JP2006147116A - Head positioning control device and disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a head positioning control device and a disk device which allow the highly precise positioning servo control by two actuators to be performed, without the displacement of a micro actuator MA52 causing a disturbance to a coarse motion control system, and also without the MA52 exceeding an operating range. <P>SOLUTION: This head positioning control device is provided with a head 1, a head positioning mechanism 7 including a voice coil motor VCM51 and the MA52, a position detecting element 60 for outputting a head position signal from a reproducing signal of the head 1, and a positioning control section 6 for controlling the VCM51 and the MA52. The position detecting element 60 outputs a micro position signal P_head and a coarse position signal X_vcm with mutually different resolution from the reproducing signal of the head 1. A fine motion control section 62 calculates the controlled variable of the MA52 based on the micro position signal. A coarse motion control section 61 calculates the controlled variable of the VCM51 based on the coarse position signal X_vcm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a disk device such as a magnetic disk device or an optical disk device, and a head positioning control device mounted on the disk device.

  In recent years, with the progress of ubiquitous technology, high-density disk devices that record and reproduce large volumes of video information, audio information, character information, etc. at high speed by positioning the head at the target position at high speed have been marketed. Is strongly requested by. In particular, the demand for using a magnetic disk device for a mobile terminal device is increasing, and further downsizing of the magnetic disk device is being promoted. As described above, as the size of the disk device is reduced and the recording density is increased, a demand for higher accuracy in positioning the head has become more severe.

  Along with the miniaturization of the disk device, the friction of the bearing portion and the vibration from the outside influence the drive control by the actuator, and this influence cannot be ignored when positioning the head. Since the influence of friction on the positioning mechanism causes a decrease in positioning accuracy along with vibration, it is important to eliminate the influence of friction as the disk device becomes smaller and the recording density is increased.

  The positioning mechanism of the disk device includes a linear actuator called a direct acting type and a rotary actuator called a swinging type, both of which are supported by a bearing portion. Such a bearing portion always has a frictional force that is a reaction force against the movement of the head support portion by driving the actuator. For example, when the movement is started from a state where the head support portion is stationary, a driving force exceeding the frictional force based on the static friction between the bearing portion and the head support portion is required. Further, after the head support portion starts to move, a frictional force based on dynamic friction acts between the bearing portion and the head support portion. In general, the static friction is larger than the dynamic friction, and therefore a larger driving force is required when the movement is started from a state where the head support portion is stationary. Such a difference between static friction and dynamic friction makes it difficult to move smoothly, and positioning control may not be performed accurately.

  Further, as the disk device is reduced in size, the bearing portion also becomes smaller, and the influence of the frictional force on the movement of the head support portion becomes larger. Further, since the head support portion is also small and light, for example, the reaction force of a flexible printed circuit (hereinafter referred to as FPC) that is connected to the head and transmits an electrical signal is also similar to the friction force against the movement of the head support portion. Have a major impact. As described above, along with the miniaturization of the disk device, the frictional force of the bearing portion, the reaction force of the FPC, and the actuator vibration due to the spindle vibration are factors that hinder the miniaturization of the disk device and the high recording density.

  Further, the downsizing of the disk device has led to the reduction in the size and weight of the actuator, and the vibration resistance characteristics of the head positioning control system have been reduced. In the future, in order to apply the disk device to mobile devices, it is indispensable to achieve both compactness and vibration resistance.

  Therefore, in order to perform high-speed and high-precision positioning of the head, it is expected that a future disk apparatus will generally have a configuration having two actuators, a coarse actuator and a fine actuator. A configuration having a coarse actuator and a fine actuator is called a piggyback actuator, a two-stage actuator, or a dual-stage actuator.

  That is, a coarse actuator such as a voice coil motor (VCM) moves the head support portion and the head by rotating the head support portion around a rotary bearing provided in the housing of the disk device. The coarse actuator is mainly used for large head movements such as seek / settling and multiple track jumps.

  On the other hand, the fine actuator (microactuator (MA)) is provided between the coarse actuator and the head to move the head. The fine movement actuator is mainly used for fine positioning of the head at high speed such as track following or one track jump.

  Since the fine actuator can be controlled and driven in a higher band than the coarse actuator, it is possible to improve the vibration resistance characteristics by the high band control, and the fine actuator is arranged between the coarse actuator and the head. The head can be positioned while suppressing the influence of friction.

  Conventionally, several control methods using such a two-stage actuator have been proposed (see, for example, Patent Documents 1 and 2).

  Patent Document 1 discloses a magnetic disk device including a servo control system of a two-stage actuator. In this servo control system, the fine movement actuator detects a head position error (target) detected based on a head reproduction signal. The head is positioned by feeding back a signal (difference between the position and the current position of the head), while the coarse actuator performs positioning by feeding back a signal obtained by adding the displacement amount of the fine actuator to the position error signal.

  Here, the fine actuator is composed of a piezoelectric element, and the amount of displacement is proportional to the input signal (input voltage) to the piezoelectric element. Therefore, the amount of displacement of the fine actuator can be estimated based on the input signal to the fine actuator. A signal obtained by adding the displacement amount of the fine movement actuator to the position error signal corresponds to a position error between the target position and the position where the head is moved by the coarse movement actuator.

  Therefore, the servo control system of Patent Document 1 realizes high-precision positioning of the head by cooperative control of the coarse actuator and the fine actuator while controlling and driving the fine actuator near the center of the operation range by such a control method. is doing.

  Patent Document 2 discloses a magnetic disk device including a servo control system of a two-stage actuator. In this servo control system, a fine actuator and a coarse actuator are detected based on a reproduction signal of a head. The head positioning is performed by feeding back the head position error signal. That is, unlike the control system of Patent Document 1, the displacement amount of the fine actuator is not input to the coarse motion control system.

According to such a control method, the servo control system of Patent Document 2 is configured to operate stably with a certain degree of accuracy using only the coarse actuator even when the control of the fine actuator is saturated.
Japanese Patent No. 3089709 JP-A-10-255418

  However, in the control system disclosed in Patent Document 1, the coarse actuator and the fine actuator are cooperatively controlled only by the position error signal based on the reproduction signal of the head, and the displacement amount of the fine actuator is controlled by the coarse actuator. Since this is an input signal of the means, the operation of the coarse actuator is disturbed by the fine actuator, and the operation of the fine actuator is disturbed by the coarse actuator. That is, there is a problem that the residual vibration occurs and the head positioning settling time becomes long.

