JPH01199367A - Head position correction method for magnetic disk drives - Google Patents

Abstract

PURPOSE:To improve a settling characteristic by storing a dislocating quantity in each servo sector position for magnetic disk one round and on the other hand, executing a drive for the minimum step width of a head actuator at a fixed time interval. CONSTITUTION:For example, when a track position T is dislocated as shown in the figure, dislocating quantities D1-D6 in the timings of respective sector pulses are detected and stored based on each servo informations. In such a way, the dislocating quantity Di in each servo sector position is detected and stored once. On the other hand, not that a stepping motor is intermittently controlled by the stored each dislocating quantity Di, but that it is driven for the minimum step width in a microstep. Thus, since a driving width is small and a magnetic head can be eliminated unstableness in being widely oscillated just after it is position-controlled, the settling characteristic can be made good.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a head position correction method for a magnetic disk device.

[Prior Art] In a cartridge type magnetic disk device, when a magnetic disk cartridge is installed in a drive device, the magnetic disk contained in the cartridge is chucked by the spindle of the drive device. In this case, the magnetic disk becomes eccentric with respect to the spindle, resulting in runout during rotation.

Therefore, in order to cause the magnetic head to correctly follow the target track, the head position is corrected and controlled for the eccentricity of the magnetic disk.

As one method of such head position correction control,
When positioning the head, some systems read servo information from servo sectors formed at a plurality of locations on each track, detect the amount of positional deviation of the head, and intermittently correct the positional deviation based on this.

In positional deviation correction control using this method, for example, if the track position 11T is displaced with respect to the magnetic head as shown in FIG. 6(a), each servo information of that track is read, Positional deviation amount D1~Dn
is detected intermittently.

When correcting the head position, the magnetic head is driven based on each detected positional deviation amount Di. As a result, the head position H is intermittently controlled so as to follow the displacement of the track position T, as shown in FIG. 2(b).

In the example shown in the figure, a large positional deviation error d occurs after being controlled by the positional deviation amount D4 and immediately before being controlled by the positional deviation amount. As described above, in this conventional method, there is a problem in that when the track position suddenly changes, a large positional deviation correction error occurs immediately before control is performed at the next timing.

In addition, if the magnetic head is driven greatly in order to correct the large amount of positional deviation at the next timing, the head position will fluctuate greatly and become unstable immediately after driving, as shown in J in the same figure, resulting in a settling characteristic. There was a problem with it being bad.

[Objective] In view of the above-mentioned problems, it is an object of the present invention to provide a head position correction method for a magnetic disk device that reduces head positional deviation errors and improves settling characteristics.

[Configuration] For this purpose, the present invention stores the amount of positional deviation at each servo sector position over the circumference of the magnetic disk, drives the head actuator in accordance with the amount of positional deviation at one servo sector position, and then drives the head actuator in accordance with the amount of positional deviation at one servo sector position. The head actuator is characterized in that the head actuator is driven by the minimum step width at regular time intervals when the head actuator is driven to the positional deviation amount of the servo sector position.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a schematic diagram of a disk surface of a magnetic disk device according to an embodiment of the present invention.

In the figure, on the disk surface of the magnetic disk 1.

Tracks T and -T openings are formed, and eight servo sector positions are formed at equal intervals on each track.

Predetermined servo information S for detecting the amount of positional deviation of the magnetic head with respect to each track is recorded in the servo sector SS. Also, servo sector SS on each track
The space between them is a data area DA in which various data are recorded and reproduced by the user.

FIG. 2 is a block configuration diagram of the magnetic disk device of this embodiment. In FIG. Controlled by commands from 4.

The inside of the magnetic disk device 2 includes a removable disk cartridge 21, a mechanism section 22 that drives the disk cartridge 21 and the magnetic head, and a mechanism section 22 that controls the mechanism section 22 and records and reproduces information on the magnetic disk 1. It consists of an electronic circuit section 23.

The spindle motor 22a is connected to the disk cartridge 21.
It drives the magnetic disk l housed within the spindle motor drive circuit 23a. The index sensor 22b detects an index position that serves as a reference position when the magnetic disk 1 rotates.

The door lock solenoid 22c locks the disk cartridge 21 to prevent it from being pulled out from inside the magnetic disk device 2 while the disk cartridge 21 is rotating.
b.

The stepping motor 22d causes the magnetic head 22e to seek from each track T to Tn on the magnetic disk 1, and is driven in microsteps by a stepping motor drive circuit 23c.

The information recording and reproducing circuit 23d reads servo information S from the magnetic disk 1 and records and reproduces data. The interface circuit 23s sends and receives commands and data to and from the disk controller 4.

