JPH04176063A - magnetic disk device - 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]

[Purpose of the Invention] (J! Field of Industrial Application) The present invention relates to a magnetic disk device (41) that positions a magnetic head on a target data track according to servo information provided on the magnetic disk. (Prior art) In order to increase track density in magnetic disk drives, servo information for positioning the magnetic head is formed on the magnetic disk in advance, and the magnetic head is positioned according to the servo information. The sector servo method is known as one of such positioning methods.In the sector servo method, a servo consisting of a pattern that repeats at a predetermined period is used in a part of the sector (servo sector) on the track. Information is formed in advance, and this servo information is read by a magnetic head and sampled at a sampling period determined by the number of sectors and the rotation speed of the disk, thereby generating a position error signal indicating the position error of the head with respect to a desired track. The position of the magnetic head is controlled so that this position error signal is minimized.Among magnetic disk devices, small hard disk devices and floppy disk devices are often installed in portable personal computer devices, etc. It is easy to receive external vibrations and shocks.It is difficult to maintain perfect head positioning and follow the target track against such vibrations and shocks.Therefore, in the past, servo information was stored in the data recording section. By creating a configuration that obtains as much as possible in balance with the above, the servo band can be increased to improve vibration resistance, and by attaching the entire magnetic disk to a vibration isolating mechanism, it is possible to ensure positioning accuracy. By the way, in the sector servo method, magnetic/rad position error signals cannot be obtained between sectors, so if the number of servo sectors is suppressed from the perspective of improving format efficiency, the period during which no position error signal can be obtained becomes longer. Therefore, in response to disturbances such as shock and vibration, the ability of the magnetic head to follow the target track (track following performance) and the O response when the magnetic head goes off-track due to disturbance (disturbance suppression characteristics) are poor, making it difficult to accurately There is a problem that positioning cannot be maintained and the selective positioning characteristics deteriorate.In addition, in sample value control systems, there is generally a phase delay due to sample hold, but J5 is used so that this phase delay does not affect the control system. It is said that it is necessary to limit the servo band to about 1/7 or less of the sampling frequency. If you limit the servo band in this way,
The gain in the frequency band where disturbance exists is reduced, and the vibration resistance characteristics are reduced. (Problems to be Solved by the Invention) As described above, in conventional magnetic disk drives using, for example, sector servo system, #'
Due to the inability to obtain a position error signal for the iS air head, the limited number of servo sectors due to format efficiency, and the low gain of the servo system in the frequency band where disturbances exist, external vibrations and shocks may occur. It is difficult to make the magnetic head correctly follow the target track due to external disturbances, and there is a problem in that the response is poor when off-track due to external disturbances. SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic disk device that can correctly position a magnetic disk on a target track despite disturbances such as vibrations and shocks. [Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned 81 problems, the magnetic disk device of the present invention detects the position of the magnetic head in the radial direction of the magnetic disk, and detects the position of the magnetic head in the radial direction of the magnetic disk. After differentiating the signal to the second order or higher, the high-frequency components of the differential output signal are suppressed by a filter means, and the position error signal obtained from the output signal of this filter means and the servo information on the magnetic disk are calculated. Obtain the difference signal from the basic control signal, integrate this difference signal, and calculate O? for the head movement mechanism. ! It is characterized by obtaining a IIIMll signal. The position of the magnetic head in the radial direction of the magnetic disk is detected, for example, as the position of a moving part of a head moving mechanism that moves a magnetic head in the radial direction of the magnetic disk. Furthermore, according to a more preferred example of the present invention,
