JPH03201272A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To automatically adjust the seek time to standards by changing the detection gain of a speed detecting means, which detects the movement speed of a magnetic head, to change the actual movement speed of the magnetic head. CONSTITUTION:A head arm 2 is used as the magnetic head driving means which drives a magnetic head 4 in the disk diametrical direction. The speed detecting means which detects the movement speed of the magnetic head 4 and is freely varied the detection gain consists of a head position detecting sensor 6, amplifying circuits 16 to 18, 27, and 28, capacitors 25 and 26, inverting amplifying circuits 29 and 30, comparing circuits 21 and 22, a multiplexing circuit 20, and a gain control circuit 33. The error between a speed profile output and the output of the magnetic head movement speed detecting means whose detection gain is freely varied is detected to seek a prescribed number of tracks by the magnetic head 4, and the detection gain of the movement speed detecting means of the magnetic head 4 is so adjusted that the seek time at this time satisfies standards. Thus, the seek time is automatically adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to magnetic disk drives, and particularly to automation of seek time adjustment of magnetic disk drives.

B0 Summary of the Invention The present invention provides a magnetic head driving means for driving a magnetic head in the disk radial direction, a speed detecting means with variable detection gain for detecting the moving speed of the magnetic head, and a magnetic head driving means for driving a magnetic head in the disk radial direction, a speed detecting means for detecting the moving speed of the magnetic head and having a variable detection gain, and detecting the current magnetic head position and a target track. a profile generation means for generating a velocity profile output according to the difference in position; and a drive control means for controlling the magnetic head drive means according to the difference between the velocity detection output from the velocity detection means and the velocity profile output from the profile generation means. , seek time measuring means for measuring the time it takes for the magnetic head to seek a predetermined number of tracks using a predetermined speed profile output from the profile generating means; and control means for controlling the detection gain of the speed detecting means based on the output of the seek time measuring means. and so that the seek time when controlling the magnetic head to seek a predetermined number of tracks satisfies the standard while detecting the error between the predetermined speed profile output and the output of the magnetic head movement speed detection means. Furthermore, the detection gain of the magnetic head moving speed detection means is automatically adjusted.

C1 Conventional technology In a magnetic disk drive, a magnetic disk is rotated by a spindle motor, and recording tracks are formed on the recording layer of the disk surface of the magnetic disk to record data, for example, concentrically or spirally. ing.゛When recording or reproducing data on a magnetic disk, the magnetic head is moved at high speed to the target recording track (
After performing the seek operation, control is performed such that the magnetic head scans the center of the recording track (tracking control all).

In order to make the magnetic head seek at high speed in this way,
The moving speed of the head arm carrying the magnetic head is controlled according to the distance from the current head position to the target track, that is, the number of tracks that need to be moved, and the disk of the magnetic head mounted at the tip of the head arm is controlled. The movement speed in the radial direction is controlled.

For example, when the target track is far away, as shown in Figure 5, the magnetic head is accelerated to the maximum acceleration to a constant speed (usually the maximum speed), and then the number of remaining tracks remains constant until the predetermined number of tracks is reached. The magnetic head is moved at a certain speed, and after the number of remaining tracks becomes less than a predetermined number of tracks, it is decelerated at a predetermined acceleration.In other words, while detecting the speed of the magnetic head, the speed is inversely proportional to the number of remaining tracks. Then, the magnetic head is positioned at the center of the target track while detecting the position of the magnetic head. Control the movement of the magnetic head to
In this case, the seek time is the time from when the magnetic head starts accelerating until the speed reaches zero. Note that the settling time is the time from when the speed becomes zero until the magnetic head is positioned at the center of the target track.

