JPH03147575A - Magnetic disk driver - Google Patents

Abstract

PURPOSE:To drive a magnetic disk being inexpensive and having a high performance by integrating a current flowing to the driving motor of the magnetic head to estimate a moving speed of the magnetic head, comparing a position of the head estimated therefrom and a position detected from a signal generated in the case the magnetic head crosses a gap between tracks, and correcting an estimated position. CONSTITUTION:A current integration circuit 13 is provided in order to estimate a moving speed of a magnetic head 1 by integrating a current flowing to a driving motor 16 of the magnetic head 1, and from a signal of the estimated moving speed by the current integration circuit 13, a position of the magnetic head 1 is also estimated. On the other hand, when the magnetic head 1 crosses a gap between tracks provided on the recording surface of a magnetic disk, a pulse signal is generated, therefore, a CPU 9 can know exactly the present position of the magnetic head 1 by detecting the pulse signal. Accordingly, the comparing the detected position and an estimated position, the estimated position is corrected, and also, by applying correction to an estimated speed, as well, the subsequent estimation is executed. In such a way, positioning correction can be executed exactly, and the magnetic disk of high performance can be driven.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a magnetic disk drive device.

(Prior Art) Conventionally, in a magnetic disk drive device, various access methods for positioning a magnetic head on a predetermined track have been provided, such as a method using a step motor, a method using a DC motor, and a method using a voice coil motor. Recently, since it is necessary to position the magnetic head at high speed, many devices use a DC motor or a voice coil motor as a drive motor.

Many DC motors or voice coil motors used in magnetic disk drives have built-in encoders for rotational angle detection or position detection in order to perform accurate positioning at high speed. Further, for positioning correction, one side of the recording surface of the magnetic disk is a servo disk, and servo tracks are set in advance on the disk surface. Then, the position signal of this servo track is read by the magnetic head, and the position is determined by following the position signal and electrically locking.

FIG. 4 is a diagram showing the above-mentioned conventional magnetic disk drive device.

In the figure, 21 is a head disk assembly;
A magnetic disk 22 is disposed within the head disk assembly 21.
is rotatably supported and rotated by a spindle motor (not shown). A head positioner 23 supports the magnetic head 24 in a swingable manner. The head positioner 23 has a built-in servo preamplifier (not shown) and amplifies the servo track position signal detected by the magnetic head 24. 25 is a drive motor such as a voice coil motor for driving the magnetic head.

26 is a position detection circuit that detects the position signal of the servo track, 27 is a reference speed generation circuit that sets the reference speed of the magnetic head 24 according to the detected position, and 28 is a current value when the magnetic head is controlled in the speed mode. This is an electronic tachometer that integrates and outputs a speed signal.

29 is a comparator, and 30 is a power amplifier that drives the drive motor 25 based on the output signal of the comparator 29.

In the magnetic disk drive device configured as described above, the magnetic head 24 is initially controlled in a speed mode, and the moving speed of the magnetic head 24 is set depending on the number of tracks from the current track position to the desired track position. After moving to a desired track under the speed mode control, the magnetic head 24 is controlled to be always positioned at the center of the track by switching to position control.

(Problem to be Solved by the Invention) However, in the above conventional magnetic disk drive device, an encoder is built into the drive motor 25, and the drive motor 25 is used to detect the current position of the magnetic head 24.
costs will increase.

Furthermore, when using a small magnetic disk drive device that has only a small number of magnetic disks, one surface of the magnetic disk recording surface is used as a servo surface, which increases the cost.

The present invention solves the problems of the conventional magnetic disk drive described above, and provides an inexpensive and high-performance magnetic disk drive that does not incorporate an encoder and does not use one of the magnetic disk recording surfaces as a servo surface. The purpose is to provide equipment.

(Means for Solving Problem i1) To this end, the magnetic disk drive device of the present invention includes a current integrating circuit for integrating the current flowing through the drive motor of the magnetic head to estimate the moving speed of the magnetic head; A CPU is provided for estimating the position of the magnetic head from the moving speed signal.

On the other hand, inter-track gaps are provided at regular intervals on the recording surface of a magnetic disk, and a DC pulse detector is provided to detect a signal generated when a magnetic head crosses the inter-track gaps. There is.

