Abstract: Methods and systems in a data storage device selectively employ a seek time array and/or a seek time list to accurately predict a time required for a seek operation to move a transducer in the data storage device a given seek distance. The seek time list and/or seek time profiles are automatically compiled in the data storage device based on seek time entries located in a servo data table located in the data storage device.

Abstract: Apparatus and method for reducing the generation of acoustic noise in a disc drive. A seek is carried out to move a head from an initial track to a destination track on a corresponding disc surface using a servo circuit which outputs a series of current command values indicative of successive magnitudes of current to be applied to an actuator motor. A velocity profile provides a sequence of demand velocities indicative of the desired velocity at each of a succession of time periods during the seek. Closed loop velocity control is achieved by comparing the actual velocity of the head to the corresponding demand velocity and adjusting the current in relation to the velocity error therebetween. During initial stages of the seek, however, open loop control is initially performed using a current profile table which shapes the initial stages of current to a desired waveform, irrespective of the velocity profile and the velocity error.

Abstract: A hard disk drive which moves a transducer across a disk surface so that the transducer has an essentially sinusoidal acceleration trajectory. The transducer may be integrated into a slider that is incorporated into a head gimbal assembly. The head gimbal assembly may be mounted to an actuator arm which can move the transducer across the disk surface. The movement of the actuator arm and the transducer may be controlled by a controller. The controller may move the transducer from a first track to a new track in accordance with a seek routine and a servo control routine. During the seek routine the controller may move the transducer in accordance with a sinusoidal acceleration trajectory. The sinusoidal trajectory may reduce the high harmonics found in square waveforms of the prior art, and thus minimize the acoustic noise of the head gimbal assembly and reduce the settling time of the transducer for reducing the duration of the seek routine.

Abstract: A disk device has a head for recording and reproducing data to and from a disk-shaped recording medium. A carriage for supporting the head is provided. A driver is included for moving the carriage in the direction of a radius of the disk-shaped recording medium. Also provided is a controller controlling the driver based on a speed profile selected from among a plurality of preset speed profiles. The speed profile is selected in response to values stored in a memory indicating a disturbance to the head.

Abstract: Disclosed herein is a head-positioning control system designed to move a head to a target position over a disk used as a recording medium. The system causes an actuator to perform a seek operation, thus moving the disk from a prescribed start position to the target position. The system generates seek profile data representing a motion which the head makes during the seek operation. On the basis of the seek profile data, the gain of the system is estimated. A gain-adjusting value is calculated from the gain thus estimated. The gain-adjusting value is applied, adjusting the gain of the system to an appropriate gain.

Abstract: An apparatus and method for minimizing audible noise in disc drives during idle periods uses a low-noise velocity profile and/or low noise position profile to govern the movement of a seeking actuator assembly. The low-noise velocity profile is selected to govern all actuator movement and seeking during idle periods, i.e., during internal drive housekeeping operations. The noise level associated with each actuator position in the drive is preferably determined through actual tests and/or modeling and is utilized to determine the low noise profiles. The relative amount of time the actuator assembly spends in the relatively noisier actuator assembly positions may also be optimally reduced thus reducing the overall amount of noise generated by an idle disc drive.

Abstract: A method and apparatus for estimating position and speed of a read/write head in a disc drive, based upon the back EMF of the voice coil motor involves estimating the voltage across the voice coil motor and estimating the voltage across a current-sensor resistor in the voice coil circuit, preferably with a differential amplifier. Further, a coil resistance voltage is estimated by measuring the voltage across the current-sensor resistor with a differential amplifier and amplifying the voltage across the current-sensor resistor by a gain value. Finally, the combined voltage across the current-sensor resistor and the characteristic coil resistance is subtracted from the voltage across the voice coil motor, yielding the back EMF of the voice coil motor. The back EMF is representative of head velocity which may be integrated to yield position. Accordingly, the back EMF can be used to control the speed and position of the read/write head.

Abstract: A method, apparatus, and computer program product for a hard disk drive servomechanism. In one embodiment, the apparatus comprises a disk which has a surface, a spindle motor that rotates the disk, a transducer which can write information onto the disk and read information from the disk, and an actuator arm that can move the transducer across the surface of the disk. The apparatus further includes a controller. The controller can determine a seek length from a first track to a second track, determine a seek time based on the seek length, scale the seek time in response to a velocity error between a calculated velocity and a design velocity for the seek length, and control the actuator arm to move the transducer across the disk surface from the first track to the second track using an acceleration trajectory.

Abstract: A method, apparatus and computer program for performing a servo seek according to a voltage-constrained sinusoidal acceleration trajectory. In one embodiment, the apparatus comprises a hard disk drive which has a disk with a surface, spin motor, transducer, and an actuator arm to move a transducer across the surface of the disk. The apparatus further includes a controller that controls the actuator arm and to perform a seek having a length. The actuator arm moves the transducer across the surface of the disk with an essentially sinusoidal acceleration trajectory using a substantially constant voltage. In another embodiment, the substantially constant voltage is based on the maximum voltage from a power supply.

