JPH0684306A - Disk storage device - Google Patents

Abstract

(57) [Abstract] [Purpose] The delay due to feedback compensation is reduced, stability is maintained even for position signals containing noise, disturbance is suppressed and access time is shortened, and the head is highly accurate. (EN) Provided is a disk storage device which can be positioned in a position where the fluctuation of the positioning operation due to disturbance is reduced. A microcomputer 30 for estimating and storing a disturbance compensation signal 28 is provided, and a first adder 29 for adding the disturbance compensation signal 28 as a feedforward signal to a positioning compensation signal 23 to a drive circuit 25 for compensation is provided. .
Further, when the positioning compensator 22 for estimating the speed signal from the drive signal 26 is provided, instead of the drive signal 26, a signal proportional to the disturbance compensation signal 28 is subtracted from the drive signal 26 and input to the speed estimation means 22. Second adder 5 to correct
0 is set.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk storage device such as a magnetic disk device or an optical disk device.
A compensation signal that cancels the disturbance acting on the head positioning control system is calculated and stored, and this compensation signal is used as a part of the input signal to the drive circuit to suppress the disturbance and improve the head positioning accuracy. The present invention relates to means for shortening the positioning time.

[0002]

2. Description of the Related Art In many cases, a conventional magnetic disk drive employs a method in which a magnetic head floats as the disk rotation speed increases. Should be located outside the data area. Generally, a method called a retract spring is used to push the actuator in one direction, or the head is retracted outside the data area by the weight of the actuator. The spring force, the self-weight of the actuator itself, and the like cause disturbances and have a great influence on the head positioning control system, and cause a variation in the transient response due to a steady position deviation and a difference in the moving direction.

Further, in the disk storage device, since the disk is rotating at a high speed, it vibrates at the rotation frequency, and this vibration acts as a disturbance on the position signal, degrading the positioning accuracy.

When a speed control system is used as a control system for moving the head to a target track and a method of estimating the speed signal from the position signal and the drive signal is used as the speed detector, the disturbance of the disk vibration causes a detection error. Brings
There is a problem that the response of the speed control system varies.

Further, in the conventional optical disk device, a coarse actuator for moving a large distance when moving and positioning the head and a fine actuator for fine positioning at the tip of the coarse actuator are prepared. , The head is mounted on the fine actuator. The fine actuator needs to be operating in order to perform minute positioning, but if the eccentricity of the disk is large compared to the stroke of the fine actuator, positioning by the fine actuator becomes impossible and positioning accuracy deteriorates. was there.

As a conventional disturbance compensation method, Japanese Patent Publication No. 1-
As described in Japanese Patent No. 43378, there is proposed a compensation method in which an error signal between an estimated speed signal and a speed signal is fed back and added to the input of a power amplifier as a disturbance canceling signal.

[0007]

With the increase in capacity and speed of disk storage devices, the width between the tracks has become narrower and the actuator has been significantly reduced in weight. As a result, the effects of disturbances have become increasingly non-negligible. In a disk storage device, when the center of rotation of the disk and the center of gravity of the disk do not coincide, the disk vibrates at the rotation frequency. Therefore, it is important to suppress disturbance. There is a limit to the expansion of the response frequency range of the conventional closed loop system to suppress the disturbance due to the resonance characteristic of the head support mechanism system.

As a method of estimating and suppressing disturbance, Japanese Patent Publication No. 1-43378, which is the above-mentioned prior art, is a method for amplifying and feeding back an error between a detected speed signal and an estimated speed signal, and a low-frequency disturbance. However, in order to suppress high-frequency mechanical vibration, since a signal obtained by differentiating a position signal containing high-frequency noise is used as the speed signal, the S / N of the speed signal decreases. ,
The frequency band of the position differentiating circuit cannot be increased. For this reason,
There is a problem that high frequency disturbance and vibration cannot be suppressed. Further, in the method of feeding back the estimation error, there is a delay due to the feedback compensation, so that a good effect of the disturbance compensation cannot always be obtained.

An object of the present invention is to reduce the delay caused by feedback compensation and to ensure stability even with respect to a position signal containing noise, while suppressing disturbance to shorten the access time and reduce the head time. It is an object of the present invention to provide a disk storage device that can perform positioning with high accuracy and reduce variations in positioning operation due to disturbance.

[0010]

In order to achieve the above object, the present invention represents at least one disk that is rotationally driven and the radial and circumferential positions of the disk recorded on the disk. A head for reading a servo signal, a position detector for generating a position signal representing the position of the head from the servo signal, an actuator to which the head is fixed, and a drive circuit for outputting a drive signal according to an input signal to drive the actuator. And a controller that outputs a movement command according to a control signal input from the outside,
In a disk storage device equipped with a head positioning servomechanism, which comprises a positioning compensator that calculates a positioning compensation signal based on a movement command from the controller so as to match the position signal with a target position, and outputs it to a drive circuit,
Estimating means for estimating a disturbance compensation signal that cancels the disturbance as a function of the drive signal and the position signal, storage means for storing the disturbance compensation signal, and input of the drive circuit using the disturbance compensation signal stored in the storage means as a feedforward signal. The present invention proposes a disk storage device provided with a first correction means for adding and correcting a signal.