When moving the magnetic head from one track to another on a magnetic disk, a state in which the integrating operation of the integrating means that integrates the difference signal between the output signal of the filter means and the basic control signal is stopped when the head moving mechanism is accelerated. As, by open loop control with maximum acceleration! tJ11 control, and when decelerating, the integrating means performs an integral operation, and the control is performed by closed-loop control that decelerates according to the target speed. (Function) When the position signal indicating the position of the magnetic head in the radial direction of the magnetic disk is first differentiated, a speed f signal corresponding to the moving speed of the magnetic -\rad is obtained.This speed If signal is further differentiated, that is, the position By second-order differentiation of the signal, an acceleration signal corresponding to the movement of the magnetic head when a disturbance such as vibration or impact is applied to the head movement mechanism can be obtained. Therefore, if the head moving mechanism is controlled using a signal obtained by integrating the difference signal between the acceleration signal containing this disturbance and the basic control signal obtained by calculating the position error signal obtained from the servo information, Head position errors caused by disturbances are quickly suppressed, and track following performance and disturbance characteristics are improved. Even if the position signal is differentiated to the third order or higher, the acceleration fO information due to the disturbance is preserved, so by changing the position error signal based on the servo information accordingly, the same O result can be obtained. When the position signal is differentiated by the second order or higher, the high-frequency noise components contained therein are emphasized, which may actually deteriorate the control characteristics, but the filter means suppresses the high-frequency components of the differentiated output signal. As a result, stable a control characteristics without the influence of noise can be obtained. Additionally, by stopping the integration operation of the integrator during the open-loop control period when the head movement mechanism accelerates, the integrator will not become saturated during open-loop control, and the head movement mechanism will smoothly transition to closed-loop control. The ability of the mechanism to follow the target speed is improved. (Example) Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a head positioning system of a magnetic disk device according to an embodiment of the present invention. The magnetic disk 2 is rotationally driven by rotation of a spindle l by a spindle motor (not shown). The magnetic disk 2 is, for example, a hard disk or a floppy disk, and a magnetic head 3 records and reproduces data. The magnetic disk 2 is constructed in the same manner as a known magnetic disk compatible with the sector thermistorem method, and for example, as shown in FIG.
A guard zone 21 is provided on the outer periphery of one or both sides, and a data zone 22 is provided on the inner periphery.
A servo sector 23 is provided in each zone, and a data sector 24 is provided in each data zone 22. data zone 2
It is assumed that the number of sectors of 2 is +01MK, for example. Further, as shown in FIG. 3, the servo sector 23 includes an erase section 31 for detecting the servo sector 23, and an AGC
fiiS32, guard zone 21 and data zone 220
A zone detecting section 33 for discrimination and a positioning section 34 in which a servo pattern is written are provided. Therefore, when detecting the servo sector 230 by the magnetic head 3, the magnetic head gap 35t in FIG.
When the servo track is centered, the center of the gap 35 can basically be aligned with the center of the next data track according to the rotation of the spindle 1. Specifically, the signal recorded on the magnetic disk 2 is reproduced by the magnetic head 3 as shown in FIG.
It is sufficient to hold the peaks of the signals A, B, C, and D as described later, and generate a head position error signal from AB and CD, so that the gap 35 passes through the center of the track. Next, the configuration of the head positioning system in Figure 1#1 is shown in the fifth figure.
This will be explained with reference to the control block diagram shown in the figure. In FIG. 1, the head moving mechanism 4 is a mechanism that moves the magnetic head 3 in the radial direction of the magnetic disk 20 in accordance with a control signal. Linear voice coil motor (LVCM) 6
It consists of Further, the carriage 5 of the head moving mechanism 4 is provided with a linear scale 7, and an IJ near scale 7 is provided near the linear scale 7, and the carriage 5 is provided with an IJ near scale 7 in the vicinity of the linear scale 7. An optical sensor 8 is provided that detects the relative position of 5 and outputs a position signal consisting of a continuous signal. These linear scale 7 and optical sensor 8 constitute an optical scale sensor shown in FIG. Note that 1) the mounting positions of the near scale 7 and the optical sensor 8 will be described later. The signal reproduced by the magnetic head 3 is amplified by a preamplifier 9 and then input to the μCPU 13 via an AGC amplifier 10, a peak hold circuit 11, and an A/Di converter 12. The A/D converter 12 samples the output of the peak hold circuit 11 for each servo sector 23, and reproduces the servo pattern of the position detection section 34 to obtain peak hold values of four signals A, B, C, Digitize D. The JICPU 13 receives A-B from the output of the human/D converter 12. CD is calculated to obtain a position error signal indicating the error in the relative position of the magnetic head 3 with respect to the track on the magnetic disk 2, and based on the position error signal, a basic control signal C (hereinafter referred to as basic control signal) is generated using a known method. It is determined by compensation calculation and output as a digital value. The digital value of this basic control signal is D/
It is converted into an analog signal by A conversion 514. On the other hand, the device signal composed of the optical sensor 8 is transmitted to the amplifier 1.
