JPS6364681A - Positioning device for head of magnetic disk system - Google Patents

Abstract

PURPOSE:To simplify a device and to improve accuracy in terms of deciding the timing of controlling and switching, and a predetermined position by permitting a control part to digitally decide the occurrence of reference speed information, switching from a speed control to a position control and whether a magnetic head stays on a target or not. CONSTITUTION:According to moving instructions from the magnetic head 20, a CPU 70 converts 81 the reference speed information Drv to take for Vrv, amplifies the difference between plural Vs obtained by converting 63 outputs Vs from a position detection means 50 from frequency to voltage, changes over a switch 84 wit the aid of a control switching signal VP, drives a head motor 41, controls the moving speed of the head 20 and attains Vf = Vrv. The CPU 70 counts pulses Ps formed 62 from the position signals Vs, decreases Drv every track, calculates a distance up to the target from a signal Ds obtained by converting 61 the Vs and outputs Drp. The Vrp is converted 81 to amplify 83 the difference between plural Vs, and a phase is corrected 85 to attain Vs = Vrp. When the distance is less than the one pitch of a track, the switch 84 is changed over with the aid of the signal VP to control the position. If the drift lies within a permissible value in a prescribed time, a write control signal WC is outputted to permit writing on a disk. With this constitution, the device is simplified and accuracy in terms of positioning is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention provides an IF! The present invention relates to a head positioning device that moves a magnetic head in the radial direction of a magnetic disk to position it on a target track.

(Summary of the Invention) The present invention moves a magnetic head in contact with a magnetic disk in a magnetic disk system constituting a hard disk system such as a personal computer in the radial direction of the magnetic disk to position it on a target track. However, by using a position detection means such as an optical scale that can detect the position of the magnetic head with respect to the concentric trunk on the disk based on the output voltage, the magnetic head is detected from one track pitch with respect to the target trunk. Until the magnetic head reaches a position at a small predetermined distance, the moving speed of the magnetic head is controlled to decrease as it approaches the target track (11L), and when the magnetic head reaches a position at a predetermined distance from the target track, In a head positioning device that controls the position of a magnetic head so that the head is oriented on a target track, the output voltage of a position detection means is converted into digital data by an A/D converter and then supplied to a control section composed of a CPU. , the reference speed data or reference position data obtained from the control unit is converted into an analog voltage by a D/A converter to obtain a reference speed voltage or reference position voltage, and the control unit converts the output data of the A/D converter to the target trunk. By calculating the distance of By determining the timing of switching to control and determining whether or not the magnetic head is positioned on the target track, the apparatus is simplified and accuracy is improved.

(Prior Art) In a magnetic disk system that constitutes a hard disk system such as a personal computer, a magnetic head that contacts a magnetic disk is moved in the radial direction of the magnetic disk to position it on a target track. Using a position detection means, such as an optical scale, which can detect the position of the magnetic head with respect to concentric tracks on the disk using an output voltage, the magnetic head is positioned at a predetermined distance smaller than one track pitch from the target track. Until the position is reached, the moving speed of the magnetic head is controlled so that it decreases as it approaches the target track, and when the magnetic head reaches a position at a predetermined distance from the target trunk, the magnetic head is oriented on the target trunk. A method is being considered in which the position of the magnetic hand is controlled so as to

In this case, conventionally, a reference speed voltage generating circuit obtains a reference speed voltage of a value corresponding to the distance from the magnetic head to the target track, for example, a value proportional to the square root of the distance from the magnetic head to the target track. The moving speed of the head is controlled, and when the magnetic head reaches one track before the target track, a voltage comparison circuit compares the output voltage of the position detection means with a reference voltage, and the output voltage of the position detection means matches the reference voltage. Then switch from speed control to position control,
Thereafter, another voltage comparison circuit compares the output voltage of the position detection means with another reference voltage to determine whether or not the magnetic head is positioned on the target track.

(Problem to be Solved by the Invention) However, the conventional device generates a reference speed voltage, switches from speed control to position control, and determines whether the magnetic head is positioned on the target track. Since this is carried out using a dedicated analog circuit, the device becomes complicated, and it is difficult to determine the reference speed voltage obtained, the timing of switching from speed control to position control, and whether or not the magnetic head is positioned on the target track. Each method has the disadvantage of decreasing accuracy.

