JP2928631B2 - Method and apparatus for controlling magnetic disk storage device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic disk storage device, and more particularly, to a disk storage device for moving and tracking a plurality of heads arranged to face a disk storage surface. The control method and apparatus of

[Conventional technology]

Conventionally, in a magnetic disk device, as the recording density of a disk has been increased, the positioning accuracy of a head has been increased. For example, as shown in JP-A-60-35383, a first actuator group has been used. A method is disclosed in which a second actuator is provided, and the displacement of each head detected by the first actuator group is weighted to be a control signal of the second actuator.

Japanese Patent Application Laid-Open No. 64-67778 discloses a hybrid servo system in which coarse driving is performed based on position information on a servo surface.
A method is disclosed in which one of the read / write heads outputs data plane position information to a bimorph actuator.

[Problems to be solved by the invention]

In the above-described conventional two-stage servo actuator, although consideration has been given to eliminating the effects of thermal off-track and assembly errors using the second actuator, each head is collectively following, and No consideration is given to the fact that each of the tracks follows each predetermined track to reduce the access time associated with head switching.

Further, in the bimorph actuator, since servo information of each head is not always obtained, it is necessary to correct the displacement of each head at the time of head switching, and there is a problem that the access time becomes longer.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic disk storage device capable of reducing the access time in switching heads on the same cylinder as in a seek operation and accessing adjacent tracks, and a control method thereof.

[Means for solving the problem]

In order to achieve the above object, writing of at least one piece of information arranged on a recording surface composed of a plurality of rotating disks arranged coaxially at intervals and recording tracks on each disk. Or a head that performs reading, a head arm that supports each head, a support member that supports the head arm collectively, and a minute displacement element that is attached to the head arm and minutely displaces the respective head in the seek direction. A coarse movement actuator for moving the respective heads collectively in the seek direction by moving the support member in the seek direction, wherein the respective heads rotate during the following operation. The micro-displacement element is driven so as to follow each predetermined track while reading servo information previously recorded on the disk. It is intended.

Further, in order to reduce the access time for head switching, the method for controlling a magnetic disk
There is a first head that reads or writes information recorded on a recording track, and a second head that reads or writes information next, and the track being followed by the second head and the next When the difference from the target track for reading or writing is within the movable range of the minute displacement element, the target track is followed in advance using the minute displacement element.

In order to secure the movable range of the micro displacement element, in the control method of the magnetic disk storage device, during the following, each head reads the respective servo information recorded on the recording track, and sets each predetermined information. Of each of the micro-displacement elements to follow the current track, obtain a signal corresponding to the difference between the target track of at least one head and the current track, and further perform the micro-displacement of the micro-displacement element to finely displace the head. Find the signal corresponding to
The movement amount obtained by adding the respective signals is moved using a coarse movement actuator.

Further, in order to reduce the access time, at least one rotating disk having a recording surface, at least two heads disposed on one recording surface of the rotating disk, and a head arm supporting each head A support member that collectively supports the head arms, a micro-displacement element attached to each head arm to micro-displace each of the heads in the seek direction, and moving the support member in the seek direction. A method for controlling a storage device of a magnetic disk, comprising: a coarse actuator for moving respective heads collectively in a seek direction, wherein a first step of reading information recorded on a recording track or recording information during following is performed. And the second head on the same recording surface as the first head read out the servo information of each head, and read each predetermined track. The center of is obtained so as to track-following.

[Action]

As each head follows a predetermined track,
Since each minute displacement element is driven and the coarse movement actuator is driven according to the displacement of the minute displacement element, the access time for head change to another head of the same cylinder is reduced.

Further, when there is a head to be used for the next seek in the movable range of the minute displacement element, the seek time is reduced because the head is moved by driving the minute displacement element in advance.

When the seek amount exceeds the movable range of the minute displacement element, the minute displacement element and the coarse actuator are simultaneously driven, the minute displacement element is driven to the maximum movable range, and the remaining seek amount is within the movable range of the minute displacement element. Since the minute displacement element is sometimes driven in the direction opposite to the previous displacement direction, the access time required for setting the head at the time of seeking is reduced.

In addition, since each minute displacement element is driven such that each head always follows a predetermined track, the influence of thermal deformation of a member and an assembly error is reduced.

〔Example〕

A first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the disk storage device of the present invention. In this embodiment, a voice coil motor (VCM) 1 is used as a coarse movement actuator, a piezoelectric element 2 is used as a minute displacement element for fine movement, and a bus (Bus) and a random access memory are used as a position control device 3. (RAM) 5, Programmable read only memory (PROM) 6, and central processing unit (CP
U) Using a microcomputer consisting of 7,
Each track on each disk surface of the plurality of disks 8 is divided into a plurality of sectors, and a sector storage which is one of a so-called data surface servo method is a disk storage device in which servo position information and data information are alternately stored for each sector. A disk storage device of the system is described.