5 to the differentiator 16, where it is second-order differentiated. The position signal from the optical sensor 8 corresponds to changes in the relative position of the carriage 5 with respect to the base, and is a nine-continuous signal. When this signal is differentiated by the gold order, a speed signal corresponding to the distance of movement of the carriage 5 is obtained, and when differentiated by the second order, An acceleration signal will be obtained. The differential output signal (acceleration f! number) from this differentiator 16 is
The signal is input to a low-pass filter 17 for suppressing high-frequency components (noise components) emphasized by differentiation. The analog basic control signal from the D/A converter 14 is input to the non-inverting input terminal of the operational amplifier 18, and the output signal from the low pulse filter 17 is input to the inverting input terminal of the operational amplifier 18. Therefore, the operational amplifier 18 obtains a difference signal between both signals. This difference signal is integrated by an integrator 19.
The output signal 9 is input as a control signal to a drive amplifier 20 for driving the linear voice coil motor 6 of the head moving mechanism 4. Here, when a disturbance such as a shock or vibration is applied to the head moving mechanism 4, the position signal detected by the optical scale sensor composed of the linear scale 7 and the optical sensor 8 suddenly changes due to the impact vibration of the carriage 5. do. When this position signal is amplified by the amplifier 15 and second-order differentiated by the differentiator 16, a large acceleration signal corresponding to the movement of the carriage 5 due to impact and vibration is obtained. Since this acceleration signal is input to the operational amplifier 18 via the low-pass filter 17, a large difference signal is output from the operational amplifier 18. This difference signal is integrated by an integrator 19 and input to a drive amplifier 20. As a result, head positioning errors caused by disturbances such as shocks and vibrations are quickly suppressed, and track following performance and disturbance characteristics are improved. Figure 6↓ and the seventh cause are diagrams for explaining the situation when a shock is applied as a disturbance to the head moving device s4. In the conventional case where there are no 17 systems, FIG. 7 shows the case of this embodiment. In both figures, (a) shows the position y of the magnetic head 3, (b) shows the disturbance Rl) S, and (C) shows the current IC of the Fi millilinear whistle coil motor, respectively. As is clear from the figure, according to the present invention, the magnetic
- It can be seen that the positional error of the RAD 4 is quickly corrected, and the positioning error itself is reduced by one order of magnitude or more. Further, the pressure from the optical sensor 8 generally includes high-frequency noise components other than the position signal. Therefore, optical sensor 8
If the differentiator 16 collects the 6-force signal from the 6-force signal, the noise component will be emphasized, which may deteriorate the characteristics of head positioning control. Low-pass filter 17Fi, differentiator] 6 to O to prevent such noise from being added to the control system.
It is provided to suppress high frequency components of the differential output signal. FIG. 8 is a block diagram showing another embodiment of the present invention, and the difference from FIG. 1 is that the integration operation of the integrator 19 is controlled by μCPU13. βCPU13
When seeking, that is, moving the magnetic head 4 from one track to another on the magnetic disk 2, open-loop control is performed on the bed moving mechanism 4 at the maximum acceleration KFi during acceleration, and when decelerating, the tape is ^・Perform closed-loop control that decelerates according to the target speed. During open loop control, a large difference signal is continuously transmitted to the integrator 19.
