JPH03288380A - Writing position control system for servo signal - Google Patents

Abstract

PURPOSE:To write a servo signal in a proper position by detecting the abutting position of a magnetic head and a stopper in a head disk assembly and correcting the data at a standard position set in advance toward respective tracks. CONSTITUTION:The magnetic head is moved by controlling a VCM driving mechanism 32 with the standard position in a memory 42 as a target in respect to the track set at the outer-most periphery of a magnetic disk. A voltage to be supplied to the driving mechanism 32 is monitored by a VCM voltage detector 44, and the movement distance of the head is measured by a laser range finder 36a. The abutting position of the stopper and the head is calculated by subtracting the returning amount of the head caused by the elasticity of the stopper which is measured in advance, from the measured distance of the range finder 36a when the supply voltage is rapidly increased to the peak. With this calculated position as the servo signal writing position of the track set at the outermost periphery, all the standard positions of the tracks in the memory 42 are corrected, and the servo signal is written in the position.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for controlling the writing position of a servo signal, and more specifically, the present invention relates to a method for controlling the writing position of a servo signal, and more specifically, a servo signal is written to a magnetic disk of a head disk assembly (hereinafter abbreviated as HDA) by a servo writer. This method controls the position of the magnetic head with respect to the track during writing.

[Prior Art] A hard magnetic disk device used in an information processing device is
Due to the miniaturization of parts, it has been grouped into HDA. Figure 3 (
Figure a) shows a perspective external view of the HDA, and figure (b) shows a plan view. In the HDAI shown in FIG. 1A, a plurality of hard magnetic disks (hereinafter simply referred to as magnetic disks or disks) +2 are mounted on a spindle 13 inside a housing 11 and rotated by a rotation mechanism 2. A magnetic head 14a and a support arm 14b are provided for both the front and back surfaces of each disk 12, and the support arm 14b is attached to a common support rod 15 and rotated by a horizontal VCM drive machine 16, and each magnetic head 14a corresponds to the support arm 14b. Seek to a track on the disk.

In order to limit the seek range within the effective range of the disk 12, a positioning arm 17 is provided on the support rod 15, and a rubber outer stopper 18a and an inner stopper + are provided on the drive mechanism 16.
8b are provided respectively. In Figure (b), the center of each disk 12 is 01, the radius of the outer peripheral edge Eg is Le
And the radius Ls excluding the unused ΔL from the edge Eg
An outer stopper 14a is provided at a position, and this position is set as the outermost track, and a minute track, for example,
A large number of tracks TR are set at intervals of a pitch p of μm. When accessing data, the computer of the magnetic disk device reads the position data of each track stored in the memory, the magnitude and supply time of the voltage supplied to the drive mechanism 16, and rotates the drive mechanism 16 according to this. Then, the magnetic head +4b seeks the designated track.

Now, in order to access data, it is necessary to position the magnetic head 14a at the correct position with respect to the track, and for this purpose a servo system is used. There are various servo methods, but in this case, it is called a data surface servo method, in which a servo signal is written in advance at a position corresponding to each track on each disk by a servo writer, and this is used when accessing data. A readout and position control mechanism allows the magnetic head to correspond correctly to the track.

FIG. 3(C) shows a schematic structure of the writing mechanism 3 of the servo writer for HDAI. VC on base board 31
The M drive mechanism 32 is fixed, and the drive arm 34 is attached to the rotating shaft 33 that rotates thereby. Drive arm 3
A drive pin 35 is attached to the tip of the drive pin 3, and a mirror 3Gb is attached to the side surface of the drive pin 35. Further, a laser distance meter 36a is fixed to the base board 31, and the moving distance of the drive arm 34 is measured by interference of laser reflected light from the mirror 3Gb. When writing a servo signal, the HDAI is positioned and attached to the writing mechanism 3. As shown in FIG. 3(b), the housing 11 of the HDAt is provided with an arcuate cutout hole 19 at a position corresponding to the support arm +4b, through which the drive bin 35 is supported. It abuts against the side surface of arm 14b. Under the control of the microprocessor, the horizontal VCM driver 32 rotates the rotary shaft 33, and the magnetic head 14b seeks the designated track as described above. The position of the magnetic nodule during the seek is measured by a laser distance meter, and when it is confirmed that it is at the predetermined track position, the drive mechanism 32 is stopped, and the servo writer performs servo control on the sought track. It is used to write signals.