Specifically, the estimating means sets one representative track or a plurality of representative tracks or all the tracks representing the disk as the target tracks immediately after the power is turned on, or immediately after the power is turned on, and at fixed time intervals immediately after the power is turned on. , The head is positioned on the target track, the synchronous disturbance compensation signal that suppresses the disturbance that acts at the same circumferential direction position while the disk is rotated a plurality of times is calculated, and the data of the synchronous disturbance compensation signal of the representative track is interpolated to obtain the target. Means for obtaining a synchronization disturbance compensation signal on a track other than the track and for storing the synchronization disturbance compensation signal in the storage means as a function of the position on the disk surface, and the first correction means is a synchronization corresponding to the position on the disk surface. It is a means for outputting the disturbance compensation signal as a feedforward signal.

The estimating means sets one representative track or a plurality of representative tracks or all tracks representing the disk as a target track immediately after the power is turned on, or immediately after the power is turned on, and at regular intervals immediately after the power is turned on, and the head is set on the target track. Position, and calculate the DC disturbance compensation signal that suppresses the DC disturbance that acts on the target track while the disk rotates multiple times, and interpolates the data of the DC disturbance compensation signal of the representative track on the tracks other than the target track. A means for obtaining a direct current disturbance compensation signal and storing the direct current disturbance compensation signal in the storage means as a function of the position on the disk surface, and the first correction means is a feedforward signal for the direct current disturbance compensation signal according to the position on the disk surface. Can also be used as a means for outputting.

Further, the estimating means sets one representative track or a plurality of representative tracks or all the tracks representing the disc as the target tracks immediately after the power is turned on or immediately after the power is turned on and at regular intervals immediately after the power is turned on. Position the head on the disk, calculate the AC disturbance compensation signal that suppresses the AC disturbance that acts on the target track while the disk rotates multiple times, and interpolate the data of the AC disturbance compensation signal of the representative track to track other than the target track. Is a means for obtaining an AC disturbance compensation signal on the disk and storing the AC disturbance compensation signal in the storage means as a function of the position on the disk surface, and the first correcting means feeds the AC disturbance compensation signal according to the position on the disk surface. A means for outputting as a forward signal is also possible.

Further, the estimating means sets one representative track or a plurality of representative tracks representing the disk as the target tracks immediately after the power is turned on or immediately after the power is turned on and at regular intervals immediately after the power is turned on, and the target tracks are set. Position the head on the disk, calculate the AC disturbance compensation signal that suppresses the AC disturbance that acts on the target track while the disk rotates multiple times, and interpolate the data of the AC disturbance compensation signal of the representative track to track other than the target track. Determining an AC disturbance compensation signal on the above, storing the AC disturbance compensation signal in the storage means as a function of the position on the disk surface, and then mounting the head on a new representative track or a plurality of representative tracks or all representative tracks. Position and act on new target track while disk rotates multiple times The DC disturbance compensation signal for suppressing the DC disturbance is calculated, and the DC disturbance compensation signal of the new representative track is interpolated to obtain the DC disturbance compensation signal on the track other than the new target track. Means for storing the DC disturbance compensation signal as a function of position, wherein the first correcting means outputs a signal obtained by adding the AC disturbance compensation signal and the DC disturbance compensation signal corresponding to the position on the disk surface as a feedforward signal. May be

In any case, the second correction means is provided between the output side of the drive circuit and the output side of the estimation means and the input side of the positioning compensator, and the positioning compensator functions as a function of the drive signal and the position signal. Has a speed signal estimating means for estimating the speed signal of the head, and the second correcting means obtains a signal by subtracting a signal proportional to the disturbance compensation signal from the drive signal,
Instead of the drive signal, the subtracted signal may be output to the speed signal estimation means.

[0016]

In the present invention, the estimating means for estimating the disturbance compensation signal for canceling the disturbance of the disk storage device, the means for estimating the estimated position signal and the estimated velocity signal of the head,
And a means for amplifying an error between the position signal and the estimated position signal.

When the disturbance does not act on the positioning control system, the position signal and the estimated position signal coincide with each other. However, when the disturbance acts on the positioning control system, an error occurs between the position signal and the estimated position signal. This error occurs because the disturbance is acting.Therefore, according to the disturbance compensation value obtained by amplifying the estimated position error signal, which is the difference between this position signal and the estimated position signal, it is necessary to cancel the disturbance. Can generate various signals.

The estimating means adds the disturbance compensation values calculated while the disk rotates a plurality of times for each position in the same circumferential direction and averages them, or calculates the calculated disturbance compensation values and the times before and after the disturbance compensation values. A synchronous disturbance compensation signal that suppresses disturbance acting at the same circumferential position is calculated from the moving average of the disturbance compensation values. The synchronous disturbance compensation signal calculated in this manner reduces the influence of non-reproducible noise included in the position signal.

