimator according to the first embodiment of the present invention; FIGS.
A block diagram (b) obtained by equivalently converting the block diagram of
A block diagram expressing the block diagram of FIG.

FIG. 4 is a block diagram for explaining an operation of suppressing disturbance applied to the magnetic disk device according to the first embodiment of the present invention, and a block diagram obtained by equivalently converting the block diagram of FIG. b)

FIG. 5 is a cutoff frequency characteristic diagram with respect to a disturbance applied to the magnetic disk device of the first embodiment of the present invention;

FIG. 6A is a diagram illustrating a disturbance waveform applied to the magnetic disk device according to the first embodiment of the present invention and a time waveform diagram of a disturbance estimation signal output from the disturbance estimator, and a disturbance estimation signal output from the disturbance estimator. (B) is a drive current time waveform diagram when no input is made to the device, and (c) is a time waveform diagram of a track error when the disturbance estimation signal output from the disturbance estimator is input to the corrector to cancel the disturbance fluctuation.

FIG. 7 is an open-loop frequency characteristic diagram of the positioning control system when the disturbance estimator according to the first embodiment of the present invention considers the inductance of the drive coil.

FIG. 8 is an open-loop frequency characteristic diagram of the positioning control system when the disturbance estimator according to the first embodiment of the present invention does not consider the inductance of the drive coil.

FIG. 9 is a circuit configuration diagram of a capacitor and a resistor connected in parallel to the drive coil according to the first embodiment of the present invention.

FIG. 10 is a block diagram of a changed portion of the disturbance estimator according to the first embodiment of the present invention.

FIG. 11 is a block diagram showing a configuration of a magnetic disk drive according to a second embodiment of the present invention.

FIG. 12 is a block diagram showing an overall configuration of a positioning control system according to a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Magnetic disk 2 Magnetic head 3 Arm 4 Bearing 5 Drive coil 6 Stator (yoke) 7 Actuator (Actuator means) 10 Driver (Drive means) 11 Voltage detector (Voltage detector) 12, 16 Disturbance estimator (Disturbance estimation) Means 13 Position Detector (Position Detecting Means) 14 Position Controller (Position Controlling Means) 15 Corrector (Correcting Means) 32, 33 First Multiplier (First Multiplying Means) 43 First Integrator (No. 1 integrator) 44 second multiplier (second multiplier) 34, 35 second integrator (second integrator) 37 comparator (comparator) u drive signal e position error signal c position control signal v head moving speed v _est rate estimate signal τ drive torque .tau.d disturbance .tau.d _est disturbance estimation signal Ia drive current Ia _est estimated current Ea induced voltage Ea _est induced voltage estimation signal Va _est voltage estimation signal β Positive signal

Claims (6)

[Claims] An actuator for positioning a head with respect to a disk; a drive for the actuator; a voltage detector for detecting a voltage generated in driving the actuator and outputting a voltage signal;
Disturbance estimation means for estimating the magnitude of disturbance applied to the head from the drive signal and the voltage signal and outputting a disturbance estimation signal; and a current position of the head from servo information prerecorded on the disk and detected by the head. And a position control means for generating and outputting a position control signal corresponding to the error signal, wherein the drive signal includes the position control signal and the disturbance estimation signal. A disk device characterized by being obtained by synthesizing a disk device. 2. The disturbance estimating means includes: a comparing means to which a voltage signal detected by the voltage detecting means is input; a first multiplying means for multiplying the driving signal by a first coefficient; Second multiplying means for multiplying the output by a second coefficient, first integrating means for integrating the output of the comparing means,
A second integrating means for integrating a value obtained by subtracting an added value of an output of the second multiplying means and an output of the first integrating means from an output of the first multiplying means; Compares the voltage signal with the output of the second integrating means,
2. The disk device according to claim 1, wherein the result is output to the second multiplying means and the first integrating means. 3. An actuator for positioning a head with respect to a disk, a driving unit for the actuator, a voltage detecting unit for detecting a voltage generated in driving the actuator and outputting a voltage signal,
Position detecting means for generating and outputting an error signal corresponding to the current position of the head from servo information previously recorded on the disk and detected by the head, and a position for generating and outputting a position control signal corresponding to the error signal Control means, and disturbance estimation means for estimating the magnitude of disturbance applied to the head from the voltage signal and the position control signal and outputting a disturbance estimation signal, wherein the drive signal comprises the position control signal and the disturbance estimation A disk device configured to be obtained by synthesizing signals. 4. The disturbance estimating means includes: comparing means to which the voltage signal detected by the voltage detecting means is input; first multiplying means for multiplying the position control signal by a first coefficient; A second multiplication means for multiplying the output of the second multiplication means by a second coefficient, a first integration means for integrating the output of the comparison means, and an output of the second multiplication means from the output of the first multiplication means. Second integration means for integrating the subtracted value, wherein the comparison means compares the voltage signal with the output of the second integration means, and compares the result with the second multiplication means and the first 4. The disk device according to claim 3, wherein the output is made to the integrating means. 5. The disk device according to claim 1, wherein a control band of said disturbance estimating means is set to be larger than a control band of said position control means. 6. A permanent magnet fixed to at least one of the yokes in a pair of yokes opposed to each other with a gap therebetween, and a magnetic gap formed by the permanent magnet and the yoke. 6. A circuit comprising a drive coil disposed therein and connected to a circuit in which a capacitor and a resistor are connected in series in parallel with the drive coil. The disk device as described above.