Patent application number | Description | Published |
20080253269 | POSITIONING SYSTEM MOUNTED ON PROBE MEMORY DEVICE AND POSITIONING METHOD THEREOF - A probe memory device carries out positioning with the use of a servo pattern provided in a servo area on a recording medium, and the recording medium and a probe head section are reciprocatingly moved (scan-moved) by vibration at a specific frequency in a one-axis direction. At this time, based on information from the servo area, relative position information between the recording medium and the probe head section is acquired, the relative position information is processed at a control section, and then, feedback control is carried out for carrying out position correction relative to an actuator. | 10-16-2008 |
20090073600 | POSITIONING CONTROL SYSTEM AND POSITIONING CONTROL METHOD - There is provided with a positioning control system including: a head moving unit; a position detecting unit detecting a head position at predetermined time intervals; an error detecting unit detecting a position error of the head for a target position; a disturbance detecting unit detecting a non-periodic disturbance; a modifying unit modifying a first position error signal corresponding to a first head position detected in a first rotation period based on a second position error signal corresponding to a second head position detected one period length before; and a feedback controller, wherein the modifying unit modifies the first signal after reducing an amplitude of the second position error signal when a detected timing of the second head position is included in a predetermined time range with respect to a detected timing of the non-periodic disturbance detected in a second rotation period which is one period before the first rotation period. | 03-19-2009 |
20090109567 | SEEK CONTROL APPARATUS AND METHOD FOR GENERATING CONTROL DATA FOR SEEK CONTROL - There is provided a method for generating acceleration data used in feed-forward control of head seeking, wherein, a seek distance and one of a seek period and the count of samples are received; a weighting factor for the change rate of acceleration between adjacent sample times is determined respectively; and an optimum acceleration at each sample time is obtained by performing an optimization calculation that minimizes an objective function under a constraint condition based on variables representing accelerations at each sample time, either the seek period or the count of samples, and the seek distance. | 04-30-2009 |
20090219646 | POSITIONING CONTROL SYSTEM AND METHOD THEREFOR - There is provided with a positioning control system which includes: a head moving unit configured to move a head for recording or reproducing information with respect to a disk capable of recording information; a position detecting unit configured to detect a position of the head; an error detecting unit configured to detect a position error signal of a detected head position with respect to a predetermined target position; a compensation controller configured to generate control input by performing phase lead compensation and phase delay compensation for the position error signal and supply the control input to the head moving unit; and a gain controller configured to control at least one of gains the phase lead compensation and the phase delay compensation based on frequency components contained in the position error signal and an amplitude of the position error signal. | 09-03-2009 |
20110019299 | LOAD/UNLOAD CONTROL METHOD AND APPARATUS FOR A MAGNETIC DISK DRIVE - According to one embodiment, an estimation method comprises measuring and creating. The measuring is configured to measure a head velocity and a terminal voltage of a coil of a voice coil motor at least two times before unload in a control system eliminating an influence caused by a transient response of inductance of the voice coil motor. The calculating is configured to a calculate torque constant and a coil resistance based on command voltages and at least two measured head velocities and terminal voltages of the coil. | 01-27-2011 |
20130030743 | METHOD FOR IDENTIFYING HIGH-SPEED FREQUENCY RESPONSE OF MULTIRATE SYSTEM AND APPARATUS THEREFOR - There is provided with a method of identifying a frequency response of a controlled object at a sampling period of control input in a multiplexed-input multirate system in which a sampling period of control output is even “P” multiples of the sampling period of control input wherein the control object is represented by FIR filter, an M-series signal corresponding to an acquisition data length Mp×P−1 is generated, the Mp indicates a period of the M-series signal, an impulse response value of the controlled object is estimated based on the M-series signal and output data outputted from the controlled object by inputting the M-series signal thereto, and the frequency response of the controlled object is identified by performing a discrete Fourier transform on the impulse response value. | 01-31-2013 |
Patent application number | Description | Published |
20080291568 | MAGNETIC DISK APPARATUS AND METHOD FOR CONTROLLING MAGNETIC HEAD - A magnetic disk apparatus includes: a driving unit; a position error feedback control system; and a velocity control system. The driving unit is configured to move a magnetic head operative for magnetic recording/reproduction of information on a magnetic disk. The position error feedback control system is configured to perform feedback control of the driving unit based on difference between target track position and detected position of the magnetic head. The velocity control system is configured to vary a target velocity curve based on position of the magnetic head before motion, the target track position of the magnetic head, and position of a data sector to be subjected to recording/reproduction, for using a control mathematical model of the driving unit to control the driving unit so that velocity of the driving unit follows the target velocity curve. | 11-27-2008 |
