JP2000222848A - Magnetic disk apparatus and its magnetic-head positioning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the positioning control operation of a magnetic head by a method wherein the gain of an actuator for fine adjustment is measured, the magnetic head is positioned in a positioning region in which servo information is written on a magnetic disk medium and which is used to measure the gain of the actuator for fine adjustment and the control characteristic of the actuator for fine adjustment is adjusted on the basis of the measured result of the gain. SOLUTION: An actuator-gain measuring device 2 for fine adjustment measures the gain of a piezoactuator on the basis of the difference between a position error signal 23 and a piezoactuator drive signal 18 when a magnetic head 14 is positioned in a positioning region used to measure the gain of an actuator, for fine adjustment, on a magnetic disk medium 15. When the gain is within a proper range, a piezoactuator gain signal 16 is output to a magnetic- head positioning controller 4. When the gain is outside the range, it is regarded as a measuring abnormality, and the gain signal 16 is not updated. Without increasing the bandwidth of the magnetic-head positioning controller 4, a head positioning error amount is reduced, and an S/N ratio can be ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head positioning device for a magnetic disk drive, and more particularly, to a coarse movement actuator for performing a coarse movement for positioning a magnetic head on a target track, and a magnetic head for precisely positioning the magnetic head on a target track. The present invention relates to a magnetic head positioning device in a magnetic disk drive having a fine movement actuator for performing a fine movement for performing positioning at the center of a magnetic disk.

[0002]

2. Description of the Related Art Conventionally, a magnetic head positioning device in a magnetic disk device is provided for positioning a magnetic head on a target track with high accuracy, as shown in, for example, Japanese Patent Application Laid-Open No. 2-227886.

Here, in order to explain the outline of a magnetic head positioning control device in a conventional magnetic disk device provided with a fine movement actuator control characteristic measuring device for positioning a magnetic head at the center of a target track more precisely, Please refer to FIG. 1 described in detail in an embodiment of the present invention.

A magnetic head positioning device for a magnetic disk drive includes a positioning control CPU 1, D / A converters 6, 7,
Piezo drive amplifier 8, VCM (voice coil motor) drive amplifier 9, position error signal generation circuit 10, A
/ D converter 11, piezo actuator 12 as a fine movement actuator, VCM as a coarse movement actuator
13 and a magnetic head 14. The positioning control CPU 1 further includes a fine movement actuator gain measuring device 2, a sine wave generator 3, and a magnetic head positioning controller 4. In the figure, reference numeral 15 denotes a magnetic disk medium.

Next, the operation will be described.
Is servo information (not shown in FIG. 1 and A in FIG. 2) written on the magnetic disk medium 15 (A1 in FIG. 2).
2) is read and a servo signal 22 is output. The position error signal generation circuit 10 receives the servo signal 22 and outputs a position error signal 23. The A / D converter 11 receives the position error signal 23 and outputs a discretized position error signal. The piezo actuator gain measuring device 2 in the positioning control CPU 1 applies a sine wave signal 17 to the discretized position error signal output from the A / D converter 11 and the piezo actuator drive signal 18 output from the adder 5. The added signal is input, and the piezo actuator gain signal 16 is input.
Is output.

Here, the gain of the piezo actuator gain signal 16 is the ratio of the input to the output of the piezo actuator, and the input is equal to the drive signal (electric signal) of the piezo actuator 12 output from the piezo drive amplifier 8. , Output = the ratio of “movement amount (distance) of the magnetic head 14 by the piezo actuator”. This movement amount is obtained from the digital value of the position error signal, and is calculated by the piezo actuator gain measuring device 2 by calculation. You.