In view of this point, the present invention provides a magnetic disk system that includes:
Using a position detection means capable of detecting the position of the magnetic head with respect to a concentric trunk on the disk based on the output voltage, the magnetic head in contact with the magnetic disk is moved in the radial direction relative to the magnetic disk and placed on the target trunk. This head positioning device is designed to simplify the device and improve accuracy.

(Means for Solving the Problems) A head positioning device for a magnetic disk system according to the present invention is a head positioning device for a magnetic disk system that moves a magnetic head in contact with a magnetic disk having concentric tracks in the radial direction of the magnetic disk. a driving means; a position detecting means capable of detecting the position of the magnetic head with respect to the concentric trunk on the magnetic disk based on its output voltage; and an A/D converter that converts the output voltage of the position detecting means into digital data. , a control section to which the output data of this A/D converter is supplied, and a D/A converter that converts the reference speed data or reference position data obtained from this control section into an analog voltage; A unit supplies reference speed data to the D/A converter when the magnetic head starts moving to a target track on the disk, and calculates the speed based on the reference speed voltage obtained from the D/A converter. means for controlling the moving speed of the magnetic head, and receiving the reference speed data from the magnetic head after the magnetic head reaches one trunk ahead of the target track based on the output data of the A/D converter. means for determining whether the magnetic head has reached a position at a predetermined distance smaller than one track pitch with respect to the target trunk based on the output data of the A/D converter; a means for determining, when determining that the magnetic head has reached a position at the predetermined distance from the target track;
By supplying reference position data to the A converter, the above D/A
means for controlling the position of the magnetic head on the disk based on the reference voltage T obtained from the converter; means for determining whether the magnetic head is positioned on the target track by determining whether the output data of the /D converter remains within a predetermined range for a predetermined period of time; configured.

(Function) According to the head positioning device for a magnetic disk system according to the present invention configured as described above, generation of reference speed data, switching from speed control to position control, and positioning of the magnetic head on a target track can be performed. Judgments such as whether or not the target trunk This improves the accuracy of decisions such as whether or not a person has done something.

(Cumbersome) FIG. 1 shows an example of a head positioning device for a magnetic disk system according to the present invention.

A large number of annular trunks T are concentrically formed on the magnetic disk 10, and the magnetic disk 10 is driven to rotate at a rotational speed of, for example, 3600 revolutions per minute. The magnetic head 20 that comes into contact with the magnetic disk 10 is attached to a head arm 30.
When the head arm 30 is rotated about a shaft 31 by a head drive motor 41, it moves in the radial direction of the magnetic disk 10. The head drive motor 41 is rotationally driven by the output current of the motor drive circuit 42.

In connection with the head arm 30, a position detection means 50 composed of an optical scale or the like is provided, and the position detection means 50 detects a value that varies depending on the position of the magnetic head 20 with respect to the trunk T on the magnetic disk 10. , a voltage Vs whose repetition frequency changes depending on the moving speed of the magnetic head 20 is obtained. The output voltage Vs of the position detection means 50 is
The digital data D is supplied to the A/D converter 61.
Converted to S. Further, the output voltage V of the position detection means 50
s is supplied to the pulse forming circuit 62, and each time the output voltage Vs of the position detecting means 50 reaches a predetermined value, one magnetic head 20 crosses the track T on the magnetic disk 10. 1 pulse P per
s is obtained.

Furthermore, the output voltage Vs of the position detecting means 50 is supplied to a frequency/voltage converter 63, and the value changes according to the repetition frequency of the output voltage Vs of the position detecting means 50. 20
A voltage Vf whose value changes depending on the moving speed of is obtained.

Then, the output data Ds of the A/D converter 61 and the output pulse Ps of the pulse forming circuit 62 are supplied to a control section 70 including a CPU.

The control unit 70 outputs reference speed data Drv as described later.
Alternatively, reference position data Drp can be obtained.