For example, when the target track is close, the magnetic head is accelerated at the maximum acceleration as shown in Figure 6, and after the number of remaining tracks becomes less than a predetermined number of tracks, it is decelerated at a predetermined acceleration. In other words, while detecting the speed of the magnetic head, for example, the speed is reduced to be inversely proportional to the number of remaining tracks, and the speed is controlled to be zero near the target track, and then the position of the magnetic head is detected. However, the movement of the magnetic head is controlled so that the magnetic head is positioned at the center of the target track.Problems to be Solved by the InventionThe above-mentioned seek time is, for example, the time required to record data in a magnetic disk device or This greatly influences the access time, which is one of the important performances during playback, and a standard has been established for this seek time. Therefore, in the manufacturing process of a magnetic disk device, for example, the seek time when the magnetic head seeks 1/3 of the disk radius is sufficiently adjusted so that it falls within a predetermined standard value, and the adjusted magnetic disk device is shipped. .

Conventionally, seek time adjustment has been done manually using a volume control, and the weight of the head arm, the torque of the motor that drives the head arm, the output of the head position detection sensor, etc. vary among individual magnetic disk drives. ,
This required a lot of man-hours for adjustment, leading to an increase in manufacturing costs. Also, the volume was inferior in reliability compared to ordinary resistors.

The present invention has been made in view of the above circumstances, and eliminates the need for manual steps to adjust the seek time of magnetic disk drives, and eliminates the influence of variations in the weight of helad arms among individual magnetic disk drives. An object of the present invention is to provide a magnetic disk device which can automatically adjust the seek time without any trouble and has higher reliability.

80 Means for Solving the Problems A magnetic disk drive according to the present invention includes a magnetic head driving means for driving a magnetic head in the disk radial direction, and a speed detecting means having a variable detection gain for detecting the moving speed of the magnetic head. and a profile generating means for generating a speed profile output according to the difference between the current magnetic head position and the target track position, and a profile generating means for generating a speed profile output according to the difference between the speed detection output from the speed detecting means and the speed profile output from the profile generating means. a drive control means for controlling the magnetic head drive means, a seek time measurement means for measuring the time it takes for the magnetic head to seek a predetermined number of tracks based on a predetermined velocity profile output from the profile generation means; and the seek time By having a control means for controlling the detection gain of the speed detection means based on the output of the measurement means, the above! ll! solve the problem.

F5 action The magnetic disk drive according to the present invention allows the magnetic head to seek a predetermined number of tracks while detecting the error in the output of the moving speed detection means of the magnetic head whose speed profile output and detection gain are variable. The detection gain of the magnetic head movement speed detection means is adjusted so that the seek time satisfies the standard.

G. Embodiment Hereinafter, an embodiment of a magnetic disk device according to the present invention will be described with reference to the drawings. FIG. 1 is a block circuit diagram of a magnetic disk device according to the present invention.

In FIG. 1, for example, disk surfaces 3A and 3 of two magnetic disks 3 are placed at one end of the Y-shaped helad arm 2.
Magnetic heads 4A and 4 scan B, 3C and 13D, respectively.
B, 4C14D is installed.

Each disk surface 3A, 3B, 3C of the magnetic disk 3,
3D, recording tracks TRI to TR4 corresponding to each phase of the head position detection sensor 6, which will be described later, are sequentially and cyclically formed. That is, each recording track TRI to TR
In order to detect the positions of the magnetic heads 4A, 4B, 4C14D with respect to the recording tracks TR1-TR4, a position detection signal consisting of, for example, four phases is used, and each phase of this position detection signal detects the position of the magnetic heads 4A, 4B14C2 with respect to each recording track TR1-TR4.
It shows the positions of each of the 4D.

The head arm 2 rotates around a rotating shaft 5, thereby moving the magnetic nozzles 4A, 4B, and 4C14D (hereinafter referred to as magnetic heads 4) as one body in the radial direction of the magnetic disk 3. A large number of recording tracks TR formed concentrically on each disk surface 3A, 3B, 3C13D (hereinafter referred to as disk surface 3) of the magnetic disk 3.
Tracking control of the magnetic head 4 can be performed on I to TR4.

