JPH01196776A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To correctly position to an arbitrary track by using a circuit for storing a moving direction until the moving direction of a magnetic head is switched by receiving an instruction, a circuit for storing a corrected value according to the moving direction and a selecting circuit for feeding an error correcting signal to a positioning circuit. CONSTITUTION:An internal control circuit 6 emits a signal to the positioning circuit 5 in order to move the magnetic head 2 to a track X specified by a signal from a host device 7. The control circuit 6 incorporates a dislocation error compensating circuit 11 and feeds the error correcting signal corresponding to the moving direction to the positioning circuit 5. The circuit 11 includes the circuit 8 for storing a dislocation correcting value according to the moving direction of the head 2, the circuit 9 for storing the direction until the moving direction is switched and the selecting circuit 10 for outputting the quantity alphaor alpha' of correction to the positioning circuit 5 based on the outputs of both circuits and the circuit 5 drives a stepping motor 4 based on the error correcting signal to move the head 2. According to the constitution, the dislocation due to the difference of the moving direction of the head can be remarkably reduced to correctly position to the track.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device, and particularly to a magnetic disk device that uses a stepping motor to position a magnetic head.

[Prior Art] Conventionally, the positioning accuracy of the magnetic head of a magnetic disk device that uses this type of stepping motor to position the magnetic head has been determined by the characteristics and mechanical history of the stepping motor.

[Problem to be solved by the invention]

In the conventional magnetic disk drive described above, the positioning accuracy of the magnetic head is determined by the characteristics and mechanical history of the stepping motor, so when positioning the magnetic head to an arbitrary track, the movement from the previous track is Different positional deviation errors occurred depending on the direction and amount of movement. For this reason, there was a problem that positioning to an arbitrary track could not be performed accurately.

[Purpose of the invention]

The purpose of the present invention is to improve the disadvantages of the conventional example,
An object of the present invention is to provide a magnetic disk device that can accurately position an arbitrary track.

[Means to solve the problem]

The present invention includes a magnetic head, a stepping motor that drives the magnetic head, and a positioning circuit that positions the magnetic head by driving and controlling the stepping motor in response to a seek command signal from a host controller.

Then, a positional deviation error compensation circuit for the magnetic head is provided on the input side of the positioning circuit, and the positional deviation error compensation circuit is used to determine the moving direction of the magnetic head in response to a seek command input from the host control device, and to determine the moving direction of the magnetic head, and A moving direction memory circuit stores a predetermined moving direction until the magnetic head is switched, and a correction amount memory circuit records in advance a correction value tα for the amount of positional deviation according to the moving direction of the magnetic head, based on the outputs of these two circuits. and a selection circuit that sends an error correction signal to the positioning circuit, thereby attempting to achieve the above-mentioned object.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

The embodiment shown in FIG. 1 includes a magnetic disk 1 as a recording medium, a magnetic head 2 for writing and reading information on the magnetic disk 1, a carriage 3 supporting the magnetic head 2, and a carriage 3. A stepping motor 4 to drive, a positioning circuit 5 that positions the magnetic head 2 by driving and controlling the stepping motor 4, and an internal control circuit 6 that sends a seek control signal and an error correction signal to the positioning circuit 5. Internal control circuit 6
and a higher-order control device 7 that sends a seek command signal to the host computer.

Of these, the internal control port 6 outputs a seek control signal to the positioning circuit 5 in order to move the magnetic head 2 to the track X specified by the seek command signal input from the host control device 7. This internal control circuit 6 has a built-in positional deviation error compensation circuit 11 shown in FIG. 2, and is configured to send an error compensation signal corresponding to the direction of movement to the positioning circuit 5.

The positional deviation error compensation circuit 11 receives a correction amount storage circuit 8 that stores a correction value for the amount of positional deviation depending on the moving direction of the magnetic head 2 and a seek command signal from the host controller 7 to move the magnetic head 2. Determine the direction and move the magnetic head 2
a movement direction memory circuit 9 that stores the movement direction at that time until the next movement occurs and the movement direction is switched;
The selection circuit 10 outputs a correction amount as an error correction signal to the positioning circuit 5 based on the output of the correction amount storage circuit 8 and the movement direction storage circuit 9.

