JPS6080182A - Head positioning device for magnetic recording and reproducing equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention is directed to a head positioning device for a magnetic recording/reproducing device, and in particular, to improving the head positioning accuracy of a magnetic head straightening device using a stepping motor. The present invention relates to a head positioning device for a magnetic recording/reproducing device.

[Background of the invention]

In conventional magnetic recording and reproducing devices with removable magnetic disks such as floppy disks, the positioning error of the magnetic head is required to be below a certain tolerance in order to maintain compatibility between devices. Ru.

This tolerance varies depending on the number of tracks per unit length (track density) and the configuration and dimensions of the magnetic head.
If a Tony-Louleyse type head with guard holes on both sides of the data is used, the value corresponds to the width of the Tony-Louleyse gap in the dog formation.

Therefore, if the track density is high, a more precise head positioning accuracy is required.

FIG. 1 is a schematic perspective view of a conventional example of a head positioning device that has been widely used in floppy disks.

In this Figure 1, 1 is a stepping motor, 2 is a pulley press-fitted into the shaft of the stepping motor, and 3V
4 is a rail fixed to the floppy disk drive head (not shown), 5 is a carriage, 6 is a head arm, 7 is an upper rut head, 8 is a lower magnetic head, 9 is a magnetic head (not shown) 6. A chucking device for loading a self-recording medium (floppy disk) into a floppy disk drive; 1o is a reference track sensor.

The operation of the head standing device with such a configuration is as follows:
The rotation angle of the stepping motor 1 fixed to the chassis changes in steps according to a control signal. Therefore, the pulley 2 also rotates in a stepwise manner. This rotation of the pulley 2 causes the carriage 5 to move linearly along the rail 4 via the steel belt 3.

That is, the carriage 5 moves linearly in accordance with the rotation of the stepping motor 1 that changes in a stepwise manner. In other words,
Since the stepping motor 1 rotates at regular intervals, the carriage 5 performs linear motion at regular intervals.

Therefore, the upper and lower magnetic heads 7. are attached to the carriage 5 and the head arm 6 fixed to the carriage 5.
8 performs linear motion at regular intervals 2. It is something.

By setting this interval to the interval between tracks (reciprocal of the track density), the upper and lower magnetic heads 7.8 are positioned at the track positions.

The upper reference track position sensor 1o is used to detect when the upper and lower magnetic heads 7.8 have reached the reference track position (usually the outermost track position) by detecting the position of the carriage 5. be.

Positioning error factors in a magnetic recording/reproducing device using such a magnetic head positioning device include (1) angular error of the stepping motor (usually about ±3% of the rotation angle), and (2) absolute value accuracy of the pulley diameter. , (3) Accuracy in attaching the rail to the chassis, (4) Accuracy in chucking the magnetic disk, expansion and contraction due to temperature and humidity of the f5+magnetic disk, etc.

In the current magnetic recording/reproducing device using a 3-inch diameter magnetic disk, the total of these is about 80 μm, and due to the tunnel erase width limitation mentioned above, it is possible to use a 3-inch diameter magnetic disk from 10'0 Tpi (tracks/inch: number of tracks per inch). 15
Approximately 0 Tpi is the limit of track density, which is an obstacle to increasing the density.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a head positioning surface for a magnetic recording/reproducing device, which improves head positioning accuracy and realizes high-density recording in a magnetic head positioning device using a stepping motor. It is.

[Summary of the invention]

The configuration of the head positioning device for a magnetic ball distribution and reproducing device according to the present invention includes at least a head positioning device for a one-way recording and reproducing device that positions a magnetic head using a stepping motor, which includes means for counting tracks, and a means for counting tracks in advance. Provided with non-volatile data storage means or the like that stores a value for correcting the head positioning error for each track within the range where the head positioning error occurs around the position,
The stepping motor is configured to perform 1tIIJ# according to the correction value of the data storage means.

The details are as follows.

That is, the present invention improves head positioning accuracy by reducing magnetic head positioning errors caused by factors (1), (2), and (3) among the positioning error factors mentioned above. This is what I did.

Head positioning errors due to these factors vary from stepping motor to stepping motor and from component to component, and therefore vary from magnetic recording/reproducing device to magnetic recording/reproducing apparatus and from track to track.

In the present invention, the head positioning error after assembling the head positioning device is measured in advance for each floppy disk drive, and the floppy disk drive is equipped with a means for correcting the error, the correction value is stored for each floppy disk drive, and the correction value is used for the floppy disk drive. By controlling the head position, head positioning errors are absorbed and head positioning accuracy is improved.