  Therefore, there is an improvement measure that shortens the head positioning settling time by controlling the operation of the fine actuator by adopting a configuration in which the control band of the fine actuator is set higher than that of the coarse actuator. It is impossible to eliminate vibrations caused by movement.

  In the control system disclosed in Patent Document 2, since the coarse actuator (VCM) and the fine actuator (MA) are controlled and driven by one head position signal, both the VCM and MA move to the target position. try to. Therefore, when the control bands are different from each other, for example, when the MA is in a high band and the VCM is in a low band, there is a possibility that the operation range may be exceeded by the MA operating fast. Further, since the fine motion control system detects the VCM operation as a disturbance and the coarse motion control system detects the MA operation as a disturbance, it becomes a double control, so an overshoot occurs and the settling time becomes longer. .

  The present invention has been made in view of the above points, and the object of the present invention is to perform highly accurate positioning servo control by two actuators, a coarse actuator and a fine actuator, while the displacement of the fine actuator is coarse. It is an object of the present invention to provide a head positioning control device and a disk device that can be performed without causing disturbance of the system and without the fine movement actuator exceeding the operating range.

  A head positioning control device according to the present invention includes an information recording disk on which servo information is recorded, a head that reproduces at least information recorded on the information recording disk, a coarse motion actuator that positions the head, and the coarse motion A fine movement actuator interposed between the actuator and the head, a head positioning mechanism including the coarse movement actuator and the fine movement actuator, and a position for detecting the head position based on the reproduction signal of the head and outputting the head position signal Detecting means, and positioning control means for controlling the coarse actuator and the fine actuator.

  The positioning control means drives a coarse motion control system including a coarse motion drive means for driving the coarse motion actuator and a coarse motion control means for outputting a control amount signal to the coarse motion drive means, and the fine motion actuator. And a fine movement control system including a fine movement control means for outputting a control amount signal to the fine movement drive means, wherein the position detection means is a first head having a relatively high resolution from the reproduction signal of the head. Two position signals, a position signal and a second head position signal having a relatively low resolution, are output, and the fine movement control means controls the fine movement actuator based on the first head position signal. The coarse motion control means calculates a control amount for controlling the coarse motion actuator based on the second head position signal.

  According to this configuration, the fine movement control system controls the fine movement actuator by the first head position signal having a relatively high resolution, whereas the coarse movement control system has a coarse movement by the second head position signal having a relatively low resolution. Since the dynamic actuator is controlled, in the coarse motion control system, the follow-up sensitivity to the fine operation (interference operation) of the fine actuator is reduced. That is, the coarse motion control system does not regard the motion of the fine motion actuator as a disturbance, and the mutual interference between the motions of the two actuators is reduced. Therefore, the vibration response generated at the time of head positioning in the control of the two-stage actuator is prevented, and the head positioning settling time is shortened. Further, since the mutual interference is reduced, it is not necessary to greatly separate the respective control bands, and cooperative control in a high band is possible. That is, the two actuators can cause the head to follow the track (target position) with high accuracy while suppressing position errors due to friction, FPC reaction force, and vibration.

  Further, since the position detection means detects the first and second head position signals having different resolutions from each other based on the reproduction signal of the head, a detection means is separately provided for detecting the head position signal having a low resolution. There is no need.

  Here, the servo information includes two position signals, a track number signal and an inter-track position signal, which are arranged at equal intervals in the circumferential direction of the information recording disk, and the position detecting means includes the track number signal and The head position detected with the same number of bits as the number of bits per track of the inter-track signal is output as a first head position signal and shifted with respect to the number of bits per track of the track number signal and the inter-track signal. The head position detected with the predetermined number of bits may be output as the second head position signal.

  Unlike this, the servo information includes inter-track position signals arranged at equal intervals in the circumferential direction of the information recording disk, and the position detection means has the same number of bits per track of the inter-track signal. The head position detected by the number of bits is output as a first head position signal, and the head position detected by a predetermined number of bits shifted with respect to the number of bits per track of the inter-track signal is a second head position signal. May be output as

  Note that the number of bits of the second head position signal may be appropriately set according to the operation of the head positioning control device, the settling time, and the like.

  The control band of the fine movement control system is preferably set to 1.5 times or more of the control band of the coarse movement control system.

  In other words, when the control band of the coarse motion control system and the control band of the fine motion control system are too close, the control operation of the coarse motion actuator and the fine motion actuator interferes, but the control bandwidth of the fine motion control system By setting it to 1.5 times or more of the control band of the system, it can be solved. Further, by reducing the control band of the coarse motion control system relative to the control bandwidth of the fine motion control system, the coarse motion control system does not follow the control operation in the high frequency band of the fine motion control system. As a result, control interference between the fine motion control system and the coarse motion control system is avoided.

  Further, it is preferable that a control band of the fine movement control system is set higher than a resonance frequency of the head positioning mechanism, and a control band of the coarse movement control system is set lower than the resonance frequency.

  Since the control band of the coarse motion control system is limited by the resonance frequency of the head positioning mechanism, the coarse motion control system is set lower than the resonance frequency, while the fine motion actuator is interposed between the coarse motion actuator and the head. Therefore, the fine movement control system is not affected by the resonance frequency, so that the two-stage actuator can be controlled in a high band by setting the control band of the fine movement control system higher than the resonance frequency.

  The coarse motion control system may further include a vibration sensor, and the control band of the coarse motion control system may be adjusted according to a detection signal of the vibration sensor.

  That is, when the fine movement actuator exceeds the operating range due to vibration, it is possible to compensate the position error for the vibration by increasing the control band of the coarse movement control system. When the vibration detected by the vibration sensor is a synchronous vibration, the position error can be compensated by adjusting the control band of the coarse motion control system by, for example, learning control.

  The coarse motion control means may further include a temperature sensor, and adjust a control band of the coarse motion control system in accordance with a detection signal of the temperature sensor.

  That is, the torque constant of a coarse actuator such as a VCM changes due to a temperature change, and its control band changes apparently. However, the torque constant of the coarse actuator is estimated based on the detection signal of the temperature sensor, and the estimated result is Accordingly, it is possible to keep the control band at the design value by correcting the control gain of the coarse motion control system.

  The position detection means switches driving / stop of the fine movement actuator based on a first condition related to the magnitude of the position error with respect to the target position of the head, and the second head position when stopping the fine movement actuator. The resolution of the signal may be increased.