Further, the CPU has means for comparing the detected position and the estimated position and correcting the estimated position.

(Function) According to the present invention, as described above, a current integrating circuit is provided to estimate the moving speed of the magnetic head by integrating the current flowing through the drive motor of the magnetic head, and the current integrating circuit estimates the moving speed of the magnetic head. The position of the magnetic head is further estimated from the moving speed signal.

On the other hand, since a pulse signal is generated when the magnetic head crosses an inter-track gap provided on the recording surface of the magnetic disk, the CPU can accurately know the current position of the magnetic head by detecting the pulse signal.

Therefore, the detected position is compared with the estimated/determined position, the estimated position is corrected, and the estimated speed is also corrected for subsequent estimation.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of a magnetic disk drive device showing an embodiment of the present invention.

1 is a magnetic head for reading/writing, 2 is an amplifier for reading/writing, 3 is a read amplifier that amplifies the read signal to a level that can be converted into a pulse, and 4 is a device that removes high frequency components including unnecessary noise from the read signal. low pass filter,
5 is a pulse detector that converts the read signal into pulses.

6 is a servo burst detector. On the recording surface of the magnetic disk, a servo pattern section for detecting trunk position shift is written between sectors, and a read voltage envelope read from this servo pattern section is converted into a DC voltage.

7 is an A/D converter that converts the servo pattern output voltage converted into a DC voltage value by the servo burst detector 6 into a digital signal, and the digital value of the coated servo pattern output voltage is transferred to a microcomputer (CPLI) 9 sent to.

Reference numeral 8 denotes a DC pulse detection unit that detects a state in which there is no read signal on the magnetic disk (DC erase state) and generates a digital pulse. When a DC erase state is detected, a pulse is generated and the CPU 9 is notified.

Reference numeral 10 denotes a D/A converter that converts a digital signal command sent from the CPt 19 into an analog DC voltage signal. This command causes the magnetic head 1 to move on the magnetic disk.
is moved to the desired track, and the drive motor 16 is moved and stopped for more precise positioning and correction.

Reference numeral 11 denotes a DC amplifier that amplifies the voltage converted into an analog signal by the D/A converter to an appropriate voltage after making necessary corrections. Reference numeral 12 denotes a motor driver, which causes current to flow through the coil of the drive motor 16 in accordance with a command value from the DC amplifier 11 .

Further, 13 is a current integrating circuit that integrates the current flowing through the motor driver, and 14 is a current integrating circuit that converts the moving speed of the magnetic helad l obtained by integrating the current into a digital signal, and converts it into a digital signal.
It is an A/I) converter that sends to I9.

The CPU 9 calculates the moving distance of the magnetic helad 1 based on the speed information sequentially sent from the AID converter 14.

However, the moving distance of the magnetic head 1 obtained in this way is an estimated value, and various errors are accumulated, resulting in a difference between the actual position of the magnetic head 1 and the estimated value.

Therefore, it is necessary to detect and correct this error. If a conventional surface servo method is adopted at that time, one of the recording surfaces of the magnetic disk is used exclusively for the servo surface, but in this embodiment, the sector servo method is adopted, and the magnetic disk that was conventionally used as the servo surface is used as the servo surface. The recording surface is also used as a data surface.

Figure 2 is a comparison diagram of magnetic disk recording surfaces, Figure 2 (A) 1
FIG. 2 (CB) is a diagram showing a normal data surface, FIG. 2 (CB) is a diagram showing a data surface with intermittent tracks, and FIG. 2 (C) is a waveform diagram when the magnetic head is moving.

In FIGS. 2(A) and 2(B), the shaded area N is the recording track, and the white area g between them is the inter-track gap, in which nothing is normally written and the track is in a DC erased state.

On the recording surface, that is, the DC detection surface, of the magnetic disk used in the magnetic disk drive device of the present invention, recording trunks N are intermittently deleted at regular intervals, as shown in FIG. 2(B).
A wide inter-track gap G is formed. In this embodiment, one track is deleted every six tracks.

Next, a case where the magnetic head 1 crosses this DC detection surface as indicated by arrow A will be described.

