Abstract: An apparatus and method for removing mechanical resonance in a disc drive using an adaptive notch filter. Mechanical resonance harmful to a system is removed by a notch filter that adaptively varies the frequency characteristics of the filter with respect to the mechanical resonance frequency existing in the system.

Abstract: There are provided a method and apparatus for high-speed compensating repeatable run-out in a hard disk drive. The method includes a) obtaining a value of a position error signal (PES) of the hard disk drive, the PES being a relative position signal of the head with respect to the center of the target track of the disk; b) determining whether the head is in the settling mode; c) if the head is in the settling mode, compensating the RRO error without feeding back the PES; and d) if the head is in the track-following mode, compensate the RRO error by feeding back the PES. Accordingly, an excessive RRO error is compensated. Even though the hard disk drive receives an external shock or is assembled in an offline servo writing manner, the performance of the hard disk drive does not deteriorate.

Abstract: Provided are a method of generating a current trajectory for seek control of a hard disc drive and a seek control system using the same, the method including setting a current trajectory from harmonics of a sinusoidal wave; calculating a power consumed by a target device to be controlled using the current trajectory; and determining coefficients of the harmonics so as to minimize the power consumed by the device.

Abstract: A method and apparatus for controlling a track seek servo of a disk drive. The method of controlling the track seek servo of the disk drive having a transducer and a disk with a plurality of tracks, includes moving a transducer to a space over a target track of the plurality of tracks according to a track seek controlling process in which an asymmetrical sine wave acceleration trajectory a(t) is used in a track seek mode.

Abstract: An apparatus and method for removing mechanical resonance in a disc drive using an adaptive notch filter. Mechanical resonance harmful to a system is removed by a notch filter that adaptively varies the frequency characteristics of the filter with respect to the mechanical resonance frequency existing in the system.

Abstract: 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.

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 method and apparatus for writing a servo signal for controlling the position of a head on a disk during the manufacture of a hard disk drive. The present invention provides a method and apparatus for writing servo information on a magnetic disk through a magnetic head by driving an actuator of a hard disk drive (HDD) directly without employing a servo writer using control of a laser. Furthermore, when there is need for increasing the density in tracks per inch (TPI) to obtain a high capacity HDD, HDD manufacturers do not have to produce a new servo writer, thereby reducing production cost.

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 method of estimating a motor torque constant including the steps of measuring a current and a speed of motor at sampling time during rotating of the motor and calculating the motor torque constant Kt* by a multiplicity of the measured current values and speed values.

Abstract: A method and apparatus for writing a servo signal for controlling the position of a head on a disk during the manufacture of a hard disk drive. The present invention provides a method and apparatus for writing servo information on a magnetic disk through a magnetic head by driving an actuator of a hard disk drive (HDD) directly without employing a servo writer using control of a laser. Furthermore, when there is need for increasing the density in tracks per inch (TPI) to obtain a high capacity HDD, HDD manufacturers do not have to produce a new servo writer, thereby reducing production cost.

Abstract: Method of reducing power consumption in a disk drive system by controlling movement time of a read/write head from a present track and present sector to a target track and target sector. The method includes the steps of determining a first variable indicative of a first time period in which to move the actuator head from the present track to the target track along a radial arc traced by the movement of the actuator head and determining a second variable indicative of a second time period measured from the present servo sector to when the target servo sector advances to the radial arc. The actuator head is moved at a first rate substantially equal to the first time period if the first variable and the second variable are equal. The actuator head is moved at a second, slower rate if the first variable and the second variable are not equal. Moving the actuator head at a slower rate reduces power consumption and increases battery life.

Abstract: A control algorithm compensates for a bias force disturbance and a runout disturbance of an actuator by means of a state feedback to decrease the number of the design parameters, thereby simplifying the design process. A compensation system for the disturbances includes a state variable calculating device for receiving a discrete feedback input signal representative of an actual position of a magnetic head mounted on a front end of the actuator, so as to generate state variables; a differentiating device for differentiating the discrete feedback input signal to generate a velocity signal; and a state feedback control device for receiving the state variables, the velocity signal and the discrete feedback input signal, so as to generate a discrete control input signal to be applied to the actuator.

Abstract: A method of estimating the gain of a servo control system including an actuator, in which input data supplied to the actuator and the actuator's position data are applied to a gain estimate formula in a closed loop discrete value system for controlling the actuator, so as to estimate the gain of the servo control system.