  That is, when the position error is relatively large (such as during an access operation or a track jump), the fine motion actuator is stopped and the positioning control is performed using only the coarse motion actuator. In this case, since only the coarse motion actuator is driven and there is no control interference, the coarse motion control system controls the coarse motion actuator based on the position signal with high resolution. On the other hand, when the position error is relatively small (such as track following in the target track), the fine motion actuator is driven, and positioning control is performed by a two-stage actuator of a coarse motion actuator and a fine motion actuator.

  The position detecting means may decrease the control band of the coarse movement control system when driving the fine movement actuator, and increase the control band of the coarse movement control system when stopping the fine movement actuator.

  As described above, when both the fine actuator and the coarse actuator are driven, control interference is avoided by reducing the control band of the coarse control system relative to the control band of the fine control system, while the fine actuator is controlled. When stopping the actuator and driving only the coarse actuator, the accuracy of positioning control is ensured by increasing the control band of the coarse control system.

  The position detecting means may switch the control method of the coarse motion control system based on a second condition related to the magnitude of the position error relative to the target position of the head and the displacement of the fine motion actuator.

  That is, the control method of the coarse motion control system is switched between the case where the position error is relatively small and the displacement of the fine motion actuator has no margin in the motion range (there is a possibility of exceeding the motion range) and the case where it is not.

  Specifically, the position detecting unit controls the coarse actuator based on a coarse movement position error signal that is a difference between the second head position signal and a target position, based on the second condition. A control amount for controlling the coarse actuator is calculated based on a first control method for calculating a control amount and a signal obtained by adding a displacement amount or an estimated displacement amount of the fine actuator to the coarse position error signal. Switching to the second control method may be performed.

  That is, when the position error is relatively small and the displacement of the fine movement actuator has no margin for its operation range, a control method for calculating a control amount for controlling the coarse movement actuator based on the coarse movement position error signal If not, the control amount for controlling the coarse actuator is calculated based on a signal obtained by adding the displacement amount or the estimated displacement amount of the fine actuator to the coarse position error signal. As a result, when the displacement of the fine movement actuator has a margin in the operation range, the fine movement actuator causes the head to follow the target track while the head is stopped near the target position by the coarse movement actuator. .

  Thus, the access time and the settling time can be shortened by driving / stopping the fine motion actuator and switching the control method of the coarse motion control system in accordance with the position error and the displacement of the fine motion actuator.

  The head includes a recording head that records information on the information recording disk and a reproducing head that reproduces information recorded on the disk, and the fine movement control system operates during recording of the recording head and reproduction of the reproducing head. You can do it.

  This limits the number of times (frequency) of driving the fine actuator, which is advantageous in terms of extending the life of the fine actuator.

  The fine movement control system includes an MR offset (positional deviation between the recording head and the reproducing head caused by processing accuracy, and a recording head at an arbitrary track (a radial position of the disk) generated when the head rotates around a rotary bearing). And the position deviation in the track direction between the reproducing head and the reproducing head) may be adjusted.

  Thus, at the time of reproducing information, the head is moved finely at high speed because the movement of the head corresponding to the MR offset is performed by the fine movement actuator.

  The fine movement actuator may be composed of a thin film piezoelectric element.

  The fine movement control means adjusts a control amount signal output to the fine movement driving means so that a control voltage output to the fine movement actuator is equal to or less than a threshold value determined according to the element characteristics. Is desirable.

  Unlike this, the fine movement driving means stores a control voltage threshold value determined in accordance with element characteristics of the fine movement actuator, and the control voltage output to the fine movement actuator is less than or equal to the threshold value. The output may be limited to

  In either case, the fine actuator does not exceed its operating range.

  The threshold value may be a control voltage at which the electric resistance of the thin film piezoelectric element is 1 MΩ or less.

  The coarse motion control system may further include constant disturbance estimation control means.

  As a result, disturbance compensation such as friction and FPC reaction force is performed in the coarse motion control system independently of the fine motion control system.

  The coarse motion control system may further include a rotation synchronization disturbance control unit, and the rotation synchronization disturbance control unit may use the first head position signal as an input signal.

  As a result, the disk rotation synchronization disturbance is compensated in the coarse motion control system independently of the fine motion control system.

  The disk device of the present invention is a disk device on which the above head positioning control device is mounted. This disk device is a disk device capable of recording and reproducing information at a high speed, and is a disk device capable of realizing miniaturization and high recording density.

  As described above, according to the head positioning control device and the disk device of the present invention, the coarse motion actuator is controlled based on the head position signal with low resolution, and the fine motion actuator is controlled based on the head position signal with high resolution. As a result, the mutual interference between the operations of the two actuators is reduced, and cooperative control in a high band can be realized. As a result, it is possible to cause the head to follow the track while suppressing positional errors due to friction, FPC reaction force, vibration, and the like, and a high-speed and high-precision head positioning control device and disk device are realized.

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

(Embodiment 1)
FIG. 1 shows a schematic configuration of a magnetic disk device on which the head positioning control device according to the first embodiment is mounted. In the figure, reference numeral 1 denotes a composite magnetic head (hereinafter referred to as a magnetic head) composed of a reproducing head which is a GMR head applying a magnetoresistive effect and a recording head which is an induction type inductive magnetic head, and 3 is a magnetic head. A head slider 4 on which the head 1 is mounted is a suspension arm that supports the magnetic head 1 so as to face the magnetic disk 2 via the head slider 3. The suspension arm 4 is supported by the carriage 5. The carriage 5 is rotatably supported by a rotary bearing 53 that is fixed to a housing (not shown) of the magnetic disk device.

  Reference numeral 51 denotes a voice coil motor (VCM) comprising a coil 51a and a magnet 51b forming a magnetic circuit. The VCM 51 constitutes a coarse actuator that controls the positioning of the magnetic head 1. Reference numeral 52 denotes a microactuator (MA) including a piezoelectric element (piezo element, PZT element) disposed between the suspension arm 4 and the head slider 3, and this MA52 constitutes a fine movement actuator that controls the positioning of the magnetic head 1. To do.

  The VCM 51 drives the suspension arm 4 via the carriage 5 to move the magnetic head 1 around the rotary bearing 53 together with the MA 52.

  FIG. 2 is a diagram illustrating the configuration of the MA 52. Since the detailed configuration of the MA 52 is described in Japanese Patent Laid-Open No. 2002-134807, this is incorporated herein, and only the basic configuration will be described here.