FIG. 2(C) shows the waveform of the read signal read by the magnetic helad 1 when the magnetic helad 1 crosses the track, and the output signal waveform of the I)C pulse detector 8 is shown in FIG. As shown, when the magnetic head 1 crosses tracks on the DC detection surface, DC pulses are generated at portions where the tracks are intermittently deleted. CPU 9 is this DC
By detecting the pulse, it is possible to accurately know that the currently moving magnetic head l has crossed the inter-trunk gap G, that is, the current position of the magnetic head l.

Fig. 3 is an explanatory diagram of positioning correction when using this OC detection surface, Fig. 3 (A) is a time chart of the flow value of the motor flowing to the drive motor, and Fig. 3 CB> is an estimation of the moving speed of the magnetic head. FIG. 3(C) is a time chart of the moving distance of the magnetic head.

In the figure, when the magnetic head 1 is moved from the position St to the position 32, a motor current as shown in Figure 3 (A) flows through the drive motor of the magnetic head l, and this current is integrated. is the estimated moving speed of the magnetic head l shown in FIG. 3(B).

In FIG. 3(C), the broken line indicates the actual position of the magnetic head 1, and the solid line indicates the estimated position obtained from the integration of the motor current.Since the estimated position has an error from the actual position, it remains as it is for a long distance. If the target position S2 (track) is moved, there is a possibility that the target position S2 (track) is moved to an incorrect track. Therefore, in this embodiment, the deviation is calculated by detecting the DC pulse described above, and the estimated position value is corrected.

For example, when the magnetic head l moves from Sl to S2, the DC pulse I is first detected at timing tl. At that point, the estimated value of the moving distance of the magnetic head l is P
+ On the other hand, if the position where the DC pulse 1 is generated when the throat 1 moves toward the magnetic field is ρ2, it can be seen that there is an error between the estimated value p+ and the correct position 92. Here C
Due to this error, PU 9 changes the current estimated position from p to p.
t and also corrects the estimated speed, and performs subsequent estimation.

Similarly, correction was made for DC pulse 2, and the magnetic nodule l was 3.
When it is positioned at position 2, its estimated position p has moved to almost the correct position.

Thereafter, in order to correctly position the magnetic head l at the center of the track, the position is corrected accurately using a servo burst signal written between each sector on the recording surface.

Note that the present invention is not limited to the above embodiments,
Various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

(Effects of the Invention) As described above in detail, according to the present invention, the moving speed and position of the magnetic head are estimated by integrating the current flowing through the drive motor of the magnetic head, and the Since the current position of the magnetic head can be accurately known by the magnetic head crossing the provided inter-track gap, the positioning can be accurately corrected by comparing the two.

In addition, the encoder in the drive motor can be removed, and there is no need to use one side of the disk recording surface as a servo disk for positioning correction, and the disk surface that was conventionally used as a servo surface can be used as a recording surface. Storage capacity can be increased at low cost.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a magnetic disk drive device showing an embodiment of the present invention, FIG. 2 is a comparison diagram of magnetic disk recording surfaces, FIG. 2(A) is a diagram showing a normal data surface, and FIG. B) is a diagram showing a data surface with intermittent tracks, FIG. 2(C) is a waveform diagram when the magnetic head moves, FIG. A) is a time chart of the motor current flowing through the drive motor, FIG. 3 (B) is a time chart of the estimated moving speed of the magnetic head nozzle, and FIG. 3 (C) is a time chart of the moving distance of the magnetic head. FIG. 4 is a diagram showing a conventional magnetic disk drive device. DESCRIPTION OF SYMBOLS 1...Magnetic head, 2...Amplifier, 3...Read amplifier, 4...Low pass filter, 5...Pulse detector, 6...Servo burst detector, 7...A
/D converter, 8...DC pulse detection section, 10...
・D/A converter, 11... DC amplifier, 12...
・Motor driver, 13...Current integration circuit, 14...
・A/D converter.

Claims (1)

[Scope of Claims] (a) means for estimating the moving speed of the magnetic head by integrating the current flowing through the drive motor of the magnetic head; (b) means for estimating the position of the magnetic head from the moving speed; c) means for detecting the position of the magnetic head based on a signal generated when the magnetic head crosses inter-track gaps provided at regular intervals on the recording surface of the magnetic disk; and (d) comparing the detected position with the estimated position. What is claimed is: 1. A magnetic disk drive device comprising means for correcting an estimated position.