The disk 8 is rotated concentrically and at a constant speed by a spindle motor 15. The position detector 14 includes an amplifier 10, a demodulator 11, and an analog-to-digital converter (ADC) 12, and performs servo control for each sector as the disk 8 rotates through each head 9 facing each disk surface. Detect location information and data information. A signal indicating the head position read by each head 9 is amplified by each amplifier 10 and each demodulator
Sent to 11. Each demodulator 11 uses the input position signal to
The sub position error signal PESQi (n) having a phase difference of 90 degrees from the main position error signal PESNi (n) and the track number TRKNi (n) are output. Here, i indicates a head number. Also, n
Is for indicating the order of signals obtained in an arbitrary sector as the disk 8 rotates. For example, the track number obtained at a certain sample time of the i-th head is TR
In the case of KNi (n), TRKNi (n + 1) indicates the track number at the next sample time. For this reason, the sample interval period is determined by the rotation speed of the disk 8 and the number of sectors in one track. In FIG. 2A, corresponding to the head position
2B shows the relationship between PENSNi (n) and PESQi (n), and shows the relationship between TRKNi (n) corresponding to the desired position of the head in FIG. 2B.

Next, among the operations of the position control device 3, the fine movement drive signal UF
The operation up to the calculation of (n) will be described with reference to the block diagram of FIG. It should be noted that the third
The components in the figure are not independent hardware components, but merely auxiliary means for understanding the operation performed by the position control device 3 realized by the microcomputer.

The position control device 3 first takes in the track number TRKNi (n), the main position error signal PESNi (n) and the sub position error signal PSEQi (n) sampled by the ADC 12 in the phase selecting section 30, Relative error signal representing displacement
According to the track number TRKNi (n), PESi (n) is given by: PESi (n) =-PESNi (n) where TRKNi (n) = 4
* K PESi (n) =-PESQi (n) where TRKNi (n) = 4
* K + 1 PESi (n) = PESNi (n) where TRKNi (n) = 4
* K + 2 PESi (n) = PESQi (n) where TRKNi (n) = 4
* K + 3 (1) (where k represents an integer) FIG. 2A, FIG. 2B, and FIG. 2C show the relationship of the above equation. Further, the position control device 3
KNi (n) and PESi (n) are added at the total joint 31 to obtain a second
Absolute position signal APOSi proportional to the head position shown in Figure D
(N) is calculated. The target position information TG (n) given from the controller 13 becomes the target position information TGi (n) of each head in the position control device 3, and the total joint 32 becomes TGi (n).
An absolute error signal APESi (n) is calculated by subtracting the absolute position signal APOSi (n) from (n). The above is summarized as follows.

APOSi (n) = TRKNi (n) + PESi (n) (2) APESi (n) = TGi (n) = − APOSi (n) (3) The position control device 3 calculates the absolute error signal APESi (n )
Is calculated by the integration operation unit 33 so that is set to zero. The integration operation unit 33 includes a total junction unit 34, a one-sample delay unit 35, a multiplication unit 36, and a saturation processing unit 37 for performing the integration operation, and the fine movement drive signal UFi (n)
Is calculated. Here, KI of the multiplying unit 36 represents an integral gain, and determines the response of the head minute positioning control system using the piezoelectric element. Also, UFMAX and UFMIN of the saturation processing section 37
Indicates that the upper limit and the lower limit of the signal OTDTi (n) input to the saturation processing unit 37 are limited by UFMAX and UFMIN. Summarizing the above, the fine drive signal UFi (n) is expressed as follows: X1 (n) = X1 (n-1) + APESi (n) (4) OTDTi (n) = KI * X1 (n) (5) Is obtained as The fine movement drive signals corresponding to these heads are respectively calculated in each sector, and values corresponding to all heads are calculated.

Next, in the operation of the position control device 3, the coarse movement drive signal UC
The operation until calculating i (n) will be described with reference to the block diagrams of FIGS. 4A and 4B. It should be noted that, similarly to FIG. 3, the components in FIGS. 4A and 4B are not independent hardware components but understand the operation performed by the position control device 3 realized by the microcomputer. It is only an auxiliary means for doing so.

FIG. 4A is a block diagram showing calculation contents in a seek operation. In FIG. 4A, the position control device 3 firstly uses the total joint portion 40 to obtain a minute movement signal UFs (n) of the s-th head specified by the controller 13 to control the minute movement data stored in the position control device 3 in advance. The displacement element target drive signal (UFMIN + UFMAX) / 2 is subtracted, and the subtracted signal is converted by the multiplier 41 into a displacement amount, which is output as a small displacement element error displacement PZER (n). Therefore, the small displacement element error displacement PZER (n) is as follows: PZER (n) = KPZ * (UFs (n)-(UFMIN + UFMAX) / 2) (7) Here, KPZ is a voltage displacement conversion gain constant of the piezoelectric element 2.

Next, the total joining section 42 adds TGs (n) and PZER (n) and outputs a coarse movement drive target position TGC (n). further,
The total junction 43 subtracts the absolute position signal APOSs (n) of the s-th head specified by the controller 13 from TGC (n), and outputs a coarse motion error signal CPES (n). TGC (n) and C
PES (n) is as follows.

