Samsung Electronics Co., Ltd.

Seagate Technology International

Da-woon Chung

Kwang-jo Jung

Jung-Ho Lee

Jun Young Jeong

Byoung-kul Ji

Ho-Chul Shin

Chang-ik Kang

Dong-Wook Lee

Chan-hyuck Boo

A method and apparatus for adaptively controlling a motor considering a state of disturbance applied to a system. The method includes changing a frequency bandwidth of a frequency response characteristic in a motor control system according to a state of disturbance applied to the motor control system, and controlling a speed of the motor by applying the changed frequency bandwidth to the motor control system.

Method and apparatus for controlling a motor

The flying heights of magnetic heads of a disk drive are set using an FOD (flying on demand) method in a bank mode. A first signal for adjusting the flying height of a magnetic head is issued to each magnetic head and the value of the first signal is scaled by scale values set for the magnetic heads, respectively, with one of the scale values differing from the others. The value of the first signal is changed until the magnetic head associated with the scale value different from the others touches down. A flying height for the magnetic head which touched down is determined based on the value of the first signal at the time of touch-down. The process is repeated, however with a different bank of scale values each time and set in such a way as to cause the sequential touch-down of the remaining magnetic heads, and determinations of flying heights for the magnetic heads.

Method of controlling flying height of magnetic head and disk drive using the method

A method and apparatus for exactly compensating for a track zero position when copying a reference servo pattern in a disc drive adopting a reference servo track copying method. The method of compensating for a track zero position in a reference servo track copy system for copying a reference servo pattern in a head disc assembly into which a reference disc, on which the reference servo pattern is recorded, produced offline and at least one blank disc are assembled, includes: searching for a collision position of an actuator arm against a stopper for limiting the displacement of the actuator arm on the reference servo pattern; calculating an optimal track zero position based on the searched collision position; and copying the reference servo pattern on all disc surfaces from the calculated optimal track zero position.

Method of compensating for track zero position in reference servo track copying system and disc drive using the same

A track following control apparatus and method for a hard disk drive (HDD) is disclosed and includes an estimator receiving a position error signal from a HDA and generating estimated state information for a magnetic head in response to the position error signal, and a controller receiving the estimated state information and generating a control signal controlling operation of the HAD, wherein the estimator and controller are variably configured according to a write mode or a read mode.

HDD track following control apparatus and method

A Hard Disk Drive (HDD) and related write control method are disclosed. The write control method includes; detecting a free fall state during a current write operation to a current sector, waiting until completion of the current write operation to the current sector, and thereafter stopping the current write operation and unloading a read/write head performing the current write operation.

HDD write control method and apparatus

Provided is a method and apparatus for controlling a motor of a disk drive. The method is used to stably control the startup current of a motor by considering a voltage drop and the disk drive uses the method. The method includes managing power-on reset retry information generated during the startup of the motor and determining the startup current of the motor that corresponds to a power-on reset retry count included in the power-on reset retry information.

Method of controlling startup current of motor and disk drive using the method

Provided is a self servo writing method of writing a final servo signal based on a reference servo signal in a hard disk drive, and more particularly, a method of writing a uniform final self servo signal by compensating for a non-uniform width of tracks where a reference servo signal is written, a hard disk drive using the method, and recording medium storing the method. The self servo writing method includes measuring the width of a target track based on the reference servo information, calculating the deviation between the measured width and a target width, and writing the final servo information while following the target track based on the center position of the target track calculated using the reference servo information and the calculated deviation of track width. According to the self servo writing method, the final servo information is written on tracks having a uniform width, even if the reference servo information is written on tracks having a non-uniform width.

Self servo writing method, hard disk drive using the same, and recording medium storing the method

The present invention relates to a hard disk drive performing a seek control method using a multi-sinusoidal wave acceleration profile, where the seek control method is capable of coping with a variation in a voice coil motor driving current due to variances in a peripheral environment. The seek control method of the present invention includes: calculating a seek time scaling (STC) related to variations in a voice coil motor (VCM) driving current due to variation in a peripheral environment; calculating an acceleration distance ratio (ALR) of an acceleration distance to a maximum seek distance without a coast mode according to the STC; calculating position profiles in an acceleration mode, the coast mode and a deceleration mode, respectively, using both the STC and the ALR; and performing a seek operation by generating the VCM driving current according to the position profiles and applying the VCM driving current to a VCM.

