JPH05120817A - Method and device for controlling positioning head - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the head positioning control system of a magnetic disk drive. [Structure] Detected position error signal 11 and drive signal 26
From the above, the microcomputer 30 estimates the head position when no disturbance or internal force is applied, and the difference between this and the detected head position is used as the disturbance compensation signal 28 to correct the drive signal 26. [Effect] It is possible to suppress residual vibration caused by disturbance and internal force,
It is possible to improve the positioning accuracy and shorten the access time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head positioning control method and device for a magnetic disk device, an optical disk device and the like.

[0002]

2. Description of the Related Art In a magnetic disk, a magnetic head generally floats as the number of revolutions of a disk rises. To protect the data storage area, the head is moved to the data area when starting and stopping. Positioning control is performed outside. For this reason, a spring called a retract spring is used to push the actuator for driving the head in one direction, or the head is retracted to the non-data area by the weight of the actuator. The external force such as the spring force or the self-weight of the actuator itself has a great influence on the head positioning control system, and causes a variation in the transient response due to a steady position deviation or a difference in the moving direction. Further, in the magnetic disk device, since the disk rotates at high speed, it vibrates at the rotation frequency, and this vibration is superimposed on the position signal as a disturbance. Further, in a magnetic disk device, a damper is generally inserted between a base on which a disk or an actuator is mounted and a main base in order to block vibrations from the outside, but when the actuator moves the head, The generated driving force is transmitted as a reaction force to the base, causing vibrations in the base and the disc. These vibrations act as a disturbance on the head positioning control system. As a result, in order to move and position the head to the target track and access the data on the disc, it is necessary to wait until the base vibration and the disc vibration become small. There was a problem that the access time was extended.

Further, in the conventional optical disk device, a coarse actuator for moving a large distance in order to move and position 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. In order to perform minute positioning, the fine actuator must be operating.However, if the disc eccentricity is large compared to the stroke of the fine actuator, the coarse actuator must be used for positioning. There was a problem that the accuracy was lowered.

As a conventional disturbance compensation method for coping with these problems, as described in Japanese Patent Publication No. 1-43378, the estimated speed signal and the error signal of the speed signal are fed back to the input of the power amplifier. A method of performing compensation by adding as a disturbance canceling signal to the above, a disk device having a damping mechanism for absorbing vibration energy due to a reaction force of the driving force of an actuator, as described in JP-A-57-94961, Proposed.

[0005]

With the increase in capacity and speed of disk storage devices, track widths are becoming narrower and actuators are becoming lighter in weight, but as a result, the effects of vibrations caused by external disturbances and internal forces will increase. It cannot be ignored anymore. As described above, when the center of the disk of the disk storage device does not coincide with the center of gravity, the disk vibrates at the rotation frequency and the base vibration due to the reaction force of the actuator driving force when moving the head to the target track. May remain as residual vibration even when the head reaches the target track and reads or writes data. There is a limit to suppressing these vibrations by increasing the response frequency of the conventional closed loop system due to the resonance characteristics of the head support mechanism system. Further, as a method of estimating a disturbance, the method of amplifying and feeding back the error between the detected speed signal and the estimated speed signal, which is described in Japanese Patent Publication No. 1-43378, can suppress low-frequency disturbance, but Since a signal obtained by differentiating a position signal containing high-frequency noise is used as, the S / N of the speed signal decreases in the high-frequency region, and the frequency band of the position differentiating circuit cannot be increased. Therefore, there is a drawback that high frequency disturbance and vibration cannot be suppressed. On the other hand, the method described in JP-A-57-94961 can absorb the reaction force energy of the actuator driving force by the damping mechanism to reduce the vibration, but the actuator may be disturbed or the disc may be eccentric. Alternatively, when the disk support member vibrates, there is a problem that these vibrations cannot be suppressed.

An object of the present invention is to provide a head positioning control method and apparatus capable of suppressing vibrations caused by external disturbances and internal forces to achieve highly accurate head positioning and shorten access time.

[0007]

According to the present invention, position information relating to the position of the head is detected from servo information read by the head from a disk, and the detected position information and a given target position are position-compensated. Input to the means to generate a positioning compensation signal, and the positioning compensation signal is input to a drive circuit to generate a drive signal for driving an actuator to which the head is fixed, and the drive signal causes the head to move to the target position. In a head positioning control method of controlling to move, a disturbance compensation signal is estimated and calculated by inputting the drive signal and position information, and the estimated and calculated disturbance compensation signal is added to the positioning compensation signal.
The drive signal is corrected (claim 1).