TGC (n) = TGs (n) + PZER (n) (8) CPES (n) = TGC (n) −APOSs (n) (9) Next, the position control device 3 outputs the coarse movement position error signal. CPES
A coarse drive signal is calculated to make (n) zero. First, the target speed generator 44 generates a target speed signal TGVEL (n) according to CPES (n) as shown in the following equation so that the head can move a plurality of tracks in a short time.

Here, α represents the deceleration at the time of deceleration of the head. In addition, the speed calculator 45, from the APOSs (n), outputs the estimated speed signal VEL.
(N) is calculated. The speed calculation unit 45 is a one-sample delay unit
48, a total junction 49 and a multiplier 50, and the absolute position signal AP
VEL (n) is calculated from the backward difference of OSs (n) as follows.

 VEL (n) = (APOSs (n) -APOSs (n-1)) / TS (11) where TS represents a sample period.

Next, the total junction 46 subtracts VEL (n) from TGVEL (n) and calculates the speed deviation VERROR (n). Further multiplication unit
47 multiplies the VERROR (n) by the gain KV to generate the coarse drive signal
UC (n) is calculated. VERROR (n) and UC (n) are as follows: VERROR (n) = TGVEL (n) -VEL (n) (12) UC (n) = KV * VERROR (n) (13)

FIG. 4B is a block diagram showing the operation content in the following operation. In FIG. 4B, the position control device 3
First, from the fine movement drive signal UFs (n) of the s-th head specified by the controller 13 by the total joint 40,
A small displacement element target drive signal (UFMIN + UFMAX) / 2 previously stored in the position control device 3 is subtracted, and the subtracted signal is converted by the multiplier 41 into a displacement amount, and the small displacement element error displacement PZER (n ). Therefore, the small displacement element error displacement PZER (n) is as follows: PZER (n) = KPZ * (UFs (n)-(UFMIN + UFMAX) / 2) (7) Here, KPZ is a voltage displacement conversion gain constant of the piezoelectric element 2.

Next, the total joining section 42 adds the TGs (n) and the PZER (n) to output the coarse movement drive target position TGC (n). Further, the total junction 43 subtracts the absolute position signal APOSs (n) of the s-th head specified by the controller 13 from TGC (n), and outputs a coarse motion error signal CPES (n). TGC (n)
And CPES (n) are as follows.

TGC (n) = TGs (n) + PZER (n) (8) CPES (n) = TGC (n) −APOSs (n) (9) Next, the position control device 3 outputs the coarse movement position error signal. CPES
A coarse drive signal is calculated to make (n) zero. First, CPES (n) passes through a series compensation operation processing unit 51 that performs position compensation such as phase advance and phase delay, filtering, and the like.
Coarse operation signal CPS (n) is obtained, multiplied by gain Kpz in multiplication section 52, and coarse operation signal UC (n) is output.

The position control device 3 sends the fine drive signal UFi (n) and the coarse drive signal UC (n) corresponding to all the heads calculated as described above to the fine drive device 17 and the coarse drive device 16, respectively. Output.

The coarse drive 16 is a digital-to-analog converter (DA)
C) 18 and a current feedback power amplifier (IPA) 19. The fine movement driving device 17 includes a DAC 20 and a voltage feedback power amplifier (VPA) 21. Calculated by the position control device 3,
The coarse drive signal UC (n) is output to the DAC 18, and the fine drive signals UF1 (n), UF2 (n), UF3 (n) and UF4 (n) are output to the DAC 20.
Is output to Further, the DACs 18 and 20 perform digital-to-analog conversion of the input signal to perform a coarse analog drive signal UC.
(T), fine movement analog drive signals UF1 (t), UF2 (t), UF
3 (t) and UF4 (t) are output. The IPA 19 receives the coarse motion analog drive signal UC (t), and supplies a drive current I (t) proportional to this signal to the VCM1. Further, the VPA21 is provided with fine movement analog drive signals UF1 (t), UF2 (t), UF3 (t), UF4
(T) is input, and the drive voltage V1 (t), V
2 (t), V3 (t), and V4 (t) are output to each piezoelectric element 2. The VCM 1 simultaneously drives all the heads 9 in the radial direction of the disk 8 via the carriage 22. A piezoelectric element 2 is mounted in the middle of a head arm 23 connecting the carriage and each head 9 so that the head 9 can be slightly displaced in the radius (radial) direction of the disk 8. .

As described above, the position control device 3 fetches the servo position information by the position detector 14 for each sample period TS, calculates a fine drive signal, and outputs the signal to the fine drive device 17,
The coarse drive signal is calculated and output to the coarse drive device 16 to drive the piezoelectric element 2 and the VCM 1 to move and position the head to a target track. In the positioning control system using the piezoelectric element 2 described in this embodiment, in order to set the head 9 at a target position, the position of the piezoelectric element 2 that converges within the movable range of the piezoelectric element 2 is determined by the carriage moved by the VCM 1. Determined at 22 positions. Therefore, it is necessary to set the head 9 within the movable range of the piezoelectric element 2.