On the other hand, the other tip 2B of the helad arm 2
A head position detection sensor 6 is provided. The head position detection sensor 6 is configured to transmit light emitted from a light source 7 to a reticle 9 through a scale 1o attached to the tip of the head arm 2 via a lens 8, and the transmitted light is transmitted to, for example, five photoelectric sensors. The light is guided to an optical sensor 11 composed of a conversion element.

The reticle 9 and the scale 1o each have slits at predetermined intervals, and when the position of the scale 10 with respect to the reticle 9 changes with the rotation of the head arm 2, the optical sensor 11 is detected through the reticle 9 and the scale 1°. The amount of light incident on each photoelectric conversion element is changed.

That is, as the magnetic head 4 is moved in the radial direction of the disk, the recording tracks TRI to TR4 of the magnetic head 4 are
Detection signals DET+, DETz,
DETs and DET4 can be obtained from four charging conversion elements among the five photoelectric conversion elements. For example, when the magnetic head 4 moves inwardly or outwardly across the recording tracks TRI to TR4 at a constant speed, the signal level sequentially changes into a triangular waveform having a phase difference of 90 degrees, as shown in FIG. Then, the position WT1 corresponding to the phase that crosses the 0 level in an upward direction to the right,
The slits are formed such that T2, T3, and T4 roughly track the magnetic head 4 sequentially to four adjacent recording tracks TRI to TR4, respectively. Therefore, when the head arm 2 is rotated, the detection signal DET,
~DET.

By detecting the point in time when the magnetic head 4 crosses the O level in an upwardly rightward direction, it is possible to detect that the magnetic head 4 is located at positions TIT2, T3, and T4, respectively. Furthermore, by obtaining differential signals of the detection signals DET, ~DET, from the head position detection sensor 6, the moving speed of the head arm 2 when the head arm 2 is rotated, that is, the moving speed of the magnetic hand 4 can be determined. can be detected.

Based on the above measurement principle, the multiplex circuit l
1s15 receives the detection signals DET, -DET through the amplifier circuits 16, 17, 18, and 19, selects a detection signal for one phase that maintains linearity on the target track, and outputs the selected output to the position. It is output as a detection signal S.

The multiplex circuit 20 also includes a capacitor 25.2.
6 and the amplifier circuit 16, I7 via the amplifier circuit 27.2B.
These detection signals DET, 5DET,
The magnetic head 4 receives the differential signal and receives the inverted differential signal of the differential signal via the inverting amplifier circuits 29 and 30, selects a differential signal with linearity and correct directionality, and sends the selected output to the recording track by the magnetic head 4. It is output as a speed detection signal Sv representing the speed of crossing. The control circuit 40 amplifies or attenuates the speed detection signal Sv by controlling the gain of a gain control direction l1133 configured with an amplifier, for example, and supplies the amplified or attenuated speed detection signal Svz to the addition circuit 44. .

Note that the selection control of the multiplex circuit 20 is performed by control signals from the comparison circuits 21 and 22. That is, the detection signals D obtained through the amplifier circuits 16 to 18 in the comparison circuits 21 and 22, respectively.
ET, ~DET, and the resulting signal level rises every time the magnetic head 4 crosses four recording tracks, resulting in two control signals S whose phases are 180 degrees different from each other.
Selection control of the multiplex circuit 20 is performed using Tl and ST□. Further, the track cross pulse generation circuit 31 generates control signals ST+, ST+, which have different phases from each other.
A recording track count signal ST3 whose signal level rises every time the magnetic head 4 crosses one recording track is generated using St
i is output to the control circuit 40.

Thus, in this embodiment, the helad arm 2 is used as a magnetic head driving means for driving the magnetic helad 4 in the disk radial direction, and is used as a speed detecting means with a variable detection gain for detecting the moving speed of the magnetic head 4. is composed of the head position detection sensor 6, amplifier circuits 16 to 18, 27, 28, capacitors 25, 26, inverting amplifier circuits 29, 30, comparison circuits 21, 22, multiplex circuit 20, and gain control circuit 33. .