Further, according to the present invention, prior to the data access to the disk, an initial value is given to the internal variable for the estimation calculation to perform the estimation, and the correction of the drive signal based on the result of the estimation is immediately performed at the start of the data access. (Claim 2).

Further, according to the present invention, the position detecting means for detecting the position information regarding the position of the head from the servo information read by the head from the disk, and the position information detected by this means and the given target position are inputted. A positioning compensation means for generating a positioning compensation signal, a driving circuit for receiving the positioning compensation signal to generate a driving signal for driving an actuator to which the head is fixed, and a disturbance for receiving the driving signal and position information. Estimating means for estimating and calculating a compensation signal; adding means for adding the disturbance compensation signal estimated by the estimating means and the positioning compensation signal;
A control means for controlling the head to move to the target position by the drive signal is provided (claim 3).

Further, according to the present invention, prior to the data access to the disk, an initial value is given to an internal variable for estimation calculation to cause the estimation means to perform the estimation, and the correction of the drive signal based on the result of the estimation corrects the data. It is made possible to perform it immediately at the start of access (claim 4).

Further, according to the present invention, when the servo information of the disk is information indicating the radial and circumferential positions of the disk surface, a memory means is added to the estimating means, and the estimating means is a power source of the disk device. Is turned on and a disturbance compensation signal is estimated for each track at predetermined intervals and stored in the storage means, and at the time of disk data access, the disturbance of the corresponding track stored in the storage means. The drive signal is corrected using a compensation signal (claim 5).

Further, according to the present invention, the estimating means estimates the disturbance compensation signal using the servo signal only for a predetermined track, and the disturbance compensation signals for other tracks are obtained using the servo signal. The estimation is performed by interpolation of the estimated disturbance compensation signal (claim 6).

Further, the present invention provides a head positioning control device for a disk device, wherein one surface of the disk is a servo surface having only servo information and all the other surfaces are shared surfaces on which servo information and data are recorded. First detection means for detecting position information of the servo head from servo information read by the servo head facing the servo surface, and position of the data head from servo information read by the data head facing the common surface Second detection means for detecting information,
Positioning compensating means for inputting the position information detected by the second detecting means and the given target position to generate a positioning compensating signal and the positioning compensating signal are inputted to drive the actuator to which the head is fixed. A drive circuit that generates a drive signal, an estimation unit that estimates and calculates a disturbance compensation signal by inputting the drive signal and position information, and an addition that adds the disturbance compensation signal estimated by the estimation unit and the positioning compensation signal. And a control means for controlling the head to move to the target position by the drive signal (claim 7).

Further, according to the present invention, a high-pass filter having a predetermined cutoff frequency is provided between the estimating means and the correcting means (claim 8).

Further, according to the present invention, prior to the data access to the disk, an initial value of an internal variable for estimation calculation is given to cause the estimation means to perform the estimation, and the correction of the drive signal based on the result of the estimation causes the data access. It can be done immediately at the start (Claim 9).

Further, in the present invention, the disk is a magnetic disk or an optical disk (claims 10 and 11).

[0017]

When the vibration caused by the disturbance or the internal force does not act on the positioning control system, the detected head position signal and the estimated position signal estimated by the estimating means coincide with each other. However, when the positioning control system is vibrated due to disturbance or internal force, an error occurs between these signals.
This error is a signal necessary to cancel the vibration caused by disturbance or internal force, so by inputting this to the drive circuit as a disturbance compensation signal, the disturbance or vibration is canceled and the positioning accuracy is improved and access time is improved. Can be shortened.

[0018]

EXAMPLES The present invention will be described in detail below with reference to examples. FIG. 1 is a block diagram showing an embodiment of a magnetic disk device to which the head positioning control of the present invention is applied. A voice coil motor (VCM) 2 is used as an actuator. The voice coil motor 2 is the spindle motor 3
It is possible to move and position the head 1 to an arbitrary track on the disk 4 which is rotationally driven by. All of these components are listed on the base 5.

