JPH02292783A - Magnetic head positioning control method - Google Patents

Abstract

PURPOSE:To perform the positioning of a magnetic head without generating a read/write error in a short time by performing the positioning of the magnetic head by seeking the magnetic head to a position near to the center of a nearly targeted track by calculating seek length, and applying servo control at an on-track state required at that track. CONSTITUTION:Since the seek length to the track to be sought is calculated considering deviation between the magnetic heads to be switched in advance and seek is performed based on the seek length, the seek can be performed at the position near to the center of the nearly targeted track. Next, servo correction is performed by reading out servo information from a sought position and generating a state so as to be set at the on-track state with a range set in advance. Therefore, a servo correction quantity after the seek can be comparatively reduced. In such a way, a time required for the servo correction after the seek can be shortened, and average seek time can be reduced, and also, the reproducibility of read/write by the servo correction can be secured.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is a method for recording and recording information by rotationally driving a magnetic recording medium.
The present invention relates to a method for controlling the positioning of a magnetic head with respect to a recording track in a magnetic recording medium drive device that performs reproduction, and in particular,
The present invention relates to a method for controlling the positioning of a magnetic head during a head change in an information recording medium drive device having a plurality of magnetic heads.

[Conventional technology]

Various types of disk drives are known for recording and/or reproducing information by rotationally driving an information recording medium, for example, a disk-shaped magnetic recording medium (hereinafter referred to as a magnetic disk). However, especially for small-sized devices that require a large amount of information, a disk drive device also called a hard disk drive device (hereinafter referred to as an HDD device) is often used. This HDD device rotates a magnetic disk, which has a magnetic recording layer formed on the surface of a hard disk, at high speed, and makes a magnetic head supported by a slider float above the surface of the magnetic disk to perform recording/reproduction. There is.

As shown in the perspective view of FIG. 3, this type of HDD device has two
hard disks la and lb (generally, the hard disks are represented by the symbol l), a spindle motor 3 for rotationally driving the hard disk 1 (see FIG. 4 described later), a swing arm 8, and a spindle motor 3 attached to the swing arm 8. A heel slider 21 is supported by a head base 10 facing the recording surface of the hard disk 1 via a cantilever support spring 9, also called a flexure, and a magnetic heel 2 is integrally provided with the heel slider 21. and a stethoping motor 11 that swings the swing arm 8 to transport the magnetic head 2 in the radial direction of the hard disk 1.
It basically consists of.

The swing arm 8 is attached to a swing shaft erected on the base plate 4 via a port 13, and the bolt 13
It is possible to swing around the center.

Further, a steel belt 14 is stretched over the end of the swing arm 8 on the opposite side with respect to the swing axis, and this steel belt 14 is attached to the drive shaft of the stamping motor 11. The magnetic head 2 is wound around the hard disk l in accordance with the stepping motion of the stamping motor 11 so that a desired track position can be selected by moving the magnetic head 2 in the radial direction of the hard disk l. In this case, the magnetic head transport mechanism 1 is constructed by the swing arm 8, the steel belt 14, the pulley lla, and the stepping motor 11.
5 are configured. The main body of the HDD device configured as described above is, for example, the spacer section 16 and the elastic packing l.
A cover 19 is attached to the base plate 4 with a sealing means 18 consisting of 7 in between, and is tightened with bolts to be sealed.

By the way, when moving the magnetic head 2 using the stepping motor 1l as described above, positioning of the magnetic head 2 becomes difficult as the density increases. In other words, HDD
Since each material inside the device has a different expansion coefficient,
There is a problem called thermal off-trunk, where the position of the magnetic head 2 relative to the recording track shifts due to temperature changes.For example, in a 5.25-inch hard disk drive, the servo is generally disabled when the temperature exceeds 400TPI. It is difficult to position the magnetic head 2 without using.

Therefore, it is necessary to introduce some kind of servo means, which is a positioning control that writes servo information to the magnetic disk I, reads this servo information, and positions the magnetic head 2 at a fine track position of the recording trunk based on the read servo information. Various methods have been proposed.

For example, patent application No. 62-19922 filed by the present applicant.
4, positional deviation is detected by moving the magnetic head from the recording track to a predetermined servo track, and in the servo track on which staggered servo information is written, the positional deviation is detected by the first index signal and hardware timer generation. Second
Two index signals are obtained within the circuit, and these two signals are used as the window timing of the servo data big amplifier circuit and as an interrupt signal to notify the microcontroller that the servo pattern has arrived. The servo data pickup circuit generates two windows (UP, DOWN) corresponding to the servo information, performs V/F conversion during each window period, and performs UP/DOWN counting. This will be explained with reference to FIGS. 4 to 6. FIG. 4 is a block diagram showing a control system of a conventional disk drive device, FIG. 5 is a configuration diagram of a positional deviation detection circuit, and FIG. 6 is a timing chart of the positional deviation detection circuit.