The sine wave generator 3 in the positioning control CPU 1 outputs a sine wave signal 17 when a piezo actuator gain measurement command is issued from a host device (not shown), and a piezo actuator gain measurement command is issued. If not, the sine wave signal 17 is not output. Magnetic head positioning controller 4 in positioning control CPU 1
Is input from the position error signal generation circuit 10 via the A / D converter 11 to the discretized position error signal, and performs positioning control so that positioning can be performed on a target track specified by a higher-level device (not shown). A piezo actuator drive signal 18 and a VCM drive signal 19, which are signals, are output. The magnetic head positioning controller 4 performs phase lead / lag compensation and PID
(Proportional plus Integral plus Differntial: Proportional / Integral / Derivative) Compensation, the output signal is obtained by closed loop control using an optimal regulator, and the like.

When the piezo actuator gain measurement command is issued and the piezo actuator gain signal 16 is output from the fine movement actuator gain measurement device 2, the magnetic head positioning controller 4 follows the piezo actuator gain signal 16. The gain in the magnetic head positioning controller 4 is adjusted so that the control characteristic of the piezo actuator 12 becomes equal to the design value. The adder 5 in the positioning control CPU 1 receives the sine wave signal 17 and the piezo actuator drive signal 18 and outputs a piezo actuator drive signal including a sine wave.

The D / A converter 6 receives the piezo actuator drive signal 18 and outputs a piezo actuator drive signal which is an analog quantity. The D / A converter 7 has a VC
An M drive signal 19 is input and a VCM drive signal, which is an analog amount, is output. The piezo drive amplifier 8 inputs a piezo actuator drive signal of an analog amount and outputs a piezo actuator drive current 20. The VCM drive amplifier 9 receives a VCM drive signal, which is an analog amount, and outputs a VCM drive current 21.

The VCM 13 receives a VCM drive current 21 and moves a carriage to which a magnetic head 14 is attached at the tip, and performs positioning to a positioning target cylinder specified by a host device (not shown). The piezo actuator 12, which is a fine movement actuator, receives the piezo actuator drive current 20, moves the magnetic head 14 at the leading end of the carriage, and performs precise positioning using a positioning target cylinder designated by a host device (not shown).

FIG. 4 is a conceptual diagram showing an example of a state of writing servo information on a magnetic disk medium in a conventional magnetic disk device. On the magnetic disk medium A1, servo information A2 is written for each servo sector.

As a conventional example relating to the writing of servo information to a magnetic disk medium in the above-described magnetic disk device, a technique described in, for example, Japanese Patent Application Laid-Open No. 7-65363 has been proposed. This publication is intended to write servo information with higher accuracy than the current state, and the servo information area includes a plurality of non-magnetic areas arranged at intervals in a direction orthogonal to the data track,
A magnetic recording medium is disclosed in which servo information can be magnetically recorded in a region between non-magnetic regions so as to reach the non-magnetic region.

Further, as a conventional example relating to the head actuator drive control of the above-mentioned magnetic disk drive, for example, a technique described in Japanese Patent Application Laid-Open No. 9-82048 has been proposed. The gazette is intended to realize high-precision head positioning. In a feedback control system for executing positioning control, a position error signal is transmitted to a main driving unit and an auxiliary driving unit in a predetermined low frequency region. A drive control method is disclosed in which the input signals are input with their phases opposite to each other, and the response gain for each input is adjusted to eliminate the resonance mode that vibrates in the radial direction of the disk.

As another conventional example relating to the head actuator drive control of the magnetic disk drive,
For example, a technique described in Japanese Patent Application Laid-Open No. 10-255418 has been proposed. This publication aims to freely set a servo band ratio between a microactuator and a coarse actuator, and to determine a position error between a target position and an observation position of a head by a first control for driving and controlling the coarse actuator. And a feedback means for inputting to the second control means for driving and controlling the microactuator, wherein the displacement of the microactuator with respect to the coarse actuator is not input to the first control means. It has been disclosed.

[0015]

However, the above-mentioned prior art has the following problems.

The first problem is that, when the vibration amplitude at the time of measuring the control characteristics of the fine movement actuator becomes large, the linearity of the servo information cannot be maintained due to the sensitivity characteristics of the magnetic head, and the accuracy of the position error signal required for the measurement is lost. Therefore, the excitation amplitude can be increased only to the extent that the linearity of the servo information is maintained. Therefore, when measuring the control characteristics of the actuator for fine movement, the amount of movement of the head due to the vibration is smaller than the amount of runout of the head positioning.
The ise ratio (S / N ratio) cannot be secured.