Further, by narrowing the resolution of the correction data within the range where head positioning errors occur around the center position of the track, highly accurate head positioning can be achieved.

As a means of position error correction, it is possible to easily realize this by utilizing the fact that the rest position of the stepping motor after stepwise rotation changes slightly by controlling the internal magnetic field of the stepping motor. This is what I did.

In other words, according to the signal from the track counter, the magnetic head position W is centered around the track center position, and data for correcting the error is output from the PROM to correct the error. This is designed to cause the motor to slightly deviate.

[Examples of inventions]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Each structure according to the present invention will be explained with reference to each figure.

First, FIG. 2 is a circuit diagram of a head positioning device for a magnetic recording/reproducing apparatus according to one embodiment of the present invention.

The illustrated circuit configuration is newly added to the stepping motor 1 shown in FIG.

In the figure, 1 is a stepping motor, 11 is a trunk counter for counting tracks, 12 is a FROM (programmable read only memory) for data storage, 13 is a converter, 14 is a stepping motor driver, 15 is an oscillator, and 16 is a frequency divider.

First, to explain the input signal, 5TEP is a signal sent from an h-level controller to move the magnetic head by one track.

In Honjisuke-ri IJ, the stepping motor 1 rotates by a certain angle every 91 times of falling of 5TEP.

In addition, the DI ECT 10N also instructs the rotation direction of the stepping motor 1 using a signal from the higher-level controller.
When this signal is at a low level, the magnetic head moves toward the inner track of the magnetic disk.

TKφφke, reference track position sensor 1 in Figure 1 above
With an output of 0, it becomes low level when the upper and lower magnetic heads 7.8 reach the reference track position.

Further, the POVVERON signal is a signal that becomes high level as soon as the power of this system is turned on.

Next, the operation of each part will be explained.

The track counter 11 is set at the top when the power is turned on.

Move the lower magnetic head 7.8 to the reference track position (the outermost track of the magnetic disk, usually the track number 7 is set to 0 and the track number increases by 1 each time it moves inward one track).
Increase by increments. ) and is reset (set to 0).

Usually, the output rack number is indicated by count UP or count DOWNL from the higher-level controller.

The output Qo, Q> of the lower two bits of the binary value of the track counter 11 is applied to the D1 terminal of the stepping motor driver 14 through the EOR gate, and the Q1 is similarly applied to the D2 terminal.

Therefore, Dl of the stepping motor driver 14
, D2 terminal, when the track counter 11 is counted up, the change in (D2, D+) is (0,0
) → (o, i) → (1, 1) → (i, o) → (0, 0)
→... is repeated.

Conversely, when counting DO'WN, (0,0)→(
1,0) → (1,1) → (0,1) → (0°0)...
This is repeated.

This stepping motor driver 14 has the following characteristics:
Hitachi's new IC, I (AI3421F, 3rd
The figure is a rotation principle diagram showing the operating principle of the stepping motor.

Therefore, when the D1 terminal is at a low level, the current corresponding to the input voltage of the input terminal El in FIG. 2 flows through the switch transistor T2. '13 turns on, the A-phase winding of the stepping motor 1 is caused to flow in the a direction, and when the D1 terminal is at a high level, the switch transistor T1'
, l114 is turned on, the signal is caused to flow in the direction b. Flow commutation according to the input voltage of the input y-element E2 is similarly performed by the switching transistors 1115 to ''P8.

That is, the voltage applied to the input terminals E1 and E2 changes between I and D2 by the input signals to Dl and D2m.
I)+AI straight stepper motor 1 phase A and B
It is stamped on the phase winding.

Therefore, if, for example, a commercially available non-hybrid type stepper motor is used as the stepping motor 1, D 1 w D2 as described above is determined by the count UP or DO'WN of the track counter 11.
Since the heir signal changes, the magnetic field inside the stepping motor 1 rotates as shown in FIG. 3, causing the stepping motor 1 to rotate. Therefore, the magnetic head moves every 1 trough by 2 minutes.

Next, correction of positioning error will be explained.

Figure 4 shows the voltage of the stepping motor windings as 1i11
14 is an explanatory diagram of a control method showing a astronomical value of a minute change in stationary position when

In other words, part 2 in the figure shows the rest position of the stepping motor when the voltage ratio applied to the A-phase winding and the B-phase winding is exceeded. The horizontal axis shows the voltage of the human phase winding and the B phase winding, and the vertical axis shows the rest position.

As a result, by controlling the voltage from the balanced position when the same voltage is applied, ±1/2 steps can be achieved.
It can be seen that the stationary position can be controlled.