Further, the estimating means can also calculate a DC disturbance compensation signal which is an average value of the disturbance compensation values, and can also calculate an AC disturbance compensation signal obtained by subtracting the DC disturbance compensation signal from the synchronous disturbance compensation signal. The storage means stores the disturbance compensation signal obtained by the estimation means as described above as a function of the position on the disk surface.

After performing the above operation on the representative tracks on the disk surface, the disturbance compensation signals of the unstored tracks are interpolated from the disturbance compensation signals of the representative tracks stored in the storage means to compensate the disturbances of all the tracks. The signal is obtained and stored in the storage means.

The first correction means outputs the disturbance compensation signal stored in the storage means as a feedforward signal according to the head position on the disk surface, and adds this signal to the positioning compensation signal of the positioning control system. It can be input as an operation signal to the drive circuit to cancel disturbances, improve positioning accuracy, and shorten access time.

The disturbance compensation signal estimated by the estimation means is stored in the storage means immediately after the power of the disk storage device is turned on, or immediately after the power is turned on, and at fixed time intervals thereafter, until the disturbance compensation signal stored in the storage means is updated. During the period, a correction operation is performed using the stored disturbance compensation signal. According to this method,
Even if the calculation speed of the estimation means is slow, a stable correction operation can be executed, disturbances and vibrations can be canceled, positioning accuracy can be improved, and access time can be shortened.

Further, a positioning compensator having a speed estimating means for estimating a speed signal by synthesizing a signal obtained by passing a differential signal of the position signal through a low pass filter and a signal obtained by passing an integrated signal of the drive signal through a high pass filter is adopted. If you are
Since the position signal includes the disturbance due to the disturbance, the velocity estimation result also has an error.

On the other hand, according to the first correction means of the present invention, since the position signal input to the speed estimation means does not include the disturbance, the influence of the disturbance is eliminated.

Further, in the disk storage device of the present invention, instead of the drive signal input to the speed estimating means,
Second correction means is provided for inputting a signal obtained by subtracting the disturbance compensation signal from the drive signal to the speed estimation means. With this correction method, the speed estimating means is not affected by disturbance, and the variation in the response of the positioning control system can be reduced.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a disk storage device according to the present invention will be described below with reference to FIGS.

<< First Embodiment >> FIG. 1 is a block diagram of a magnetic disk device showing an embodiment of a disk storage device according to the present invention. In this embodiment, the voice coil motor VCM2 is used as the actuator. VCM2 is
The head 1 is moved to an arbitrary track on the disk 4 in the disk radial direction and positioned. The disk 4 is rotationally driven by the spindle motor 3. All of these components are mounted on the base 5. Position detector 6
Is composed of an amplifier 7 and a demodulation circuit 8. Servo signals are recorded on the disk 4, read by the head 1, amplified by the amplifier 7, and sent to the demodulation circuit 8. The demodulation circuit 8 outputs, as position signals, a position error signal 9a indicating a position error up to the center of the closest track, a radial direction position signal 9b, and a circumferential direction position signal 9c. The demodulation circuit 8 includes a main position error signal PESN (not shown) and a sub position error signal PE (not shown) having a 90 ° phase difference.
SQ is created, and a position error signal PES, that is, 9a having a proper polarity according to the head position is created and output from the main position error signal PESN and the sub position error signal PESQ.

FIG. 2A shows the main position error signal PESN, the sub position error signal PESQ, and the position error signal PES, that is, 9
It is a figure which shows the relationship with a. The radial position signal 9b is
This is a track number represented by a digital signal indicating the absolute position of the head 1 in the radial direction of the disk. The relationship between the radial direction position signal 9b and the position error signal 9a is shown in FIG.

FIG. 2B is a diagram showing the relationship between the radial position signal 9b and the circumferential position signal 9c. The circumferential position signal 9c is a sector number represented by a digital signal representing the position of the head 1 in the circumferential direction of the disk. The relationship between the radial direction position signal 9b and the circumferential direction position signal 9c is expressed in FIG.

When the controller 20 of FIG. 1 outputs the movement command 21 to the positioning compensator 22, the positioning compensator 22 calculates and outputs the positioning compensation signal 23. The calculation method of the positioning compensation signal 23 is, for example, ME.
E &DANIEL's"MAGNETICRECO"
RDING "Vol.2 (McGraw-HillBoo
k Company), pp. 53-84,
Position error signal 9a, radial position signal 9b, and drive signal 2
6, there is a method of calculating by the speed control system until the head 1 reaches the vicinity of the target track, and by the position control system after approaching the target track. Generally, in a magnetic disk device, an operation of moving a large distance when a positional deviation is large is called a seek operation, and an operation of controlling a position when the positional deviation is small is called a following operation. The means for realizing the positioning compensator may be an analog control system or a digital control system.