Further, in order to improve the head positioning run-out, it is desired to increase the band of the magnetic head positioning controller.
Since the band of the magnetic head positioning controller is limited by mechanical resonance, improvement is difficult. Similarly, it is conceivable to increase the servo information on the magnetic disk medium in order to improve the head positioning run-out.However, increasing the servo information reduces the data information and reduces the capacity of the magnetic disk device. It is difficult to increase. For these reasons, it is difficult to improve the head positioning runout.

The second problem is that, due to the first problem, it is not possible to secure an S / N ratio of a signal necessary for measuring the fine movement actuator control characteristics. For this reason, in the head positioning device of the magnetic disk drive, the control characteristics of the actuator for fine movement cannot be measured accurately.

The third problem is that the control characteristics of the actuator for fine movement cannot be measured accurately due to the second problem. For this reason, the magnetic head positioning control cannot be performed accurately.

An object of the present invention is to provide a magnetic head positioning apparatus in a magnetic disk drive capable of more accurately measuring the control characteristics of a fine movement actuator and performing a magnetic head positioning control with high accuracy.

[0021]

SUMMARY OF THE INVENTION The present invention comprises a coarse actuator for positioning a magnetic head on a target track;
A magnetic head positioning device in a magnetic disk drive comprising a fine movement actuator for positioning the magnetic head more precisely at the center of the target track; gain measuring means for measuring the gain of the fine movement actuator;
The magnetic head is positioned in a fine movement actuator gain measurement positioning area provided on a magnetic disk medium and in which servo information is written more than usual, and the control characteristics of the fine movement actuator are adjusted based on the measurement result of the gain measurement means. And a positioning control means.

Further, there is provided a sine wave generating means for generating a sine wave signal required for the gain measurement of the gain measuring means,
The gain measuring means includes: a position error signal of the magnetic head;
The gain of the fine movement actuator is measured based on a signal obtained by adding the sine wave signal to a fine movement actuator drive signal for positioning the magnetic head in the vibrating state on the target track, and the positioning control means includes: The control characteristic of the actuator for fine movement is adjusted based on the measurement result so as to be equal to a design value.

The gain measuring means determines whether or not the measurement result of the gain of the fine movement actuator is within an appropriate range. If the measurement result is within the appropriate range, the measurement result is determined by the positioning control means. Is output.

Further, the positioning region for measuring the fine movement actuator gain is provided on an outer peripheral portion on the magnetic disk medium.

Further, the positioning area for measuring the fine movement actuator gain is provided at a position other than the outer peripheral portion on the magnetic disk medium.

Further, the positioning area for measuring the fine movement actuator gain can be determined based on the track layout of the magnetic disk medium.

The servo information writing density in the fine movement actuator gain measurement positioning area can be increased in accordance with the processing speed of the positioning control system.

According to the present invention, there is provided a magnetic disk drive comprising a coarse movement actuator for positioning a magnetic head on a target track and a fine movement actuator for positioning the magnetic head more precisely at the center of the target track.
Gain measuring means for measuring the gain of the fine movement actuator; positioning the magnetic head in a fine movement actuator gain measurement positioning area provided on a magnetic disk medium and in which more servo information is written than usual; And a positioning control means for adjusting the control characteristics of the fine movement actuator based on the measurement result.

The magnetic head positioning device in the magnetic disk drive according to the present invention will be described with reference to FIGS. 1 and 2. A part (the outer peripheral portion in FIG. 2) on the magnetic disk medium (A11 in FIG. 2) will be described. ) Contains normal servo information (A in FIG. 2).
In addition to 12), servo information (A13 in FIG. 2) for further increasing the positioning accuracy is written, and the area in which more servo information is written than the normal servo information is defined as a fine movement actuator gain measurement positioning area ( A1 in FIG.
Set as 4).