Therefore, by controlling the voltages of the A-phase winding and the B-phase winding, magnetic and radial positioning can be performed to any desired position.

In addition, ■ in the same figure shows that the voltage applied to the A-phase winding and the B-phase winding is PWM modulated (pulse width modulation).
The static position when changing the duty ratio is shown. This shows that by changing the duty ratio of the A-phase winding and the B-phase winding, the stationary position can be controlled in the same way as when changing the voltage ratio.

However, the actual head positioning error by the head positioning device does not cover the entire range of ±1/2 steps around the center of the track.

The frequency distribution diagram of the head positioning error shown in FIG. 5 shows the actually measured value of the frequency distribution at the rest position, and it can be seen that the actual head positioning error falls within ±115 steps.

Therefore, the relationship diagram of the voltages of the A and B phase windings required to correct the head position error within 115 steps can be expressed as follows:

As shown in Figure 6, the correction is oJ within ±115 steps.
- It is efficient to have the ability to correct the range of ±1/2 steps by changing the bait voltage (■ wire) or the duty (1 song of ■).

Further, if the storage α range of ±115 steps is performed at the same division ratio of ±1/2 steps (for example, 64 divisions or 128 divisions), the head positioning error can be further corrected.

Correction of positioning errors is performed as follows.

First, after assembly is completed, measure the voltage (or duty ratio) that should be applied to the human phase winding and B phase winding so that the positioning error is 0 on each commercial track (usually, the positioning error is measured on the disk). It is known that the positioning error can be measured by writing a special signal to the position and reading this signal with a magnetic head.)
. Data corresponding to this voltage value or duty is stored in the FROM 12 shown in FIG.

As a result, correction data for reducing the positioning error to 0 for each drive and each track is convoluted inside the FROM 12.

Therefore, when this drive is used for the first time, a signal for setting the error tray to 0 for each track is outputted from the FROM 12 in proportion to the output of the track counter 11, and , the stepping motor 1 is stopped at a position where the positioning error is O by the onboard 3 stepping motor driver 14.

Next, a specific example of the valley configuration of the transformer 13 shown in FIG. 2 will be explained with reference to the circuit diagrams in FIGS. 7 and 8.

First of all, Figure 7 is an example of a scrap structure using D/A (digital/analog) Henkei Mei.

As already mentioned, 12 is a PROM, 14 is a stepping motor driver, and 17 is a D/A converter.

In other words, the data convoluted into PR,0M12 is
It is converted into an analog voltage value by the D/A converter 17,
The driver transistors T9 and TIO drive the input terminal El+E2 of the stepping motor driver 14 at a constant voltage.

Therefore, this is a method suitable for controlling with the voltage shown in (■) in FIG. 4 above.

Next, FIG. 8 is a circuit diagram relating to a method of changing the duty in another example of signal generation.

In the figure, 12 is a PROM, 14 is a stepping motor driver, 15 is an oscillator, 16 is a frequency divider, and 18 is a digital comparator, which share the oscillator 152 and frequency divider 16 in FIG. 2, which will be described later. .

That is, the divider 16 always divides the pulse of the oscillator 15 into binary values.

Therefore, a carry occurs every certain pulse, and flip-flops FF2 and FF3 are reset. The digital comparator 18 compares the output value of PR, 0M12 and the output value of the frequency divider 16, and if they match, sets the flip-flop FF2 or FF3, respectively.

Thus, a tutee signal according to the value of PROM12 is generated in flip-flops FF2 and FF3, switching driver transistors '1'11 and T12.

Therefore, Vcc of the tute ratio according to the data of PRO4vf12 is applied to the input terminal E+ + E2 of the stepping motor driver 14.

This method uses the driver transistor 'ltt l TI
2 is a saturation operation, so it is efficient.

Next, for a while, in the system described in FIG.
12, it is necessary to reset the track counter 11 when the power is turned on.

Here, FIG. 9 is a timing chart diagram when power is turned on.

That is, when the POWERON signal rises, the previous second
The Noritsu flop FFI shown in the figure is set, and the track counter 11 consisting of an up/down counter enters the count DOWN mode.

Further, the output pulse of the oscillator 15 is frequency-divided by a frequency divider 16, passes through NAI and NA2 in the figure, and is applied to the CLK terminal of the track counter 11.

At this time, the 5TEP signal is at a high level by a gate (not shown). The output pulse period of the frequency divider 16 is
Normally, it may be set to about several meters (8).

Therefore, for each dmia, the track counter 11 counts DO'WN, and the stepping motor 1 also rotates to move the magnetic head in the direction of the reference track.

