JPS63171479A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To constantly position a data head at a proper position on a data track by correcting a position shift based on a signal from a storing device by a controller and moving the data head to a normal position. CONSTITUTION:A servo head 1 is positioned on the specific data track by a position controller 7. The position shift in the respective data heads 2 from the data track is detected from the output of detecting cores 2a, 2b. Voltage waveforms are compared in a position detector 5, the voltage difference is detected, thereby, the position shift can be detected, digitized in an A/D converter 6 and stored in the storing device 9. The quantity of the position shift stored by the head 2 to be positioned is outputted to the controller 7 from the storing device 9. The controller 7 outputs a motor driving signal C correcting this quantity of the position shift in order to align the centers of the data head to be positioned and the data track in the positioning of the head 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device, and particularly to an improvement in a control system for positioning a data head thereof.

[Conventional technology]

In general, a magnetic disk drive has magnetic disks stacked in multiple stages and a data head that writes or reads data in close proximity to the corresponding track on each magnetic disk. The desired track can be accessed at high speed. To execute this access, one side of one of the magnetic disks is normally used as a servo surface, and position information is written there. On the other hand, a servo head is provided to read the position information from this servo surface, and positioning control is performed based on the position information output from this servo head, and the access is executed.

FIG. 4 shows a general schematic configuration of such a magnetic disk device. In FIG. 4, (1) and (2) are a servo head and a data head that read position information or data recorded on a magnetic disk, a magnetic disk is shown, and αυ is a spindle motor that holds and rotates this magnetic disk αα. (Ll is a carriage that holds the servo head (1) and data head (2) together, α
3Fi A motor that supports this carriage a2 and drives it forward and backward in the radial direction of the magnetic disk drive, Q41.
Fi is a control device that controls the drive of this motor a3.

FIG. 5 is a perspective view of the servo head (1).

In the figure, α9 is a support body e ("c) is a recording/reproducing core provided on this support body. The magnetic disk αG#:t shown by a dotted line in the figure is close to the surface of the hub in the direction of the arrow. The data head (2) also has the same structure.

In a magnetic disk drive having such a configuration, the data head (2) is moved to a desired data track position by motor control by the controller α, and a block diagram of the control system is shown in FIG. In this figure, (3) is the core Qc of the servo head (1) and data head (2) described above.
, (2c) an amplifier that amplifies the signal detected from the
+41d Above servo head (1), data head (2)
A head selector that selects one of the heads.

(5) is a position detector that forms and outputs a position signal from the detection signal from the servo head (1); and (6) t:t is an A/D converter that converts this position signal from analog to digital.

(7) generates a motor drive signal C to control the head position based on the position signal from this A/D converter (6), positioning command A from the central processing unit (not shown), and head selection command B. A position restraint device that emits.

(8) Fi is a motor driver that drives motor 0 using this motor drive signal C.

Next, the operation will be explained. Data recording/reproduction is performed by a data head (2) that is close to a magnetic disk that rotates at a constant rate.
This is done by moving in the radial direction and writing and reading data to and from a plurality of data tracks formed on each surface of the magnetic disk αα. The operation of moving the data head (21) to the desired data track position is as follows:
First, the position controller (7) which receives the positioning command A and the head selection command B issues a motor drive signal C. The motor driver (8) that receives this motor drive signal C drives motor a3.
to drive. The carriage @ is moved in the radial direction of the magnetic disk by the motor (8), and the servo head (1) detects a signal from the servo surface. This signal passes through an amplifier (3) and a head selector (4), is formed as a position signal by a position detector (5), is digitized by an A/D converter (6), and is sent to a position controller (7). . Based on this position signal, a position controller (7) and a motor driver (8) drive and control the motor side to position the servo head and issue a completion signal. The above is a well-known operation.

By positioning the servo head (1) in this manner, the data head (2) integrated therewith can be positioned on a desired data track, and the above-mentioned access is performed.

[Problem that the invention seeks to solve]

Conventional magnetic disk drives are configured as described above, so if thermal or mechanical strain occurs in the carriage (2) due to environmental changes such as temperature or changes over time, position information can be detected and positioning performed. A relative positional deviation occurs between the servo head (11) that is performing the reading and writing and the data head (2) that reads and writes data, and even if the servo head (11) is positioned at the correct position, the data head (2) is not on the data track. In other words, there is a problem in that the data head is misaligned with respect to the positioning system, reducing the reliability of data recording and reproduction.

The present invention was made to solve this problem, and an object of the present invention is to provide a magnetic disk device in which a data head is always positioned at an appropriate position on a data track.

[Means for solving problems]

A magnetic disk device according to the present invention includes a detection core formed in a data head for detecting a positional deviation between the data head and a data track, and a position detector that outputs the amount of positional deviation based on a signal from the detection core. , and a memory for storing the detected amount of positional deviation, and the controller positions the data head so as to correct it based on the stored amount of positional deviation.

[Effect]

In this invention, the amount of positional deviation between the data track and the data head is output from the position detector and stored in the memory based on the signal from the detection core.

The controller positions the data head so as to correct the stored positional deviation amount.

[Embodiments of the invention]

The present invention will be explained below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a data head control system of a magnetic disk device according to the present invention. In the figure, (1) to (8) are similar to the conventional example. A perspective view of the data head (2) in this magnetic disk device is shown in FIG. 2, and (2a) and (2b) in FIG.
) are detection cores provided near both ends of the data head (2) to detect positional deviation between the data head (2) and the data track. In addition, the position detector (5) in FIG. 1 has the same function as the conventional one, and also has the above-mentioned detection core (2a).