Seek control method of hard disk drive, recording medium storing method and hard disk drive adopting method

A method and apparatus directed to acceleration-based track-seeking servo control of a disk drive, which minimize jerk generated at the start and end of track seeking, thereby reducing mechanical noise of the disc drive while shortening track-seek time. In the method directed to acceleration-based track seeking servo control of a disk drive, a transducer is moved to a target track by a track seeking control using an acceleration trajectory of a function where acceleration change is zero at the start and end of track seeking.

Method and apparatus of acceleration-based track seeking servo control of disk drive

In a method of writing a reference servo signal of a hard disk drive having a spiral reference servo signal that is referred to when writing a final servo signal is written while a head is moved across a disk for a predetermined time at a target movement velocity, an actual movement velocity of the head is detected from a counter electromotive force generated in a voice coil motor that moves that head, for the predetermined time during which the spiral reference servo signal is written, and the head is controlled to maintain the target movement velocity by feeding back the detected actual movement velocity.

Method of writing a reference servo signal of hard disk drive and apparatus suitable therefor

A fast settling servo control method and apparatus for a hard disc drive and a method and apparatus estimate an acceleration coefficient of a voice coil motor (VCM) actuator suitable for the settling servo control method and apparatus for disc drives, which allow a head to stably and rapidly move to a target track when a track seek operation is performed in the hard disk drive. The settling servo control apparatus includes a state estimator which estimates position information of a head, velocity information of the head, voice coil motor (VCM) current information, and external disturbance information based on a position error signal (PES); a feedback gain multiplier which respectively multiplies the position information of the head and the velocity information of the head by predetermined feedback control gains each and outputs the multiplication results as feedback control inputs; a pulse generator which generates a pulse signal used for cancellation of slow poles with reference to at least one of initial VCM current information, initial external disturbance information, and previous control input information as well as initial position information of a head and initial velocity information of the head; and an adder which sums the feedback control inputs, the external disturbance information, and the pulse signal generated from the pulse generator and outputs the summation result to a voice coil motor (VCM) actuator as a control input.

Settling servo control method and apparatus for hard disc drive and method and apparatus for estimating acceleration constant of voice coil motor actuator suitable for the settling servo control method and apparatus

An apparatus and a method to remove a resonance frequency of a system in which an unnecessary resonance frequency occurs in a head stack assembly (HSA) having a head for reading/writing data. The HSA is identified and filtered to prevent mechanical damage caused by resonance. The system is artificially excited to identify a potential resonance frequency of the system. The system is designed so that the identified resonance frequency is filtered. Thus, resonance frequency components outside of Nyquist frequency bandwidth of the system can also be identified. Also, the resonance frequency can very easily be identified in a time domain without a complicated calculation process such as an additional frequency transformation process. Coefficients of a programmable filter are updated using the identified resonance frequency to prevent mechanical damage caused by resonance and improve a servo tracking performance and reliability of data.

Apparatus and method of removing resonance frequency in system

An offline self servo writing method capable of improving servo writing accuracy and reducing copying time by designing a servo pattern of a reference disk to have the same resolution as a final servo pattern, and a disk drive using the method. The offline self servo writing method includes a servo information writing process performed after a reference disk, where a reference servo pattern having the same resolution as a final servo pattern, is written and one or more blank disks are assembled in the disk drive, wherein the servo information writing process is performed by simultaneously writing identical final servo information on all disks including the reference disk by using the reference servo pattern while following tracks of the reference disk.

Method, medium, and apparatus for offline self servo writing and disk drive using the same

A method and an apparatus detect and compensate for a mechanical resonance frequency occurring in a system. The apparatus includes an excitation unit that increases a gain of a predetermined frequency band of a driving signal, a resonance frequency detector frequency-transforming a response signal, and detecting the resonance frequency in a frequency domain, an excitation signal generator separately generating a first excitation signal and a second excitation signal, a mixer mixing one of the first excitation signal or the second excitation signal with a driving signal that does not pass through the excitation unit, and inputting a result of the combination to the system, a resonance determination unit determining whether resonance occurs in the system, and a system controller determining a frequency of one of the first excitation signal or the second excitation signal input when resonance occurs in the system, as the resonance frequency.

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Suwon-si, South Korea

Da-woon Chung