This reference speed data Drv or reference position data Drp
are supplied to the D/A converter 81 and converted into reference speed voltage Vrv or reference position voltage Vrp, which are analog voltages, respectively. The reference speed voltage Vrv or reference position voltage Vrp obtained from the D/A converter 81 is supplied to differential amplifier circuits 82 and 83, and the output voltage Vf of the frequency/voltage converter 63 is supplied to the differential amplifier circuit 82 for position detection. The output voltage Vs of the means 50 is applied to the differential amplifier circuit 8.
3, the output voltage of the differential amplifier circuit 82 is supplied to the terminal V of a switch 84 in which the terminal m is switched to either side of the terminal V or the terminal p, and the output voltage of the differential amplifier circuit 83 is phase-corrected. It is supplied to the terminal p of the switch 84 through the circuit 85. A control switching signal VP for switching between speed control and position control as described later is obtained from the control section 70, and this control switching signal VP is supplied to a switching control terminal of a switch 84, and the control switching signal VP is supplied to a switching control terminal of a switch 84, and is switched depending on the level state of the control switching signal VP. Then, the terminal m of the switch 84 is switched to the terminal V side or the terminal P side, and the voltage obtained at the terminal m of the switch 84 is supplied to the motor drive circuit 42.

Data to be written to the magnetic disk IO by the magnetic head 20 is obtained from the terminal 91 and sent to the write control circuit 9.
2. A write control signal WC is obtained from the control unit 70 for controlling switching between a write permission state and a write prohibition state as described later, and this write control signal WC
is supplied to the write control circuit 92, and the write control circuit 92, depending on the level state of the write control signal WC,
It is switched to a write-enabled state in which data obtained at the terminal 91 is supplied to the magnetic head 20 or a write-inhibited state in which supply of data obtained at the terminal 91 to the magnetic head 20 is blocked.

FIG. 2 shows a control operation program executed by the control unit 70 to control the movement of the magnetic head 20 to the target track and the writing of data to the magnetic disk IO after the movement by the above-mentioned apparatus.

The control unit 70 starts with an operation or instruction to start moving the magnetic head 20 to the target track, and first in process 101 sets the control switching signal vp to a high level state, which is a speed control state, and switches the D/A converter to a high level state. 8
Reference speed data Drv is output to 1. Control switching signal v
By setting p to the light level state and supplying the reference speed data Drv to the D/A converter 81, the terminal m of the switch 84 is switched to the terminal V side, and the D/A converter is switched based on the reference speed data Dr■. Reference speed voltage Vrv obtained from 81 and frequency/voltage converter 63
The voltage difference between the output voltage Vf of So that the moving speed is equal to the reference speed determined by the reference speed data 1) rv,
The moving speed of the magnetic head 20 is controlled. The reference speed data Drv is set to sufficiently increase the reference speed at the beginning as shown in FIG. 3, and therefore the moving speed of the magnetic throat 20 is set to be sufficiently high at the beginning.

The control unit 70 then proceeds to process 102 to count the output pulses Ps of the pulse forming circuit 62, and further proceeds to decision 103 to determine from the count value of the pulses PS that the magnetic head 20 has reached a track a predetermined number of times before the target track. If it is determined that the magnetic head 20 has reached a track a predetermined number of times before the target trunk, the process proceeds to process 104 and sets the reference velocity data [lrv to 1].
Decreasing for each track. By decreasing the reference speed data [)rv for each track, the reference speed voltage V
rv decreases track by track, and the moving speed of the magnetic head 20 gradually decreases. The control unit 70 then proceeds to the digital controller 105 and determines whether the magnetic head 20 has reached one track ahead of the target track based on the count value of the pulse Ps, and determines whether the magnetic head 20 has reached one track ahead of the target trunk. When it is determined that this is the case, the process proceeds to process 106 where the distance to the target track is calculated from the output data Ds of the A/D converter 61, and the reference speed data Drv output to the D/A converter 81 is calculated based on the distance to the target track. Make it compatible with.

The control unit 70 further proceeds to decision 107 to determine whether A/
From the output data Ds of the D converter 61, the magnetic head 20
determines whether it has reached a position at a predetermined distance smaller than one track pitch from the target track, and when it is determined that it has reached a position at a predetermined distance from the target track, the process proceeds to process 108, where the control Switching signal vp is position system'<n
At the same time, the basic position data Drp is output to the D/A converter 81 in place of the reference speed data Drv. The basic position data Drp corresponds to the output voltage VsO value of the position detection means 50 when the magnetic head 20 is located on the track T of the magnetic disk 10, and such reference position data Drp is 81 and the control switching signal vp is set to a low level state, the terminal m of the switch 84 is switched to the terminal p, and the reference value of the predetermined value obtained from the D/A converter 81 based on the reference position data Drp is switched. Position voltage Vrp and output voltage Vs of position detection means 50
The difference voltage from the differential amplifier circuit 83 to the phase correction circuit 85
is supplied to the motor drive circuit 42 through be done.