Then, the magnetic head positioning device is provided with a fine movement actuator gain measurement positioning area (A in FIG. 2).
In 14), the fine movement actuator gain is measured, and if the measurement result is within the appropriate range of the fine movement actuator gain,
A gain measuring means (2 in FIG. 1) for outputting to the positioning control means (4 in FIG. 1) is provided.

Further, the magnetic head positioning device adjusts the gain of the controller in accordance with the output value of the fine movement actuator gain measured by the gain measuring means (2 in FIG. 1) (4 in FIG. 1). And a sine wave generating means (3 in FIG. 1) for generating a sine wave signal required for measurement.

[Operation] The magnetic head positioning device in the magnetic disk drive of the present invention serves as a positioning area for measuring the actuator gain for fine movement in order to increase the positioning accuracy in addition to the normal servo information on the outer peripheral portion on the magnetic disk medium. Is writing servo information. For this reason,
Since the run-out amount of the head positioning can be reduced without increasing the bandwidth of the head positioning controller,
Signal / Noise ratio (S / N ratio) can be secured.

Further, the magnetic head positioning device in the magnetic disk drive of the present invention writes servo information for improving positioning accuracy only on the outer peripheral portion of the servo medium. For this reason, the amount by which the data information is reduced is slight, and the capacity of the magnetic disk device does not become extremely small.

Further, the magnetic head positioning device in the magnetic disk drive of the present invention can secure an S / N ratio required for measurement of control characteristics of the fine movement actuator.
For this reason, the control characteristics of the fine movement actuator can be accurately measured, and the magnetic head positioning control can be accurately performed.

[0035]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

First Embodiment (1) Description of Configuration FIG. 1 is a conceptual diagram showing a configuration example of a magnetic head positioning device of a magnetic disk drive according to a first embodiment of the present invention. In FIG. 1, a magnetic head positioning device for a magnetic disk device according to an embodiment of the present invention includes positioning control CPUs 1 and D
/ A converters 6, 7, piezo drive amplifier 8, VCM
(Voice coil motor) A drive amplifier 9, a position error signal generation circuit 10, an A / D converter 11, a piezo actuator 12 as a fine movement actuator, a VCM 13 as a coarse movement actuator, and a magnetic head 14 are provided.

Further, the positioning control CPU 1 includes a fine movement actuator gain measuring device 2, a sine wave generator 3, a magnetic head positioning controller 4, and an adder 5. In the figure, reference numeral 15 denotes a magnetic disk medium.

The function of the main part (positioning control CPU 1) of the magnetic head positioning device in the magnetic disk drive will be described.
Are the position error signal 23 of the magnetic head 14 output from the position error signal generation circuit 10 and the magnetic head 1 in the vibrated state.
A sine wave signal 17 from the sine wave generator 3 is added to a piezo actuator drive signal 18 for positioning the position 4 on the target track.
Is added to the piezo actuator 12 based on
Measure the gain of.

Further, the fine movement actuator gain measuring device 2 determines whether or not the measurement result of the gain of the piezo actuator 12 is within a proper range. Positioning controller 4
If the measurement result is not within the appropriate range, the measured value is determined to be abnormal, and the piezo actuator gain signal 16 is not updated.

Here, the gain of the piezo actuator gain signal 16 is the ratio of the amount of movement of the output to the input signal of the fine movement actuator 12, as described above.
The ratio of the input "drive signal (electric signal) of the fine movement actuator 12 output from the fine movement drive amplifier 8" to the output "movement amount (distance) of the magnetic head 14 by the fine movement piezoelectric actuator". The movement amount is obtained from a digital value of the A / D converter 11 corresponding to the position error signal 23 of the position error signal generation circuit 10, and is calculated by the fine movement actuator gain measuring device 2 by calculation. Here, the movement amount of the magnetic head 14 by the fine movement actuator includes the movement amount of the coarse movement actuator VCM 13 at the time of measurement, but is not included in the fine movement actuator gain. Signal 16 is
It is a measurement result of the gain of the actuator for fine movement. Therefore, when the piezo actuator gain signal 16 is output from the fine movement actuator gain measuring device 2, the magnetic head positioning controller 4 can obtain the piezo actuator gain from the fine movement actuator gain measuring device 2.