[Problem to be Solved] In the above writing, the standard position of each track is set in advance starting from the position Le of the outer stop and pad 18a and stored in the memory, and this is read out and transferred to the magnetic nozzle 14b.
However, there is a problem with the position of the outer stopper 18a provided on the HDAI. In other words, the installation of the struts and pads 18a and 18b is performed using the HDAI
This is done during the assembly work, and once the work is completed, the lid is attached to the casing +1, and after that, in principle, it is unnecessary to modify the interior. However, the mounting position of each Strason River 8 is not particularly accurate and varies considerably, and since it is made of rubber, it is elastic.

In even more severe cases, the stopper 18a or 18b may be missing. Due to these factors, it is inevitable that the stop position of the door 14a becomes uncertain due to the magnetism. As described above, the start position of the magnetic access operation is the position where the magnetic head contacts the outer stopper 18a, and if the magnetic head stops outside this position, it is considered that the access operation is defective. Become.

On the other hand, the standard position preset in the servo writer does not match this contact position, and therefore the servo signal writing position becomes defective. Therefore, a method is needed to accurately detect the contact position, calibrate a standard position stored in a memory, and write a servo signal to the calibrated position. In the above description, the mounting position of the inner stopper 18b is not a problem because there is a certain amount of leeway.

This invention was made in view of the above, and detects the contact position between the magnetic head and the stopper, calibrates the standard position data for each track set in advance, and writes the servo signal at the correct position. The purpose of this invention is to provide a write position control method that can perform the following steps.

[Means for Solving the Problems] The present invention provides a plurality of hard magnetic disks, magnetic heads,
and a microprocessor, a VCM drive mechanism that drives the magnetic head under the control of the microprocessor, and a stopper that limits the seek range of the magnetic head to the effective range of the disk. This is a write position control method in a servo writer that has a laser distance meter that measures the moving distance of a magnetic head, and that is equipped with an HDA and writes servo signals to each magnetic disk using the magnetic head. A VCM drive mechanism is controlled to move the magnetic head to a standard position previously stored in memory with respect to a track set on the outermost circumference of the magnetic disk.

The voltage supplied to the VCM drive mechanism during movement is monitored, and the distance traveled by the magnetic head is measured using a laser distance meter. By subtracting the previously measured return amount of the magnetic head due to the elasticity of the stopper from the distance measured by the laser rangefinder at the time when the supply voltage suddenly increases and reaches its peak value, the contact between the stopper and the magnetic head can be calculated. The contact position is calculated. Using this as the servo signal writing position for the outermost track, the standard positions of all tracks including the outermost track stored in the memory are calibrated. A servo signal is written to each calibrated position by a servo writer.

[Operation] In the above-described servo signal writing position control method, the magnetic head is moved by the VCM drive mechanism, aiming at a standard position with respect to the outermost track, which is stored in advance in the memory. The point in time when the supply voltage to the VCM drive mechanism being monitored during this movement suddenly increases and reaches its peak value is detected, and the elasticity of the stopper measured in advance is determined from the distance measured by the laser rangefinder at this point. The contact position between the stopper and the magnetic head is calculated by subtracting the return amount of the magnetic head. This is the writing position of the servo signal for the track set on the outermost circumference of the magnetic disk, and the standard positions of all the tracks stored in the memory are calibrated. In writing servo signals, each track is correctly positioned by a calibration position, and a servo signal is written to each track by a servo writer.

[Example] Figures 1 (a), (b), and (c) are block diagrams of the main parts of the servo writer and detection of the contact position in an example of the servo signal writing position control method according to the present invention. 3 is a method and a table of standard and calibration positions stored in memory.