  The MA 52 includes two piezoelectric element actuators 52a and 52b that are driven by push-pull. Each piezoelectric element actuator 52a, 52b is composed of an upper electrode 521, a piezoelectric element 522, and a lower electrode 523, as shown in an enlarged view in FIG. By controlling the voltage applied to the two piezoelectric element actuators 52a and 52b, the head slider 3 is slightly displaced. That is, when the piezoelectric element actuator 52a extends in the direction A and the piezoelectric element actuator 52b contracts in the direction B, the head slider 3 rotates in the direction of the arrow C.

  The head positioning mechanism 7 is configured by the head slider 3, the suspension arm 4, the carriage 5, the VCM 51, the MA 52, and the rotary bearing 53.

  Next, a control system for positioning the magnetic head 1 will be described. In FIG. 1, reference numeral 6 denotes a positioning control unit that controls the VCM 51 and the MA 52, and the positioning control unit 6 includes a coarse motion control unit 61, a fine motion control unit 62, a fine motion drive unit 64, and a coarse motion drive unit 65. Reference numeral 60 denotes a position detection unit. The position detection unit 60 outputs two signals having different resolutions as signals indicating the current head position, as will be described in detail later.

  3 shows a block diagram of the head positioning control system of the magnetic disk apparatus, FIG. 4 shows a detailed block diagram of the fine movement control unit 62, and FIG. 5 shows a detailed block diagram of the coarse movement control unit 61. FIG. 6 shows a detailed block diagram of the VCM state estimator 63 included in the coarse motion control unit 61. Next, the operation sequence of the head positioning control system in the magnetic disk apparatus will be described with reference to FIGS.

  The magnetic head 1 is moved on the magnetic disk 2 by a two-stage actuator composed of a VCM 51 and an MA 52. Servo signals (track number signal and inter-track position signal (burst signal)) are recorded as position information on the magnetic disk 2, and the magnetic head 1 detects the servo signal and uses the head signal as a position detector. 60.

  The position detection unit 60 detects the track position (track number) and the inter-track position of the magnetic head 1 based on the head signal, and a fine position signal P_head as a first head position signal that represents the current position of the magnetic head 1. The approximate position signal X_vcm as the second head position signal is output. Details of the operation of the position detector 60 will be described later.

  The fine movement control system that controls the MA 52 includes a subtractor 62 </ b> S, a fine movement control unit 62, and a fine movement driving unit 64.

  The fine position signal P_head output from the position detector 60 is input to the subtractor 62S. The subtractor 62S takes the difference between the target position signal R and the fine position signal P_head and outputs a position error signal Pe to the fine movement control unit 62.

  As shown in FIG. 4, fine movement control unit 62 includes an integrator 62I, an integral feedback gain Ki (block 621), and a position error feedback gain Kp (block 622).

  The integrator 62I outputs a position error integration signal Pei from the position error signal Pe. The fine error control signal (control amount) C_ma is output from the fine movement control unit 62 to the fine movement drive unit 64 by multiplying the position error integration signal Pei by the integral feedback gain Ki and the position error feedback gain Kp.

  The fine movement control unit 62 is not limited to the above configuration. For example, two integrators may be added to the position error signal Pe, and the fine motion control signal C_ma may be generated by multiplying the coefficients of the proportional differentiator (phase advance compensator) and the integrator.

  The fine movement drive unit 64 generates and outputs a fine movement drive signal U_ma from the fine movement control signal C_ma, thereby controlling and driving the MA 52.

  Here, the fine movement control unit 62 adjusts the fine movement control signal C_ma output to the fine movement driving unit 64 so that the fine movement driving signal U_ma is equal to or less than the threshold value determined according to the element characteristics of the MA 52. That is, the fine movement control signal C_ma is limited so that the electric resistance of the piezoelectric element 522 is less than or equal to a predetermined value. The threshold value (the operation threshold value of MA52) may be, for example, a control voltage (fine movement drive signal U_ma) at which the electrical resistance of the piezoelectric element 522 is 1 MΩ or less.

  The fine movement control unit 62 may not adjust the fine movement control signal C_ma, but the fine movement driving unit 64 may output the fine movement driving signal U_ma so as not to exceed the threshold value.

  On the other hand, the coarse motion control system that controls the VCM 51 includes a subtractor 61S, a coarse motion control unit 61, and a coarse motion drive unit 65.

  The approximate position signal X_vcm output from the position detection unit 60 (a signal having a coarser resolution than the fine position signal P_head as described later) is input to the subtractor 61S. The subtractor 61S takes the difference between the target position signal R and the approximate position signal X_vcm and outputs the coarse movement position error signal Pe_vcm to the coarse movement control unit 61.

  As shown in FIG. 5, the coarse motion control unit 61 outputs an integrator 61I that outputs a position error integrated signal Pei from the position error signal Pe, an integral feedback gain Ki (block 611), and a position error feedback gain Kp (block 612). And a velocity feedback gain Kv (block 613), and a VCM state estimator 63 as a constant disturbance estimation control means.

  Two signals are input to the VCM state estimator 63. As will be described later, one is a coarse motion control signal C_vcm calculated by the coarse motion control unit 61, and the other is a rough position signal X_vcm output from the subtractor 63S and output from the VCM state estimator 63. The estimated position error signal Pee, which is the difference from the estimated displacement signal Xe_vcm.

  That is, as shown in FIG. 6, the VCM state estimator 63 includes a state variable A (block 63A), an input variable B (block 63B), and an output variable C (block 63C) when the VCM 51 is modeled. The integration element 1 / S (block 63I) and the VCM state estimation gain Ke (block 63G) are included. The VCM state estimator 63 estimates the moving amount and moving speed of the magnetic head 1 by the VCM 51 based on the estimated position error signal Pee and the coarse motion control signal C_vcm, and calculates the estimated displacement signal Xe_vcm and the estimated speed signal Ve_vcm. Output. Note that the estimated position error signal Pee multiplied by the VCM state estimator gain Ke is a compensation signal Pee "for reducing the estimation error of the VCM state estimator 63.

  The coarse motion control unit 61 multiplies each of the coarse motion position error signal Pe_vcm, the position error integrated signal Pei, and the estimated speed signal Ve_vcm by the position error feedback gain Kp, the integral feedback gain Ki, and the speed feedback gain Kv. Are added by the adder 61A to generate a coarse motion control signal C_vcm that makes the coarse motion position error signal Pe_vcm small. Here, an integral value of the coarse movement position error signal Pe_vcm may be used.