The sine wave generator 3 generates a sine wave signal 17 necessary for measuring the gain of the fine movement actuator gain measuring device 2. The magnetic head positioning controller 4 positions the magnetic head 14 in a fine movement actuator gain measurement positioning area (A14 in FIG. 2 described later) provided on the magnetic disk medium 15 where servo information is written more frequently than usual. The control characteristic of the piezo actuator 12 is adjusted to be equal to the design value based on the measurement result of the actuator gain measuring device 2. The adder 5 adds the piezo actuator drive signal 18 and the sine wave signal 17 from the sine wave generator 3.

The other components of the magnetic head positioning device in the magnetic disk device than the above-mentioned main components will be described together with the following operations.

FIG. 2 is a conceptual diagram showing an example of writing servo information on a magnetic disk medium in the magnetic disk device of the embodiment of the present invention. In FIG. 2, a magnetic disk medium A mounted on the magnetic disk device of the embodiment of the present invention
Numeral 11 includes a fine movement actuator gain measurement positioning area A14 in which more servo information A13 (in this embodiment, for example, servo information having three times the normal density) is written than normal servo information A12. .

The difference between the embodiment of the present invention and the prior art is that, as described above, a fine movement actuator gain measurement in which more servo information A13 is written on the magnetic disk medium 15 than normal servo information A12. And a positioning control CPU including the fine movement actuator gain measuring device 2, sine wave generator 3, magnetic head positioning controller 4, and adder 5.
1 is that the processing described in the following operation description is executed based on a predetermined control program.

(2) Description of Operation Next, the operation of the embodiment of the present invention will be described in detail with reference to FIGS.

1 and 2, the magnetic head 14 is
The servo information (A12 in FIG. 2) written on the magnetic disk medium 15 (A11 in FIG. 2) is read, and a servo signal 22 is output. The servo signal 2 in FIG.
2 is actually taken out using a conductor from the direction in which the voice coil 13 is arranged, but is omitted for the sake of understanding. Further, the position error signal generation circuit 10
4 is a servo signal 2 read from the magnetic disk medium 15
2 is input and the position error signal 23 is output. The A / D converter 11 receives the position error signal 23 from the position error signal generation circuit 10 and discretizes the servo information (A12 in FIG. 2).
And outputs the discretized position error signal to the magnetic head positioning controller 4.

The fine movement piezo actuator gain measuring device 2 in the positioning control CPU 1 is a host device (not shown).
When the piezo actuator gain measurement command is supplied to the sine wave generator 3 from the controller, the magnetic head positioning controller 4 moves the magnetic head 14 to the fine movement actuator measurement positioning area on the magnetic disk medium 15 (A14 in FIG. 2).
After the positioning, the discrete position error signal output from the A / D converter 11 and the piezo actuator drive signal 18 output from the adder 5 are added to the sine corresponding to the piezo actuator gain measurement command. A signal to which the wave signal 17 is added is input, and a piezo actuator gain signal 16 for fine movement is output.

When a piezo actuator gain measurement command is issued from a host device (not shown), the sine wave generator 3 in the positioning control CPU 1 causes the magnetic head positioning controller 4 to move the magnetic head 14 to the magnetic disk medium 15.
The sine wave signal 17 is output after waiting for positioning in the fine movement actuator measurement positioning area (A14 in FIG. 2), and is not output if no measurement command has been issued.

The magnetic head positioning controller 4 in the positioning control CPU 1 inputs the discretized position error signal and uses the positioning control signal so as to perform positioning on a target track designated by a host device (not shown). A piezo actuator drive signal 18 and a VCM (voice coil motor) drive signal 19 are output. The magnetic head positioning controller 4 performs phase lead / lag compensation and PID (Proportional Plu
s Integral plus Differntial (proportional / integral / differential) compensation, the output signal is obtained by closed loop control by an optimal regulator, and the like.

