Hitachi, Ltd.

Hitachi Koki Co., Ltd.

Hiromu Hirai

Kenji Mori

Takashi Yamaguchi

Haruaki Otsuki

Hideaki Amano

Isao Kobayashi

Mikio Tokuyama

Muneo Kawamoto

Souichi Tohyama

Shin Hamano

Yoosuke Hamada

Yasuhiro Yoshimura

Masahito Kobayashi

Yoshinori Takeuchi

Hidekazu Kohira

Toshihiro Yamada

Takao Terayama

Takashi Yoshida

Tsuyoshi Takahashi

Masataka Kawauchi

Katsuhiro Tsuneta

Ryoji Okada

Fujio Tajima

Toshiaki Makino

Satoru Yamaura

Sadanori Nagaike

Teruyoshi Higashiya

Jun Naruse

Yuichi Koizumi

Takeshi Yoshida

Marutomo Goto

Hideyuki Kimura

Yosuke Hamada

Yuji Nishimura

Takashi Kohno

Takashi Kono

Akio Takatsuka

Toshio Matsushita

Yo Ikebe

Susumu Ebihara

Tomomasa Yoshida

Fuyuto Takase

Toshihiko Simizu

Tomoko Kumagae

A magnetic disk apparatus for recording information on and reproducing information from a magnetic disk with a magnetic head. A magnetic head supporting device includes a slider having the magnetic head mounted thereon, a flexible section supporting the slider, and a supporting section connected to the flexible section. The slider, the flexible section, and the supporting section are integrally formed from a same material. A rotary-type or linear-type positioning mechanism positions the magnetic head at a predetermined radial position of the magnetic disk.

Magnetic disk apparatus with slider and slider supporting mechanism including flexible section integrally formed from same material

Magnetic disk unit 1 is connected to personal computer 400 through recording mode selecting means 2, and recording mode selecting means 2 can select one of 3 recording modes (high reliability, large capacity, and high speed) and magnetic disk unit 1 records information with the recording method selected by recording mode selecting means 2. The controllability of the magnetic disk unit 1 and personal computer 400 is improved significantly by selecting the most suitable recording method according to the characteristics of information to be recorded.

Storage device capable of using both optical and magnetic disk units for

A rotary information recording/reproducing apparatus has a carriage rotatable by the first and second driving coils about an axis that moves an information recording/reproducing head radially to an associated recording disk for head positioning relative to the disk. The angle between a line connecting the center of the first driving coil and the center of the carriage pivot shaft and a line connecting the head and the center of the carriage pivot shaft is set to be not greater than 90 degrees while the angle formed between the first and second driving coils about the center of the carriage pivot shaft is within the range of from 100 degrees to 150 degrees, whereby reduction in the size and thickness of the apparatus can be achieved. A magnet-yoke assembly, which is subject to a reaction force, is mounted to a base by sheet springs and reaction-force damping members interposed therebetween so that the magnet-yoke assembly is independent from and infinitesimally rotatable relative to the base. The provision of the two driving coils and the reaction-force damping members effectively prevents the carriage pivot system and the disk spindle from being excited by the reaction force to thereby assure a high-speed and highly-accurate head positioning.

Rotary information recording/reproducing apparatus carriage actuator

A disk apparatus has a gain identifying apparatus for identifying a gain from a control signal for controlling each head to a detection position signal, a memory device to store the identified gain, and an apparatus for correcting the control signal on the basis of the gain at at time point when each head which is provided for each recording surface of disks is located at each of a plurality of track positions.

Disk apparatus and its control method

A magnetic disk unit comprising a one-piece carriage structure having a small thermal off-tracking amount, with the carriage structure including a rotary shaft; guide arms integrally supported on a guide-arm retainer at their proximal ends and extending independently and parallely; bearing retainers formed on both ends of the guide-arm retainer; and bearings fixed on the bearing retainers rotatably connecting the guide-arm retainer to the rotary shaft. A center line in a direction of thickness of the outermost guide arm is located outside of that of the bearing in a direction of height thereof, and a concave portion is continuously formed on the bearing retainer. Thermal coefficients of expansion of the guide arms and the guide-arm retainer are substantially equal, with the carriage structure being fashioned of an alloy mainly containing Al and Si, eutectic crystal Si particles in the guide arm and/or the guide-arm retainer. The average value of the longest eutectic crystal Si particles therein is 1.6 .mu.m or less or the number of the eutectic crystal Si particles if 5.0 or more per 100 .mu.m.sup.2. In the carriage of manufacturing the carriage of the carriage structure is heated for five to fifteen hours at a temperature of 300.degree. to 500.degree. C. after die casting.

Magnetic disk unit and manufacturing method of carriage structure thereof

A disk drive has a data recording medium disk, a head disposed facing a recording surface of the disk, for reading and writing data, a positioning mechanism for supporting and moving the head, a position detector for detecting the position of the head and outputting a position detection signal, and a control unit for processing the position detection signal and outputting a position control signal to the positioning mechanism. The control unit calculates a target acceleration signal for a given target track so as to make a turnaround frequency of a frequency component of the target acceleration signal coincident with a resonance frequency of the head positioning mechanism, calculates a target position for a head positioning operation in accordance with the target acceleration signal, calculates a position command value by inputting the target position signal to a model (inverse model) of an approximate inverse system to a position control system which includes the head positioning mechanism and the position detector, and outputs a position tracking error to the positioning mechanism, the position tracking error being the difference between the position command value and the position detection signal of the head.