The display lamp 23f is used to display the operating status of the magnetic disk device 2, etc. The control circuit 23g controls each part within the electronic circuit section 23.

The magnetic disk device 2 of this embodiment has the above configuration, and the eccentricity correction operation will be explained next.

FIG. 3 shows this eccentricity correction operation. When the magnetic disk drive 2 receives a reseek command from the disk controller 4, it first drives the stepping motor 22d to move the magnetic head 22e to the commanded target track. Positioning is performed (processing 51).

As shown in FIG. 1, eight servo sectors SS are formed in each track, and in the control circuit 23g, based on the reference timing detected by the index sensor 22b, As shown in , sector pulse SP indicates the reading timing of each servo sector SS.
has been created. Each part within the electronic circuit section 23 operates in synchronization with this sector pulse SP.

Here, in that track, one rotation of the magnetic disk 1, that is, each servo information S of eight servo sectors SS is read to detect the amount of one positional deviation, and the data is stored. Now, for example, track position T
is displaced as shown in Figure 4(b),
Based on each servo information S, the positional deviation amount D1-D at the timing of each sector pulse is detected and stored (processing 52).

Next, a variable iJ is set (process 53), and first, the deviation between the positional deviation amount Di and D2 is determined.

By the way, since the stepping motor 22d is driven in microsteps by the stepping motor drive circuit 23c, the stepping motor 22d is driven in units of a fixed minimum step width, rather than continuously.

Here, the number of steps m to which the minimum step width corresponds to the deviation between the positional deviation amounts D and D3 is determined (process 54). Also, if the period of the sector pulse SP is t, then the time t between servo sectors is t
The unit t is calculated as 7 m (processing 55), and the sign Fi of the deviation is determined as to whether the deviation between the calculated time t1 and the above-mentioned positional deviation amount D and D8 is positive or negative.
(processing 56).

Next, check the variable i (process 57), and if i is not 8 (N in process 57), add 1 to the variable i (process 58).
), return to 54 above.

Thereby, processing is sequentially performed in the same manner as above from the deviation between the positional deviation amount D2 and 0 to the deviation between the positional deviation amount D7 and 01. Moreover, when 1=8, the positional deviation amount D1
The deviations of D and D are processed in the same way.

The above process is executed during the first rotation of the magnetic disk 1. In process 57, when i=8 (Y in process 57), the sector pulse SP is turned on during the second rotation of the magnetic disk l. Check the timing (process 59).

When the sector pulse SP turns on (“L” level in FIG. 4(a)) (V in process 59), the sector pulse SP
The stepping motor 22d is driven by the positional deviation amount Di detected from the servo information S of the servo sector SS corresponding to .

For example, if it is now the timing of the positional deviation amount D1, as shown in FIG. Driven to follow (process 60
).

Next, the time t1 and the sign Fi of the deviation stored in the process 56 are read out, and after one hour t has elapsed, the magnetic head 22e
is driven one step in the direction corresponding to the sign Fi of the deviation (process 61). This process is to drive one step in the same direction at every time ti until the sector pulse SP is turned on next time. However, in the example shown in the same figure, the deviation between the positional deviation amount D and the distance corresponds to two steps, and the time ti=
Since t,/2, it is driven only once.

When the sector pulse SP is turned on (Y in process 59),
The magnetic head 22e is driven by the positional deviation amount D2 (process 60). In this case as well, the deviation between 1 positional deviation amount D2 and D3 corresponds to 2 steps, and the magnetic head 22e is driven once after time t2 has elapsed.
The step is rotated (process 61).

Next, when the sector pulse SP is turned on (Y in process 59)
) and the positional deviation amount (processing 60). In this case, since the deviation between one positional deviation amount D3 and D4 corresponds to one step, time t3 = period t0, and the above-mentioned processing 6
1, the magnetic head 22e is not driven.

Furthermore, when the sector pulse SP is turned on next (processing 59
(Y), the magnetic head 22a is similarly driven by the positional deviation amount D4 (process 60). In this case, the deviation between the positional displacement and the displacement corresponds to 5 steps, and thereafter, the actuator is driven 5 times by 1 step in the force direction of sign Fi at every time t4.

In this way, the magnetic head 22e is driven by the positional deviation amount -D every time the sector pulse SS is tanned, and after being driven by each positional deviation amount Di, the magnetic head 22e is controlled by the secondary positional deviation amount Di÷1. , stepping motor 22d
is driven one microstep at a time, and eccentricity correction control of the head position is executed.

As described above, in this embodiment, while the positional deviation amount Di at each servo sector position is detected and temporarily stored, the stepping motor 22d is intermittently activated at each stored positional deviation amount Di.
Rather than controlling it, the eel is moved by the minimum step width in the micro step.