The position detector 6 includes an amplifier 7, a demodulation circuit 8,
It is composed of a track crossing pulse generation circuit 9 and a difference counter 10. Servo signals are recorded on the disk 4, and the servo signals read by the head 1 are amplified by the amplifier 7 and sent to the demodulation circuit 8. In the demodulation circuit 8, the main position error signals PESN (not shown) and 90
Sub-position error signals PESQ (not shown) having different degrees and phases are created, and a position error signal 11 having a proper polarity is created and outputted from these error signals according to the track number. Further, the track crossing pulse generation circuit 9 receives the position error signal 11 and receives a track crossing pulse 12 at the boundary between adjacent tracks.
To occur. The time relationship between these signals is shown in FIG. Further, the difference counter 10 counts the number of track crossing pulses 12 and outputs a digital remaining track number 13 up to the target track.

When the controller 20 issues a movement command 21 to the positioning compensator 22, the positioning compensator 22 outputs a positioning compensation signal 23. As a method of calculating the positioning compensation signal 23, for example, MEE & DANIEL "M
AGNETIC RECORDING ", Vol.2, McGraw-Hill 53-84
Some are listed on the page. The position error signal 11, the number of remaining digital tracks 13, the track crossing pulse 12 and the drive signal 26 are input, and the seek operation until the head 1 reaches the vicinity of the target track is calculated by the speed control system. The position control system calculates the following movements after getting close to the target track.
This method is also used in this embodiment. The means for generating the positioning compensation signal 23 may be an analog control system or a digital control system.

The estimating means and the correcting means, which characterize the present embodiment for estimating the disturbance compensation signal for canceling the disturbance and the vibration, are composed of a CPU 31, a ROM 32, a RAM 33 and a bus 34 for connecting them. The microcomputer system 30 is the main component, and a digital output circuit (DOC) 38 for holding this and the digital disturbance compensation signal 36, and a DA converter (DAC) for converting the digital disturbance compensation signal 36 into the disturbance compensation signal 28. ) 3
7, a first AD converter (ADC1) 41 for converting the drive signal 26 into a digital drive signal 40, and a second AD converter (ADC) for converting the position error signal 11 into a digital position error signal 43 ( ADC 2) 42, digital remaining track number 13, digital drive signal 40, and digital position error signal 43 to the microcomputer system 30 for reading in a digital input circuit (DIC)
44 and an adder 29. Adder 29
Outputs an operation signal 24 which is a signal obtained by adding the disturbance compensation signal 28 and the positioning compensation signal 23. Disturbance compensation signal 2
Reference numeral 8 is a signal for canceling the base vibration and the disk vibration generated by the external force acting on the voice coil motor 2 which is an actuator and the reaction force of the driving force generated by the voice coil motor 2. Therefore, steady position deviation and residual vibration do not occur, and high-speed and high-accuracy head positioning is possible.

The block diagram of FIG. 2 is an equivalent functional block diagram of the head control system of the embodiment of FIG.
The algorithm realized in the microcomputer system 30 is represented by the transfer function of discrete time system, and z ^-1
Is an operator that means a delay of one sample. Other components are expressed as a transfer function of a continuous time system, the Laplace operator is s, and the gain of the drive circuit 25 is K.
_a (A / V), the force constant of the voice coil motor 2 is K _f (N
/ A), and the mass of the movable part on which the head 1 is mounted is M (k
g), the gain from the head 1 to the digital position error signal 43 is K ₂ (count / m), and the gain from the head 1 to the digital remaining track number 13 is K ₃ (count / m).
m), the gain from the drive signal 26 to the digital drive signal 40 is represented as K _i (count / V). Further, an external force D ₁ and a vibration (base vibration or disk vibration) D ₂ are applied as a disturbance.

Gain G₁, G₂, L₁, L₂, H is the drive signal
26 to the digital head position signal Y
Get the same-dimensional observer of discrete-time system made from Dell
In, which is expressed by the following equation. G₁= K_f・ T²/ (2M ・ K_i) G₂= K_f・ T / (M ・ K_i) L₁= 2 (1−q · cos α) / K₂ L₂= (1 + q²-2qcosα) / (T ・ K₂) H = -ML₂/ (K_f・ T ・ K_a・ G_DA) However, q = exp (-ζωT) α = cos {ωT (1-ζ²)^1/2}, Ω and ζ represent the estimated speed and damping constant, and
Set the gain of the converter 37 to G_DA It is represented by (V / count). Suppression
If the angular frequency of the desired vibration is ω1, ω is several times that
The frequency is set, and ζ is set to 0.7.