According to the present invention, an appropriate set position near the center of the piezoelectric element 2, for example, in this embodiment, a small displacement element error displacement which is a displacement amount from a center position of a movable range of the piezoelectric element 2
Target position TG given from control 13 by PZER (n)
This is added to s (n) to obtain a coarse movement drive target position TGC (n). By doing so, the VC element is displaced to the center position of the movable range of the piezoelectric element
M1 is a carriage 22 on which the head 9 and the piezoelectric element 2 are mounted.
To move. Finally, since the displacement of the piezoelectric element 2 is displaced to the center position of the movable range of the piezoelectric element 2, the small displacement element error displacement PZER (n) also settles to zero,
Stable control is possible. When the piezoelectric element 2 is affected by thermal fluctuations in the environment, the relationship between the fine movement drive signal and the amount of minute displacement between the piezoelectric element 2 changes from state A to state B as shown in FIG. It will move to. However, in the disk storage device of the present invention, the amount of displacement in the vicinity of the center of the movable range of the piezoelectric element 2 can be estimated, and the head can be reliably controlled near the center of the movable range of the piezoelectric element 2. As a result, the margin of the track width and the track interval can be reduced, and the storage capacity of the magnetic disk device can be increased.

Further, according to the present invention, when moving across a plurality of tracks, it is possible to move and position the head 9 with extremely high speed and high accuracy. FIG. 7A is a diagram showing a time response of a head position by a conventional servo system that performs head positioning only by a voice coil motor without using a minute displacement element. When the seek operation is started, the voice coil motor is driven to approach the target track and settle after overshooting. FIG. 7B is a diagram showing the time response of the head position according to the present invention. In the servo system according to the present invention, when the seek operation is started, the minute displacement element makes a full displacement in the seek direction within the movable range (0 to T ₁ ). This operation is quickly performed by the response capability of the minute displacement element. On the other hand, voice coil motors
It is driven by a well-known control method and is displaced in the seek direction, but its response is slower than that of the aforementioned minute displacement element. Accordingly, the access servo system approaches the target track by the operation of the voice coil motor with the minute displacement element fully displaced (T _{1 to} T ₂ ). Compared to the case of FIG. 7A, the time required to reach the target track is shortened by the displacement by the minute displacement element in advance. When reaching the center of the target track (T ₂ ), the minute displacement element performs an operation of positioning the head at the center of the track. Since the response capability of the minute displacement element is higher than the response capability of the voice coil motor, it is possible to cancel the overshoot of the servo system of the voice coil motor and shorten the settling time.

If the disk drive has a configuration in which a plurality of heads are mounted on one guide arm, the positional deviation between the heads attached to the same guide arm is small. One of the heads may be used as a representative head, and position information may be read only from the representative head to apply the above-described method. FIG. 8A is a sketch drawing of a head and a disk periphery of an access servo system according to the present invention. In FIG. 8A, one guide arm
23 has four heads 9P, 9Q, 9R and 9S mounted thereon. A total of 2 of the disk 8 and the disk (not shown) located thereon
The four surfaces are divided into two donut-shaped regions on the inner and outer peripheral sides, respectively, and the four heads respectively share a total of four regions. Among them, the head 9S is a representative head, and the position information read from this head is sent to the position control device 3. The piezoelectric element 2 is driven via the position control device 3 and the fine movement driving device 17, and the position correcting operation for the four heads is performed collectively.

 A second embodiment of the present invention will be described in detail.

The configuration of the disk storage device to which the present invention is applied is the same as that of the first embodiment shown in FIG. The functions of the position detector 14, coarse movement drive device 16, fine movement drive device 17, disk 8, VCM1, piezoelectric element 2, and spindle motor 15 in FIG. 1 are the same as those described in the eleventh embodiment.

The controller 13 of the present invention can simultaneously issue different target position information TGi (n) to each head among the movement commands issued to the position control device 3.

Next, in the operation of the position control device 3, the coarse movement drive signal Uci is output.
The operation up to the calculation of (n) is exactly the same as the first operation, and is represented by a block diagram in FIG. However, it should be noted that the components in FIG. 3 are not independent hardware components, but merely auxiliary means for understanding the operation performed by the position control device 3 realized by the microcomputer. That is. The position control device 13 receives the movement command from the controller, and (6)
The fine drive signal UFi (n) is calculated by the equation.

Next, among the operations of the position control device 3, the operation up to calculating the small displacement element error displacement PZER (n) will be described with reference to the block diagram of FIG. It should be noted that, like FIG. 3 and FIG. 4, the components in FIG. 5 are not independent hardware components, but understand the operation performed by the position control device 3 realized by the microcomputer. Is merely an auxiliary means.