In FIG. 4, the drive system of the HDD device controls a spindle motor 3 that rotationally drives a magnetic disk l, a stamping motor l1 that swings a swing arm 8,
A drive circuit 22 sends and receives signals to and from the head amplifier 21, and processes servo information read out by the magnetic head 2 and amplified by the head amplifier 2l, and sends electrical signals related to servo control to the drive circuit 22. The servo circuit 23 and the drive circuit 22 are connected to the interface 2.
It is mainly composed of a controller 25 which is controlled via a controller 4. This controller 25 and host computer 26 are connected by a bus 27, and are capable of processing signals detected by the magnetic head 2 or signals sent to the magnetic head 2. Further, the drive circuit 22 is equipped with a RAM table that stores excitation currents to be supplied to each excitation phase of the stepping motor 11.

On the other hand, in this conventional example, known staggered servo information is written in advance at one preset location on each track and at a position 180 degrees shifted from this location over all tracks on the magnetic disk 1.

When processing servo information, first, as shown in FIG. After that, amplifier 4 of head amplifier 21
After being amplified by 0.41 and passing through the low-pass filter 42,
Powered by IC43. Then, the servo readout signal shown in FIG.
4 and an amplifier 45, resulting in a detected and amplified signal as shown in FIG. This detected signal is subjected to voltage/frequency conversion by the V/F converter 46, resulting in a V/F converter output as shown in FIG. This V/
The F converter output is further converted to the 6th by hard logic.
The UP/DOWN (U/D) counter 4 is applied to the basic window shown in Figure ■ and the real window shown in Figure O.
7, and the result is input to the microcomputer 48 port in 8 bits. Regarding the second servo area, when the disk 1 rotates approximately 180 degrees by timer management from the output of the first internal index signal IN, the second internal index signal is output from the second internal index signal generation circuit 49. Signal IN2 is V/F converter 4
6, and the same operation is performed.

The microcomputer 48 picks up the data content output as the 8-bit data, determines the current type of Nervo Zone from the track counter number, switches the on-track range according to the type, and switches the on-track range to on-trunk or off based on the content. Determine the degree and direction of the trunk,
If necessary, the stamping motor 11 is moved by a micro step, which will be described later, via a drive circuit.

On the other hand, the stepping motor 11 used is, for example, 0.
．． It is a 4-phase univollar type motor with 9 degrees/step.The motor is excited in two phases and the winding currents of each phase A and B are unbalanced to achieve a 0. Microstepping a step angle of 9 degrees with a resolution of up to 128 stopping points, and further dividing 0.9 degrees/step into two, making one track 0.45
It is driven according to the speed. Also, since the track density of the magnetic disk 1 is 8 8 07 P I, the track pitch is approximately 28.9 μm, and this 1 bit and the above 0.45 degrees correspond to 1 step. 0.9 degrees is 128 microsteps, so 0.9 degrees is 128 microsteps.
45 degrees is half of that, 64 microsteps. Therefore, the resolution of microstep drive is 28.9/6
4 = 0.45μm/microstep゜, and of course the maximum servo correction range for each track is 28.9μ
m.

In FIG. 6, ■ is the first internal index signal IN. which is obtained by taking the index from the rotor 3a of the DD motor 3. , ■ is the second internal index signal INt
, ■ is the waveform after the first internal index signal/second internal index signal waveform shaping, ■ is the external index E
IN, ■ is write protection, ■ is servo read signal, ■ is servo signal detection amplification signal, ■ is basic window, ■ is V/F converter output, [phase] is real window, ■ is count pulse, ■ is U/ D counter, 0
indicate head selection.

The criteria for determining on-track and off-track is U in Figure 7.
As shown in the explanatory diagram showing the relationship between the /D counter output and on-track/off-track, on-track includes a narrow range on-track range NR and a wide range on-track range WR on both sides of this narrow range on-track range NR. Two of these are set.

That is, the center value (O
OH) is defined as the fine track position, and counts of ±n (n is a natural number) based on the center value are treated as on-track. In the conventional example shown in FIG. 7, ±8 counts are on-track, of which ±6 to 8
Count is wide range ontrasok range WR, ±0~
5 counts l. is the narrow range on-track range NR.

Then, the output value of the U/D counter 47 and the microstep are correlated to determine the output to the stepping motor l1, and the determined output drives the stethoping motor 11 in microsteps. In this case, for example, the center value (O O H) of the U/D counter 47 is set as the fine track position, and the output and the U/D counter 11 are
By determining the relationship between the two in advance, the drive output of the stethoping motor 11 is obtained in accordance with the U/D counter output. In this way, the narrow range ontrasok range N
When setting R and wide range on-track range WR, for example, when the magnetic head 2 is located in the narrow range on-track range NR, reading/writing is performed at the same position without microstep driving, and the wide range on-track range WR is set. When the magnetic head 2 is located in the range-on-track range WR, it moves to the center of the 5-2 microstep track and performs reading/writing.