FIG. 4 shows a microcomputer system 30.
The process for deriving the digital disturbance compensation signal W according to FIG. 4 is shown in a flow chart, and the operation of the present embodiment will be described with reference to FIGS. 1, 3, and 4. First, the AD converter 41 and the digital input circuit 44 digitize and sample the drive signal 26 to obtain a digital drive signal I (gain K _i , step 100 in FIG. 2), and the AD converter 42 and the digital input circuit 44 position error. Signal 11
To obtain a digital position error signal Y ₁ sampled (see FIG. 2, gain K ₂ , step 10).
1). Further, the digital input circuit 44 obtains a digital remaining track signal Y ₂ obtained by sampling the number of digital remaining tracks 13 (gain K _{3 in} FIG. 2, step 10).
2). Since the signals Y ₁ and Y ₂ are detected with different sensitivities of K ₂ and K ₃ , the detection sensitivity is corrected by Y = Y ₁ + (K ₂ / K ₃ ) · Y ₂ The head position signal Y is obtained (step 103).

Next, a digital estimated position error signal Y _C = Y−Y _h is calculated by subtracting the digital estimated head position signal Y _h calculated as described later from the digital head position signal Y (step 104). , And further multiplied by a gain H to obtain a digital disturbance compensation signal W = H · Y
_C is obtained (step 105). This disturbance compensation signal W is output via the digital output circuit 38 and the DA converter 37 (step 106), and the analog disturbance compensation signal 28 is output.
Is output as. When this output is finished, calculation of the digital estimated head position signal Y _h is started in preparation for the next sample. This calculation is performed by the following three equations; Step 107: X _1h = X _1h + T · X _2h + G ₁ · I + L ₁
· Y _C Step _{108: X 2h = X 2h +} G 2 · I + L 2 · Y C step _{109: Y h = K 2 ·} X 1h wherein I, the value of Y _C is a digital drive signal at that time,
A digital estimated position error signal, step 107,
The digital estimated position signal X _1h and the digital estimated velocity signal X _{2h on} the right side of 108 are the respective values calculated in steps 107 and 108 at the time of sampling one time before, and the X _{1h on the} right side of step 109 is the step 107 at that time. It is the value calculated in. Thereafter, the microprocessor system 30 suspends the processing until the processing time T seconds from step 100 elapses, and branches to step 100 when the processing time T seconds elapses (step 110). As described above, the disturbance compensator repeats the operation from step 100 to step 110 at T second intervals.

When there is no external force acting on the movable part of the head, rotation periodic vibration of the disk 4, or vibration of the base 5 and the disk 4 generated by the reaction force of the driving force of the voice coil motor 2 during the seek operation. , The digital estimated head position signal Y _h calculated as described above is calculated in steps 107 to
Since the portion of FIG. 1 corresponding to the processing of 109 simulates the response characteristics of the actual voice coil motor 2 and the head, it coincides with the digital head position signal Y. However, when the disturbance or vibration is present, an error occurs based on the disturbance or vibration between the digital head position signal Y and the digital estimated head position signal Y _h. Since the digital estimated position error signal Y _C represents this error, the disturbance compensation signal W obtained by multiplying this by the constant H for gain correction becomes a signal necessary to cancel the vibration caused by disturbance or internal force. ..

It is most desirable that the estimation calculation and the correction operation of the disturbance compensation signal W are always performed before the head starts moving. However, in order to estimate the digital estimated head position signal Y _h from the start of movement of the head, a CPU with a long operation word length or a CPU that performs floating point arithmetic capable of estimating the head position on all tracks accompanying movement is used. It becomes necessary, and the CPU becomes expensive. Therefore, even with an inexpensive CPU that performs fixed-point arithmetic, as a method of suppressing disturbance or vibration during the reading and writing of data on the target track, the estimating means is operated from several tracks before the target track, and before reading or writing data. There is a method of operating the correction means. For example, when the estimating means is operated one track before the target track and the correction operation is performed from one quarter track before the target track, the calculation range of the estimating means is only for calculating one track, and thus the inexpensive fixed point. A CPU can also bring out sufficient performance. Also,
In order to speed up the response speed of estimation, an internal variable, for example, a value proportional to the digital head position signal Y is initially set in the digital estimated position signal X _1h prior to the start of estimation, and the digital head position is set in the digital estimated speed signal X _2h. Signal Y
The velocity signal obtained by approximating and differentiating is initialized. As a method of calculating the approximate differential, for example, a backward difference method can be cited. With this initial value setting, the estimation works at the time of data access, and the correction of the drive signal becomes possible at the same time as the start.