In FIG. 1(a), 3 is a writing mechanism of the servo writer of FIG. 3(C) described above, and a signal processing section 4 is provided for this. In the signal processing section 4, standard position data for each track is stored in a memory 42. Prior to writing the servo signal, the microprocessor (MPU) 41 reads standard position data for the outermost track, and sends the necessary data to the vCM control circuit 43. This reduces the supply voltage to VC
The magnetic head 14b is supplied to the M drive mechanism 32 to rotate the rotating shaft 33, and the magnetic head 14b is rotated as described in FIG.
moves. During this movement, the supply voltage is monitored by the VCM voltage detector 44 and the monitoring data is transferred to the A/D converter 45.
The data is digitized and transferred to the MPU 41. At the same time, the moving distance of the mirror 3Gb attached to the support arm 3Gb is measured by the laser distance meter 3Ga, and the measurement data is digitized by the A/D converter 46 and sent to the MPU.
41, and is transferred to the magnetic head 14a by an appropriate calculation formula.
is converted into the distance traveled. Now, as the magnetic head 14a moves, the positioning arm 17 provided on the HDAI moves to the outer stopper 18a (both shown in FIG. 3(a) or (b)).
)), each support arm 14b1 support rod 1
5 and the elasticity of the rubber of the stopper 18, the surface of the stopper 18a is depressed and the positioning arm 17 is press-fitted into the rubber to some extent, and then returns to the abutting position and stops. The position into which this positioning arm is press-fitted is measured by the laser distance meter 36a. The key point of this invention is the method of measuring this press-fitting position. In other words, it focuses on the fact that the voltage supplied to the VCM drive mechanism rapidly increases due to the above-mentioned movement of the positioning arm. In Figure (b), the horizontal axis represents the moving distance of the head, and the vertical axis represents the VCM voltage ( Supply voltage) e is shown. Generally, when moving a magnetic head and stopping it at a predetermined position, the speed is gradually increased initially, and once a constant speed is reached, this is maintained until just before the stop position, and then the magnetic head is gradually decelerated and stopped. . For this reason, the supply voltage e increases dramatically as shown! ! It is controlled as ((+) of a constant value eo following (()) and descending (c). Now, if the abutment position of the positioning arm 17 and the stopper 18a is La, it is controlled against the elasticity of the rubber. In order to press-fit the arm, more pressure than before is required.
The supply voltage e rises rapidly and becomes a curve with a peak value e■. From then on, it will continue unless the supply voltage is stopped (
(ne), or lower the voltage to F
It is something that rains. Note that when the stopper 18a is missing, the constant value eQ continues, so that the missing can be detected. As a result of the above, it is assumed that the positioning arm 17 is press-fitted into the stopper 18a at the time when the supply voltage reaches the peak value e■. This press-fitting position is measured by a laser distance meter and converted to the moving distance Lb of the magnetic head. Thereafter, the magnetic head returns to the contact position (distance La) due to the elasticity of the stopper. This return amount is Lc shown in the figure. As described above, it is necessary to write the servo signal for the outermost track at the contact position La. However, since La has not yet been determined, the return amount Lc is determined in advance by actual measurement, and this is calculated as Lb.
The contact position La is obtained by subtracting from the above. Note that the elasticity of rubber varies, and the pressing force of the positioning arm 17 is not strictly constant, so it is necessary to actually measure an appropriate number of HDAs to find the average value of Lc.

The above contact position detection method is applied to FIG. 1(a).

The output voltage of the VCM voltage detector 44 is monitored by the MPU 41, and when the output voltage reaches the peak value em, the data of the distance Lb measured by the laser distance meter 36a is as follows.
It is input to the MPU 41 and temporarily stored in the memory 42. The return amount LC measured in advance and stored in the memory 42 as described above is subtracted from Lb by the MPU to determine the contact position La.

FIG. 1(c) shows a table of the standard position distance (standard distance) Ls stored in advance in the memory 42 and the calibration position distance (calibration distance) Ls' obtained by calibrating this distance. Let the number of the outermost track be O, and the standard distance to this is LS
Let it be D. Lsl for track number 1 is Ls
o minus the pitch p (or adding it depending on the position of the laser distance detection), and similarly, LsN for the final number N is Lso-Np. On the other hand, the calibration distance f! IiL s ' is La for the number O, and is obtained by multiplying p by the track number and subtracting it, and the table is rewritten to this.