First, the total joints 61, 62, 63, and 64 are converted from the fine movement drive signals UFi (n) obtained by the equation (6) into the minute displacement element target drive signals ( UFMIN + UFMAX) / 2 is subtracted, and the subtracted signal is sent to the maximum value detection unit 65 and the minimum value detection unit 66, and the maximum value UF
Output iMAX and minimum value UFiMIN. Total joint 67 is UFiM
AX and UFiMIN are added, and the result of addition is multiplied by 68
Is multiplied by 0.5, and the average value of UFiMAX and UFiMIN is output as the small displacement element error displacement PZER (n). Further, the position control device 3 determines the coarse movement drive signal UC (n) by performing the calculations of the equations (8) to (13).

The position control device 3 outputs the fine drive signal UFi (n) and the coarse drive signal UC (n) calculated as described above to the fine drive device 17 and the coarse drive device 16, respectively, and controls each head. Movement positioning to the target track can be performed independently.

FIG. 8B is a schematic diagram showing how each head is positioned on a target track belonging to a different cylinder. No. 8B
In the figure, No. 2 head 9B, No. 3 head 9C, No. 4 head
9D, the track belonging to the K-th cylinder is positioned, and the first head 9A is positioned at the track belonging to the K + 1-th cylinder. In the servo system according to the present invention, when reading a file stored from track K on the fourth disk surface 8D to track K + 1 on the first disk surface 8A, data is read by the fourth head 9D. During this operation, the minute displacement element 2A corresponding to the No. 1 head 9A is driven to position the No. 1 head on the (K + 1) th track in advance, and the state shown in FIG. 8B can be obtained. Conventionally, a method of causing all heads to follow the same cylinder is used, and it takes time to perform a seek operation in accordance with the change of the target cylinder. Can be Here, the disk device of the data surface servo system is taken as an example, but the same method can be used for a disk device of the hybrid servo system.

Another embodiment of the present invention will be described with reference to FIG. 8C. The coarse movement actuator (not shown) and the piezoelectric element 2R cooperate with each other to cause the head 9R to follow a predetermined track so that the head 9R follows the recording track on the disk 8. The disk 8 is a disk for the sector servo system, and servo information is recorded intermittently in the circumferential direction. When the head 9R is on-track by the above method to read or write recorded information (during following), a head 9S different from the preceding head 9R arranged on the same disk 8 is instructed by the controller. The piezoelectric element 2S is operated so as to follow the predetermined track so as to be on-track. Here, if the track position designated by the controller to the head 9S is within the movable range of the piezoelectric element 2S, the head 9S is moved to the designated track, and if the track position is outside the movable range of the piezoelectric element 2S, The head 9S is moved to the center point or the vicinity of the limit point to turn on the track. As a result, if the head that reads or writes information next to the head 9R is 9S and the track used for reading or writing is within the movable range of the piezoelectric element 2S, the information is already read or written by the head 9R. During this time, the movement of the head 9S has begun, and the time required for head change can be significantly reduced. This series of operations is determined by a determination unit (not shown). That is, the determination unit receives the head number and the track number used for reading or writing the current information specified by the upper controller, and also inputs the head number and the track number of the head to be used next, From the difference between the track numbers of the two heads,
It is determined whether or not the piezoelectric element 2 can be moved, and an output signal corresponding to the amount of movement is output from the determining means. Further, when the displacement amount of the piezoelectric element 2S fluctuates from the initial value (zero point) and the head 9S is following, the coarse motion actuator follows while compensating the displacement amount of the piezoelectric element 2S, Further, the access time for the next head change can be reduced.

 Further, another embodiment will be described below.

FIG. 9 is a block diagram showing a configuration of a head position control device (access servo mechanism) of the magnetic disk storage device of the present invention. In FIG. 9, a control device A100 has a function of operating an access servo mechanism in response to a command including an address given from a higher-level device. Control device A100 outputs a power amplifier drive signal in response to the command. This signal is amplified by the power amplifier 101 and applied to the voice coil motor 102. The voice coil motor 102 simultaneously drives all the heads 103a, 103b, 104, and 103d in the radial direction of the magnetic disk 105 via the carriage 106. Also, carriage 1
Piezo element between 06 and each head 103a, 103b, 104, 103d
111a, 111b, 111c, 111d are mounted, and the heads 103a, 10
3b, 104, and 103d can be minutely displaced in the radius (radial) direction of the disk 105. The magnetic disk 105 is concentrically rotated by a spindle motor 107 at a constant speed. A servo surface 120 on which position information of each track is recorded is formed on one of a plurality of disk surfaces of the magnetic disk 105, and the other surface is a data surface 130a for storing both data information and servo information. 130b, 130d
It has become. Servo head 104 corresponding to servo surface 120
Is read by the amplifier 121 and read into the control device A100 as a position signal. On the other hand, each head 103a, 103b, 103d corresponding to the data surface 130a, 130b, 130d
The signals read by are read amplifiers 131a, 131b, 131d
, And one of them is selected by the multiplexer 132. The selected signal is input to the control device A100 as a data signal, and is input to the control device B including a microcomputer and a digital signal processor via the AD converter 151.