  The coarse motion control unit 61 is configured to generate the coarse motion control signal C_vcm by multiplying the coarse motion position error signal Pe_vcm by the coefficients of the proportional differentiator (phase advance compensator) and the integrator. May be.

  Further, the coarse motion control unit 61 may use a speed signal calculated by the difference of the fine position signal P_head instead of using the estimated speed signal Ve_vcm. In this case, the configuration of the magnetic disk device is as shown in FIG.

  In addition, as shown in FIG. 8, the coarse motion control unit 61 uses a disturbance (force) applied to the magnetic head 1 in the VCM state estimator 63 instead of using the integrated value of the position error signal Pe (position error integrated signal Pei). The estimated disturbance amount signal Fe_vcm may be used so as to estimate the amount of disturbance, position disturbance). That is, after each of the coarse motion position error signal Pe_vcm, the estimated speed signal Ve_vcm, and the estimated disturbance amount signal Fe_vcm is multiplied by the position error feedback gain Kp, the speed feedback gain Kv, and the disturbance compensation feedback gain Kd, these are multiplied by the adder 61A. The coarse motion control signal C_vcm may be generated by adding.

  The movement speed of the magnetic head 1 and the amount of disturbance (force disturbance, position disturbance) applied to the magnetic head 1 are estimated by the fine position signal P_head, the coarse movement control signal C_vcm of the coarse movement control unit 61, and the fine movement of the fine movement control unit 62. The estimation may be performed by a two-input one-output estimator using the control signal C_ma.

  The coarse motion drive unit 65 generates and outputs a coarse motion drive signal U_vcm from the coarse motion control signal C_vcm output from the coarse motion control unit 61, thereby controlling and driving the VCM 51.

  Next, the position detection unit 60 will be described. The position detection unit 60 outputs two signals having different resolutions based on the head signal. That is, the position detection unit 60 includes a resolution adjustment unit 601 as shown in FIG. A head signal is input to the resolution adjustment unit 601, and the resolution adjustment unit 601 detects the head position from the head signal (track number signal and inter-track signal). At this time, the resolution adjustment unit 601 outputs the head position detected with the same resolution as the head signal (the same number of bits per track of the head signal) as a fine position signal P_head to the fine movement control system. The head position detected with a resolution coarser than the signal (a predetermined number of bits obtained by shifting the number of bits per track of the head signal) is output to the coarse motion control system as an approximate position signal X_vcm. For example, when the head signal is 14 bits, the resolution adjustment unit 601 uses the fine position signal P_head as a signal whose position is detected by the same 14 bits, and shifts the approximate position signal X_vcm by 3 bits with respect to 14 bits to reduce the resolution. What is necessary is just to make it the signal which detected the position by making it 1/8. The number of bits to be shifted may be set in advance in consideration of the operation of the positioning control system and settling time.

  As a result, in this head positioning control system (servo system), the MA 52 positions the magnetic head 1 on the target track on the magnetic disk 2 based on the fine position signal P_head with a fine resolution as cooperative control of the two-stage actuator. The VCM 51 is controlled and driven so as to position (still) the magnetic head 1 on the target track on the magnetic disk 2 based on the approximate position signal X_vcm independent of the fine position signal P_head. The More specifically, the MA 52 performs feedback control using the position error signal Pe based on the fine position signal P_head, and the VCM 51 is based on the estimated value of the estimator 63 that receives the coarse motion control signal C_vcm and the approximate position signal X_vcm. , Feedback control is performed by the coarse motion position error signal Pe_vcm by the VCM 51, thereby performing cooperative control of the two actuators.

  As a result, in the coarse motion control system, the tracking sensitivity to the fine operation (interference operation) of the MA 52 is lowered. That is, the coarse motion control system does not regard the operation of the MA 52 as a disturbance, and the mutual interference between the operations of the two actuators 51 and 52 is reduced. Therefore, the vibration response generated at the time of head positioning in the control of the two-stage actuator is prevented, and the head positioning settling time is shortened.

  In addition, since the mutual interference between the operations of the two actuators 51 and 52 is reduced, cooperative control in a high band becomes possible. For example, the control band of the fine movement control system may be set higher than the resonance frequency of the head positioning mechanism 7, and the control band of the coarse movement control system may be set lower than the resonance frequency. The control band of the fine movement control system is preferably 1.5 times or more of the control band of the coarse movement control system. By doing so, the coarse motion control system is less sensitive to the high frequency operation of the fine motion control system, and the cooperative control in the high band is realized while avoiding the interference of the control operation between the MA 52 and the VCM 51.

  Further, the VCM 51 operates only in a low band with a large displacement, and the MA 52 performs only a high band operation with a small displacement, while providing an operation threshold value of the MA 52 in the fine movement control system, thereby operating the MA 52 in an operating range. The tracking control of the magnetic head 1 can be performed without exceeding.

  As a result, it is possible to cause the magnetic head 1 to follow the track while suppressing position errors due to friction, FPC reaction force, and vibration, and high-speed and highly accurate head positioning control is realized.

Next, a simulation performed for the head positioning control according to the first embodiment will be described. The conditions for this simulation are as follows.
Rotational speed: 3600r / min
Track density: 165,000 track / inch
Track pitch: 0.154 μm
Sampling frequency: 15 kHz
Servo band: 1.5 kHz
Here, the control band of MA52 is designed to be 1.5 kHz, and the control band of VCM51 is designed to be 800 Hz. The frequency of bending resonance of the positioning mechanism 7 of the magnetic head 1 that affects the control band of the coarse motion control system is 1.2 kHz.

  The resolution of the two position signals is 9 bits for the fine position signal P_head and 7 bits for the approximate position signal X_vcm.

  Further, in this simulation, the voltage applied to the MA 52 is limited to 5V. That is, the operation threshold value of MA52 is 5V.

  FIG. 9 shows the simulation results. FIG. 9A shows the frequency response of the servo loop, and FIG. 9B shows the step response. In addition, a continuous line is an Example (example which employ | adopted the control method of this invention), and a broken line is a comparative example (example which employ | adopted the conventional control method). According to FIG. 11A, it can be seen that the follow-up characteristic is improved in the embodiment, and that the embodiment has improved convergence and settling time against disturbance.