FIG. 2 is a schematic flowchart showing the procedure for detecting the abutting position of L and calibrating with respect to the standard position. When the servo writer starts, the MPU activates the VCM drive circuit and the magnetic head moves relative to the standard distance LSD (■), and in parallel with this, the laser distance meter calculates a total of Ae1 for the moving distance of 7 degrees (■). . When the monitored VCM voltage e reaches the peak value em (yes in ■), the distance Lb of Herad at this point is measured and stored in the memory (■). Next, the contact distance L for the contact position is determined by the MPU.
a=Lb-Lc is calculated (2), and the standard distance Ls in the memory table is calibrated and rewritten to the calibration distance Ls' (2). The calibration distance Ls' is read by the MPU, and servo signals are written to each track (2).

[Effects of the Invention] As is clear from the above explanation, in the servo signal writing position control method according to the present invention, when the positioning arm contacts the stopper, the voltage supplied to the VCM drive mechanism rapidly increases. Focusing on showing the peak value at the peak value, the measured return amount of the magnetic head due to the elasticity of the rubber of the stopper is subtracted from the position of the magnetic head at the time when the supply voltage reaches the peak value, and then the stopper and magnetic head are The contact position with the outermost track is calculated, and the standard positions of all tracks stored in memory are calibrated using this as the correct position for the outermost track, and the servo signal is written correctly by the servo writer to the calibrated position. This has a great effect in that a correct servo signal can be written to each track regardless of the positional defect of the HDA stopper.

[Brief explanation of the drawing]

FIGS. 1(a), (b), and (C) are block diagrams of main parts of a servo writer, a curve diagram of VCM supply voltage, and a memory in an embodiment of the servo signal writing position control method according to the present invention. 2 is a flow chart for each figure in FIG. 1, and FIGS. 3(a), (b), and (c) are perspective external views of the HDA and FIG. 2 is a plan view and a structural diagram of a writing mechanism of a servo writer with respect to the plan view. 1...Head disk assembly (HDA), l.
...Housing, 2...Magnetic disk, 3.
... Spindle, 4a... Magnetic head, 4b... Support arm, 5... Support rod, 6... VCM drive mechanism, 7... Positioning arm, 8... Stopper, 9... Notch hole, 2...rotation mechanism,
3...Writing mechanism, 31...Base board,
32... VCM drive machine horizontal mechanism 3... Rotating shaft, 34...
... Drive arm, 35... Drive pin, 36a... Laser distance meter, 3Gb... Mirror, 4... Signal processing unit, 41... Microprocessor (MPU),
42...Memory (MEM), 43...VCM control circuit, 44...VCM voltage detector, 45.46-...
A/D converter, ■～■...Step number of flowchart. Figure 1(a)

Claims (1)

[Claims] (1) A head disk assembly including a plurality of hard magnetic disks, a magnetic head, and a stopper that limits the seek range of the magnetic heads within an effective range is provided with a microprocessor and a stopper that limits the seek range of the magnetic heads to an effective range. a VCM that is controlled by a processor and drives the magnetic head;
In the servo writer, which has a drive mechanism and a laser distance meter that measures the moving distance of the magnetic head, the head disk assembly is mounted, and the magnetic head writes a servo signal to each magnetic disk. The above-mentioned VCM
The drive mechanism is controlled to move the magnetic head, and during the movement, the supply voltage to the VCM drive mechanism is monitored, and the distance traveled by the magnetic head is measured by the laser distance meter, and the supply voltage is a constant voltage. By subtracting the previously measured return amount of the magnetic head due to the elasticity of the stopper from the distance measured by the laser distance meter at the time when the distance increases more rapidly and reaches the peak value, it is possible to determine whether the stopper and the magnetic head are in alignment. Calculate the contact position, use the contact position as the write position of the servo signal for the outermost track, calibrate the standard positions of all tracks including the outermost track stored in the memory, and calibrate A servo signal write position control method, characterized in that the servo signal is written to each position by the servo writer.