FIG. 5 shows an example of seek operation of the conventional magnetic disk device, and FIG. 6 shows an example of seek operation of this embodiment. FIG. 5 is a diagram showing a main position error signal PESN when a head seeks a distance of 32 tracks and follows a target track in a conventional magnetic disk device. As shown in FIG. 3, since the main position error signal PESN crosses zero every two tracks, the signal PESN has a triangular waveform and finally settles to zero. However, since the driving force of the voice coil motor 2 while the head is moving is transmitted to the base 5 as a reaction force and causes the base 5 and the disk 4 to vibrate, the head cannot follow the target track after reaching the target track. You can see that it is vibrating. On the other hand, FIG. 6 shows the operation of the magnetic disk device according to the present embodiment under the same conditions. As with the case of FIG. 5, a triangular wave-like response is shown, and finally it is settled to zero. However, despite the base vibration and the disk vibration, no vibration occurs after reaching the target track, and it can be clearly seen that the residual vibration is suppressed.

FIG. 7 is a block diagram showing another embodiment of the magnetic disk device to which the method of the present invention is applied. Blocks given the same numbers as in FIG. 1 indicate blocks having the same contents. The difference from FIG. 1 is that two position detectors 6a and 6b are provided and a high pass filter 50 is installed at the outlet of the DA converter 37. The positioning compensator 22 receives the movement command 21 from the controller 20, and moves the head 1b facing the servo signal / data signal shared surface 4b to a target track so as to move and position the head 1b to a target track.
Is output. Therefore, based on the signal read from the head 1b, the position detector 6b detects the position error signal 11b, the track crossing pulse 12b, and the number of remaining tracks 13b.
3 is calculated and output.

On the other hand, since the servo signal and the data signal are alternately written on the track of the servo signal / data signal shared surface 4b, the servo signal read from the head 1b is read from the servo signal dedicated surface 4a. It is more discrete than the servo signal. As a result, the frequency band of the demodulated position signal is wider for the position signal demodulated from the servo signal dedicated surface 4a. Therefore, when the frequency component of disturbance or vibration is high, the position signal read from the servo signal / data signal shared surface 1b may be deteriorated. Therefore,
The signal read from the servo signal dedicated surface 4a is input to the position detector 6a, and the output thereof is used to estimate the disturbance compensation signal 28a in the same manner as in the case of FIG. Since the heads 1a and 1b move integrally with the movable part, the position signal read from the head 1a and the position signal read from the head 1b should match. However, the heads 1a and 1b may be mechanically offset, and in this case, a DC offset appears in the position signal. Therefore, in order to make the low frequency disturbance compensation signal insensitive, the disturbance compensation signal 2
8a is passed through a high pass filter 50, and its output signal is used as a new disturbance compensation signal 28b. High pass filter 50
8 can be realized by using a differential amplifier (op amp) OP, resistors R ₁ and R ₂ and capacitors C ₁ and C ₂ as shown in FIG. Besides, there is a method of realizing the high-pass filter as software in the microcomputer system 30, that is, a method of realizing it as a digital filter.

The disturbance compensation signal 2 obtained as described above
8b is connected to the input of the adder 29, and the microcomputer system 30 controls the estimating means to operate from one track before the target track and the correcting means to operate from one quarter track before the target track. ,
That is, as a result of experimenting this example under the same conditions as described in the example of FIG. 2, the state became the same as that shown in FIG. As described above, even in a disk storage device in which a position compensation signal from the servo signal / data signal shared surface cannot sufficiently generate the disturbance compensation signal, if the position compensation signal is generated using the position signal from the servo signal dedicated surface, disturbance or It is possible to position the head on a target track by suppressing vibration.

