Fujitsu Corporation

Eiji Okamura

Kazuhiko Takaishi

Eisaku Takahashi

Kazuhide Ohba

Atsushi Satoh

Tatsuya Gofuku

Isao Suda

Chihiro Ono

Takashi Tokairin

Tsutomu Sasaki

Takeyori Hara

Susumu Hasegawa

Hirofumi Suzuki

Katsumi Shirai

Norihiko Suzuki

Takahiro Ono

Koichi Tohkairin

Kenji Endo

Hirokazu Ishizaki

Masaru Saiki

A motor drive control unit includes a chip in which everything about a control system is provided and controls a spindle motor which rotates magnetic disks at a constant speed. When a measurement instruction is received from a disturbance generating unit and the upper-level device, sine wave disturbance is generated in the revolution speed of the spindle motor which depends on the motor drive control unit. A speed detecting unit detects the revolution speed of the spindle motor as measured data while the disturbance is being generated by the disturbance generating unit. A measured data transferring unit transfers the detected measured data detected by the speed detecting unit to the upper-level device, wherein control characteristics such as gains and phases with respect to frequencies of the motor control unit are computed.

Rotary-motor-loaded device and control characteristic measurement method and program

Position information PosN and PosQ are compared and position information Posand Posin which influences of an error of a position sensitivity gain appear oppositely are calculated. Subsequently, a weight gain G=M and a weight gain G=(1&#x2212;M) are obtained from the position information Pos. A multiplication value obtained by multiplying the third position information Posby the weight gain Gand a multiplication value obtained by multiplying the fourth position information Posby the weight gain Gare added and synthesized, thereby calculating a decoded position.

Position demodulating method and circuit of disk apparatus

A disk apparatus has a disk medium with sector areas that have a servo area and a data area along the same cylinder. The servo areas also have a sector mark indicative of the servo area, a code indicative of a cylinder address, and a predetermined servo pattern to detect a head position, all magnetically recorded in the servo area. A disk control section uses a head portion to detect the head position on the basis of a read signal of the servo pattern and positions the head portion at an arbitrary cylinder to perform reading and writing operations. The disk apparatus also has a time measuring counter for starting to measure an elapsed time each time a predetermined position in the servo area is detected, and a time setting register for storing a time from a detection time point of the predetermined position in the servo area to the generation of the sector pulse. A coincidence detecting section is provided to detect that the elapsed time measured by the time measuring counter coincides with the set time of the register, while a pulse generating section is provided for generating the sector pulse when the coincidence is detected by the coincidence detecting section.

Disk apparatus using coincidence detection to generate variable sector

A positioning control system is provided with a controlled device which has resonance characteristic and is positioned at a designated position; position detector for detecting a moved position of the controlled device in accordance with a servo signal or the like; arithmetic controller such as a DSP (Digital Signal Processor) adapted to generate a drive signal based on a position detection signal from the position detector and the designated position; and a drive adapted to move the controlled device in accordance with the drive signal from the arithmetic controller. The arithmetic controller includes a low pass filter which has an abrupt slope and a discontinuous pole in the gain-frequency characteristics thereof to suppress the resonance characteristics. Preferably, the low pass filter is constituted by a combination of a notch filter and an elliptical function filter.

Positioning control system

For a balance adjustment due to a reduction in size and weight of an actuator, an arm portion, an axis attaching portion, and a coil supporting portion are arranged so that the centers of gravity on the coil side are located on a straight line connecting a rotational center and the center of gravity on the head side. Further, the improvement of an assembling efficiency of a VCM, an increase in torque, a one-touch fixing of an FPC connecting band, a noise prevention of a read pattern, and an insulation between the base and cover due to a bias of an MR read head are accomplished. A sector mark is detected by comparing a peak detection pulse and its reference polarity signal. A redundancy is provided to a reference detection polarity signal so that a read signal can be detected even if any one of the read signals of the sector marks is dropped out. A gray code detecting section for recognizing a cylinder address also detects on the basis of a peak detection pulse and a polarity signal due to the reading of a gray code. A memory space to store a program is divided into an ROM space of a small electric power consumption and an RAM space of a large electric power consumption and stores each peculiar program.

Head positioning control for disk apparatus using peak detection,

An existent filing apparatus transfers position information to a developing device. A microcontroller unit of the developing device calculates the current value for moving a head by using the position information in accordance with a firmware, and supplies the current value to the filing apparatus. The filing apparatus drives a motor on the basis of the current value, detects the current head position and supplies the detected head position to the developing device. The microcontroller unit of the developing device determines the next current value by using the head position information in accordance with the firmware, and a monitoring means of the developing device monitors the operation of the filing apparatus on the basis of the head position information and displays the monitored operation.

Developing system and measuring system for filing apparatus

A positioning control system for a controlled device, such as a disk drive head, estimates a moving time for moving the controlled device from a current position of the controlled device to a newly designated position. The system sets the estimated moving time as a target moving time. Positioning elements then move the controlled device to the designated position in response to the target moving time. Positioning elements may include an actuator for moving the controlled device, a position detector for tracking movement of the controlled device, and a control element for controlling the actuator. The control element calculates a trajectory for the controlled device to follow based on the target moving time, and controls the actuator based on the calculated trajectory and controlled device position as determined by the position detector. The control system may also have a position correcting element included in the control element. The correcting element compares the actual position of the controlled device with a calculated position of the controlled device and makes necessary adjustments.

In a system for monitoring settling of a transient response of a load controlled by a following controller, a state estimation unit generates a state estimation quantity which shows an estimated state of the load. A settling evaluation function operation unit generates an evaluated output by inputting, to a predetermined settling evaluation function, the state estimation quantity and a control quantity output to the load by the following controller. A count unit generates time data showing a time elapsed since commencement of supervision of settling. A comparator unit compares the evaluated output and the time data with each other, and replaces the time data of the counter unit with the evaluated output on the basis of a comparison result. A decision making unit generates a settling completion signal when the time data shows a predetermined time.

Settling monitor system for a following servo

Disclosed is a system for more precisely controlling the speed of a magnetic tape transport motor in an information storage apparatus of a magnetic tape type, by including a program for controlling the speed of the magnetic tape transport motor in the microprogram for controlling the information storage apparatus of a magnetic tape type.

Growing community of inventors

Kawasaki, Japan

Eiji Okamura