The estimating means, the storing means, and the correcting means for estimating the disturbance compensation signal for canceling the disturbance and the vibration include the microcomputer 30, the digital output circuit DOC 38 for holding the digital disturbance compensation signal 36, and the digital disturbance compensation signal 36. A DA converter DAC 37 for converting into a disturbance compensation signal 28, and a drive signal 26 with a digital drive signal 40.
A first AD converter ADC41 for converting to the second AD and a second AD for converting the position error signal 9a into the digital position error signal 43
It is composed of a converter ADC 42, a radial position signal 9b, a circumferential position signal 9c, a digital drive signal 40, and a digital input circuit DIC 44 for reading the digital position error signal 43 into the microcomputer 30, and a first adder 29. The microcomputer 30 has a CPU 31.
, A ROM 32, a RAM 33, and a bus 34 connecting them.

The first adder 29 adds the disturbance compensation signal 28 and the positioning compensation signal 23, and outputs the result as the operation signal 24. The disturbance compensation signal 28 is the actuator V
It is a signal that cancels external forces acting on CM2 and disturbances such as disk vibration. As a result, in the disk storage device of this embodiment, steady position deviations and vibrations do not occur, and high-speed and highly accurate head positioning is possible.

FIG. 3 is a block diagram of a discrete time system showing an algorithm implemented in the microcomputer 30. In FIG. 3, z ~ ¹ means a delay of one sample. The other components are expressed as continuous-time transfer functions. s represents a Laplace operator. In addition, the gain of the drive circuit 25 is KA (A / V), the force constant of the VCM 2 is KF (N / A), and the mass of the movable part mounting the head 1 is M.
(Kg), the gain from the position in the radial direction of the head to the digital position error signal 43 is K2 (count / m), and the gain from the drive signal 26 to the digital drive signal 40 is KI.
It is expressed as (count / V). External force D1
And the vibration D2 of the disk is added.

Here, a method of deriving the digital disturbance compensation value W by the microcomputer 30 will be described. First, the digital input circuit DIC44 and the first AD converter A
The DC 41 converts the drive signal 26 into a digital drive signal 40, samples the digital drive signal 40, and stores the sampling result as a variable I. Further, the second AD converter ADC42 converts the position error signal 9a into the digital position error signal 43, the digital input circuit DIC44 samples the digital position error signal 43, and stores the sampling result as a variable Y. Further, the radial position signal 9b and the circumferential position signal 9c are sampled, and the results are stored as R and θ, respectively.

Following the sampling operation, as shown in (1), << Y >> = Y- <Y> (1) A value obtained by subtracting the digital estimated position error signal <Y> from the digital position error signal Y is calculated, This value is stored as a digital estimation error signal << Y >>.

Further, as shown in (2), W = H * << Y >> (2) A value obtained by multiplying the digital estimation error signal << Y >> by a gain H is stored as a digital disturbance compensation value W.

In preparation for the next sampling, the digital estimated position signal represented by (3) is calculated, and <X1> = <X1> + T * <X2> + G1 * I + L1 * << Y >> (3) Variable <X1> Memorize as.

Next, the digital estimated velocity signal represented by (4) is calculated and stored as <X2> = <X2> + G2 * I + L2 * << Y >> (4) variable <X2>.

The digital estimated position error signal represented by (5) is calculated and stored as <Y> = K2 * <X1> (5) variable <Y>.

The microcomputer 30 has the above (1)
The processing calculations from (5) to (5) are repeated at intervals of T seconds.

In FIG. 3, the gains G1, G2, L1,
L2, H is the gain of the same dimension observer of the discrete time system made from the transfer function model from the driving signal 26 to a digital position error signal ^{Y, G1 = KF * T 2} / (2M) (6) G2 = KF * T / M (7) L1 = 2 {1-exp (-2ζωT) · cos (ωT√ (1-ζ 2))} / K2 (8) L2 = {1 + exp (-2ζωT) -2exp (-ζωT ) ・ Cos (ωT√ (1-ζ ² ))} / TK2 (9) H = -M * L2 / (KF * T * KA) (10) (6), (7), (8), (9 ), (10).

Ω and ζ in (8) and (9) represent the estimated speed and the damping characteristic. In this case, set ω to a frequency that is several times the angular frequency of the vibration that you want to suppress, and set ζ to 0.
It is considered that it may be set to about 7.

External force acting on the movable part of the head and the disk 4
When there is no rotation-synchronized vibration of, the digital estimated position error signal <Y> calculated as above matches the digital position error signal Y. However, in the presence of disturbance or vibration, the digital position error signal Y and the digital estimated position error signal <Y> produce an error. This error is generated because disturbance or vibration is generated, and the digital disturbance compensation value W obtained by amplifying the digital estimation error signal << Y >> which is obtained by amplifying this error cancels the disturbance such as external force or vibration. It becomes the necessary signal to do.

