Abstract: Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position one or more heads proximate to one or more disk surfaces of the one or more disks; and one or more processing devices, comprising an actuator mechanism control system configured for controlling the actuator mechanism. The one or more processing devices are configured to: output a multi-rate excitation to at least one multi-rate notch filter of the actuator mechanism control system; detect a frequency response of the actuator mechanism in response to the multi-rate excitation; and calibrate the at least one multi-rate notch filter of the actuator mechanism control system, based at least in part on the detected frequency response of the actuator mechanism.

Abstract: Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position one or more heads proximate to one or more disk surfaces of the one or more disks; and one or more processing devices, comprising an actuator mechanism control system configured for controlling the actuator mechanism. The one or more processing devices are configured to: output a multi-rate excitation to at least one multi-rate notch filter of the actuator mechanism control system; detect a frequency response of the actuator mechanism in response to the multi-rate excitation; and calibrate the at least one multi-rate notch filter of the actuator mechanism control system, based at least in part on the detected frequency response of the actuator mechanism.

Abstract: Various illustrative aspects are directed to a data storage device, comprising one or more disks; an actuator mechanism configured to position one or more heads proximate to one or more disk surfaces of the one or more disks; and one or more processing devices, comprising an actuator mechanism control system configured for controlling the actuator mechanism. The processing devices are configured to: apply coefficients for a multi-rate notch filter to a servo control loop; measure a multi-rate error rejection transfer function; determine whether a peak of the multi-rate error rejection transfer function is greater than a multi-rate error rejection transfer function threshold; and modify, responsively to determining that the peak of the multi-rate error rejection transfer function is not greater than the multi-rate error rejection transfer function threshold, the parameters of the multi-rate notch filter based at least in part on the peak of the multi-rate error rejection transfer function.

Abstract: A data storage device comprising a first actuator configured to actuate a first head over a first disk surface, and a second actuator configured to actuate a second head over a second disk surface. A plurality of access commands are received from a host, and a cost metric is computed for executing a seek to execute each access command of the plurality of access commands, wherein the cost metric is based on an access latency of the seek, a power consumption of the seek, and an estimated combined current draw of the first and second actuators during the seek. The access commands are sorted into an execution order based on the cost metrics computed for the access commands.

Abstract: A data storage device is disclosed comprising a first actuator configured to actuate a first head over a first disk surface, and a second actuator configure to actuate a second head over a second disk surface. A first seek of the first head over the first disk surface is initiated during a first seek time based on a first seek profile. A second seek of the second head over the second disk surface is initiated during a second seek time based on a second seek profile. When the second seek time at least partially overlaps the first seek time and at least the second seek profile is a de-rated seek profile, the second seek profile is adjusted to avoid an overcurrent condition.

Abstract: A data storage device is disclosed comprising a first actuator configured to actuate a first head over a first disk surface, and a second actuator configured to actuate a second head over a second disk surface. A seeking control signal is generated and used to control the first actuator to seek the first head over the first disk surface. The seeking control signal is filtered with a decoupler to generate a decoupler control signal, wherein the decoupler comprises a nominal decoupler and an adaptive decoupler. A tracking control signal is generated based on the decoupler control signal, and the tracking control signal is used to control the second actuator in order to access the second disk surface using the second head.

Abstract: A disk drive configured with micro-actuator interconnect conditioning. The disk drive includes a disk, a head, an actuator, a piezoelectric element, a hardened conductive adhesive, a voltage-supply circuit, and a controller. The head is configured to access the disk. The actuator includes a suspension supporting the head, and an arm supporting the suspension. The piezoelectric element is disposed on the suspension, is electrically connected to a first drive line and a second drive line, and is configured to change the position of the head. The hardened conductive adhesive is electrically connected to at least one connecting part of the piezoelectric element and the first drive line. The voltage-supply circuit is configured to supply a voltage to the piezoelectric element. The controller is configured to control a voltage-control circuit each time a designated process is executed, and to apply a voltage to the piezoelectric element with a prescribed maximum absolute value.

Abstract: In one embodiment, a magnetic disk apparatus comprises a magnetic disk for recording information; a magnetic head that reads information from, or writes information to, the magnetic disk; an actuator device that drives the magnetic head; and a control system that controls the driving of the actuator device. The actuator device is configured by a dual stage actuator comprising a fine actuator that drives the head and a coarse actuator that drives the magnetic head together with the fine actuator. The control system includes a fine controller that generates an operational value for driving the fine actuator and a coarse controller that generates an operational amount for driving the coarse actuator. The control system includes a mechanism for smoothly changing the operational amount generated by the fine controller immediately before saturation resulting from an applied voltage limit of the fine actuator or at the time the fine actuator returns to a control range from the saturation.

Abstract: In one embodiment, a magnetic disk apparatus comprises a magnetic disk for recording information; a magnetic head that reads information from, or writes information to, the magnetic disk; an actuator device that drives the magnetic head; and a control system that controls the driving of the actuator device. The actuator device is configured by a dual stage actuator comprising a fine actuator that drives the head and a coarse actuator that drives the magnetic head together with the fine actuator. The control system includes a fine controller that generates an operational value for driving the fine actuator and a coarse controller that generates an operational amount for driving the coarse actuator. The control system includes a mechanism for smoothly changing the operational amount generated by the fine controller immediately before saturation resulting from an applied voltage limit of the fine actuator or at the time the fine actuator returns to a control range from the saturation.

