JPS60219680A - Magnetic disc device - Google Patents

Abstract

PURPOSE:To prevent the generation of re-seek control by changing over the control into the speed control so as to restore a VCM within a supervisory position if the VCM is deviated out of the set supervisory position and changing over the control to the positioning control when the VCM restores within the supervisory position. CONSTITUTION:An MPU7 grasps the speed and control state of a voice coil motor VCM at preset point of time based on the inputted data and its data and speed information/control information being a reference stored in a reference information memory circuit 10. When the VCM is not reached to a positioning control start position (b), a speed error signal with the reference speed is outputted to a VCM drive circuit 9 via a D/A converting circuit 8 and a switching circuit 12 so as to apply the speed control. When the movement of the VCM reaches the positioning control start position (b), the switching circuit 12 is switched to the position of an analog positioning circuit 11 by the control of the MPU7 and the analog positioning circuit 11 applies position control. Thus, the generation of a seek error due to instability of seek control is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a magnetic disk device that digitally processes a position signal indicating the moving position of a magnetic head to perform speed control and positioning control. The present invention relates to a positioning control method for positioning the magnetic head to a certain position under stable control.

(b) Background of the Technology Magnetic storage devices using rotating recording media have been developed and put into practical use in the direction of higher recording densities and i-track densities. This has led to significant advances in magnetic recording technology and circuit technology, and as a result, small and medium-sized magnetic disk drives have come into practical use using these advanced technologies.

On the other hand, with the development of information processing technology, there is a strong demand for the practical implementation of magnetic storage devices that can withstand high-speed processing demands.One way to meet these demands is to move the target position on the recording medium at high speed. In addition, studies have been made to position the magnetic head with high precision.

However, there has been a desire to put into practical use a positioning control method that positions the magnetic head at a target position with even higher speed, higher precision, and a more stable control method.

(c) Prior art and problems Next, we will discuss conventional seek control to a target position on a recording medium of a magnetic disk device that digitally processes position signals (speed control and target position for moving to a target position on a recording medium). A method for positioning control (referred to as seek control) will be described with reference to one drawing.

Figure 1 is a schematic diagram of seek control of a conventional magnetic disk device.
FIG. 2 shows an outline of the positioning control.

In the figure, 1 is the servo head and 2 is the amplifier.

3 is a position signal generation circuit, 4 is a track crossing pulse generation circuit, 5 is an analog/digital conversion circuit (hereinafter referred to as an A/D conversion circuit), 6 is a counter circuit, 7 is a microprocessor (hereinafter referred to as MPU),
Reference numeral 8 indicates a digital/analog conversion circuit (hereinafter referred to as a D/A conversion circuit), 9 indicates a voice coil motor drive circuit (hereinafter referred to as a VCM drive circuit), and 10 indicates a reference information memory circuit.

In FIG. 2, a indicates a positioning stop position, b indicates a positioning control start position, C indicates a position signal, and d indicates one track width.

FIG. 1 shows a servo head 1 that reads information on a servo surface on which position detection information is recorded. An amplifier 2 that amplifies the position detection information read by the servo controller 1, a position signal generation circuit 32 that generates a position signal C for seek control from the position detection information, and a track passing pulse on the medium from the position detection information. Track crossing pulse generation circuit that generates track crossing pulses 4. A/D conversion circuit 5 which converts the output of the position signal generation circuit 3 into a digital signal. A counter circuit 6 for counting the output of the track crossing pulse generation circuit 4. A/D
Key υ7. Performs seek control to the target position on the recording medium from the output of the conversion circuit 5 and the output of the counter circuit 6. MPU
A D/A conversion circuit 8 that converts the control signal from 7 into an analog signal. Recording/recording by the output control signal of the D/A conversion circuit 8
A VCM drive circuit 9 for driving a VCM that moves a reproducing head (not shown) or the like. It consists of a reference information memory circuit 10 that stores reference information regarding speed control and positioning control.

Magnetic disk drives can be roughly divided into two methods: a method in which a seek control signal to a target position on a recording medium is controlled using an analog signal, and a method in which a seek control signal to a target position on a recording medium is controlled by digital processing. In addition, as a method of controlling by digital processing, there is a dedicated servo method that has a dedicated servo surface for seek control and performs seek control, as shown in Figures 1 and 2, and a method that uses position information recorded on the data surface. There is a data plane servo system that performs seek control using digital processing. Conventionally, when seeking control is performed using digital processing, the data plane servo system is generally adopted.

In addition, in the data side servo method, servo information can only be obtained intermittently, so the track number is written at the beginning of each sector that divides the trunk on the recording medium, and the instability of seek control makes it difficult to obtain the servo information. , correction can be easily made when the position is deviated from the target position.

On the other hand, in the dedicated servo system as shown in FIG.