In this embodiment, the control device B is a single device. However, as will be described later, processing inside the device is multiplexed by time sharing, and substantially has a plurality of control devices B. There is no difference from having. This control device B150,
It has a function of driving the above-mentioned piezo elements 111a, 111b, 111c, 111d, and outputs the driving signals to the DA converters 152a, 152b, 152c, 152.
Piezo element via d and amplifiers 155a, 155b, 155c, 155d
Input to 111a, 111b, 111c, 111d. Among them, a constant voltage corresponding to almost the center of the movable range is always applied to the piezo element 111c corresponding to the servo head 104 during operation.
Further, control device B150 sends and receives an interface signal with control device A100, and manages the operation of the access servo mechanism. The multiplexer 132 receives a head selection signal from one of the control device A100 and the control device B150, and outputs head data corresponding to the selection signal to the AD converter 151.

FIG. 10 schematically shows a detailed structure around the head and the disk. In FIG. 10, the spindle motor
One of the disk surfaces which rotate integrally by the 107 is a servo surface 120, and a servo signal (position information) defining the position of each track on the servo surface 120 is recorded. This servo signal is read by the servo head 104. The remaining disk surfaces are data surfaces 130a, 130b, 130d for recording data information. Each of these data planes is divided into areas called sectors.
The servo position information area 141a, 1 is located at the beginning of each sector.
41b and 141d are provided. When the data head detects this portion, a sector interrupt occurs in the control device B150. The data area 14 is located after the servo position information.
2a, 142b, 142d are provided. Data heads 103a, 103b, 103d corresponding to each data surface as the disk rotates
Pass over these areas, the acquisition of servo position information and the reading / writing of data are performed alternately. On the other hand, these heads 103a, 103b, 104, 10
3d is attached to the head arm 163 via the support spring 162. The piezo elements 111a, 111b, 111c, and 111d are incorporated in the head arm 163, and are controlled by the control device B150. The head arm 163 is fixed to the carriage 106, and the carriage 106 is driven by the voice coil motor 102 in the radial direction of the disk.

FIG. 11 is a block diagram schematically showing a configuration of control device A100. In FIG. 11, the servo position information on the servo surface 120 is read by the servo head 104 and
The signal is amplified by 21 and input to the control device A100 as a position signal. This position signal is demodulated by the position detection circuit 211 and becomes a linear position signal proportional to the distance from the center of each track. The control device A100 has two operation modes called a seek operation mode and a following operation mode.

The seek operation mode is an operation mode in which the head is moved across tracks. At this time, the linear position signal is input to the track crossing detection circuit 212 and the speed detection circuit 215. The track crossing detection circuit detects a linear change in the position signal when the head 104 passes through each track, and converts the change into a pulse. This pulse is input to the difference counter 213. When moving between tracks, the moving amount x is set in advance by the reference counter from the upper controller.
Since the number of tracks to be moved is reduced each time the pulse is applied, the difference counter 213 always holds the required number of tracks up to the target track. The required number of tracks is input to the speed pattern generation circuit 214. The speed pattern generation circuit 214 outputs a speed command signal according to the required number of tracks. On the other hand, the speed detection circuit 215 inputs the value of the current flowing through the voice coil motor 102 together with the linear position signal, and calculates the movement speed of the voice coil motor. This speed is subtracted from the above-mentioned speed command signal, and the difference signal is amplified by the power amplifier 101, and the voice coil motor 1
Drive 02.

When the target track is reached in the seek operation mode, the operation mode is switched 217, and a following operation mode is set. In the following operation mode, the linear position signal is input to the following compensation circuit 216. The following compensation circuit 216 performs a phase compensation calculation process, a filtering process, and the like on a linear position signal, that is, a position deviation from the track center, and outputs the signal. The signal is amplified by the power amplifier 101 to drive the voice coil motor 102. The following operation mode is continued until the next seek start command is given.

FIG. 12 is a flowchart showing the contents of processing normally executed by control device B150. The control device B150 also performs the position control processing of the servo system of the piezo element by this processing and time sharing when a sector interrupt occurs, which will be described later. In FIG. 4A, when a seek operation is not being performed, a following process is being executed (step 301), and the process is waiting for a seek start command to come (step 302). When a seek start command is received, acceptance of a sector interrupt is prohibited, and the position control processing of the piezo element's servo system is stopped (step 303).
Next, in the direction of the target track, the data head
The piezo elements 111a, 111b, 111d corresponding to 103a, 103b, 103d are expanded or contracted (step 304). The VCM is driven by the controller A, and the seek operation proceeds (step 3).
05), when the head reaches a predetermined position near the target track (step 306), the inhibition of the acceptance of the sector interrupt is released, and the position control processing of the piezo element servo system is restarted (step 307), and the following processing is performed. The head is positioned on the target track by position control (step 301). Thereafter, the state becomes the following state until the next seek instruction is received.