When the magnetic head reaches the reference track position, the signal TKφφ from the reference track position sensor 10 goes low and resets the flip-flop FF1.
Reset the track counter 11.

Therefore, the value of the track counter 11 and the actual track position match, and from then on, 5 TEP.

In response to the DIRECTION input, the upper and lower magnetic heads 7.8 are positioned at positions with little positioning error by the above-described correction operation.

Next, FIG. 10 is a circuit diagram of a head positioning device for a magnetic recording/reproducing apparatus according to another embodiment of the present invention.

In the figures, the previous Figures g2 and 8 and the same part No. 2 show the same parts.

Therefore, in this embodiment, when the head positioning error is corrected by PWM modulation in the embodiment explained in FIG. , output Qo-Q of PROM12
The number of bits in □ increases.

The present example shown in the circuit of FIG. 10 is an attempt to improve this.

The operation of each part will be explained.

The output pulse of the oscillator 15 is frequency-divided by a frequency divider 16. The digital comparator 18 compares the output value of the frequency divider 16 and the output value of the PROM 12, and if they match, sets the flip-flops FF2, FF, and 3, respectively.

In addition, the output of the branching unit 16 is connected to zkN through the AND shown in the figure.
When all D inputs are 1, the flip-flop FF
2 and F'F3 are reset at the same time.

For the above AND, as shown in Figures 5 and 6 above, the range for correcting the head positioning error is ±115 steps, so if the data in PROM 12 is all 0, the stepping motor is What is necessary is to input the output of the frequency divider 16 which resets the flip-flops PF2 and F'F3 when the duty reaches a duty (38% from FIG. 6) that allows deviation of 1.

Therefore, a duty signal according to the value of 280M12 and the output of AND is generated at the outputs Q of the seven lip-flops FF2 and FF3, and switches the dry transistors Tll and T12.

FIG. 11 shows these timings. The other movements are exactly the same as the Fuodori example shown in FIG.

According to the above-described embodiment of the present invention, it is possible to improve the positioning accuracy of an open loop head positioning device using a stepping motor.

In other words, the positioning error has decreased from ±20μm in the conventional case to ±20μm.
5μm, and even for 3-inch floppy disks, the sum of all error factors can be improved to approximately ±22μm, making it possible to improve the recording density to 200Tpl, twice as much as before. It is something.

Although the above explanation was based on a floppy disk, the present invention is not limited to use only with floppy disks, but can be widely used in open-loop position control systems using stepping motors. .

In addition, in the example of the converter that changes the duty ratio shown in FIG.
Alternatively, it is also possible to remove the flip-flop FF3'r.

Further, FROM may be any non-volatile storage means, such as ultraviolet erasable R, OM, mask 11. Regardless of the OM, it is obvious that a battery-backed RAM (random access memory) may also be used.

〔Effect of the invention〕

According to the present invention, the head positioning accuracy can be improved by simply adding electronic components to the conventional head positioning device without using a new head positioning device.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of a conventional head positioning device;
FIG. 2 is a circuit diagram of a head positioning device for a magnetic recording/reproducing apparatus according to an embodiment of the present invention. FIG. 3 is a diagram of the rotation principle of a stepping motor. FIG. 4 is an explanatory diagram of a stepping motor control method. , Fig. 5 is a frequency distribution diagram of head positioning errors, Fig. 6 is a relational diagram of the voltages of the A and B phase windings required to correct head position errors within 115 steps, and Figs. 7 and 8 are ＼Each circuit diagram of the converter, FIG. 9 is a timing chart diagram when starting up the power W, and FIG. 10 is a head positioning device of a magnetic recording/reproducing device according to another preferred embodiment of the present invention. The circuit diagram of FIG. 11 is a timing chart thereof. 1...Stepping motor, 7...Upper magnetic head,
8... Lower magnetic head, 10... Reference track position sensor, 11... Track counter, 12... FRO
M-, 13... Converter, 14... Stepping motor driver, 15... Oscillator, 16... Frequency divider, 1
7...D/A conversion 3rd day 4-2 +007',=I27 5'' I do not hold position I 64th prisoner 10O7o near 2V T to φφ $ q 2

Claims (1)

[Claims] 1 degree At least, in the head positioning device of the magnetic ball distribution reproducing device that positions the magnetic head using a stepping motor, there is a means for counting tracks, and a means for counting the tracks in advance within the range where the head positioning error occurs around the center position of the track. A non-volatile data storage means is provided in which a value that describes the head positioning error for each track is recorded, and the stepping motor is controlled by 1J by the correction value of the data storage means. A head positioning device for a magnetic recording/reproducing device which takes the Lgj characteristic as a sign of Lgj.