Seek control to the target position on the recording medium is performed using control information created and output by the MPU 7 from the output of the A/D conversion circuit 5 and the output of the counter circuit 6. As shown by the dotted line in FIG. 2, the positioning start position is Due to the instability of the seek control, where the moving speed of the VCM (not shown) is not sufficiently decelerated, it may go too far and stop at the next track. If the track number is misaligned, the information corresponding to the track number is determined by the dedicated servo positioning device (not shown) and sought again.The process of the host device (not shown) at this time is a seek error process. There was a problem in that this was evaluated as a decrease in the processing performance of the magnetic disk device.

(d) Purpose of the Invention The object of the present invention is to provide a new magnetic disk device that solves the above problems, and particularly in a device that digitally processes seek control information and reads the seek control information from a dedicated servo surface. The object of the present invention is to realize a magnetic disk device that can prevent the occurrence of re-seek control that causes seek errors.

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1. A magnetic disk device that performs speed control and positioning control for positioning the magnetic head by digitally processing No. 1018, and monitors whether the magnetic head deviates from a positioning target position by a predetermined amount or more during positioning control. monitoring means, first switching means for switching to speed control in order to return to within the monitoring position when the deviation from the target position is greater than or equal to the monitoring position set by the monitoring means; In such a case, this can be achieved by a magnetic disk device characterized in that it is provided with a second switching means for switching to positioning control to prevent the occurrence of repositioning control which causes one positioning error.

(f) Examples of the invention The present invention will be explained below with reference to the drawings.

FIG. 4 shows a positioning control status diagram according to an embodiment of the magnetic disk device according to the present invention.

In the figure, 11 represents an analog positioning circuit, and 12 represents a switching circuit. Also, Figure 1.

The same symbols as in the second column indicate the same contents, and e and f are positional deviation correction start positions (positional deviation monitoring line).

g and h are position f where position signal C starts positional deviation correction.
Points that intersect with le are shown.

This embodiment uses the components explained in FIG. 1, the position signal C from the position signal generation circuit 5, and the MPI.
An analog positioning circuit 11 that performs positioning control while correcting the positional deviation between the stop position a and the current position based on the control signal from I7. MP selects whether to control from the analog positioning circuit 11 side or from the D/A conversion circuit 8 side.
It is composed of a switching circuit 12 that is switched by a control signal from U7.

Next, the operation of this embodiment will be explained.

The servo data read by servo head l is sent to amplifier 2.
The signal is amplified and output to the position signal generation circuit 3 and track crossing pulse generation circuit 4. The A/D conversion circuit 5 converts the position signal C into a digital signal and outputs it to the MPU 7.

The counter circuit 6 counts the track crossing pulse generation circuit 4 and outputs the counted number to the MPU 7.

Based on the input data, the MPU7 determines the current VCM (
(not shown) to understand the speed and control status.

Compare that data with the reference speed information and control information stored in the reference information memory circuit 10, and if the positioning control start position has not been reached, a speed error signal with respect to the reference speed is sent to the D/A converter. 8. V via switching circuit 12
Output to CM drive circuit 9.

Perform speed control.

Next, when the movement of the VCM (not shown) reaches the positioning control start position, the switching circuit 12 is switched to the analog positioning circuit 11 side under the control of the MPU 7, and the analog positioning circuit 11 performs positioning control. If, during this control, the predefined positional deviation monitoring line e is exceeded as shown in FIG. The speed is decelerated so that the position is within one position deviation correction start position e, and positioning control is performed again by the analog positioning circuit 11.

By switching the control method in this way, stable positioning is achieved. In this embodiment, 9 positional deviation correction start positions e,
f is placed at a position shifted by 1/4 track from the target stop position a.

(g) Effects of the Invention According to the present invention as described above, it is possible to provide a magnetic disk device that can prevent the occurrence of seek errors due to instability of seek control even in the case of the servo surface servo method. There is.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of seek control of a conventional magnetic disk device.
FIG. 2 shows an overview of positioning control, FIG. 3 shows an embodiment of the magnetic disk device according to the present invention, and FIG. 4 shows a state diagram of positioning control according to the present invention. In the figure, 1 is the servo head and 2 is the amplifier. 3 is a position signal generation circuit, 4 is a track crossing pulse generation circuit, 5 is an A/D conversion circuit, 6 is a counter circuit, 7 is a liver υ, 8 is a D/A conversion circuit, 9 is a VCM
10 is a reference information memory circuit, 11 is an analog positioning circuit, and 12 is a switching circuit. Dormitory 2 Town – Kuken 4th Show

Claims (1)

[Claims] A magnetic disk device that digitally processes a position signal indicating a moving position of a magnetic head and performs speed control and positioning control for positioning the magnetic head, wherein the magnetic head moves a predetermined distance from the positioning target position during positioning control. monitoring means for monitoring the deviation from the target position; first switching means for switching to speed control in order to return to the monitoring position when the deviation exceeds the monitoring position set by the monitoring means; a second switching means for switching to positioning control when the position has returned to within the monitoring position.