A method is conceivable in which the digital disturbance compensation value W, which is a signal obtained by amplifying the digital estimation error signal << Y >>, is fed back and output as a part of the operation signal. However, with respect to the noise included in the position signal with the delay due to the feedback compensation, there is a possibility that the performance may be rather deteriorated due to the feedback delay.

Therefore, the influence of non-reproducible noise is reduced,
Moreover, in order to prevent a delay due to feedback, a synchronous disturbance compensation signal obtained by averaging the disturbance compensation values for each circumferential position while the disc is rotated a plurality of times is used as a function of the position of the head on the disc surface. It is stored in the RAM 33 in the form of a table.

FIG. 4 is a flow chart showing the procedure for creating a synchronization disturbance compensation table for storing the synchronization disturbance compensation signal.

At step 401, the positioning compensator 22 positions the head 1 on the representative track.

In step 402, following the start of the positioning operation, the estimating means starts the calculation of the disturbance compensation value W.

In step 403, the process waits until the disturbance compensation value W reaches a steady state.

In step 404, the average value of the disturbance compensation value W at the same circumferential position is calculated, and the calculation result is stored as a function of the position on the disk surface. For example, as the representative track, the synchronization disturbance compensation signal Wave at the circumferential position θ while the disk makes 100 rounds with the track number R
To calculate (θ), follow and perform 1 from the first lap.
It is assumed that the average value of the disturbance compensation values at the same circumferential position up to the 00th round is calculated. Track number R, circumferential position θ,
When the disturbance compensation value at the kth round is W (R, θ, k), the synchronous disturbance compensation signal W at the track number R and the circumferential position θ is W.
ave (R, θ) is Wave (R, θ) = {ΣW (R, θ, k)} / 100 (11) However, Σ (addition) is from k = 1 to 100. At each circumferential position, (11) is calculated and Wave (R,
θ) However, (θ = 0, 1, ... θmax) is stored in the disturbance compensation table.

In step 405, the head is moved onto a new representative track, and steps 401 to 404 are repeated. The representative track may be one track on the disc surface, all tracks, or a plurality of tracks.

In step 406, interpolation is performed from the sync disturbance compensation table of the adjacent representative track to obtain the sync disturbance compensation signal of the track not selected as the representative track. The interpolation method in the case of a plurality of representative tracks is, for example, the disturbance compensation tables Wave (R1, θ) and Wave (R2, θ) of two adjacent representative tracks R1 and R2, where (θ = 0, 1, 2, , .Theta.max), two data at the same circumferential direction position .theta. Are approximated by a linear expression, and the synchronous disturbance compensation signal at the circumferential position .theta. Is calculated for another track. If this operation is executed for all circumferential positions, the synchronous disturbance compensation table for all areas of the disk surface can be created. In the case of one representative track, the interpolation method is 0th-order interpolation, that is, the synchronization disturbance compensation signals of all tracks are the same, and therefore no new table is created.

In this way, after storing the synchronous disturbance compensation table as a function on the disk surface, the digital disturbance compensation signal is sent via the digital output circuit DOC 38 and the DA converter DAC 37 according to the position of the head 1 on the disk surface. 36 is output to the first adder 29 as a feedforward signal. By outputting the feedforward signal in this manner, the seek control system for moving the head to the target track and the following control system for positioning the head on the target track are always operated to suppress disturbance.

FIG. 5 is a diagram showing the response of the conventional control system in the state where the following control system is operating. FIG. 6 is a diagram showing a response of the control system of the present invention in a state where the following control system is operating. As is clear from the comparison between the two, by reducing the vibration generated in the conventional example of FIG. 5 in the present invention of FIG. 6, the access time can be shortened and the positioning accuracy can be improved.

In the procedure for creating the synchronous disturbance compensation table, step 404 in FIG. 4 synchronously adds the disturbance compensation values at the same circumferential position of the head while the disk rotates a plurality of times to reduce non-reproducible noise. It has become. As another method of realizing the procedure of step 404, there is also a method of calculating and deriving a moving average of the disturbance compensation value at the circumferential position in a certain sample and the disturbance compensation value continuously calculated before and after the disturbance compensation value. Also with this method, the noise component included in the disturbance compensation value can be cut and the same effect can be obtained.

Further, in the positioning compensator having the speed estimation means for estimating the speed signal by synthesizing the signal obtained by passing the differential signal of the position signal through the low-pass filter and the signal obtained by passing the integrated signal of the drive signal through the high-pass filter, Therefore, when the position signal includes disturbance, the velocity estimation result also has an error. In a disk storage device in which the disk 4 is eccentric, when a conventional control system is used to repeatedly seek and follow a certain number of tracks, as shown in FIG.
There is a problem in that the response of the position error signal varies when switching from seek to following.

On the other hand, in the present invention, the disturbance compensation signal is added to the positioning compensation signal by the first adder 29 to cancel the disturbance, and the position signal input to the speed estimating means is Since the disturbance is not included, the influence of the disturbance disappears.