[Problem to be solved by the invention]

Incidentally, an off-track limit called an off-trunk margin is determined for the HDD device, and if this limit is exceeded, an error occurs and reproducibility of writing/reading cannot be ensured.

Therefore, even if on-track is efficiently controlled by setting the narrow range and wide range on-track range as described above, the magnetic head may exceed the off-track margin due to some kind of disturbance or insufficient servo correction during seek. If this happens, an error will eventually occur, and the Ontrasock control will lose its meaning.

On the other hand, like the HDD device mentioned above, two hard disks
In devices equipped with magnetic heads 2 for each side of a and lb, there are cases in which the same magnetic head 2 is used for hexagonal seek, and cases in which the seek is performed with a hexagonal change. Since the fine track position will shift due to each shift between the four magnetic heads 2, make sure to perform servo correction.
It is necessary to control the position of the magnetic head. However, if servo correction is performed from the beginning every time the head is changed and positioning control is performed until the centers of the magnetic head 2 and the recording track are perfectly aligned, there is a problem that the average seek time becomes long.

This invention was made in view of the above-mentioned technical background, and its purpose is to achieve fine tracking in a short time even if there is a bedside change during a seek, and to improve write/read performance. An object of the present invention is to propose a method for controlling the positioning of a magnetic head of a magnetic disk drive device without the risk of causing errors.

[Means to solve the problem]

The above purpose is to read out a pair of staggered servo information written in advance corresponding to the recording tracks by disposing a magnetic head on each of a magnetic recording disk having a plurality of recording surfaces, and based on the read servo information. In a magnetic head positioning control method for positioning a magnetic head with respect to a recording track on a magnetic recording disk, when switching the head from one magnetic head to another (hereinafter referred to as head change), The seek length is calculated by taking into account the amount of deviation between the new magnetic head and the original magnetic head, and then the servo information is written to the target recording track. This is achieved by reading and positioning the magnetic head so that it is in a preset on-track state, and then enabling reading or writing.

[Effect]

According to the above means, when there is a head change, as a first step, the control device calculates the seek length to the track to be sought in consideration of the deviation between the magnetic heads that are switched in advance, and then calculates the seek length to the track to be sought. Since it seeks based on the position, it seeks to a position roughly close to the center of the target track, and as a second step, reads the servo information from the sought position and performs servo correction so that it is on-trunk within a preset range. This will be done. Therefore, the amount of servo correction after seek is relatively small, which reduces the time required for servo correction after seek, reduces the average seek time, and improves read/write reproducibility due to servo correction. It is possible to secure the following.

〔Example〕

Hereinafter, an example of implementation of the present invention will be described with reference to the drawings.

FIG. 1 is a flowchart showing a processing procedure for positioning a magnetic head within a drive circuit in an HDD device according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the operation timing of the embodiment. Note that the HDD device, the hardware configuration for detecting servo information, the processing method for each servo information, etc. are the same as in the conventional example, so their explanation will be omitted, and the configurations that can be considered to be the same or the same as those in the conventional example will be omitted. Elements will be described using the same reference numerals.

In this positioning control, a stump pulse signal is input when the magnetic head 2 is located at a track on one of the recording surfaces of the magnetic disk l and is performing reading or writing, and the head is changed along with the stump pulse signal. This is the control when is executed. In this case, first, the drive circuit 220CP is connected from the controller 25 side.
A step pulse is input to U (central processing unit).

At this time, the moving direction of the magnetic head 2 immediately after the first step pulse input, that is, the direction, is extracted (step 1...hereinafter referred to as S in the figure). Next, the selection state of the currently selected magnetic head (host head) is extracted (step 2) and the CP
As shown in FIG.
TEP) (T, in Figure 2). Note that when this step pulse (STEP) is input, the seek complete signal (S.COM.) is turned OFF.
is in a state of After capturing the step pulse (STEP) as described above, the step pulse (STE
P) Extract the host head again in consideration of the head change during reception (step 4), compare the host head selection state stored in step 2 with the host head selection state obtained in step 4, and extract the host head again (step 4). Check whether the has been switched (Step 5...
After T2 in FIG. 2), the old host selection information is updated (step 6).