FIG. 9 is a block diagram showing another embodiment of a magnetic disk device to which the method of the present invention is applied. Blocks given the same numbers as in FIG. 1 indicate blocks having the same contents.
In this embodiment, in addition to the position error signal 11 the demodulation circuit 8
This is different from the case of FIG. 1 in that a sector signal 60 that outputs a sector number representing the circumferential position of the disk 4 as a digital signal is output. In the embodiment shown in FIG. 1, the disturbance and the vibration are suppressed in real time, but it may be difficult to realize due to the performance of the hardware of the estimating means. For example, in order to suppress high-frequency vibration, a high-speed CPU or memory is required for the estimation means, but when only a low-cost microcomputer system can be used, it takes time to estimate the disturbance compensation signal, and positioning time increases. On the contrary, it may become longer. Therefore, in the present embodiment, a disturbance compensation signal for canceling the disturbance or vibration acting on the disk storage device is measured in advance immediately after the power is turned on, and the measurement result is used for the subsequent compensation operation. This cancels out reproducible disturbances and vibrations such as rotational periodic vibrations of the disk that occur when the center of rotation of the disk 4 and the center of gravity do not match, and external forces that act on the voice coil motor 2. Is effective for.

Servo information and data information are alternately written for each sector on the tracks on all surfaces of the disk 4.
The microcomputer system 30 inputs a sector signal 60, a digital position error signal 43, a digital remaining track number 13, and a digital drive signal 40 via a digital input circuit 44 when the head crosses a sector, and compensates for disturbance from these. Although the signal is calculated, the operation of the estimating means for estimating the disturbance compensation signal is the same as that shown in the embodiment of FIG.

Next, how the disturbance compensation signal is estimated and stored immediately after the power is turned on and at regular intervals thereafter will be described with reference to the flowchart of FIG. Figure 1
Reference numeral 0 denotes a disturbance compensation signal table creation routine, which is started immediately after the power is turned on and at regular intervals thereafter. When activated, first, the head 1c facing the uppermost surface positions the head on one predetermined track, for example, the outermost track (step 201). Next, in order to extract a disturbance compensation signal that suppresses only reproducible vibrations and disturbances, it waits until the positioning operation reaches a steady state. For example, after switching from seek to following, the process waits until the disk makes one round (step 202). When the positioning operation reaches a steady state, the disturbance compensation signal is stored in the disturbance compensation signal table of the RAM 33 in correspondence with the sector number fetched through the digital input circuit 44 (step 203). Next, the head 1d facing the lowermost surface is also subjected to the same operations as steps 201, 202 and 203 (steps 204 to 206). Finally, the disturbance compensation signal table for another head that was not tabulated,
The table created in step 203 and step 206
The table created in step 1 is linearly interpolated and calculated, and the result is stored in the RAM 33 (step 207).

The disturbance compensating signal table creation routine as described above is started immediately after the power is turned on and at regular intervals thereafter, and the operation after rewriting the table is performed by referring to the disturbance compensating signal corresponding to the head number and the sector number. Output through the digital output circuit 38 and the DA converter 37,
The correction operation is performed by adding to the adder 29. FIG. 11 shows the vibration of the position error signal caused by the synchronous vibration of the disc 4, etc., but according to the present embodiment, this is eliminated as shown in FIG.

In the above example, only the disturbance compensation signals of the two surfaces of the uppermost surface and the lowermost surface are measured, and the others are estimated by linear interpolation. You may go. Although only one representative track was measured for one surface, the size may be different depending on the radial position of the disk of the head 1, so that a plurality of tracks on one surface, for example, the outermost circumference, the middle circumference, It is also possible to measure the innermost circumference, or measure every 10 tracks from the innermost circumference to the outermost circumference, and for other tracks, interpolate and obtain from the data of close tracks. Although the above is an example of the magnetic disk, the invention can be applied to other rotating plates such as an optical disk.

[0037]

According to the present invention, even if vibrations caused by disturbances or internal forces occur, they can be canceled out and residual vibrations can be reduced. Therefore, it is possible to improve the positioning accuracy and shorten the access time. Become.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of a magnetic disk device to which the method of the present invention is applied.

FIG. 2 is a block diagram showing an equivalent function of a head control system.

FIG. 3 is an explanatory diagram of a position signal.

FIG. 4 is a flowchart showing a head control operation of the first embodiment.

FIG. 5 is a diagram showing an example of a response waveform of a conventional head control system.

FIG. 6 is a diagram showing an example of a response waveform of the head control system of the present invention.

FIG. 7 is a block diagram showing a second embodiment of a magnetic disk device to which the method of the present invention is applied.

FIG. 8 is a diagram showing a configuration example of a high-pass filter.

FIG. 9 is a block diagram showing a third embodiment of a magnetic disk device to which the method of the present invention is applied.