FIG. 13 is a flowchart of a position control process of the servo system of the piezo element activated by the sector interrupt. When a sector interrupt occurs (step 311), the multiplexer 132 is operated to operate the data heads 103a, 103b, 1
Fetch each servo position information from 03d (step 312).
The servo position information from each captured data head is
Each is converted into a positional deviation from the center of the target track (step 313). These position deviations are independently added to the cumulative sum of the past position deviations (step
314). Each cumulative sum corresponding to each of the obtained data heads 103a, 103b, 103d is a corresponding DA converter 152a, 152b,
The signal is a signal for driving each of the piezo elements 111a, 111b, 111d via 152d and amplifiers 155a, 155b, 155d. That is, the control operation of the piezo element is performed by the integration operation.

In this embodiment, the response of the head position when the seek operation is performed is the same as that of the first embodiment shown in FIGS. 7A and 7B.

〔The invention's effect〕

According to the present invention, the micro-displacement element that micro-displaces each head is controlled so that each head can follow a predetermined track, so that head switching on the same cylinder can be performed at high speed and access can be performed. This has the effect of reducing the time.

In addition, since both the actuator and the micro-displacement element that move the head and the micro-displacement element mounted on the tower can be controlled at the same time, there is also an effect of reducing the access time of the seek operation of moving over a plurality of tracks.

Further, since each head can follow a predetermined track, it is possible to reduce a margin of a following track width and an interval between tracks due to thermal deformation of a member or an assembly error, thereby increasing a storage capacity of the magnetic disk device. There is.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of a disk storage device according to a first embodiment and a second embodiment of the present invention. FIGS. 2A and 2B show servo position information detected by a position detector. FIGS. 2C and 2D are views for explaining servo position information calculated in the position control device, and FIGS.
FIG. 4A is a diagram for explaining an operation up to calculating a fine movement driving signal output from the position control device. FIG. FIG. 4B is a block diagram showing the contents of calculation in the following operation. FIG. 5 is a diagram for explaining a process in which a small displacement element error displacement is calculated in the position control device according to the second embodiment;
The figure shows the voltage / displacement characteristics of the piezoelectric element and the characteristic fluctuation due to the environmental temperature.Figure 7A shows the time response of the head position when the position is controlled only by the VCM.Figure 7B shows both the VCM and the piezoelectric element. FIG. 7 is a diagram showing a time response of a head position when position control is performed using the. FIG. 8A is a perspective view of another embodiment, and FIG. 8B is a side view of another embodiment. FIG. 8C is a perspective view of another embodiment. Fig. 9
FIG. 2 is a block diagram illustrating a configuration of a head position control device (access servo mechanism) of the magnetic disk storage device of the present invention. FIG. 10 is a schematic sketch showing a detailed structure around the head and the disk. FIG. 11 is a block diagram schematically showing a configuration of control device A100. FIG. 12 is a flowchart showing the contents of processing normally executed by control device B150. FIG. 13 is a flowchart of a position control process of the servo system of the piezo element activated by the sector interrupt. 1. Voice coil motor (VCM) 2. Piezoelectric element
3. Position control device, 4. Bus (bus), 5. Random access memory (RAM), 6. Programmable read only memory (PROM), 7. Central processing unit (CPU) , 8 ... disk, 9 ... head, 13
……………………………………………………………………………………………………………………………………… Controller 14 103a, 103b, 103d …… Data head, 104 ……
Servo head, 111a-d ... Piezo element, 120 ... Servo surface, 130a, 130b, 130d ... Data surface, 141a, 141b, 141d ...
... Servo position information area, 142a, 142b, 142d... Data area, 150.

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Soichi Toyama 502 Kandate-cho, Tsuchiura-city, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. In-house (56) References JP-A-60-32383 (JP, A) JP-A-2-236875 (JP, A) JP-A-2-267832 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 21/10

Claims (8)