Abstract: A seek controller corresponds to a velocity control system which produces a target value based upon a target track, a present position, and a remaining distance from a commencement of a seek operation up to a time instant when a sign of an operating amount is changed; and the seek controller corresponds to a Two Degree of Freedom control system which sets an waveform by a function of time as a target value after the time instant when the sign of the operating amount is changed. The hard disk drives applies a velocity control system based upon a deviation of head positions as to a VCM voltage saturation and a uniform velocity mode, and also, applies a Two Degree of Freedom control system with employment of a function of time having a smooth locus in a decelerated velocity mode so as to suppress residual vibrations.

Abstract: In a positioning control device for a two-stage actuator having a coarse-movement actuator and a fine-movement actuator, a notch filter having a cutoff frequency fn is provided to a coarse-movement control loop, and the fine-movement actuator is driven by a sine wave of the frequency fn. At the frequency fn, a head position signal becomes identical with an output signal of the fine-movement actuator, by which the gain of the fine-movement actuator can be estimated by an adaptive identification unit with high accuracy based on the control input to the fine-movement actuator and the head position signal.

Abstract: The magnetic disk apparatus includes a magnetic disk for storing thereinto information; a head equipped with a recording conversion element for writing information into the magnetic disk and a reproducing conversion element for reading information from the magnetic disk; an actuator arranged by a suspension for supporting the head so as to move the head on the magnetic disk, and also a drive apparatus for driving the suspension; and a stopper for limiting a movable range of the actuator, whereby a distance between a reproduction element and a recording element is measured and also a track width of the magnetic disk is measured in order to execute a self-servo write operation.

Abstract: The seek control means corresponds to a velocity control system which produces a target value based upon a target track, a present position, and a remaining distance from a commencement of a seek operation up to a time instant when a sign of an operating amount is changed; and the seek control means corresponds to a Two Degree of Freedom control system which sets an waveform by a function of time as a target value after the time instant when the sign of the operating amount is changed. The hard disk drives applies a velocity control system based upon a deviation of head positions as to a VCM voltage saturation and a uniform velocity mode, and also, applies a Two Degree of Freedom control system with employment of a function of time having a smooth locus in a decelerated velocity mode so as to suppress residual vibrations.

Abstract: A magnetic disk device comprises at least a disk having information, at least a head for reading or writing information from or into the disk, at least a micro actuator for supporting the head and positioning the head, a coarse actuator for carrying the micro actuator and positioning the head, a controller for controlling the micro actuator and the coarse actuator based on the servo information read by the head, and a host controller for determining that information is to be read. In the case where the host controller determines that the operation is in a wait mode, the positioning operation of the micro actuator is stopped.

Abstract: In a positioning control device for a two-stage actuator having a coarse-movement actuator and a fine-movement actuator, a notch filter having a cutoff frequency fn is provided to a coarse-movement control loop, and the fine-movement actuator is driven by a sine wave of the frequency fn. At the frequency fn, a head position signal becomes identical with an output signal of the fine-movement actuator, by which the gain of the fine-movement actuator can be estimated by an adaptive identification unit with high accuracy based on the control input to the fine-movement actuator and the head position signal.

Abstract: The magnetic disk apparatus includes a magnetic disk for storing thereinto information; a head equipped with a recording conversion element for writing information into the magnetic disk and a reproducing conversion element for reading information from the magnetic head; an actuator arranged by a suspension for supporting the head so as to move the head on the magnetic disk, and also a drive apparatus for driving the suspension; and a stopper for limiting a movable range of the actuator, whereby a distance between a reproduction element and a recording element is measured and also a track width of the magnetic disk is measured in order to execute a self-servo write operation.

Abstract: A sector servo type magnetic disk apparatus is provided with, in addition to servo signals, a sensor such as an accelerometer for detecting a state of a magnetic head or a support for the magnetic head at a period shorter than a sampling period of the servo signals. Since an accelerometer mounted on the magnetic head or the support for the magnetic head detects an acceleration, the control performance of a servo control system can be improved, such as reduction of generation of mechanism resonance vibrations of a carriage and improvement on detection precision of a speed signal.

Abstract: A sector servo type magnetic disk apparatus is provided with, in addition to servo signals, a sensor such as an accelerometer for detecting a state of a magnetic head or a support for the magnetic head at a period shorter than a sampling period of the servo signals. Since an accelerometer mounted on the magnetic head or the support for the magnetic head detects an acceleration, the control performance of a servo control system can be improved, such as reduction of generation of mechanism resonance vibrations of a carriage and improvement on detection precision of a speed signal.

Abstract: A magnetic disk device comprises at least a disk having information, at least a head for reading or writing information from or into the disk, at least a micro actuator for supporting said head and positioning said head, a coarse actuator for carrying the micro actuator and positioning the head, a controller for controlling the micro actuator and the coarse actuator based on the servo information read by the head, and a host controller for determining that information is to be read. In the case where the host controller determines that the operation is in wait mode, the positioning operation of the micro actuator is stopped.

Abstract: An apparatus for positioning a magnetic head includes a servo signal detection circuit for detecting a servo signal recorded on a magnetic disk in a predetermined first period, an acceleration measuring portion which is fitted to a part of a mechanism for mounting a magnetic head, outputs an acceleration signal in a direction of positioning the magnetic head, and samples the acceleration signal in a second period shorter than the first period, a comparison processing portion for comparing a deviation value computed from at least either one of the acceleration signal and the servo signal with a predetermined value, a write inhibit signal generating portion for generating a signal inhibiting write of data on a magnetic disk in accordance with the result of comparison in the comparison processing portion, and a manipulated variable compensation portion for generating manipulated variable for adjusting the position of the magnetic head from at least either one of the servo signal and the acceleration signal and a