  In this simulation, the control band of the fine movement control system is set to 1.5 kHz, and the control band of the coarse movement control system is set to 800 Hz. However, the present invention is not limited to this. The control band of the fine movement control system is higher than the resonance frequency of the head positioning mechanism 7, the control band of the coarse movement control system is lower than the resonance frequency, and the control band of the fine movement control system is one of the control bands of the coarse movement control system. If the condition of .5 times or more is satisfied, the combination of control bands is free.

  Here, the operation threshold value of MA 52 is set to 5 V, but the operation threshold value may be set to other values as long as the element characteristics (electrical resistance) do not change greatly.

(Embodiment 2)
The second embodiment is different from the first embodiment in that the control method is switched according to the position error of the magnetic head 1 and / or the displacement of the MA 52.

  FIG. 10 shows a schematic configuration of a magnetic disk device on which the head positioning control device according to the second embodiment is mounted. FIG. 11 is a detailed block diagram of the position detection unit 60.

  Here, since the mechanical configuration of the head positioning control device according to the second embodiment is the same as that of the first embodiment, the description thereof is omitted here. Further, the same components as those in the first embodiment are denoted by the same reference numerals as those in FIG. Furthermore, the description which overlaps with Embodiment 1 is abbreviate | omitted.

  As shown in FIG. 10, the head positioning control apparatus according to the second embodiment further includes a MA displacement estimation unit 66 that estimates the displacement by the MA 52 based on the fine movement control signal C_ma. Further, as shown in FIG. 11, the position detection unit 60 in the second embodiment includes a resolution adjustment unit 601 and a position signal selection unit 602. The resolution adjustment unit 601 uses a head signal as an input signal, while selecting a position signal. The unit 602 uses the fine movement control system (fine movement) position error signal Pe and the fine movement control signal C_ma as input signals.

  As will be described in detail later, the position signal selection unit 602 switches the position signal output to the coarse adjustment control system with respect to the resolution adjustment unit 601 (in other words, the second head position signal output to the coarse adjustment control system). Resolution adjustment), the stop and start of operations of the fine movement drive unit 64 and the MA displacement estimation unit 66 are switched, and further, the control band of the coarse movement control system is changed. The control band is changed by adjusting the control parameter.

  Next, the operation sequence of the positioning control device according to the second embodiment and the operation of the position detection unit 60 will be described.

(Operation 1)
Operation 1 is when the position error of the magnetic head 1 is 3 tracks or more, and the position signal selection unit 602 in the position detection unit 60 has a position error of the magnetic head 1 of 3 tracks or more based on the position error signal Pe. When this is determined, the operations of the MA displacement estimation unit 66 and the fine movement driving unit 64 are stopped, and the head position signal output from the resolution adjustment unit 601 to the coarse movement control system is switched to the fine position signal P_head. In the operation 1, the coarse motion control system moves the magnetic head 1 to the target position by speed control (illustration of the configuration of the coarse motion control unit 61 in this case is omitted). At this time, since the position signal selection unit 602 is speed control, the control band of the coarse motion control system is set relatively low (for example, 400 Hz).

(Operation 2)
Operation 2 is when the position error of the magnetic head 1 is 2 tracks or more and less than 3 tracks. When the position signal selection unit 602 in the position detection unit 60 determines that the position error of the magnetic head 1 is not less than 2 tracks and less than 3 tracks based on the position error signal Pe, the MA displacement estimation unit similarly to the operation 1. The head position signal output from the resolution adjusting unit 601 to the coarse motion control system is switched to the fine position signal P_head. The coarse motion control unit 61 performs positioning control so that the magnetic head 1 becomes the target position in the configuration shown in FIG. 5 or FIG. 8 (in this case, in FIG. 5 or FIG. 8, in place of the approximate position signal X_vcm, the fine position is controlled). Signal P_head is input). At this time, the position signal selection unit 602 raises the control band of the coarse motion control system to the upper limit (for example, 800 Hz) because it is position control only for the coarse motion control system.

(Operation 3)
Operation 3 is when the position error of the magnetic head 1 is 1 track or more and less than 2 tracks, or when the displacement of the MA 52 is 80% or more of the operation range.

  The position signal selection unit 602 in the position detection unit 60 determines that the position error of the magnetic head 1 is 1 track or more and less than 2 tracks based on the position error signal Pe, or based on the fine movement control signal C_ma. When it is determined that the displacement is 80% or more of the operation range, the operation of the MA displacement estimation unit 66 and the fine movement drive unit 64 is started, and the head position signal output from the resolution adjustment unit 601 to the coarse movement control system. Is switched to the approximate position signal X_vcm. The coarse motion control unit 61 performs positioning control so that the magnetic head 1 becomes a target position in the configuration shown in FIG.

  The control of the coarse motion control unit 61 in the operation 3 is feedback control similar to the control disclosed in Patent Document 1. That is, as shown in FIG. 10, the MA displacement estimation unit 66 estimates the estimated MA displacement signal Xe_ma from the MA 52 and outputs the estimated MA displacement signal Xe_ma to the adder 612S. The adder 612S adds the estimated MA displacement signal Xe_ma to the coarse motion position error signal Pe_vcm, and outputs the addition signal to the coarse motion control unit 61.

  As shown in FIG. 12, the coarse motion control unit 61 performs feedback control with an addition signal of the estimated MA displacement signal Xe_ma and the coarse motion position error signal Pe_vcm, and the VCM state estimator 63 receives the fine position signal P_head. And the estimated MA displacement signal Xe_ma are input, the moving amount and moving speed of the magnetic head 1 by the VCM 51 are estimated, and the estimated displacement signal Xe_vcm and the estimated speed signal Ve_vcm are output (in the VCM state estimator 63). The amount of disturbance (force disturbance, position disturbance) applied to the magnetic head 1 may be estimated (see FIG. 8)). As described above, the positioning control is performed by feeding back the estimation signal as in the first embodiment.

  Here, the estimation model of the estimator 63 is VCM51, but the same effect can be obtained when the estimation model is a two-stage actuator including MA52.

  With the above configuration, the coarse motion control unit 61 controls and drives the VCM 51 so that the moving speed of the magnetic head 1 by the VCM 51 becomes zero.

  In the operation 3, the MA 52 is also controlled by the fine movement control system, and the cooperative control of the two actuators 51 and 52 is performed.