After updating the old host selection information in step 6 above, check the direction again and respond to the change in direction, that is, the change in direction (Stesub 7)
After that, calculate the number of microsteps for the total seek length from the number of step pulses captured by StepSop 3 (step 8).
...Figure 2 T,). When using the above-mentioned Steso Pink motor 1L, one microstep corresponds to 0.45 μm, for example. Then, it is determined whether or not the number of steps of the O-trasokori calibration plate has been reached (step 9), and if there is no step signal input corresponding to the number of steps of the recalibration plate, it is determined that it is a normal seek command and the host head is activated again just before the seek. Extracts the selection state (step 10), checks whether there is a head change before seeking (step 11), and updates the host head selection information of step 6 before seeking (step 11).
Step 12). Then, the target head, i.e. the finally selected host head, is selected in step 8 above.
Seek to the target track using the microstep length obtained in Step 13 (T4 in Figure 2). Further, when it is determined in step 9 that there is a step input for the O track recalibration plate, the process moves from step 9 to a subroutine for the 0 track recalibration plate (not shown), and exits from this main routine.

When the seek is completed in step 13, the selected state of the host head after the seek is extracted again (step 14), and the head change state is checked (step 14).
. . . (see Figure 2), and the host head selection information in step 12 is updated (step 16). After this update is performed, it is then checked whether an additional step pulse (STEP) is input during the seek (step 17). In this step l7, the step pulse (
When there is an input of STEP), the process returns to step 7 again, the direction of the seek is confirmed, and the steps from step 7 onward are repeated. Also, if there is no step pulse (STEP) input, the host head's seek position has been determined on the target track sought in step 13, so wait until the host head stabilizes on that target trunk according to the seek length. , that is, waits for seven rings (step 18).

Thereafter, in step 19, on-track control of the host head on the target track is performed. In this step 19, first, it is checked as a whole whether or not there was a hesode change from the step pulse (STEP) input in step 0 to step l8 (step 19
-1) If there is a head change, read out servo tq II in the target soto trunk and perform fight rack processing (step 19-3), then turn on the seek complete signal (S.COM.). , making read/write possible. Further, if a head change has not been performed in step 19-1, it is determined whether the timing for further servo correction control has arrived (step 19-2). If it is determined in this step 19-2 that the timing for servo correction control has already arrived, fine track processing is similarly performed in the above-mentioned step 19-3. After that, after the fine track processing of this step 19-3 is completed, or after the above step 19-
If it is not the timing to perform servo correction control in step 2, a seek complete signal (S.COM.) is output, and the selected host head executes reading or writing to the target trunk (step 2o... ...Figure 2 T?). Note that the above-mentioned fine track processing selects, for example, servo correction control such that the magnetic head (host head) is located in the above-mentioned narrow range on trunk range NR, but this fine on trunk range is not necessary for the design. It is selected as appropriate depending on the situation. Therefore, in order to further shorten the average seek time, it is also possible to select servo correction control in which the magnetic head is positioned within the wide range on-track range WR described above. [Effects of the Invention] As is clear from the above description, in magnetic head positioning control in a magnetic disk drive device equipped with a plurality of magnetic heads, head switching from one magnetic head to another is performed. When the magnetic head is switched, the seek length is calculated in consideration of the amount of deviation between the switched magnetic head and the original magnetic head, the magnetic head seeks, and then the above servo information is read at the target recording track. According to this invention, which enables reading or writing after positioning the magnetic head so that it is in a preset on-track state, first, the seek length is calculated and approximately the center of the desired track is determined. The magnetic head is positioned in a short time without the risk of writing/reading errors, since the magnetic head is positioned by seeking to a position close to , and then by servo control to the on-track state required for that tracking. I can do it.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the processing procedure in the embodiment of the present invention, FIG. 2 is an explanatory diagram showing the operation timing of the embodiment, and FIGS. 3 to 7 are for explaining the conventional example. The figure is a perspective view showing the internal structure of the disk drive device, FIG. 4 is a block diagram showing the entire control system of the disk drive device, FIG. 5 is a block diagram showing a positional deviation detection circuit, and FIG. 6 is a block diagram showing the positional deviation detection circuit. FIG. 7 is a timing chart showing the operation of the detection circuit, and is an explanatory diagram showing the relationship between the value of the U/D counter and on-track/off-trunk. 1...Magnetic disk, 2...Magnetic head, 11...Stepping mode, 22...
... Drive circuit, 25 ... Controller, 6 ... Host computer. Figure 3 Figure 5 Figure 6

Claims (1)

[Claims] A magnetic head is arranged on each of a magnetic recording disk having a plurality of recording surfaces, reads a pair of staggered servo information written in advance corresponding to the recording track, and controls the magnetic head based on the read servo information. In a method for controlling the positioning of a magnetic head that performs positioning with respect to a recording track on a magnetic recording disk, when the head is switched from one magnetic head to another,
The seek length is calculated in consideration of the amount of deviation between the switched magnetic head and the original magnetic head, and the magnetic head seeks. Then, the above servo information is read out at the target recording track, and the seek length is calculated in consideration of the amount of deviation between the switched magnetic head and the original magnetic head. A method for controlling the positioning of a magnetic head, which comprises positioning the magnetic head so that it is on-track, and then enabling reading or writing.