When the piezo actuator gain measurement command is issued, the magnetic head positioning controller 4 moves the magnetic head 14 to the fine movement actuator measurement positioning area (A1 in FIG. 2) on the magnetic disk medium 15.
4) When the piezo actuator gain signal 16 is output from the fine actuator gain measuring device 2, the magnetic head positioning is performed in accordance with the piezo actuator gain signal 16 so that the control characteristic of the piezo actuator 12 becomes equal to the design value. The gain in the controller 4 is adjusted.

The adder 5 in the positioning control CPU 1
A sine wave signal 17 and a piezo actuator drive signal 18 are input, and a piezo actuator drive signal including a sine wave is output. The D / A converter 6 receives the piezo actuator drive signal 18 and outputs a piezo actuator drive signal that is an analog quantity. The D / A converter 7 outputs V
The CM drive signal 19 is input, and the coarse amount V
It outputs a CM drive signal. The piezo drive amplifier 8
An analog amount fine drive piezo actuator drive signal is input and a piezo actuator drive current 20 is output.

The VCM drive amplifier 9 receives a VCM drive signal, which is an analog quantity, and outputs a VCM drive current 21. The VCM 13 receives the VCM drive current 21 and
A carriage having a magnetic head 14 attached to the tip is driven to perform positioning to a positioning target cylinder designated by a host device (not shown). The piezo actuator 12, which is a fine movement actuator, receives the piezo actuator drive current 20, moves the magnetic head 14 at the leading end of the carriage, and performs more precise positioning with respect to a positioning target cylinder specified by a host device (not shown). .

FIG. 3 is a flow chart for explaining the operation by the positioning for fine movement in the magnetic head positioning device of the magnetic disk drive of the embodiment of the present invention.

In FIG. 3, the fine gain actuator gain measuring device 2 in the positioning control CPU 1 checks whether a piezo actuator gain measurement command has been issued from a higher-level device (not shown) (step S1). When a higher order device (not shown) issues a piezo actuator gain measurement command, the magnetic head positioning controller 4
The magnetic head 14 is positioned in the fine movement actuator measurement positioning area (A14 in FIG. 2) on the magnetic disk medium 15 (step S2).

Next, the fine movement actuator gain measuring device 2 moves the magnetic head 14 to the fine movement actuator measurement positioning area on the magnetic disk medium 15 (A14 in FIG. 2).
The piezo actuator gain, which is the gain of the actuator for fine movement, is measured from the difference between the position error signal 23 and the piezo actuator drive signal 18 when positioning is performed (step S3). When the measurement of the piezoelectric actuator gain is completed, the fine movement actuator gain measuring device 2 checks whether the measurement result of the piezoelectric actuator gain is within an appropriate range (step S4).

When the piezo actuator gain is within the appropriate range, the fine movement actuator measuring device 2 sends the piezo actuator gain signal 16 which is the measurement result of the piezo actuator gain to the magnetic head positioning controller 4.
(Step S5). On the other hand, if the piezo actuator gain is not within the appropriate range, the fine movement actuator measuring device 2 determines that the measured value is abnormal and does not update the piezo actuator gain signal 16 (step S).
6).

Incidentally, the method of measuring the piezo actuator gain in step S2 may be the same as that of the prior art, and the details thereof will be omitted.