If the integrator 19Fi continues its integration operation, it will become saturated. For this reason, when switching to deceleration operation, the magnetic head 3 causes overshading, and the tracking performance for the target speed is greatly degraded. Therefore, in this embodiment, the integration operation of the integrator 19 is stopped during the open loop control period when the head moving mechanism 4 is accelerated, so that only the proportional amplification operation of the difference signal output from the operational amplifier a18 is performed. , the integrator 19 performs an integration operation during the closed loop control period during deceleration. On/off control of the integration operation of the integrator 19 is executed by a command signal from the voice C'PU 13. Stopping the integral operation is achieved by stopping the integral operation. This prevents the integrator 19 from becoming saturated during open loop control, allowing a smooth transition to closed loop control and accurately following the target speed. Furthermore, if closed-loop control is performed during acceleration to limit the maximum acceleration so that the integrator 19 does not become saturated, a problem arises in that the seek time becomes longer. If the integration operation of the integrator 19 is stopped at
saturation can be prevented. jl! FIG. 9 shows the relationship between the target speed VRZ and the moving speed (2) of the magnetic head 30 over time when the integrator 19 is operated also during open loop control. In the figure, when the speed control starts (during acceleration), the target speed [VRZ] becomes a constant value, and open-loop control is performed during this acceleration period. Then, from the time t when the head movement speed (2) matches the target speed VRZ, the deceleration starts. Closed loop control 1 is performed during the deceleration period. In this case, even if the target speed VRZt is set quite slowly as shown in the figure (for example, an acceleration/deceleration ratio of 1:4), the magnetic head 3 will overshade, and the head movement speed (2) will greatly exceed the target speed VRZ. This overshading is caused by the saturation of the integrator 19 during open-loop control as described above.On the other hand, the JIEIO diagram shows the target speed VRZ when the integrator 519 is in an inactive state during open-loop control. Relationship between the movement speed VO of the magnetic head 3 and the time change

[Shows. Similarly to Fig. 9, when starting speed control (during acceleration), the target speed ■几Z
becomes a constant value, and open-loop control is performed during this acceleration period, but the integrator 19 is controlled by the control K- from the voice CPU 13.
The integral operation has stopped. In this state, the time t when the head movement speed ■ matches the target speed [VRZ]! Then, the speed shifts to deceleration, and closed-loop control is performed. At this time, the integrator 19 starts an integration operation under control from the μCPU 13. In this case, since the integral 519 is not saturated in the open loop control FRjK, the target speed VRZt is set to rapidly decelerate as shown in the figure.
, the magnetic head 3 will not oversheet,
The head movement speed ■ follows the target speed VRZ well. Therefore, high-speed seek can be achieved. The present invention is not limited to the embodiments described above, but can be implemented with various modifications as follows. (2) In the embodiment, the position of the carriage 5 was detected by the optical sensor 8, but it is also possible to use a magnetic sensor, an electric sensor such as an electrostatic sensor, or other sensors. (2) In the embodiment, it has been explained that the position signal is second-order differentiated in the differentiation 616, but any second-order or higher differentiation may be used. For example, if the third order differential is used, the rate of change in acceleration can be obtained. In that case, it is desirable that the basic control signal also be a signal that corresponds to the rate of change of acceleration (signal that corresponds to the rate of change of acceleration). ■ In the example, the sector servo method was explained, but the so-called servo surface servo method has a dedicated servo surface separate from the data surface. The present invention can also be applied to magnetic disk drives.In that case, a position signal obtained from servo information on a dedicated servo surface can be used instead of a position signal from a position detection means provided in the head moving mechanism. This position signal is input to the differentiator as in the previous embodiment and is differentiated on the second order or higher. ■In the actual mfll, there is a The main circuit is composed of a digital circuit using the A/D converter 12, the acPU 13, and the D/A converter 14, and includes a differentiator that differentiates the position signal to the second order or more, and a low-pass filter that suppresses the high-frequency components of the differential output signal. The sub-circuit consisting of
In this case, it is necessary to detect the acceleration or its rate of change in the 11 @ path. Since there is, IIJ
It is i! that the sampling period of the A/D converter in the @ path is less than or equal to the sampling period of the A/D converter 12 (2) in the main circuit. Delicious. Nine, if both main threshold circuits are configured with digital circuits, integration! 194 may be constructed from a digital circuit, and a KD/A converter may be disposed on the output side of the integrator. Further, the mounting positions of the linear scale 7 and the optical sensor 8 will be explained in detail with reference to FIGS. 11 to 26. Conventional head positioning systems improve disturbance suppression characteristics without increasing the servo bandwidth and directly detect and compensate for disturbances applied to the head positioning system.