20090040647 | MAGNETIC DISK APPARATUS AND MAGNETIC HEAD CONTROL METHOD - A magnetic disk apparatus includes: a driving unit; and control part configured to control the driving unit. The control part includes: a position error feedback control system and a two-degree-of-freedom control system. The position error feedback control system has an integrator and a phase-lead compensator and is operative to determine a position command based on a target position and a sensed position of the magnetic head, thereby performs feedback control on the driving unit. The two-degree-of-freedom control system receives as input a target moving distance of the magnetic head and outputs a current command to the driving unit by using a mathematical model of the driving unit. The control part updates the mathematical model, and has a first update mode in which the mathematical model is updated using the output of the phase-lead compensator while the output of the integrator is provided to the driving unit. | 02-12-2009 |
20090195913 | MAGNETIC DISK APPARATUS AND METHOD FOR CONTROLLING MAGNETIC HEAD - A magnetic disk apparatus includes: a driving section for moving a magnetic head recoding and reproducing information in a magnetic disk; and a controller for controlling the driving section. The controller includes: a position-error feedback control system having an integrator and a phase lead compensator and obtaining a position command based on difference between target position and detection position of the magnetic head to perform feedback control of the driving section; and a two-freedom-degree control system inputting a target move distance of the magnetic head and outputting a current command to the driving section by using a mathematic model of the driving section. The controller providing the driving section with an output of the integrator and therewith updating the mathematical model by using an output of the phase lead compensator, in each of the times of positioning control and seek of the magnetic head. | 08-06-2009 |
20120019955 | HARD DISK DRIVE, METHOD FOR ESTIMATING BACK ELECTROMOTIVE FORCE, AND METHOD FOR CONTROLLING VELOCITY OF HEAD - According to one embodiment, a hard disk drive includes a head, a voice coil motor, a driving circuit, an identification unit, a storage unit, and an estimation unit. The head is configured to perform write/read of information to a storage medium. The voice coil motor is configured to move the head. The driving circuit is configured to drive the voice coil motor, based on a command signal. The identification unit is configured to identify at least one parameter of a discrete-time model. The discrete-time model represents a transfer function from the command signal to a voltage drop quantity by an inductance of a coil of the voice coil motor. The storage unit is configured to store the parameter. The estimation unit is configured to estimate a back electromotive force of the coil, based on the discrete-time model including the parameter. | 01-26-2012 |
20120075742 | MAGNETIC DISK DEVICE, ELECTRONIC APPARATUS AND, HEAD CONTROL METHOD - A magnetic disk device includes a head, a coil motor, a drive circuit, a voltage detector, a head position calculation unit, a velocity calculation unit, a counter electromotive voltage calculation unit, a coil resistance estimation unit, and a control unit. The head position calculation unit calculates a position of the head for each sampling cycle on the basis of servo information. The velocity calculation unit calculates a velocity of the head for each sampling cycle. The counter electromotive voltage calculation unit calculates a counter electromotive voltage of the coil for each sampling cycle. The coil resistance estimation unit successively estimates a coil resistance value of the coil. The control unit calculates a drive instruction for controlling the velocity and outputs the drive instruction to the drive circuit. In addition, the counter electromotive voltage calculation unit subtracts a voltage drop from the inter-terminal voltage to calculate the counter electromotive voltage. | 03-29-2012 |
20120281311 | RAMP-UNLOADING SEEK CONTROL DEVICE FOR MAGNETIC DISK DRIVE - A ramp-unloading seek control device includes a voice coil motor, a detector, an instruction-current detector, a head-speed computing unit, and an identification structure. The identification structure estimates an error between a true resistance value and an estimated resistance value of the voice coil motor. The identification structure can minimize an estimated error defined as a difference between an estimated value ŷ(k) of the head speed and the head speed y(k), and employs {circumflex over (b)} | 11-08-2012 |
20130070368 | MAGNETIC DISK DEVICE AND CONTROLLING METHOD OF HEAD - A magnetic disk device includes a head, a coil, a drive circuit, a detector, a first calculation unit, a generation unit, a first estimation unit, and a control unit. The detector detects an inter-terminal voltage across the coil. The first calculation unit calculates a back electromotive force across the coil by the use of the inter-terminal voltage. The generation unit generates a target velocity as a reference value of a velocity of the head. The first estimation unit estimates a first velocity of the head and an error of the first velocity by the use of the back electromotive force. The first estimation unit estimates a second velocity for decreasing the error. The control unit calculates a control instruction to bring the second velocity close to the target velocity. | 03-21-2013 |