Kabushiki Kaisha Toshiba

Shinji Takakura

Yoshiyuki Ishihara

Shigen Yasunaka

Hiroaki Nakamura

Junichi Akiyama

Tomoko Taguchi

Takahiro Hirai

Akihiro Koga

Kohichi Kubo

Masayuki Sekimura

Takehito Yamada

Takao Ohmi

Junya Tanaka

Takamitsu Sunaoshi

Yasushi Tomizawa

Shinya Aoki

Mitsunobu Yoshida

Toshikatsu Akiba

Kohsuke Harada

Kohei Maruchi

Satoshi Kuwahara

Makihiko Ishitani

According to an embodiment, a magnetic disk device includes: a magnetic disk; an arm; a support member provided at a distal end of the arm; a magnetic head provided on the support member and configured to access the magnetic disk; a first actuator configured to rotate the arm; a second actuator configured to drive the support member; and one or more processors configured to implement a controller configured to perform seek control of the magnetic head. The controller includes: a feedback controller configured to control a first command value for driving the first actuator so as to reduce an error between a position of the magnetic head and a target position; and an iterative learning controller configured to receive an input value based on the error and output a second command value for driving the second actuator by iterative learning.

Magnetic disk device, control method, and computer program product

A tension detection device according to an embodiment includes a base, a support member, a continuous body, an external force detection unit, and a tension detection unit. One end or both ends of the support member are fixed to the base. The support member has an external force measurement section integrally provided at the one end or both ends thereof. The continuous body is conveyed while wound around an outer circumference of the support member. The external force detection unit is provided at the external force measurement section of the support member. The external force detection unit detects an external force. The tension detection unit detects tension of the continuous body based on a detection result from the external force detection unit.

Tension detection device, tension detection system, and thermal printer

According to one embodiment, an inverter device configured to be capable of switching an on or off state of each of a plurality of switching elements, on the basis of a control command signal, and operable as a single-phase inverter, includes: a pulse width modulator configured to set a voltage value at a time when one of the switching elements is set to the on state to a first voltage, and set a voltage value at a time when the other three of the switching elements are set to the on state to a second voltage larger than the first voltage, in operation as the single-phase inverter; and a detection unit configured to detect the control command signal in operation as the single-phase inverter.

Inverter device and method for detecting heat dissipation characteristics of inverter device

According to an embodiment, an inspection apparatus inspects an inverter circuit including three pairs of arms. The apparatus includes a current controller and a control signal generator. The current controller generates a control output for controlling a current to be output by the inverter circuit. The control output enables the current to approach a target value of the current. The control signal generator generates a first control signal for controlling ON/OFF of a first arm as one of the three pairs of arms based on the control output, a second control signal for fixing a second arm paired with the first arm, in an OFF-state, and a third control signal for fixing at least part of arms other than the first arm and the second arm in an ON-state.

Inspection apparatus, inspection method, and inverter apparatus

According to one embodiment, a correction device is used for an apparatus including a coil and a conductor in a vicinity of the coil. The correction device corrects an influence of a magnetic field generated by the conductor when a current flows through the coil. The correction device includes a first measuring device, a second measuring device, and a control device. The first measuring device measures a first signal of the coil. The second measuring device measures a second signal of the coil, which is different from the first signal. The control device estimates the influence acting on the coil, based on a difference between the first signal filtered by a first filter and the second signal filtered by a second filter. Furthermore, the control device controls a command signal for flowing the current to the coil, based on an estimation result of the influence.

Correction device, correction method, and magnetic resonance imaging apparatus

According to one embodiment, a servo write control apparatus is for a disk apparatus including a read element and a write element located in an outer side of a disk from the read element. The servo write control apparatus detects a plurality of first burst signals recorded in a circumferential direction of the disk by the read element. The servo write control apparatus calculates an offset in a radial direction when the write element writes a second burst signal, based on amplitude values of at least two of the first burst signals used for positioning the read element. The servo write control apparatus adjusts a write position of the second burst signal based on the offset.

Servo write control apparatus and method, and magnetic disk apparatus

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&#xd7;P&#x2212;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.

Method for identifying high-speed frequency response of multirate system and apparatus therefor

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.

Hard disk drive, method for estimating back electromotive force, and method for controlling velocity of head

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.

Load/unload control method and apparatus for a magnetic disk drive

A magnetic disk apparatus includes a magnetic disk that includes a plurality of zones in which a plurality of tracks are arranged for each of circumferences of a spiral, and gaps that are arranged between the zones to have a width a predetermined number of times larger than a track width and that are regions without providing recording bits; and a reproducing element that simultaneously makes an access to the recording bits contained in the tracks, reading information stored in the recording bits, wherein the number of the tracks is one or larger and a sum of one and the predetermined number or smaller in one of the zones.

Magnetic disk apparatus and information reproducing method

An information recording/reproducing device according to an example of the present invention includes first and second heads, a recording medium having a data area from which recording data is read by the first head and a servo burst area from which a servo burst signal is read by the second head, a driver which performs positioning of the second head based on the servo burst signal, and a resistor which covers a surface of the servo burst area and does not cover a surface of the data area. The recording data and the servo burst signal are recorded by a pulse signal.

Information recording/reproducing device

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.

Seek control apparatus and method for generating control data for seek control

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.

Magnetic disk apparatus and method for controlling magnetic head

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.

Positioning system mounted on probe memory device and positioning method thereof

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.

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Yokohama, Japan

Shinji Takakura