The absolute position of the head relative to the attached base plate had to be detected. FIG. 26 shows the configuration of a conventional head positioning system that performs the above-mentioned absolute position detection. The head positioning system shown in FIG. 26 uses a transmission type optical encoder to detect the absolute position. However, when using a transmission type optical encoder, due to space constraints,
As shown in the figure, it was necessary to add a school slit 112 to the carriage 103 via the arm 1001. As a result, the weight of the movable part of the head positioning device increases, resulting in problems such as slow access speed. In addition, since the center of gravity 0 position f is separated from the rotation axis of carry and movement, there is a problem that the characteristics against disturbances are deteriorated. Therefore, the positioning system for a magnetic disk drive of the present invention provides a head positioning system that includes a position sensor that does not significantly increase the weight of the movable part. FIG. 11 is a plan view of a magnetic disk drive in which the first mounting of the linear scale 7 and optical sensor 8 is shown as an example, and FIGS. 12 and 13 are the -rad positioning device in FIG. FIG. 6 is a top view and a side view of the rear end. The magnetic disk medium 11 is fixed to a disk 102 and rotated by a spindle motor (not shown). The carriage 103 is rotatably attached to a shaft 105 fixed to a base plate 104. The magnetic head slider 106 is fixed to the carriage 103 via a suspension strap 107. The voice coil motor 108 includes a coil bobbin 109 fixed to the carriage 103 and wound with a coil, and a stator 110 installed on the base plate 104 at the position shown in the figure. 12 and 3 at the rear end of the coil bobbin 109.
As shown in Fig. 1313, a reflective block 11 made of resin
1 is fixed. In addition, the reflection block 110 has a surface force that is constant at a distance from the rotation axis of the carriage 1030.The reflection surface 112 has reflection 5113 and absorption 5114 at equal intervals as shown in FIG. They are arranged at pitch a. Such a reflective surface 112 is
For example, it can be created by applying a light-absorbing paint to the reflective surface 112 of the reflective block 1110 and pasting a slit made of a thin plate that reflects light. Further, a sensor 115 is installed on the base plate 104 at a position as shown in FIG. sensor 11
5 has the configuration shown in FIG. 15, for example, and a light emitting diode)'
116 and the phototransistor 117, the reflective surface 1
An electric signal corresponding to the amount of reflected light of the light projected onto the light source 12 is output. When the gear 1 nozzle 103 rotates in the above configuration, the output of the sensor 115 is obtained as shown by the solid line in FIG. 16 with respect to the amount of movement of the rear end of the coil bobbin 109. Furthermore, since the ratio of the amount of movement of the rear end of the coil to the amount of movement of the head is equal to the ratio of the distance from the rotation axis of the carriage, the amount of movement of the head relative to the base plate can be obtained from the output of the sensor. Note that the sensor output of 87N can be increased by installing a mask 118 shown in FIG. 17 between the sensor and the reflective surface. However, it is desirable that @b of the slit 119 be equal to or smaller than half the pitch a. In this embodiment, the reflective block 111 is made of lightweight resin,
Since the shape is symmetrical with respect to the line connecting the rotation axis of the carriage and the head, it has a negative effect on the performance of the head positioning device. Next, in the above embodiment, the output of the sensor 115 is 1
A pseudo sine wave like the broken line in Figure 116 may disrupt the linearity of output and displacement. Therefore, in such a case, two sensors are installed and the sensors are shifted so that the phase of each output is shifted by 1/4 as shown in Figure 18, and the linearity of each output is adjusted. It is possible to obtain the correct position signal by switching between the villages that are maintained. In addition, the same effect as in 4 can be obtained by using an arrangement in which the reflective part and the absorbing part are shifted by 1/4 on the reflective surface without shifting the sensor arrangement. Note that by further increasing the number of sensors and using a plurality of outputs that are out of phase with each other, it is also possible to obtain an output with higher linearity. In the above embodiments, the reflective surface is installed at the rear end of the coil bobbin, but this does not limit the position of attachment. For example, as shown in FIG. 19, by installing the reflective surface 120 near the head dispersion portion of the carriage 103, the influence of errors due to deformation of the carriage cocoil bobbin, etc. can be reduced. Next, Figure 20 shows the WL of the linear scale 7 and optical sensor 8.