  That is, in operation 3, the magnetic head 1 is stopped near the target position (target track) on the magnetic disk 2 by the VCM 51, and the magnetic head 1 is made to follow the target track by the MA 52.

  At this time, since the coordinate control of the two actuators 51 and 52 is performed, the position signal selection unit 602 sets the control band of the coarse motion control system to be low (for example, 500 Hz) in order to prevent control interference.

(Operation 4)
Operation 4 is a case where the position error of the magnetic head 1 is less than one track and the displacement of the MA 52 is less than 80% of the operation range.

  The position signal selection unit 602 in the position detection unit 60 has a position error of the magnetic head 1 of less than one track based on the position error signal Pe, and the displacement of the MA 52 is 80% of the operation range based on the fine movement control signal C_ma. When it is determined that the head position signal is less than the value, only the operation of the fine movement drive unit 64 is started, and the head position signal output from the resolution adjustment unit 601 to the coarse movement control system is switched to the approximate position signal X_vcm.

  The coarse motion control unit 61 controls the positioning so that the magnetic head 1 becomes the target position in the configuration shown in FIG. 5 or FIG. Further, the MA 52 is controlled by the fine movement control system, and the two actuators 51 and 52 are cooperatively controlled.

  At this time, the position signal selection unit 602 sets the control band of the coarse motion control system to a low value (for example, 500 Hz) as in the operation 3.

  Therefore, a position error of 2 tracks or more / less than corresponds to the first condition for determining driving / stopping of the MA 52, and a position error of 1 track or more and less than 80% / less of the operating range of the fine actuator displacement. This corresponds to the second condition for switching the control system of the coarse motion control system.

  Here, the position signal selection unit 602 of the position detection unit 60 switches the stop / start of the operation of the fine movement drive unit 64 and the MA displacement estimation unit 66. However, as shown in FIG. 13, for example, the position detection unit 60 (position signal selection unit 602) may switch stop / start of the operation of the fine movement control unit 62.

  In the second embodiment, the same effects as in the first embodiment are obtained, and from the access operation with a large moving distance of the magnetic head 1 and the track jump operation to the adjacent track to the track following operation in the target track, By controlling and driving each operation while switching the control method, the access operation does not become an oscillating operation, and the access time and settling time can be shortened. Further, by switching between the operation 3 and the operation 4 described above, the MA 52 can be controlled while reducing the mutual interference between the two actuators 51 and 52 in the vicinity of the center of the operation range.

(Embodiment 3)
The third embodiment is different from the second embodiment in that a rotation synchronization disturbance such as a disk eccentricity having a large displacement is compensated.

  FIG. 14 shows a schematic configuration of a magnetic disk device on which the head positioning control device according to the third embodiment is mounted.

  Here, since the mechanical configuration of the head positioning control device according to the third embodiment is the same as that of the first embodiment, the description thereof is omitted here. The same components as those in the first and second embodiments are denoted by the same reference numerals as those in FIGS. Furthermore, the description which overlaps with Embodiment 1, 2 is abbreviate | omitted.

  As shown in FIG. 14, the head positioning control device according to the third embodiment estimates a rotation synchronization disturbance based on a (fine movement) position error signal Pe, and outputs a compensation signal to the coarse movement control system. 67 is further included. That is, the compensation signal is output to the adder 65A, and the adder 65A outputs an addition signal obtained by adding the compensation signal to the coarse motion control signal C_vcm to the coarse motion drive unit 65.

  With this configuration, compensation for rotational synchronization disturbance such as disk eccentricity with a large displacement is performed in the coarse motion control system.

  The operation sequence of the head positioning control device of the third embodiment is basically the same as the operation sequence of the head positioning control device of the second embodiment. In the operation 2, RRO control is added, and operations 3 and 4 are performed. RRO control is added to the coarse motion control system.

  Here, the compensation signal (RRO control amount) from the RRO control unit is added to the coarse motion control signal C_vcm, but it may be added to the coarse motion position error signal Pe_vcm as an RRO displacement amount.

  As described above, in the third embodiment, the same effects as in the first and second embodiments are obtained, and the MA 52 moves the magnetic head 1 to the magnetic disk based on the fine position signal P_head against a rotational synchronization disturbance having a large displacement. The VCM 51 is controlled and driven so that the magnetic head 1 is positioned (stationary) near the target track on the magnetic disk 2 independently of the VCM 51.

(Other embodiments)
In each of the above embodiments, the coarse motion control system may further include a vibration sensor, and when the fine motion actuator exceeds its operating range due to vibration, the control band of the coarse motion control system may be increased. By doing so, it is possible to compensate for the position error with respect to the vibration. When synchronous vibration is detected by the vibration sensor, the control band of the coarse motion control system may be adjusted by learning control, for example. By doing so, it is possible to compensate for the position error with respect to the synchronous vibration.

  The coarse motion control system may include a temperature sensor instead of the vibration sensor or together with the vibration sensor. That is, the torque constant of the VCM 51 changes due to a temperature change, and the control band apparently changes (when the atmospheric environment has a difference of 10 ° C. or more with respect to the temperature of the design condition, the torque constant of the VCM 51 changes). Therefore, if the torque constant of the coarse actuator is estimated based on the detection signal of the temperature sensor and the control gain is corrected according to the estimation result, the control band of the coarse control system can be kept at the design value. It becomes possible.

  Further, the servo signal (servo information) recorded on the magnetic disk 2 is not limited to the one including the track number signal and the inter-track position signal, and may include only the inter-track position signal. In this case, the servo pattern recorded on the disk 2 is shortened, and the user data area is enlarged accordingly. However, when the servo signal includes only the inter-track position signal, only the position between the tracks can be detected, so the dynamic range as the position detection sensor becomes small.

  Further, although the magnetic disk device has been described as an example in the above embodiment, the present invention is not limited to this example, and information recording of other modes such as an optical disk device, a magneto-optical disk device, etc. It can also be applied to devices.

  As described above, the present invention is useful for a two-stage actuator type magnetic disk device, optical disk device, magneto-optical disk device, and the like.