As a result, as is clear from FIG. 4(c), the positional deviation error of the head position H with respect to the track position T is, in most cases, less than the minimum step width of the stepping motor 22d, and as shown in FIG. ) This is a significant decrease compared to the conventional case explained in .

Further, the stepping motor 22d is always driven with a width of one step, and since the driving width is small, the magnetic head 22e is driven with a width of one step.
This eliminates the possibility of large fluctuations and instability immediately after position control, resulting in improved settling characteristics.

Next, FIG. 5 shows a schematic diagram of the disk surface of the magnetic disk 1 according to another embodiment of the present invention. In FIG. Tracks T1 to Tn on which data is recorded are formed on the disk surface, and servo information S is recorded at the index position of each track T1 to Tn. Furthermore, troughs Tr for eccentricity detection are formed on the outside of the track T.
Servo information S is recorded at eight locations in r.

With this configuration, in this embodiment, when the power of the magnetic disk device 2 is turned on, the magnetic head 22e is first positioned on the track Tr. And on this track Tr,
Processing similar to processing 52 to processing 57 in FIG. 3 is executed.

That is, the positional deviation amounts D8 to D8 of the head position are detected and stored, and based on this, the positional deviation amounts D1 to D8 are detected and stored.
The step number m2 corresponding to the deviation of each adjacent value of D, the time ti, and the sign Fi of the deviation are determined and stored.

When a seek command is received from the disk controller 4, the magnetic head 22e is positioned on the target track according to the command. Here, similarly to processes 59 to 61 in FIG.
The head position is driven based on the time ti and the sign Fi of the deviation.

As a result, as in the case of the embodiment described above, the positional deviation error of the head position relative to the track position is significantly reduced compared to the conventional case. Furthermore, in this embodiment, servo information is recorded in only one location on tracks T-Tn, and the data recording area is widened, so that the data storage capacity is increased.

In the above embodiment, the servo information S for detecting eccentricity was formed at eight locations on one track.

It goes without saying that the number of these devices may be arbitrary.

Further, although the case where a stepping motor is used as the head actuator has been described, the present invention is equally applicable to the case where a voice coil motor is used and a head actuator having a minimum step width as a drive unit is used. Of course it can be done.

[Effects] As described above, according to the present invention, the amount of positional deviation at each servo sector position over the circumference of the magnetic disk is stored, and the head actuator is driven in accordance with the amount of positional deviation at one servo sector position. After that, when driving to the positional deviation amount of the next servo sector position, the head actuator is driven by the minimum step width at fixed time intervals, so the positional deviation error of the head position is significantly reduced compared to the conventional method. In addition, since the driving width of the head actuator is small each time, the settling characteristics are improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a disk surface of a magnetic disk device according to an embodiment of the present invention, FIG. 2 is a block diagram of the magnetic disk device, and FIG. 3 is an operation showing eccentricity correction control of the magnetic disk device. Flowchart, FIG. 4 is an explanatory diagram showing the detection of the amount of positional deviation of the head and its correction operation, FIG. 5 is a schematic diagram of the disk surface of a magnetic disk device according to another embodiment of the present invention, and FIG. FIG. 6 is an explanatory diagram showing detection of the amount of positional deviation of the head and its correction operation. 1... Magnetic disk, 2... Magnetic disk device, 3
...DC power supply, 4...disk controller,
21... Disk cartridge, 22... Mechanism section,
22a... Spindle motor, 22b... Index sensor, 22c... Door lock solenoid, 22
d...Stepping motor, 22e...Magnetic head, 23...Electronic circuit section, 23a...Motor' drive circuit, 23b...Solenoid drive circuit, 23c...Stepping motor drive circuit, 23d... ...Information recording/reproducing circuit, 23e...Interface circuit, 23f...
Indicator lamp, 23g...control circuit. Figure 1 Figure 2 Figure 3 Figure 5

Claims (1)

[Claims] By reading the servo information recorded at multiple locations on the tracks of the magnetic disk, the amount of positional deviation of the head relative to the track position is detected, and the head actuator is driven by a step width corresponding to the amount of positional deviation to adjust the head position. In a head position correction method of a magnetic disk device that follows a target track, a positional deviation amount storage means for storing the positional deviation amount at each servo information position on the track, and the head actuator are arranged to adjust the position of one servo information position. A magnetic disk drive comprising: a head actuator control means for driving a head actuator at a minimum step width at regular time intervals when driving in accordance with the amount of deviation and then driving to the amount of deviation of the next servo information position. head position correction method.