On the other hand, since the drive signal includes a signal for canceling the disturbance by the correction of the first adder 29, the speed estimating means for estimating the speed signal from the drive signal is affected by the disturbance and the response of the control system is received. Variations will occur.

In order to suppress this influence, in the disk storage device of the present invention, the second adder 50 is provided, and the signal obtained by subtracting the disturbance compensation signal from the drive signal is used instead of the drive signal input to the speed estimating means. Input to the speed estimation means. By this correcting operation, the speed estimating means is not affected by the disturbance, and the variation in the response of the positioning control system can be reduced. FIG. 8 shows a response waveform when repeatedly seeking and following in this way. It can be seen that there is no variation in the response despite the disturbance acting due to the eccentricity of the disk.

<Second Embodiment> This embodiment has the same hardware as the disk storage device of the first embodiment.
The method of calculating the disturbance compensation value calculated by the estimating means is also the same as that described in the first embodiment.

FIG. 9 is a flow chart showing the calculation of the DC disturbance compensation signal and the procedure for creating the disturbance compensation table in this embodiment. The procedure of calculating the DC disturbance compensation signal after calculating the disturbance compensation value and creating the disturbance compensation table in this embodiment will be described with reference to this figure.

First, in step 901, the head is positioned on the representative track by the positioning compensator.

In step 902, following the start of the positioning operation, the estimating means starts the calculation of the disturbance compensation value W.

In step 903, the process waits until the disturbance compensation value W reaches a steady state.

In step 904, the average value of the disturbance compensation value W is calculated while the disk is rotating a plurality of times, and the calculation result is stored in the storage means as a function of the position in the radial direction of the head. For example, in order to calculate the DC disturbance compensation signal WDC (R) while the disk makes one revolution with the track number R as a representative track, it is necessary to follow and calculate the average value of the disturbance compensation values for one revolution. . Assuming that the track number is R and the disturbance compensation value at the circumferential position θ is W (R, θ), the DC disturbance compensation signal WDC (R) of the track number R is WDC (R) = {ΣW (R, θ)}. / (Θmax + 1) (12) However, Σ (addition) is from θ = 0 to θ = θmax.

In step 905, the head is moved onto a new representative track, and steps 901 to 904 are repeated. The representative track is 1 on the disc surface
One track, all tracks,
There may be multiple tracks.

At step 906, the DC disturbance compensation signal of the track not selected as the representative track is interpolated from the DC disturbance compensation table of the adjacent representative track. As an interpolation method in the case of a plurality of representative tracks, for example, the DC disturbance compensation signals of two adjacent representative tracks are approximated by a linear expression to create a table. When there is one representative track, no new table is created because the 0th-order interpolation, that is, the DC disturbance compensation signals of all tracks are the same.

After storing the DC disturbance compensation table as a function of the head position in the radial direction of the disk as described above, the data stored in the DC disturbance compensation table is fed forward through the digital output circuit 38 and the DA converter 37. The signal is output to the first adder 29. According to feedforward signal correction, the seek control system that moves the head to the target track and the following control system that positions the head to the target track are constantly operated to suppress disturbances, shorten access time and improve positioning accuracy. You can

When the positioning compensator 22 has a speed estimating means, the correction operation by the second adder 50 is
It is possible to eliminate the influence of disturbance on the speed estimation means and reduce the difference in response due to the difference in the moving direction of the seek control system.

<< Third Embodiment >> This embodiment has the same hardware as the disk storage device of the first embodiment.
The method of calculating the disturbance compensation value calculated by the estimating means is also the same as that described in the first embodiment. Furthermore, the method of calculating the DC disturbance compensation signal is the same as that described in the second embodiment.

FIG. 10 is a flow chart showing the calculation of the AC disturbance compensation signal and the procedure for preparing the disturbance compensation table in this embodiment. With reference to this figure, the AC disturbance compensation signal calculation after calculating the disturbance compensation value and the procedure for creating the disturbance compensation table will be described.

In step 1001, the head is positioned on the representative track by the positioning compensator.

In step 1002, following the start of the positioning operation, the estimation means starts the calculation of the disturbance compensation value W.

In step 1003, the disturbance compensation value W
Wait until is in a steady state.

In step 1004, the average value of the disturbance compensation value W (DC disturbance compensation signal) and the average value of the disturbance compensation values in the same circumferential direction (synchronous disturbance compensation signal) are calculated while the disk rotates a plurality of times. The calculation result (AC disturbance compensation signal) obtained by subtracting the DC disturbance compensation signal from the synchronization disturbance compensation signal is stored in the storage means as a function of the position on the disk surface. The AC disturbance compensation signal WAC (R, θ) at the track number R and the circumferential position θ is the synchronous disturbance compensation signal Wave.
Using (R, θ) and the DC disturbance compensation signal WDC (R), WAC (R, θ) = WAVE (R, θ) −WDC (R) (13).