It has a function of comparing the outputs from (2b) and outputting a signal corresponding to the difference. (9) is the detection core (z
a), detected by (2b) and the position detector (5),
A storage device that stores the digital signal of the positional deviation amount passed through the A/D converter (6) via the position controller (7).
Although not shown in Figure 1, the normal data head (2
) as shown in FIG.

In the magnetic disk device of the present invention configured as described above, positioning of the data head (2) is performed by positioning the servo head (1), as in the conventional example, and furthermore, the positioning of the data head (2) is performed by positioning the servo head (1). and data head (
In order to prevent misalignment between the data head (2) and the data track due to the relative positional deviation VC of 21, this data head (2) is
2) It also performs an operation to detect a shift between data tracks in advance. That is, according to the magnetic disk device of the present invention, 1
It has two modes: normal positioning mode and positional deviation detection mode.The operation in the nine positional deviation detection modes will be explained in detail below.First, the position controller (7) will move the servo head (1) to a specific position. Position on the data track. Here, the positional deviation of each data head (2) with respect to the data track is detected from the outputs of the detection cores (2a) and (2b). FIGS. 3A and 3B show the relative positional relationship between the t:t data head (2) and the data track α mark, and the output waveforms of the detection cores (2a) and (2b) in each positional relationship. Data head (2) in Figure 3(a)
Position P□, P2. The most desirable of P is
This is the position of P2 that is centered on the data track αQ. As shown in FIG. 3(b), the output voltage waveform v2a of the detection cores (2a) and (2b) at the position of P2 with
, ■2b are equal, but they differ in the position of Pl or P, and the difference depends on the amount of positional shift. Therefore, by comparing this voltage waveform with the position detector (5) and detecting the voltage difference, the amount of positional deviation can be detected.
The data is digitized by a D converter (6) and stored in a storage device (9). This operation is performed for all data heads (2) according to the head selection signal E.

Positioning of each data head is performed in normal positioning mode. This is similar to the conventional example, with the servo head (1
) for positioning.

At this time, the stored positional deviation amount of the data head to be positioned specified by the head selection command B is stored in the memory (
9) is output to the position controller (7). Position controller (
7) In order to align the centers of the data head to be positioned with the data track in positioning the servo head (1), a motor drive signal C is generated with the amount of positional deviation corrected. By doing this, the data head (2) is always in the third position.
It is moved to position P2 in the figure.

The core of a magnetic head is usually small and uses fine manufacturing technology such as thin film technology, so the above two detection cores (2a),
A difference may occur in the core width of (2b). In this case, even if the data head (2) is in the correct position, a difference will occur in the output voltage, but this can be easily corrected.

In other words, data is written to the magnetic disk αG from the data head (2), and the data is written in the same state (data head (2)
It is sufficient to store the output voltage difference between the detection cores (2a) and (2b) as an offset when there is no deviation of the data track αe, and this offset reset signal F is used when detecting the positional deviation of the data head. It can be sent to the position detector as

Further, the operation in the positional deviation detection mode is performed when the magnetic disk device is powered on or at predetermined time intervals.

It will be more effective if pressure is maintained to constantly monitor the positional deviation of each data head.

In the above embodiment, a magnetic disk device in which one surface of the magnetic disk αl is used as a servo surface has been described, but the present invention is not limited to this, and can also be applied to an embedded servo method, an open loop method using a stamping motor, etc. This also applies to magnetic disk drives.

〔Effect of the invention〕

As described above, the present invention includes a detection core formed in a data head for detecting a positional deviation between the data head and a data track, and a position detector that outputs the amount of positional deviation based on a signal from the detection core. , and a memory device for storing the amount of positional deviation output from this position detector,
This has the effect of preventing reading and writing of data in a state where the data head and data track are misaligned, thereby increasing the reliability of recording and reproduction.

[Brief explanation of the drawing]

1 to 3 are diagrams for explaining the magnetic disk device according to the present invention, in which FIG. 1 is a system diagram showing one embodiment of a data head position control system, and FIG. 2 is a perspective view of the data head. , FIG. 3(,) is an explanatory diagram showing the positional relationship between the data head and the data track. FIG. 3(b) is an explanatory diagram showing the output waveform of the detection core in the positional relationship, FIG. 4 is a schematic configuration diagram showing a conventional magnetic disk device, FIG. 5 is a perspective view showing the magnetic head portion thereof, and FIG. FIG. 6 is a system diagram showing a conventional control system for positioning a data head. In the figure, (1) is a servo head, +21Fi data head, (za) and (zb) are detection cores, (3) is an amplifier, (4) is a head selector, (5) is a position detector,
(6) is an A/D converter, (7) is a position controller, (8
) is a motor controller, (9) is a memory, α[ is a magnetic disk, a is a carriage, α3 is a motor, and Q41 is a control device. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] A magnetic disk that records data and is provided to rotate; a data head that is provided to move forward and backward along the semi-longitudinal direction of the magnetic disk and that records and reproduces the data; and a data head that records and reproduces the data. A carriage that holds a head, a motor that drives the carriage forward and backward, a controller that drives and controls the motor, and a controller that is formed on the data head to prevent misalignment between the data head and the data track on the magnetic disk. The controller includes a detection core for detection, a position detector that outputs a signal indicating the amount of positional deviation based on a signal from the detection core, and a storage device that stores the amount of positional deviation and outputs it to the controller. 1. A magnetic disk drive according to claim 1, wherein a device corrects the positional deviation based on a signal from the storage device and moves the data head to a normal position.