Figure 21 is a top view of the coil section of the head positioning device in Figure 920, and Figure 22 is a cross-sectional view of the voice coil motor. be. In the first installation, as in the example, the magnetic disk medium 101 is fixed to the hub 102 and rotated by a spindle motor (not shown). The carriage 103 is rotatably mounted on a shaft 105 fixed to a base plate 104. The magnetic head slider 106 is fixed to the carriage 103 via a suspension strap 107. Also, a voice coil motor 108Fi, a coil bobbin 109 fixed to the carriage 103 and wound with a coil.
and a base plate 104 (a stator 110 installed at the 0 position in FIG. In this moving scale 112, a plurality of moving slits 113 are arranged at equal intervals in the moving direction at a pitch angle α centering on the axis 105.
2a: Can be manufactured by vapor depositing metal on a glass plate or etching a metal plate. Furthermore, the stator 110 of the voice coil motor 108 includes a light emitting element 114 and a light receiving element 11 as shown in FIG.
5 and a mask 116 are embedded. these are,
It is embedded in a hole drilled in the same direction as the shaft 105 at the position shown in FIG. 20 of the stator 110. mask 116
As shown in FIG. 11K23, a detection slit 117 is provided. With the above configuration, the relative positions of the moving scale 1120 moving slit 113 and the detection slit 117 of the mask 116 change according to the rotation angle of the carriage 103, so that out of the light emitted from the light emitting element 114, the light receiving element 115I
C: The amount of light received changes. Therefore, the relationship Fi between the rotation angle of the carriage 1030 and the output of the light receiving element 115 is as shown in FIG. Note that the width of the detection slit 1170 is desirably the same as or slightly smaller than the width of the moving slit 1130. In this embodiment, there are one detection block (117#'i-), but a plurality of detection blocks may be used to stabilize the output waveform. Next, in the above embodiment, the output of the light receiving element 115 becomes a pseudo sine wave like the broken line in Fig. 24, and the linearity between the output and the rotation angle may be lost. Therefore, in such a case, two light-receiving elements 115 are installed, and the detection slits 117 are staggered so that the phases of their respective outputs are shifted by α/4 as shown in FIG. A correct position signal can be obtained by switching and using only the portion where output linearity is maintained. Further, by further increasing the number of light receiving elements 115 and using a plurality of outputs whose phases are shifted from each other, it is also possible to obtain an output with high haphazard shape. In addition, the present invention can be implemented with various modifications without departing from the scope of the invention. [Effects of the Invention] According to the present invention, after differentiating the position signal to the second order or higher, the difference between the signal with suppressed high-frequency components and the basic control signal obtained by calculating the servo information on the magnetic disk is calculated. Furthermore, by controlling the head movement mechanism using a signal obtained by integrating the difference signal, the tracking ability of the magnetic head when external electric current such as vibration or impact is applied, and the response when off-track due to external tK are improved. , the magnetic head can be correctly positioned on the target track. Before transitioning from open-loop control to closed-loop control ilK, by stopping the integral tIO integration operation during the open-loop control period during seek and acceleration of the head moving mechanism to prevent saturation of the integrator during open-loop control. This prevents the overflow from occurring and improves the ability of the head movement speed to follow the target speed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a magnetic disk device according to an embodiment of the present invention, FIG. 2 is a plan view schematically showing the arrangement of servo sectors on a sector servo type O magnetic disk, and FIG. 3 is a plan view showing the inside of a servo sector. A diagram schematically showing the configuration of the servo sector/#! Figure 4 shows the reproduction signal waveform from the servo sector on the magnetic disk, Figure 5 is a control block diagram of the head positioning control system of the magnetic disk drive of the same notice, and Figures 6 and 7 show the conventional technology and the book. FIG. 8 is a block diagram showing the configuration of a magnetic disk device according to another embodiment of the present invention, and FIGS. 9 and 10 are diagrams showing the speed tracking characteristics according to the prior art and the present invention. FIG. 11 is a plan view of a magnetic disk device using the first six examples of mounting a linear scale and an optical sensor, and FIG.