In step 1005, the head is further moved onto a new representative track, and step 100
The procedure from 1 to step 1004 is repeated. The representative track may be one track on the disk surface, all tracks, or a plurality of tracks.

At step 1006, the DC disturbance compensation signals of the tracks not selected as the representative tracks are
It is calculated by interpolating from the AC disturbance compensation table of the adjacent representative track. When there are a plurality of representative tracks, for example, a table is created by approximating the AC disturbance compensation signals of two adjacent representative tracks by a linear expression. When there is one representative track, no new table is created because the zero-order interpolation, that is, the DC disturbance compensation signals of all tracks are the same.

After storing the AC disturbance compensation table as a function of the position on the disk surface as described above, it is passed through the digital output circuit DOC38 and the DA converter DAC37,
The data stored in the AC disturbance compensation table is output to the first adder 29 as a feedforward signal. When a feedforward signal is output, the seek control system that moves the head to the target track and the following control system that positions the head to the target track are constantly operated to suppress disturbances, shorten access time, and improve positioning accuracy. .

Further, according to the correcting means by the second adder 50, as in the first embodiment, it is possible to eliminate the variations in the seek and following responses due to the eccentricity of the disk.

<Fourth Embodiment> This embodiment has the same hardware as the disk storage device of the first embodiment.
The method of calculating the disturbance compensation value calculated by the estimating means is also the same as that described in the first embodiment. Further, the DC disturbance compensation signal and the AC disturbance compensation signal calculation method are also the same as those described in the second and third embodiments.

First, a DC disturbance compensation table is created according to the procedure for creating the DC disturbance compensation signal table shown in FIG. 9, and then according to the procedure for creating the AC disturbance compensation signal table shown in FIG. To create.

After the table is created, the signal obtained by adding the AC disturbance compensation signal and the DC disturbance compensation signal corresponding to the position on the disk surface of the head 1 is used as the disturbance compensation signal via the digital output circuit 38 and the DA converter 37. Output to the first adder 29 for feedforward control. If a feedforward signal is output, the seek control system that moves the head to the target track and the following control system that positions the head on the target track are always activated to suppress disturbance.
Access time can be shortened and placement accuracy can be improved.

Further, in the correction method using the second adder 50, it is possible to eliminate variations in the seek and following responses due to the eccentricity of the disk, as in the first embodiment.

This embodiment is effective, for example, when the DC disturbance changes depending on the radial position of the head, but the AC disturbance does not change. A DC disturbance compensation table is created from a plurality of representative tracks, and one representative If the AC disturbance compensation table is created from the truck, the memory for creating the table can be saved.

[0085]

According to the present invention, even when disturbance or vibration acts on the positioning control system, the delay caused by the feedback compensation is reduced, and the stability is ensured even for a position signal containing noise. However, it is possible to obtain a disk storage device that can suppress the disturbance and shorten the access time while positioning the head with high accuracy and reduce the variation in the positioning operation due to the disturbance.

[Brief description of drawings]

FIG. 1 is a block diagram of a magnetic disk device showing an embodiment of a disk storage device according to the present invention.

2A is a diagram showing a relationship between a main position error signal PESN, a sub-position error signal PESQ, and a position error signal PES, that is, 9a, and FIG. 2B is a radial position signal 9b and a circumferential position. It is a figure which shows the relationship with the signal 9c.

FIG. 3 is a block diagram of a discrete-time system showing an algorithm implemented in a microcomputer.

FIG. 4 is a flowchart showing a procedure for creating a synchronization disturbance compensation table for storing a synchronization disturbance compensation signal of the first embodiment.

FIG. 5 is a diagram showing a response of a conventional head positioning control system in a state where a following control system is operating.

FIG. 6 is a diagram showing a response of the head positioning control system of the present invention in a state where the following control system is operating.

FIG. 7 is a diagram showing an example of a response waveform of a conventional head positioning control system.

FIG. 8 is a diagram showing an example of a response waveform of the head positioning control system of the present invention.

FIG. 9 is a flow chart showing a calculation of a DC disturbance compensation signal and a procedure of creating a disturbance compensation table according to the second embodiment.

FIG. 10 is a flowchart showing a procedure for calculating an AC disturbance compensation signal and creating a disturbance compensation table according to the third embodiment.