Abstract: The disk device of this invention includes: a disk driving section for rotating a disk; a head for recording and/or reproducing information on and/or from the disk; a head moving section for moving the head from a start position to a destination position; a temperature calculation section for calculating a temperature change at a predetermined position, wherein the calculation is carried out based on the information of the start position and the destination position; and a control section for controlling the disk driving section and/or the head moving section depending on the temperature change calculated by the temperature calculation section.

Abstract: A method for controlling the current applied to a voice coil motor (VCM) prevents overheating of a coil in the VCM. The method includes the steps of defining an acceleration interval for measuring the distance traveled by a head moved by the VCM. The method also defines a distance traveled during the acceleration interval which can be used as a reference for indicating that the coil is being overheated. The VCM is driven for the acceleration interval and the distance traveled during the interval is measured and compared to the reference distance. If the difference exceeds a threshold, then the current being applied to the coil is controlled to maintain the coil temperature within a limit. If, however, the difference does not exceed the threshold, the current being applied to the coil is controlled to meet a performance requirement.

Abstract: A method of implementing an automatic acoustic management feature for a disc drive includes receiving an acoustic/performance compromising factor from a host, tuning disc drive performance by applying the factor to a control parameter to generate a modified control parameter, and executing a loop for controlling a disc drive operation using the modified control parameter. In another embodiment, a disc drive has a base, a rotatable disc, an actuator assembly with an arm for carrying a head in transducing relation to the disc in response to a control signal, a receiver for receiving an acoustic/performance compromising factor, and a controller that monitors the position of the arm and generates the control signal. The controller executes a seeking control loop having a control parameter modified by applying a compromising factor to the parameter to tune the acoustic performance of the drive.

Abstract: Techniques are provided herein for reducing vibrations in various modes of a dynamic system. One such technique comprises incorporating vibration limiting and sensitivity constraints into a partial fraction expansion equation model of the system so as to reduce vibrations to specific levels. Another technique comprises shaping a command determined using the partial fraction expansion equation model to produce a desired output. The entire command may be shaped or only selected portions thereof which produce vibrations. Another technique involves commanding in current to produce saturation in voltage. By doing this, it is possible to command voltage switches. The times at which the switches occur can be set to reduce system vibrations. Other techniques are also provided. These include varying transient portions at the beginning, middle and/or end of a move and using Posicast inputs, among others.

Abstract: A method of controlling an actuator in a disc drive to perform a seek operation prior to a read operation is disclosed. A radial distance between the initial track and the target track is determined. A rotational distance between the initial head rotational position and the target rotational position is also determined. The magnitude of the performance benefit to be gained by reading pre-fetch and post-fetch data is estimated. Then a seek velocity profile is selected based on the radial distance, the rotational distance and the estimated magnitude of the performance benefit that would be gained by reading pre-fetch and post-fetch data. The actuator then is controlled using the selected seek profile. A disc drive for implementing this method is also provided.

Abstract: A disc drive controller corrects for rotational vibration disturbances of a head position. The controller includes multiple sets of adjustable controller gains. The controller compares an accelerometer output to an acceleration threshold and generates conditional branches as a function of the comparison. The controller updates one set of the adjustable controller gains within a computational time limit after a first conditional branching. The controller updates a second set of the adjustable controller gains within the computational time limit after a second conditional branching.

Abstract: The present invention relates to a servo control apparatus of a disk recording system and particularly to a servo control apparatus and method which are capable of controlling position of a head for recording digital data on a disk as recording media and reading the digital data.

Abstract: In a head unlatch controlling method and arrangement in a hard disk drive head unlatch controlling method, a head unlatch operation is performed in an open loop mode, using a predetermined current profile. A determination is made as to whether servo information is accurately detected during the head unlatch operation in the open loop mode. If the servo information is accurately detected, the head unlatch operation is shifted from the open loop mode to a closed loop mode on the basis of the servo information. If the servo information is not accurately detected, the head unlatch operation continues in the open loop mode.

Abstract: A disk drive and method of optimizing data access time by selecting a seek profile and/or settle criteria based on a queued or non-queued environment. The disk drive includes an actuator and a servo system, wherein the servo system is directed to move the actuator as a result of an input/output command received from a host by an interface processor. The disk drive may execute the input/output commands in a queued or non-queued environment. The servo system commands the actuator to perform a seek using a seek profile and defines settling criteria for the seek operation. The seek profile includes an acceleration profile and a deceleration profile. The method includes the step of providing a queued seek profile and a queued settling criteria for a seek used to position the actuator to execute a command in a queued environment.

Abstract: Apparatus and method for reducing the generation of acoustic noise in a disc drive. A seek is carried out to move a head from an initial track to a destination track on a corresponding disc surface using a servo circuit which outputs a series of current command values indicative of successive magnitudes of current to be applied to an actuator motor. A velocity profile provides a sequence of demand velocities indicative of the desired velocity as the head is decelerated to the destination track. During the seek, open loop current is applied to the actuator motor to accelerate the head away from the initial track, the current command values defining a rising portion wherein the current is successively increased to a first level and a subsequent falling portion wherein the current is successively decreased to a second level, the rising and falling portions each preferably characterized as a one quarter sine wave at a selected frequency.