FIG. 10 is a flowchart showing an algorithm for creating a disturbance compensation signal table.

FIG. 11 is a diagram showing an example of a position error signal at the time of following of a conventional magnetic head control system.

FIG. 12 is a diagram showing an example of a position error signal at the time of following in the third embodiment.

[Explanation of symbols]

 1 head 2 voice coil motor 4 disk 6 position detector 6a position detector 6b position detector 11 position error signal 12 track crossing pulse 13 digital remaining track number 22 positioning compensator 23 positioning compensation signal 26 driving signal 28 disturbance compensation signal 29 Adder 30 Microcomputer system 50 High-pass filter 60 Sector signal

Claims (11)

[Claims] 1. Position information regarding the position of the head is detected from servo information read from the disk by the head, and the detected position information and a given target position are input to a positioning compensating means for positioning compensation signal. Head positioning for controlling the head to move to the target position by generating a driving signal for driving the actuator to which the head is fixed by inputting the positioning compensation signal to the driving circuit. In the control method, a disturbance compensation signal is estimated and calculated by inputting the drive signal and position information, and the estimated and calculated disturbance compensation signal is added to the positioning compensation signal to correct the drive signal. Positioning control method. 2. Prior to data access to a disk, an initial value is given to the internal variable for the estimation calculation so that the estimation is performed, and the drive signal can be corrected immediately after the data access is started based on the result of the estimation. The head positioning control method according to claim 1, wherein: 3. A position detecting means for detecting position information relating to the position of the head from servo information read from the disk by the head, and the position information detected by this means and a given target position are inputted, Positioning compensation means for generating a positioning compensation signal, a drive circuit for inputting the positioning compensation signal to generate a drive signal for driving an actuator with a fixed head, and a disturbance compensation signal for inputting the drive signal and position information. An estimation means for estimating and calculating, an addition means for adding the disturbance compensation signal estimated by the estimation means and the positioning compensation signal, and a control means for controlling the head to move to the target position by the drive signal. A head positioning control device comprising: 4. Prior to data access to a disk, an initial value is given to an internal variable for estimation calculation to cause the estimation means to perform estimation, and the drive signal is corrected by the result of this estimation at the time of starting the data access. The head positioning control device according to claim 3, wherein the head positioning control device is configured so that it can be performed immediately. 5. When the servo information of the disk is information indicating the radial and circumferential positions of the disk surface, a memory means is added to the estimating means, and the estimating means turns on the power of the disk device. The disturbance compensation signal for each track is estimated and stored in the storage means at a predetermined time and for each predetermined fixed period, and the disturbance compensation signal of the corresponding track stored in the storage means is stored at the time of accessing the disk data. The head positioning control device according to claim 3, wherein the drive signal is corrected by using the correction signal. 6. The estimation means estimates a disturbance compensation signal using the servo signal only for a predetermined track, and disturbance compensation signals for other tracks are estimated disturbance compensation obtained using the servo signal. The head positioning control device according to claim 5, wherein the estimation is performed by signal interpolation. 7. A head positioning controller for a disk device, wherein one surface of the disk is a servo surface containing only servo information and all the other surfaces are shared surfaces on which servo information and data are recorded. First detecting means for detecting position information of the servo head from servo information read by the facing servo head, and position information of the data head from servo information read by the data head facing the common surface Second detection means for inputting, position compensation means for inputting position information detected by the second detection means and a given target position to generate a position compensation signal, and head for inputting the position compensation signal. A drive circuit for generating a drive signal for driving an actuator having a fixed value, and the disturbance signal is estimated and calculated by inputting the drive signal and position information. Estimating means, adding means for adding the disturbance compensation signal estimated by the estimating means and the positioning compensation signal, and control means for controlling the head to move to the target position by the drive signal are provided. Head positioning control device. 8. The head positioning control device according to claim 7, further comprising a high-pass filter having a predetermined cutoff frequency provided between the estimating means and the correcting means. 9. Prior to the data access to the disk, an initial value of an internal variable for estimation calculation is given to cause the estimation means to perform the estimation, and the correction of the drive signal based on the result of the estimation is immediately performed at the start of the data access. 9. The head positioning control device according to claim 7, wherein the head positioning control device is capable of performing the above. 10. The head positioning control device according to claim 1, wherein the disk is a magnetic disk. 11. The head positioning control device according to claim 1, wherein the disc is an optical disc.