As described above, according to the magnetic head positioning apparatus in the magnetic disk drive of the embodiment of the present invention, the position error signal of the magnetic head 14 and the piezo actuator for positioning the vibrating magnetic head 14 on the target track. The gain of the piezo actuator 12 is measured based on the signal obtained by adding the sine wave signal to the drive signal. If the measurement result of the gain of the piezo actuator 12 is within an appropriate range, the measurement result is sent to the magnetic head positioning controller 4. An actuator gain measuring device 2 for fine movement to output;
A sine wave generator 3 for generating a sine wave signal required for the gain measurement of the fine movement actuator gain measuring device 2 and a fine movement actuator gain measurement positioning provided on the magnetic disk medium 15 and having more servo information written than usual. A magnetic head positioning controller 4 for positioning the magnetic head 14 in the area A14 and adjusting the control characteristic of the piezo actuator 12 to be equal to the design value based on the measurement result of the fine movement actuator gain measuring device 2. Therefore, the following effects can be obtained.

Since the servo information A13 for improving the positioning accuracy in addition to the normal servo information A12 is written on the outer peripheral portion of the magnetic disk medium 15 as the fine movement actuator gain measurement positioning area A14, the magnetic head positioning is performed. The head positioning run-out amount (head positioning error amount) can be reduced without increasing the bandwidth of the controller 4, and as a result, the Signal /
Noise ratio (S / N ratio) can be secured. Here, the head positioning error refers to a deviation from the target track center of the magnetic head, and the deviation can be corrected by the fine movement actuator 12 or the slider in the magnetic head 14.

Further, since the servo information A13 for improving the positioning accuracy is written only on the outer peripheral portion of the magnetic disk medium 15, the data write area on the magnetic disk medium 15 is reduced, in other words, the data information is reduced. The amount is small, and the capacity of the magnetic disk drive does not become extremely small due to the positioning area A14 for the fine movement actuator gain measurement.

Further, since the S / N ratio necessary for measuring the control characteristics of the fine movement actuator can be ensured, the control characteristics of the piezo actuator 12 can be accurately measured in the positioning control of the magnetic head 14.

Further, since the control characteristics of the piezo actuator 12 can be accurately measured, the magnetic head 14 can be positioned more precisely with respect to the target track on the magnetic disk medium 15.

[Second Embodiment] The first embodiment of the present invention described above.
In the embodiment, the portion where the servo information is written more than usual for the control measurement area of the fine movement actuator is provided on the outer peripheral portion of the magnetic disk medium. However, the present invention is not limited to this. The portion in which the above-mentioned servo information is written more than usual may be any portion such as the inner peripheral portion or the middle peripheral portion of the magnetic disk medium, or may be determined based on the track layout of the magnetic disk medium.

Also, an example in which a piezo actuator is used as the fine movement actuator has been described. In the case where a head gimbal assay (HGA) is used by using a two-stage main slider and a secondary slider for this magnetic head. The piezo actuator drives the position of the main slider,
As a two-stage configuration in which the secondary slider sandwiched between the cutouts of the main slider is driven by a coil, using the positioning area A14 for fine actuator gain measurement,
Further, the head positioning runout amount (head positioning error amount) can be reduced, and the position of the fine magnetic head can be adjusted.

In the above-described first embodiment of the present invention, servo information can be written at three times the normal density for the control measurement area of the fine movement actuator.
The present invention is not limited to this. CPU for positioning control
If the processing speed of 1 is sufficiently high, more servo information may be written.

[0066]

As described above, according to the present invention,
Since the servo information for improving the positioning accuracy in addition to the normal servo information is written on the outer peripheral portion or a portion other than the outer peripheral portion on the magnetic disk medium as the positioning region for measuring the fine movement actuator gain, the head positioning control is performed. The head positioning runout amount can be reduced without increasing the bandwidth of the means, and as a result, the Signal / Noise ratio (S / N ratio) required for measurement can be secured.

Further, according to the present invention, the servo information for improving the positioning accuracy is written only on the outer peripheral portion of the magnetic disk medium or only on a portion other than the outer peripheral portion, so that the data write area on the magnetic disk medium is reduced. amount,
In other words, the amount by which the data information is reduced is small, and the capacity of the magnetic disk device does not become extremely small due to the positioning area for measuring the actuator gain for fine movement.

Further, according to the present invention, since the S / N ratio required for measuring the fine movement actuator control characteristics can be ensured, the control characteristics of the fine movement actuator can be accurately measured in the magnetic head positioning control. Can be.