In FIG. 3, the curve shown by the solid line is the amount of positional deviation caused only by the movement caused by the seek control signal output from the internal control circuit 6. The positional deviation error in track -XX is Y. The curve indicated by the broken line is the positional deviation 〒 caused by the seek control signal and error correction signal output from the internal control circuit 6. Assume that the error correction signal outputs a correction amount α when the moving direction is positive, and outputs a correction amount α' when the moving direction is negative. At this time, the positional deviation error on track -XX is Y'. Y>Y', and the positional deviation error is small.

Next, the operation of the positional deviation error compensation circuit 11 will be explained based on FIG.

In this embodiment, the stepping motor 4 is a two-phase stepping motor, and the driving current is 1. ,I.

It is assumed that the target track is positioned by the following. For example, when a command to move (movement direction quality) from track X0 to track XI shown in FIG. The magnetic head 2 is on track X.

is positioned. The difference between tracks Xl and Xl' is positional deviation error α.

When the position of track X1 is set to 1. When = T2,
The positional deviation error compensation circuit 11 outputs the movement to the track X1'' where the drive current is II>12 as an error correction signal to the positioning circuit 5.
The positional deviation error α' of I is a constant value set as α'.

Therefore, in this case, the positional deviation error compensation circuit
When a command to move from track 0 to track X1 is received by the host device 7, track X results.

This circuit outputs, to the positioning circuit 5, an error correction signal that causes movement from to track X1.

The error correction signal output from the position deviation error compensation circuit is
It may be a single signal that changes the current balance of the stepping motor 4 by a certain amount, or it may be a signal that changes the current balance of the stepping motor 4 by a certain amount.
A circuit that sets two-phase current values using two sets of DA converters may be used, and a plurality of signal groups may be used to send out the DA converter values. Further, the setting value of the correction amount depending on the movement direction may be a positional deviation error compensation circuit that uses one of the movement directions as a base value and changes only the other setting value.

FIG. 5 shows a case where positional deviation error compensation is performed only in the direction of movement. The curve shown by the solid line in FIG. 5 is the amount of positional deviation caused only by the movement caused by the seek control signal output from the internal control circuit 6.

The displacement error in trunk-xx is Y. Correction of moving direction pressure is −〒〇, and correction amount of moving direction quality is −α″
The broken line indicates the amount of positional deviation when output as an error correction signal. At this time, the positional deviation error on track -XX is YTT.

Y >Y'', and the positional deviation error is small.

〔Effect of the invention〕

As explained above, according to the present invention, there is provided a movement direction storage circuit that receives a seek command and stores a predetermined movement direction until the magnetic head movement direction is switched, and a movement direction storage circuit that stores a correction value in advance according to the movement direction of the magnetic head. a correction amount storage circuit for storing;
Since a positional deviation error compensation circuit configured with a selection circuit that sends an error correction signal to the positioning circuit based on the outputs of these two circuits is provided, the positional deviation error caused by the difference in the moving direction of the magnetic head is corrected. As a result, it is possible to provide an unprecedentedly superior magnetic disk device in which positioning to any track can be performed accurately.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing one embodiment of the present invention, FIG. 2 is an internal configuration diagram of the positional deviation error compensation circuit shown in FIG. 1, and FIGS. 3 to 5 are positional deviation error compensation circuits shown in FIG. 1. It is a figure explaining the function and operation|movement of a circuit. 2...Magnetic head, 4...Stepping motor, 5
...Positioning circuit, 7...Upper control device, 8...
Correction amount storage circuit, 9... Movement direction storage circuit, 10...
- Selection circuit, 11... positional deviation error compensation circuit. Fig. 1, P/61 Good point 7) υ
511' Group --- Sea -------" Figure 3 + atr 〆tm Figure 4 F u/7; Ya Tora /7 I Figure 5 + a red fur t1

Claims (1)

[Claims] (1), comprising a magnetic head, a stepping motor that drives the magnetic head, and a positioning circuit that positions the magnetic head by driving and controlling the stepping motor in accordance with a seek command signal from a host control device; A head positional deviation error compensation circuit is provided on the input side of the positioning circuit, and the positional deviation error compensation circuit is configured to receive a seek command input from the host controller, determine the moving direction of the magnetic head, and determine the moving direction of the magnetic head. a movement direction storage circuit that stores a predetermined movement direction until the magnetic head is switched; a correction amount storage circuit that stores in advance a correction value for the amount of positional deviation according to the movement direction of the magnetic head; and a selection circuit for sending an error correction signal to the positioning circuit.