Incidentally, the detection signal DET obtained from the remaining photoelectric conversion element of the optical sensor 11 is fed back to the light source 7 via the amplifier circuit 32, thereby maintaining the light intensity of the light source 7 at a predetermined value. is being done.

When the control circuit 40 having an arithmetic processing circuit configuration receives an instruction (command) for automatically adjusting the seek time from the control device 60, it sends a switching signal Sc! to the selection circuit 41. output,
For example, after switching the contacts by setting the switching signal Set to a high level (hereinafter referred to as H level), the magnetic head 4 outputs a speed control signal SVC having a blow isle as shown in FIG. 3, for example, according to the number of tracks sought by the controller. This results in
The control circuit 40 moves the magnetic head 4 toward the target recording track. Specifically, the adder circuit 44 is configured to receive the speed control signal Sv and the speed detection signal Sv□, and thereby the actuator is set so that the error signal obtained via the adder circuit 44 becomes O level. (not shown) to move the magnetic head 4.

Furthermore, at this time, the control circuit 40 outputs the recording track count signal S from the track cross pulse generation circuit 31.
By outputting a speed control signal Sv (based on T3), the magnetic head 4 is moved to the target recording track while counting the number of recording tracks crossed by the magnetic head 4 (hereinafter referred to as speed control mode). ).Thus, in this embodiment, the profile generating means for generating a velocity profile output according to the difference between the current magnetic head position and the target track position is composed of the control circuit 40 and the D/A converter 43, and A drive control means for controlling the magnetic head drive means according to the difference between the speed detection output from the detection means and the speed profile output from the profile generation means is composed of the addition circuit 44 and the selection circuit 41.

When the magnetic head 4 approaches the target recording track, the control circuit 40 outputs a switching signal SC2 to the selection circuit 41,
For example, after switching the contact by setting the switching signal SC2 to a low level (hereinafter referred to as L level), the D/
A position control signal SPC is output via the A conversion 843.

The adding circuit 48 receives the position control signal SFC and the position detection signal S, and transmits the resulting error signal to the integrating circuit 49.
, is output to the actuator via the phase compensation circuit 51. As a result, the magnetic head 4 is moved to a position where the error signal obtained through the adder circuit 4 reaches the O level, for example, a position TI corresponding to the phase where the detection signal DET crosses the 0 level.
(hereinafter referred to as position control mode).

In the above-described operation, the control circuit 40 uses an internal timer circuit to measure the time from when the switching signal SCZ is set to the H level until it is set to the L level, that is, the seek time. Thus, in this embodiment, the control circuit 43 is used as seek time measuring means for measuring the time it takes for the magnetic head 4 to seek a predetermined number of tracks based on the predetermined velocity profile output from the profile generating means.

Next, the control circuit 40 determines whether the time required for the magnetic head 4 to seek 1/3 of the disk satisfies the standard, for example, and if the time does not satisfy the standard, the control circuit 40 controls the gain of the gain control circuit 33. The speed detection signal Sv is controlled to amplify or attenuate, and the above seek time measurement operation is repeated until the seek time falls within the standard. Thus, in this embodiment, the control circuit 43 is also used as a control means for controlling the detection gain of the speed detection means based on the output of the seek time measurement means.

For example, as shown in FIG. 4, the gain control circuit 33 includes an amplifier 60, a feedback resistor 61 consisting of a ladder resistor, and analog switches 62 to 65. The control circuit 40 is
By turning on or off the analog switches 62 to 65, the resistance value between both ends of the feedback resistor 61 is changed, and the gain of the amplifier 60 is changed.