Further, according to the present invention, since the control characteristics of the fine movement actuator can be accurately measured, the magnetic head can be positioned more precisely with respect to the target track on the magnetic disk medium.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a magnetic head positioning device in a magnetic disk drive according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing an example of writing servo information on a magnetic disk medium in the magnetic disk device of the embodiment of the present invention.

FIG. 3 is a flowchart for explaining the operation of the magnetic head positioning device in the magnetic disk drive of the embodiment of the present invention.

FIG. 4 is a conceptual diagram showing an example of writing servo information on a magnetic disk medium in a conventional magnetic disk device.

[Explanation of symbols]

A12 Servo information A13 Additional servo information for fine movement actuator gain measurement A14 Positioning area for fine movement actuator gain measurement 1 Positioning CPU 2 Fine movement actuator gain measurement device 3 Sine wave generator 4 Magnetic head positioning controller 5 Adder 12 Piezo actuator 13 Voice coil motor 14 Magnetic head 15 Magnetic disk medium

Claims (7)

[Claims] 1. A magnetic head positioning device for a magnetic disk drive, comprising: a coarse movement actuator for positioning a magnetic head on a target track; and a fine movement actuator for positioning the magnetic head more precisely on the center of the target track. Gain measurement means for measuring the gain of the actuator; and positioning the magnetic head in a fine movement actuator gain measurement positioning area in which servo information has been written on the magnetic disk medium, and the fine movement based on the measurement result of the gain measurement means. And a positioning control means for adjusting control characteristics of an actuator for use in a magnetic disk drive. And a sine wave generating means for generating a sine wave signal required for the gain measurement of the gain measuring means, wherein the gain measuring means includes: a position error signal of a magnetic head; The gain of the fine movement actuator is measured based on a signal obtained by adding the sine wave signal to the fine movement actuator drive signal for positioning the head on the target track, and the positioning control means performs the positioning based on the measurement result of the gain measurement means. 2. The magnetic head positioning device according to claim 1, wherein a control characteristic of the fine movement actuator is adjusted to be equal to a design value. 3. The gain measuring means determines whether or not the measurement result of the gain of the fine movement actuator is within an appropriate range. If the measurement result is within an appropriate range, the gain measuring means determines the measurement result as the positioning control means. 3. The magnetic head positioning device in a magnetic disk drive according to claim 2, wherein the magnetic head output signal is output to the magnetic disk drive. 4. The positioning area for measuring a fine movement actuator gain is provided on an outer peripheral portion on a magnetic disk medium, or provided on a portion other than the outer peripheral portion on a magnetic disk medium,
4. The magnetic head positioning device according to claim 1, wherein the magnetic head positioning device is provided based on a track layout of a magnetic disk medium. 5. The servo information writing density of the fine movement actuator gain measurement positioning area can be increased according to the processing speed of a positioning control system. 7. A magnetic head positioning device in the magnetic disk drive according to claim 1. 6. A magnetic disk drive comprising a coarse movement actuator for positioning a magnetic head on a target track and a fine movement actuator for positioning a magnetic head more precisely on the center of a target track, wherein a gain of the fine movement actuator is measured. Gain measurement means for positioning the magnetic head in a fine movement actuator gain measurement positioning area in which servo information is written on a magnetic disk medium, and control characteristics of the fine movement actuator based on the measurement result of the gain measurement means. A magnetic disk drive, comprising: a positioning control means for adjusting the distance. 7. A sine wave generating means for generating a sine wave signal required for gain measurement of the gain measuring means, the gain measuring means comprising: a position error signal of a magnetic head; The gain of the fine movement actuator is measured based on a signal obtained by adding the sine wave signal to the fine movement actuator drive signal for positioning the head on the target track, and the positioning control means determines a predetermined gain based on the measurement result of the gain measurement means. 7. The magnetic disk drive according to claim 6, wherein adjustment is performed so as to obtain the control characteristic of the fine movement actuator.