Disk drive and method of controlling the same

A magnetic disk system utilizes both of voice coil motor and a piezoelectric element provided on a head supporting arm to precisely position a head to a predetermined position on a disk. The piezoelectric element is built in the distal end portion of the head supporting arm and is restricted in respect of its movement by a resilient mechanism which has low rigidity in the driving direction of the piezoelectric element and high rigidity in the other directions. The resilient mechanism is formed by pairs of doubled parallel leaf springs so arranged that each pair is disposed on either side of the piezoelectric element.

Disk system with sub-actuators for fine head displacement

Method and apparatus for control of positioning of a recording/playback head or other controlled object. When a controlled object reaches the vicinity of a target position, the control system is switched from operation as a velocity control system to operation as a position control system. By using state variables of the controlled object at that time, coefficients corresponding to the detected state variables are determined from characteristics of the controlled object which are determined in advance. By using the determined coefficient values, initial values upon start of position control of the position control system are set, and positioning control is then carried out.

Method and apparatus for control of positioning

A sample moving apparatus for positioning wafers with high accuracy, which apparatus comprises a fine adjustment actuator having a drive stroke to finely move the wafer, a fine adjustment stage driven by the fine adjustment actuator, a coarse adjustment actuator having a drive stroke to relatively coarsely move the wafer, a coarse adjustment stage driven by the coarse adjustment actuator, and a holder arrangement for attractively holding the wafer onto the wafer bearing surfaces of the respective stages. Upon selective energization of the holder arrangement of the respective stages, the wafer is moved while being attracted to the coarse adjustment stage or while being attracted to the coarse adjustment stage.

Sample moving apparatus, sample moving system and semiconductor

A vibrating-type driving unit employing a piezo-electric device is provided for conveying an object such as a sheet material. A follower roller is provided to be opposed to the vibrating-type driving unit, and A.C. power is supplied thereto so as to convey the object. In addition, a friction coefficient of surface of the follower roller is selected to be greater than friction coefficient of a driving head of the vibrating-type driving unit. With this selection, it is possible to convey the object efficiently and stably.

Method of and apparatus for conveying object by utilizing vibration

When a move command (data indicating to move a movable unit from one position to a target position) is issued, a movable unit is displaced in response to the move command. A target trajectory which is an aggregation of target positions varying with time is determined such that a residual vibration of a structure at and after the stop of displacement of the movable unit is minimized. Target positions at various times during the displacement of the movable unit are generated based on the target trajectory. The target positions at various times are supplied to a control unit which feeds back an actual position of the movable unit and produces a drive signal which makes a difference from the target position zero. The drive signal is supplied to an actuator so that a drive force is transmitted from the actuator to the movable unit which follows a change in the target position. As a result, the movable unit is moved to the target position and the vibration at and after the stop of movement is suppressed.

Method and apparatus for driving a servo system while suppressing

A first table is provided on a fixed base so that the first table can be moved in one of two directions which cross each other at right angles. A second table is provided on the first table so that the second table can be moved in the other direction. Linear motors for applying the driving force to the first and second tables to directly drive these tables are provided between the fixed base and first table and between the first and second tables.

Table device

An electric servo system has an electrical drive and a controllable object driven by the electrical drive whereby an error between an actual amount of actuation of the controllable object and a target value toward which the object is controlled is applied to the electrical drive to control the same so that the amount of actuation of the controllable object coincides with the target value. A compensator is provided on the input side of the electrical drive, for compensating the load characteristics of the controllable object such that the output of the electrical drive does not have apparent dependency on torque of the load.

Electric servo system

A magnetic tape in a reel-to-reel magnetic apparatus is transported directly from a supply reel to a take-up reel without a mechanical buffer or a vacuum column buffer. Separate drive motors are coupled to the respective reels and driven by predetermined target signals. Tape roll radii on the respective reels are determined from the amount of tape movement, that is, rotation angles of the reels and a known tape thickness, and reel moments are determined from the tape roll radii to determine a total amount of tape wound on the reels, that is, a reel status amount. During the tape transport, the tape roll radii and the reel moments change from time to time. Operation band widths or dynamic responses of the reel drive systems are equalized in accordance with the change of the tape roll radii and the reel moments so that the reel drive systems are cooperatively controlled.

Tape transport control unit

In a sheet feeding apparatus for transmitting the rotation of the motor shaft of a motor to a sheet feeding shaft for feeding a sheet by an elastic transmission mechanism, a speed state amount of either or both of the motor shaft and sheet shaft is compared to a position deviation signal at the input side of the motor and the resulting deviation signal therebetween is applied to the motor as a motor control signal to control it, thereby improving the dynamic characteristics of the sheet feeding.

Sheet feeding apparatus

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Tsukuba, Japan

Hiromu Hirai