FIG. 4 shows that at time t0, the magnetic throat 20 reaches a position at a predetermined distance smaller than one track pitch from the target track, and the speed control is switched to the position control.

When switched to position control, the position detection means 5 is shown in FIG.
As shown by the oscillating change in the output voltage Vs of 0, the magnetic head 20 approaches the target track while undergoing damped oscillation. Then, the control unit 70 executes the decision 1 after the process 108.
Proceeding to step 09, the output data Ds of the A/D converter 61 is
It is determined whether the magnetic head 20 is positioned on the target track by determining whether or not the magnetic head 20 remains within the specified range for a predetermined period of time, and the output data Ds of the A/D converter 61 continues for a predetermined period of time. When it is determined that the magnetic head 2o is within the specified range, the movement of the magnetic head 2o to the target trunk is completed. Figure 4 shows time point 1. Although the output voltage Vs of the position detecting means 5° after the odor data Ds fell within the predetermined range, the point 1. The output voltage Vs once deviates from the predetermined range at time t2, which is not a predetermined time interval from t2, and at time t3, the output voltage Vs again falls within the predetermined range, and the output voltage Vs returns to the predetermined range at time t3.
This indicates that it has been determined that the magnetic head 20 has been positioned on the target track at time t4 after a predetermined time period has elapsed since then.

Even if the magnetic head 20 is positioned on the target track in this manner, the magnetic head 20 may be deviated from the target trunk due to vibrations applied to the magnetic disk system. Therefore, the control section 70 performs a decision 111 after the movement of the magnetic head 20 to the target track is completed.
Then, by calculating the distance between the magnetic head 20 and the target trunk from the output data Ds of the A/D converter 61, it is determined whether the deviation of the magnetic head 20 from the target track is less than the allowable value. However, when it is determined that the deviation of the magnetic head 20 from the target track is less than the allowable value, the process proceeds to process 112, where the write control signal WC is
By setting the terminal 91 to a high level state, writing of the data obtained at the terminal 91 to the magnetic disk 10 is permitted, and when it is determined that the deviation of the magnetic head 20 from the target track exceeds a permissible value, the process proceeds to process 113. By setting the write control signal WC to a low level state, writing of data obtained at the terminal 91 to the magnetic disk 10 is prohibited.

(Effects of the Invention) As is clear from the above, according to the present invention, it is possible to simplify the device and improve accuracy9.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a head positioning device for a magnetic disk system according to the present invention, FIG. 2 is a flowchart showing a control operation program executed by the control unit, and FIG. 3 is a diagram showing the relationship between the position of the magnetic head and the reference speed. FIG. 4, which is a diagram showing the relationship, is a diagram showing the state of control switching and localization determination of the magnetic head. In the figure, IO is a magnetic disk, 20 is a magnetic head, 30 is a helad arm, 41 is a head drive motor, 50 is a position detection means, 61 is an A/D converter, 70 is a control unit, 81
is a D/A converter.

Claims (1)

[Scope of Claims] Head driving means for moving a magnetic head in contact with a magnetic disk having concentric tracks in the radial direction relative to the magnetic disk; a position detecting means capable of detecting the position relative to the concentric track; and an A/D converting the output voltage of the position detecting means into digital data.
a converter, a control section to which output data of the A/D converter is supplied, and a D converter that converts reference speed data or reference position data obtained from the control section into an analog voltage.
/A converter, the control unit supplies reference speed data to the D/A converter when the magnetic head starts moving to the target track on the disk, and the control unit supplies reference speed data to the D/A converter so that reference speed data is obtained from the D/A converter. means for controlling the moving speed of said magnetic head based on a reference speed voltage; and said reference after said magnetic head reaches one track ahead of said target track based on output data of said A/D converter. means for making velocity data correspond to the distance from the magnetic head to the target track; and a position of the magnetic head at a predetermined distance smaller than one track pitch from the target track based on the output data of the A/D converter. means for determining whether the magnetic head has reached the predetermined distance from the target track, supplying reference position data to the D/A converter, means for controlling the position of the magnetic head on the disk based on a reference position voltage obtained from a D/A converter, and after the magnetic head reaches a position at the predetermined distance from the target track; means for determining whether the magnetic head is positioned on the target track by determining whether the output data of the A/D converter remains within a predetermined range for a predetermined period of time; Head positioning device for magnetic disk systems.