1 is a block diagram illustrating a configuration of a disk device according to a first embodiment. It is a schematic block diagram of a fine movement actuator. FIG. 3 is a block diagram illustrating a configuration of a head positioning control device according to the first embodiment. It is a block diagram which shows the structure of a fine movement control part. It is a block diagram which shows the structure of a coarse motion control part. It is a block diagram which shows the structure of a state estimator. FIG. 3 is a diagram corresponding to FIG. 1 and shows another configuration of the disk device according to the first embodiment. FIG. 6 is a diagram corresponding to FIG. 5 illustrating another configuration of the coarse motion control unit according to the first embodiment. It is a simulation result of the control system which concerns on Embodiment 1, (a) Frequency response (b) Step response. FIG. 3 is a block diagram illustrating a configuration of a disk device according to a second embodiment. It is a block diagram which shows the structure of a position detection part. It is a block diagram which shows the structure of a coarse motion control part. It is a block diagram which shows another structure of the disk apparatus based on Embodiment 2. FIG. FIG. 6 is a block diagram illustrating a configuration of a disk device according to a third embodiment.

Explanation of symbols

1 Magnetic head (head)
2 Magnetic disk (disk)
3 Head Slider 4 Suspension Arm 5 Carriage 53 Rotating Bearing 7 Positioning Mechanism 51 VCM (Coarse Motion Actuator)
52 MA (Fine Actuator)
6 Positioning control unit (positioning control means)
60 Position detection unit (position detection means)
61 Coarse motion control unit (Coarse motion control means)
62 Fine movement control section (fine movement control means)
63 Coarse drive unit (coarse drive means)
64 Fine movement drive unit (fine movement drive means)

Claims (20)

At least a head for reproducing information recorded on the information recording disk;
A coarse actuator for positioning the head, and a fine actuator interposed between the coarse actuator and the head;
A head positioning mechanism including the coarse actuator and the fine actuator;
Position detecting means for detecting a head position based on a signal obtained by reproducing the servo information recorded on the information recording disk by the head and outputting the head position signal;
Positioning control means for controlling the coarse actuator and the fine actuator,
The positioning control means includes a coarse motion control system including a coarse motion drive means for driving the coarse motion actuator and a coarse motion control means for outputting a control amount signal to the coarse motion drive means, and a fine motion for driving the fine motion actuator. A fine movement control system including a driving means and a fine movement control means for outputting a control amount signal to the fine movement driving means;
The position detecting means outputs two position signals, a first head position signal having a relatively high resolution and a second head position signal having a relatively low resolution based on the reproduction signal of the head,
The fine movement control means calculates a control amount for controlling the fine movement actuator based on the first head position signal,
The coarse movement control means is a head positioning control device that calculates a control amount for controlling the coarse movement actuator based on the second head position signal. The servo information includes two position signals, a track number signal and an inter-track position signal, which are arranged at equal intervals in the circumferential direction of the information recording disk,
The position detection means outputs the head position detected with the same number of bits as the number of bits per track of the track number signal and the inter-track signal as a first head position signal, and also outputs the track number signal and the inter-track signal. 2. The head positioning control apparatus according to claim 1, wherein the head position detected with a predetermined number of bits obtained by shifting the number of bits per track is output as a second head position signal. The servo information includes inter-track position signals arranged at equal intervals in the circumferential direction of the information recording disk,
The position detecting means outputs the head position detected with the same number of bits as one bit per track of the inter-track signal as a first head position signal, and shifts the number of bits per track of the inter-track signal. 2. The head positioning control apparatus according to claim 1, wherein the head position detected with the predetermined number of bits is output as a second head position signal.   The head positioning control device according to any one of claims 1 to 3, wherein a control band of the fine movement control system is set to 1.5 times or more of a control band of the coarse movement control system.   The head positioning control device according to claim 4, wherein a control band of the fine movement control system is set higher than a resonance frequency of the head positioning mechanism, and a control band of the coarse movement control system is set lower than the resonance frequency.   6. The head positioning control device according to claim 4, wherein the coarse motion control system further includes a vibration sensor, and adjusts a control band of the coarse motion control system in accordance with a detection signal of the vibration sensor.   The head positioning control apparatus according to claim 4, wherein the coarse motion control unit further includes a temperature sensor, and adjusts a control band of the coarse motion control system in accordance with a detection signal of the temperature sensor.   The position detection means switches driving / stop of the fine movement actuator based on a first condition related to the magnitude of the position error with respect to the target position of the head, and the second head position when stopping the fine movement actuator. The head positioning control apparatus according to claim 1, wherein the resolution of the signal is increased.   9. The head positioning control according to claim 8, wherein the position detecting means lowers a control band of the coarse movement control system when driving the fine movement actuator and increases a control band of the coarse movement control system when stopping the fine movement actuator. apparatus.   The position detection means switches the control method of the coarse motion control system based on a second condition related to the magnitude of the position error with respect to the target position of the head and the displacement of the fine motion actuator. 2. A head positioning control device according to item 1. The position detecting means is based on the second condition,
A first control method for calculating a control amount for controlling the coarse actuator based on a coarse movement position error signal that is a difference between the second head position signal and a target position;
Switching to a second control method for calculating a control amount for controlling the coarse actuator based on a signal obtained by adding a displacement amount or an estimated displacement amount of the fine actuator to the coarse motion position error signal. Item 11. A head positioning control device according to Item 10. The head includes a recording head for recording information on the information recording disk and a reproducing head for reproducing information recorded on the disk,
The head positioning control apparatus according to claim 1, wherein the fine movement control system operates during recording by the recording head and reproduction by the reproducing head.   The head positioning control device according to claim 12, wherein the fine movement control system adjusts an MR offset.   The head positioning control device according to claim 1, wherein the fine movement actuator is formed of a thin film piezoelectric element.   The fine movement control means adjusts a control amount signal outputted to the fine movement driving means so that a control voltage outputted to the fine movement actuator is equal to or less than a threshold value determined in accordance with its element characteristics. 14. A head positioning control device according to 14.   The fine movement driving means stores a threshold value of a control voltage determined according to element characteristics of the fine movement actuator, and outputs a control voltage output to the fine movement actuator while being limited to the threshold value or less. The head positioning control device according to claim 14.   The head positioning control device according to claim 15 or 16, wherein the threshold value is a control voltage at which an electric resistance of the thin film piezoelectric element becomes 1 MΩ or less.   The head positioning control device according to claim 1, wherein the coarse motion control system further includes a constant disturbance estimation control unit. The coarse motion control system further includes a rotation synchronization disturbance control means,
The head positioning control device according to claim 1, wherein the rotation synchronization disturbance control unit uses the first head position signal as an input signal. A disk device on which the head positioning control device according to any one of claims 1 to 19 is mounted.

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