[Explanation of symbols]

 1 head 2 voice coil motor VCM 3 spindle motor 4 disk 5 base 6 position detector 7 amplifier 8 demodulation circuit 9a position error signal 9b radial direction position signal 9c circumferential direction position signal 20 controller 21 movement command 22 positioning compensator 23 positioning compensation signal 25 driving circuit 26 driving signal 28 disturbance compensation signal 29 first adder 30 microcomputer 31 CPU 32 ROM 33 RAM 34 bus 36 digital disturbance compensation signal 37 DA converter DAC 38 digital output circuit DOC 41 AD converter ADC 42 AD converter ADC 43 Digital position error signal 44 Digital input circuit DIC 50 Second adder

Claims (6)

[Claims] 1. At least one disk that is rotationally driven, a head that reads a servo signal that represents a radial position and a circumferential position of the disk recorded on the disk, and a position of the head from the servo signal. A position detector for generating a position signal, a head-fixed actuator, a drive circuit for outputting a drive signal in response to an input signal to drive the actuator, and a control signal input from the outside. A head positioning servomechanism including a controller that outputs a movement command and a positioning compensator that calculates a positioning compensation signal based on the movement command from the controller so as to match the position signal with a target position and outputs the position compensation signal to the drive circuit. In a disk storage device comprising: a disturbance as a function of the drive signal and the position signal. Estimating means for estimating the disturbance compensation signal to be killed, storage means for storing the disturbance compensation signal, and correction by adding the disturbance compensation signal stored in the storage means to the input signal of the drive circuit as a feedforward signal A disk storage device comprising: 2. The disk storage device according to claim 1, wherein the estimating unit is provided with one representative track or a plurality of representative tracks representing the disk immediately after power-on or immediately after power-on and at fixed time intervals immediately after power-on. A representative track or all tracks are set as target tracks, a head is positioned on the target tracks, and a synchronous disturbance compensation signal for suppressing a disturbance acting at the same circumferential direction position while the disk rotates a plurality of times is calculated, Means for interpolating the data of the synchronization disturbance compensation signal to obtain a synchronization disturbance compensation signal on a track other than the target track, and for storing the synchronization disturbance compensation signal in the storage means as a function of the position on the disk surface. The first correction means outputs the synchronization disturbance compensation signal corresponding to the position on the disk surface to the filter. Disk storage, characterized in that the means for outputting as a feedforward signal. 3. The disk storage device according to claim 1, wherein the estimating unit is provided with one representative track or a plurality of representative tracks representing the disk immediately after power-on or immediately after power-on and at fixed time intervals immediately after power-on. A representative track or all tracks are set as target tracks, a head is positioned on the target track, and a DC disturbance compensation signal for suppressing a DC disturbance acting on the target track while the disk rotates a plurality of times is calculated, Is a means for interpolating the data of the DC disturbance compensation signal to obtain a DC disturbance compensation signal on a track other than the target track, and for storing the DC disturbance compensation signal in the storage means as a function of the position on the disk surface, The first correcting means applies the DC disturbance compensation signal corresponding to the position on the disk surface to the flux. Disk storage, characterized in that the means for outputting as over-forward signal. 4. The disk storage device according to claim 1, wherein the estimating unit is provided with one representative track or a plurality of representative tracks representing the disk immediately after power-on or immediately after power-on and at fixed time intervals immediately after power-on. A representative track or all tracks are set as target tracks, a head is positioned on the target track, and an AC disturbance compensation signal for suppressing an AC disturbance acting on the target track while the disk rotates a plurality of times is calculated, Is a means for interpolating the data of the AC disturbance compensation signal to obtain an AC disturbance compensation signal on a track other than the target track, and for storing the AC disturbance compensation signal as a function of the position on the disk surface in the storage means, The first correction means outputs the AC disturbance compensation signal corresponding to the position on the disk surface to the flux. Disk storage, characterized in that the means for outputting as over-forward signal. 5. The disk storage device according to claim 1, wherein the estimating unit is provided with one representative track or a plurality of representative tracks representing the disk immediately after power-on or immediately after power-on and at fixed time intervals immediately after power-on. A representative track or all tracks are set as target tracks, a head is positioned on the target track, and an AC disturbance compensation signal for suppressing an AC disturbance acting on the target track while the disk rotates a plurality of times is calculated, and the representative Data of the AC disturbance compensation signal of the track is interpolated to obtain the AC disturbance compensation signal on a track other than the target track, and the storage unit stores the AC disturbance compensation signal as a function of the position on the disk surface. , A new representative track or multiple representative tracks or all representative tracks Position the head on the disk, calculate a DC disturbance compensation signal that suppresses a DC disturbance acting on the new target track while the disk rotates a plurality of times, and calculate the DC disturbance compensation signal of the new representative track. Means for interpolating to obtain a DC disturbance compensation signal on a track other than the new target track, and for storing the DC disturbance compensation signal as a function of the position on the disk surface in the storage means, the first correction means Is a means for outputting a signal obtained by adding the AC disturbance compensation signal and the DC disturbance compensation signal corresponding to the position on the disc surface as the feedforward signal. 6. The disk storage device according to claim 1, wherein the second correction means includes an output side of the drive circuit, an output side of the estimation means, and an input side of the positioning compensator. Between the drive signal and the position signal, the positioning compensator includes speed signal estimating means for estimating a speed signal of the head, and the second correcting means uses the disturbance signal from the drive signal. A disk storage device comprising means for obtaining a signal obtained by subtracting a signal proportional to a compensation signal and outputting the subtracted signal instead of the drive signal to the speed signal estimating means.