Abstract: A hard disk drive with a circuit that provides a control signal to a voice coil motor to move a head across a disk. The disk drive includes a circuit that provides a control signal to the voice coil motor to move the head. The circuit also has a state predictor and an inversion filter that compute a vibration estimate used to detect a vibration in the drive. When a threshold vibration is detected a vibration estimate is combined with the control signal to compensate for the vibration. The circuit detects the vibration without the need for an accelerometer or other sensor.

Abstract: A hard disk drive with a circuit that provides a control signal to a voice coil motor to move a head across a disk. The circuit includes a repeatable run-out estimator in a feed forward control loop to control the movement of the head. The repeatable run-out estimator compensates for a constant bias torque disturbance in the drive.

Abstract: A hard disk drive that includes a voice coil motor controlled by a servo. The servo provides a driving signal that has multiple sinusoidal waveforms. The multi-sinusoidal waveforms minimize seek time and vibrations in the drive.

Abstract: A hard disk drive with a servo circuit that provides a control signal to a voice coil motor to perform a servo to align a head with a disk track of the drive. The servo circuit includes a fifth order state estimator that provides five estimates that are used to create the control signal. The fifth order state estimator may incorporate a first flexible mode of the voice coil motor to calculate the estimates.

Abstract: A hard disk drive with a circuit that provides a control signal to a voice coil motor to move a head across a disk of a drive. The circuit includes a state estimator that provides a plurality of state estimates and a disturbance estimator that provides a disturbance estimate that is combined with the state estimates to define the control signal. The disturbance estimator compensates for flex cable disturbances, particularly during a settle mode of a seek routine.

Abstract: A hard disk drive with a voice coil motor circuit that provides a current to a voice coil motor to perform a seek routine in a seek time. The disk drive includes a temperature sensor to sense a temperature of the disk drive and a voltage sensor to sense the voltage of the voice coil motor. The circuit adjust the seek time dependent upon the sensed temperature and voltage. By way of example, the circuit will increase the seek time if there is an increase in temperature and/or a decrease in voltage.

Abstract: A hard disk drive with a voice coil motor controlled by a circuit. The circuit provides a driving current to the voice coil motor to move a head of the drive in a seek routine. The seek routine includes a settle mode that has an initial state and a velocity versus head position eigenvector. The eigenvector is changed to coincide with on the initial state when the seek routine enters the settle mode. Changing the eigenvector to coincide with the initial state induces a head velocity and movement with minimal overshoot or undershoot during the settle mode.

Abstract: A hard disk drive with a voice coil motor controlled by a circuit. The circuit provides a driving current to the voice coil motor to move a head of the drive in a seek routine. The seek routine includes a settle mode that has an initial state and a velocity versus head position eigenvector. The eigenvector is changed to coincide with on the initial state when the seek routine enters the settle mode. Changing the eigenvector to coincide with the initial state induces a head velocity and movement with minimal overshoot or undershoot during the settle mode.

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: An apparatus and method are provided for quickly and finely compensating for non-repeatable run out (NPRO) of a disc drive. The NPRO compensation control apparatus in a run out compensation apparatus of a system includes: a frequency estimator directly estimating a trigonometric function value of an NRRO frequency from a predetermined signal responding to the system using a correlation between a filter coefficient of a notch filter and a notch frequency; and an NRRO compensator canceling NRRO of the system using the trigonometric function value of the NRRO frequency estimated by the frequency estimator.

Abstract: A hard disk drive with a circuit that provides a current to a voice coil motor to move a head over a disk in a seek routine. The disk has track boundaries with discontinuities in track addresses. The circuit includes a state estimator that predicts a next state of the head. The state estimator sets an estimation error to zero when the head is over one of the track boundaries. The estimator then computes a predicted position that is used in a feed forward servo loop to generate a drive current. The drive current is provided to the voice coil motor to move the head across the disk.

Abstract: A hard disk drive that includes a voice coil motor controlled by a servo circuit. The servo circuit provides a sinusoidal driving signal that has two different harmonic frequencies. The dual harmonic waveform creates a voice coil motor jerk profile (derivative of acceleration) that is continuous. The continuous jerk profile reduces vibration and seek time of the drive.

Abstract: A servo control device for a disk drive capable of effectively compensating for a low frequency disturbance incoming to the disk drive is provided. The servo control device includes: a state variable estimator calculating a position estimation error based on a control input for controlling motion of a head and a position error signal by using a predetermined state equation; an estimation filter calculating a disturbance estimation value from the position estimation error by using a mathematical relation between a disturbance and the position estimation error; and a subtractor subtracting the disturbance estimation value from the control input.

Abstract: A settling control method and apparatus perform an improved settling control regardless of a seek distance when a disc drive track seek control operation is performed. An adaptive settling control method used in controlling the track seek mode of the disc drive includes: controlling a head to converge into a target position and a target velocity along with an eigen vector by transiting an initial state of the head motion onto an eigen vector line of a system at the time transiting from an acceleration/deceleration control mode of the track seek mode to a settling control mode.

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 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: A servo control device for a disk drive capable of effectively compensating for a low frequency disturbance incoming to the disk drive is provided. The servo control device includes: a state variable estimator calculating a position estimation error based on a control input for controlling motion of a head and a position error signal by using a predetermined state equation; an estimation filter calculating a disturbance estimation value from the position estimation error by using a mathematical relation between a disturbance and the position estimation error; and a subtractor subtracting the disturbance estimation value from the control input.

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 settling control method and apparatus perform an improved settling control regardless of a seek distance when a disc drive track seek control operation is performed. An adaptive settling control method used in controlling the track seek mode of the disc drive includes: controlling a head to converge into a target position and a target velocity along with an eigen vector by transiting an initial state of the head motion onto an eigen vector line of a system at the time transiting from an acceleration/deceleration control mode of the track seek mode to a settling control mode.

Abstract: An apparatus and method are provided for quickly and finely compensating for non-repeatable run out (NPRO) of a disc drive. The NPRO compensation control apparatus in a run out compensation apparatus of a system includes: a frequency estimator directly estimating a trigonometric function value of an NRRO frequency from a predetermined signal responding to the system using a correlation between a filter coefficient of a notch filter and a notch frequency; and an NRRO compensator canceling NRRO of the system using the trigonometric function value of the NRRO frequency estimated by the frequency estimator.