(57) [Claims] 1. A method for writing at least one piece of information on a recording surface composed of a plurality of rotating disks arranged coaxially at intervals and recording tracks provided on each of the disks. Or a plurality of heads for performing reading, a plurality of head arms for supporting the plurality of heads, a support member for collectively supporting the plurality of head arms, and the plurality of heads attached to the plurality of head arms. A magnetic disk storage device comprising: a plurality of micro-displacement elements for micro-displacement in the seek direction; and a coarse movement actuator for moving the plurality of heads in the seek direction by moving the plurality of support members in the seek direction. In the control method, one of the plurality of heads may read or write information recorded on a recording track. Then, the difference between the track on the recording surface on which another head for reading or writing information is following and the target track on which the next reading or writing on the recording surface is next is within the movable range of the micro displacement element. And driving the minute displacement element to move the other head to the target track. 2. A rotating disk having a recording surface, a head arm disposed on one recording surface of the rotating disk, and supporting first and second heads and the first and second heads. A support member that collectively supports the head arm, a plurality of micro-displacement elements attached to the head arm to micro-displace the first and second heads in a seek direction, respectively, and seek the support member. A coarse movement actuator for moving the first and second heads collectively in a seek direction by moving the heads in a seek direction, wherein the first and second heads have a predetermined recording surface. To read the servo position information from the corresponding recording surface of the rotating disk so as to follow the respective recording tracks, and drive the corresponding minute displacement element to position the first and second heads. A method for controlling a magnetic disk storage device. 3. Writing of at least one piece of information on a recording surface composed of a plurality of rotating disks arranged coaxially at intervals and storage tracks provided on each of the disks. Or a plurality of heads for performing reading, a plurality of head arms for supporting the plurality of heads, a support member for collectively supporting the plurality of head arms, and the plurality of heads attached to the plurality of head arms. A plurality of micro-displacement elements for micro-displacement in the seek direction, and a coarse motion actuator for moving the plurality of heads in the seek direction by moving the plurality of support members in the seek direction. In the control method, the plurality of heads drive the corresponding minute displacement elements so as to follow respective predetermined recording tracks, and the plurality of heads are driven. Position and at least one
A method for controlling a magnetic disk storage device, comprising: obtaining a displacement amount of a fine displacement element corresponding to one head; and driving a coarse movement actuator based on the displacement amount. 4. Writing of at least one piece of information arranged on a recording surface composed of a plurality of rotating disks arranged coaxially at intervals and storage tracks provided on each of the disks. Or a plurality of heads for performing reading, a plurality of head arms for supporting the plurality of heads, a support member for collectively supporting the plurality of head arms, and the plurality of heads attached to the plurality of head arms. A plurality of micro-displacement elements for micro-displacement in the seek direction, and a coarse motion actuator for moving the plurality of heads in the seek direction by moving the plurality of support members in the seek direction. In the control method, only servo position information is recorded on at least one recording surface of the plurality of rotating disks, and servo position information is recorded on the recording surfaces of the other rotating disks. Information and recorded information are recorded, and the plurality of heads drive the corresponding minute displacement elements so as to follow respective predetermined recording tracks, thereby positioning the plurality of heads, and Controlling the magnetic disk storage device, wherein a displacement amount of a minute displacement element corresponding to a head for reading information on a recording surface on which only position information is recorded is obtained, and a coarse movement actuator is driven based on the displacement amount. Method. 5. A two-stage access servo control method for a magnetic disk storage device that performs a following operation after a seek operation by using a coarse movement actuator and a plurality of fine displacement elements, wherein the plurality of fine displacement elements correspond to the plurality of fine displacement elements. During a period in which one of the heads is reading or writing information, a track on a recording surface on which another head for reading or writing information next performs a following operation and the next reading or writing on the recording surface When the difference from the target track to perform is within the movable range of the minute displacement element corresponding to the other head, the minute displacement element is driven to move the other head to the target track. A method for controlling a magnetic disk storage device. 6. Writing of at least one piece of information arranged on a recording surface comprising a plurality of rotating disks arranged coaxially at intervals and a storage track provided on each of the disks. Or a plurality of heads for performing reading, a plurality of head arms for supporting the plurality of heads, a support member for collectively supporting the plurality of head arms, and the plurality of heads attached to the plurality of head arms. A magnetic disk storage device comprising: a plurality of micro-displacement elements for micro-displacement in the seek direction; and a coarse movement actuator for moving the plurality of heads in the seek direction by moving the plurality of support members in the seek direction. In a period during which one of the plurality of heads reads or writes information recorded on a recording track, Inputting servo position information of a track on a recording surface on which another head that reads or writes information is performing a following operation and servo position information of a target track on which the next reading or writing on the recording surface is performed, A comparison is made with the movable range of the micro displacement element corresponding to another head, and when the difference between the track being followed and the target track is within the movable range of the micro displacement element, the other head is set to the target range. A magnetic disk storage device comprising: a position control device that outputs a drive signal to the minute displacement element so as to follow a track. 7. A rotating disk having a recording surface, a head arm disposed on one recording surface of the rotating disk, and supporting first and second heads and the first and second heads. A support member that collectively supports the head arm, a plurality of micro-displacement elements attached to the head arm to micro-displace the first and second heads in a seek direction, respectively, and seek the support member. A coarse movement actuator for moving the first and second heads collectively in the seek direction by moving the heads in the seek direction, wherein the servo position information of the first and second heads is A magnetic disk storage device provided with a position control device for inputting and outputting a drive signal to the plurality of minute displacement elements so that the first and second heads follow a predetermined track. Place. 8. Writing of at least one piece of information arranged on a recording surface comprising a plurality of rotating disks arranged coaxially at intervals and storage tracks provided on each of the disks. Or a plurality of heads for performing reading, a plurality of head arms for supporting the plurality of heads, a support member for collectively supporting the plurality of head arms, and the plurality of heads attached to the plurality of head arms. A magnetic disk storage device comprising: a plurality of micro-displacement elements for micro-displacement in the seek direction; and a coarse movement actuator for moving the plurality of heads in the seek direction by moving the plurality of support members in the seek direction. In the above, the servo head information read by the plurality of heads following is input, and the plurality of heads follow a predetermined track. A position control device that outputs a drive signal to the minute displacement element corresponding to the plurality of heads, and the position control device obtains a displacement amount of at least one minute displacement element, and calculates a displacement amount based on the displacement amount. A magnetic disk storage device, which outputs a drive signal of a coarse movement actuator by using a magnetic disk drive.