Figures 13 and 14 are diagrams showing the reflection block in Figure jlE11, Figure 15 is a diagram showing the structure of the sensor,
Figure 16 is a diagram showing the output of the sensor, Figure 17 is a diagram of mamaku, Figures 18 and 19 are diagrams showing modifications of Figure 11, and Figure 20 is a diagram showing the linear scale and optical sensor. Figure 21 is a diagram showing the coil part of the voice coil motor, Figure 22 is a cross-sectional view of the voice coil motor shown in Figure 20, and Figure 23 is a diagram showing the coil part of the voice coil motor. Figure 24 is a diagram showing the output of the light receiving element, Figure 25 is a diagram showing the output of the light receiving element.
This figure is a diagram showing the output of a light receiving element according to a modification of FIG. 21, and FIG. 26 is a diagram showing the configuration of a conventional head positioning system. 2...Magnetic disk, 3...Magnetic head, 4...
Head moving mechanism, 5.-- Carriage (moving part), 6.
−・Linear voice coil motor, 8・Optical sensor (
position detection means), 11... peak hold circuit, 13
... μCPU (control means), 16 ... Differentiator, 17
...Low pass filter, 18.--Operation amplifier (difference signal generation means), 19.. Integrator. Agent Patent Attorney Kensuke Chika Figure 2 Figure 3 ABCD Figure 4 Figure 9 Figure 15 Figure 15 Figure 16 Figure 17 Figure 18 Figure 1819 Figure l Figure 20 Figure 21 Figure 23 Figure 24 Time iPt^ Figure 25

Claims (3)

[Claims] (1) A magnetic disk on which servo information is written, a magnetic head for recording and reproducing data on the magnetic disk, and a head movement mechanism that moves the magnetic head in the radial direction of the magnetic disk in accordance with a control signal. , means for obtaining a position error signal indicating a position error of the magnetic head with respect to a desired track on the magnetic disk from servo information read by the magnetic head, and performing a predetermined calculation on the position error signal to generate a basic control signal. position detecting means for obtaining a position signal indicating the position of the magnetic head in the radial direction of the magnetic disk; means for obtaining a differential output signal by differentiating the position signal by a second order or more; filter means for obtaining an output signal with suppressed frequency components; means for obtaining a difference signal between the output signal of the filter means and the basic control signal; and integrating means for integrating the difference signal to obtain the control signal. A magnetic disk device characterized by: (2) a magnetic disk on which servo information is written in each sector on a track; a magnetic head for recording and reproducing data on the magnetic disk; and a magnetic head that moves the magnetic head in the radial direction of the magnetic disk in accordance with a control signal. a head moving mechanism for moving the head; means for generating a position error signal indicating a position error of the magnetic head with respect to a desired track on the magnetic disk from servo information read by the magnetic head; and performing a predetermined operation on the position error signal. means for obtaining a basic control signal by performing a step of detecting a position of a moving part in the head moving mechanism;
position detection means for obtaining a position signal indicating the position of the magnetic head in the radial direction of the magnetic disk; means for obtaining a differential output signal by differentiating the position signal by more than one order; and suppressing high-frequency components of the differential output signal. The present invention is characterized by comprising: filter means for obtaining an output signal of the filter, means for obtaining a difference signal between the output signal of the filter means and the basic control signal, and integrating means for integrating the difference signal to obtain the control signal. magnetic disk device. (3) When moving the magnetic head from one track to another on the magnetic disk, open-loop control is performed at maximum acceleration with the head moving mechanism stopping the integrating operation of the integrating means during acceleration. 3. The magnetic disk drive according to claim 1, further comprising control means for performing closed-loop control for decelerating in accordance with a target mode while causing the integrating means to perform an integrating operation during deceleration.