Specifically, the control circuit 40 first turns off all the analog switches 62 to 65, that is, the gain control circuit 3
3 is set to the maximum, in other words, the speed of the magnetic head 4 is set to the minimum, and the speed control signal Svc having the profile shown in FIG. is output to the adder circuit 44 to cause the magnetic head 4 to seek a specified number of tracks, for example, 173 tracks of the disk radius. Then, the seek time at this time is measured. When the seek time is longer than the specified time, the analog switches 62 to 65 are turned on in sequence to increase the speed of the magnetic head 4, and the above-described operation is repeated until the seek time reaches the specified value.

As is clear from the above explanation, by changing the detection gain of the speed detecting means for detecting the moving speed of the magnetic head 4 and changing the actual moving speed of the magnetic head 4, the predetermined number of tracks can be adjusted. The seek time (seek time) can be adjusted to within the standard. In addition, the control circuit 40 is configured with a microcomputer or the like, and the control circuit 40
By storing the operation for adjusting the seek time described above, the seek time can be automatically adjusted.

In other words, even if there are variations in the weight of the head arm 2, the torque of the motor that drives the head arm 2, the output of the head position detection sensor 6, etc. in individual magnetic disk drives, the seek time can be automatically adjusted. becomes. Moreover, by achieving automation as described above, the number of man-hours for seek time adjustment can be reduced, and manufacturing costs can be reduced. Furthermore, reliability can be improved by eliminating volume.

Note that it is also possible to consider a method of changing the actual speed of the magnetic herad 4 by changing the speed profile output described above, that is, the gain of the D/A converter 43. In a circuit configuration in which the device 43 is used also in the position control mode, even the loop gain of the control system in the position control mode changes. Therefore, by adopting a circuit configuration that can change the gain for detecting the speed of the magnetic helad 4 as in the present invention, only one D/A* converter is required, which is economically advantageous. Furthermore, since the volume is not used to adjust the seek time, reliability can be improved compared to the conventional method.

H1 Effects of the Invention As is clear from the above explanation, the present invention changes the seek time by changing the detection gain of the speed detection means for detecting the moving speed of the magnetic head to change the actual moving speed of the magnetic head. can be adjusted within the specifications.

Furthermore, automation can be achieved by adjusting and controlling the seek time using a control circuit composed of, for example, a microcomputer.

In other words, in each magnetic disk drive, the weight of the head arm, the torque of the motor that drives the head arm,
Even if there are variations in the output of the head position detection sensor, it is possible to automatically adjust the seek time. Moreover, by achieving automation as described above, the number of man-hours for seek time adjustment can be reduced, and manufacturing costs can be reduced. Furthermore, reliability can be improved by eliminating volume.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram of a magnetic disk device according to the present invention, FIG. 2 is a diagram showing the relationship between recording tracks and magnetic head position detection signals, and FIG. 3 is a diagram showing a speed profile. FIG. 4 is a specific circuit diagram of the gain control circuit, and FIGS. 5 and 6 are diagrams showing the speed of the magnetic head during seek. 4A, 4B, 4C14D...Magnetic helad 6...Head position detection sensor 15.20...Multiplex circuit 21.22...Comparison circuit 25.26...Capacitor 31...Track cross pulse Generation circuit 33...gain control circuit 40...control circuit 41...selection circuit 43...D/A converter 44.48...addition circuit

Claims (1)

[Scope of Claims] A magnetic head driving means for driving the magnetic head in the disk radial direction, a speed detecting means having a variable detection gain for detecting the moving speed of the magnetic head, and a current magnetic head position and a target track position. profile generating means for generating a speed profile output according to the difference between the two; and a drive control for controlling the magnetic head driving means according to the difference between the speed detection output from the speed detecting means and the speed profile output from the profile generating means. means, seek time measuring means for measuring the time it takes for the magnetic head to seek a predetermined number of tracks based on a predetermined speed profile output from the profile generating means; and detection by the speed detecting means based on the output of the seek time measuring means. 1. A magnetic disk device comprising: control means for controlling gain.