公开(公告)号：JPH11112289A

公开(公告)日：1999-04-23

申请号：JP26203597

申请日：1997-09-26

Applicant: IBM

Inventor： KAGAMI NAOYUKI ,  TOKIZONO AKIRA ,  HIEN FUU DAN ,  ARN SHARMA ,  MUTUTANBII SURIIJAYANTA

IPC: G11B5/55 ,  G05B15/02 ,  G11B5/596 ,  G11B21/08 ,  G11B21/10 ,  H03H17/02 ,  H03H17/04 ,  G11B19/00

Abstract: PROBLEM TO BE SOLVED: To prevent filter output from becoming discontinuous at the time of switching a filter characteristic by setting the output value of a delay means with an initial value setting means at the time of changing a filter coefficient by the setting of a coefficient setting means. SOLUTION: The hardware state machine(SM) 29 of a hardware sequencer(SA) 23 calculates respective parameters and judges an operation mode. The SM 29 compares the mode of previous execution, which is held in an inner variable or the like, with a present mode. When the mode is changed, the parameters of the filter characteristics for the respective operation modes, which are stored, are set and the initial value of the inner variable is set. When the filter characteristic is changed, the filter coefficient of the digital filter suddenly changes. Thus, the filter output becomes discontinuous when the inner variable (delay value) until previous time is used as it is. A value Uss obtained by multiplying a value Css estimated to be control output at the time of switching the filter and the gain together is obtained and the delay value is set.

公开(公告)号：MY125903A

公开(公告)日：2006-08-30

申请号：MYPI9903012

申请日：1999-07-16

Applicant: IBM

Inventor： SRI-JAYANTHA SRI MUTHUTHAMBY ,  SHARMA ARUN ,  DANG HIEN PHU ,  KAGAMI NAOYUKI ,  NAKAGAWA YUZO ,  TOKIZONO AKIRA ,  YONEDA ISAO

IPC: G11B21/02 ,  G11B5/596 ,  G11B27/36 ,  G11B21/10 ,  G11B21/21

Abstract: METHODS AND SYSTEMS FOR DETECTING AND CORRECTING FOR UNDESIRABLE VIBRATIONS IMPACTING THE SERVO SYSTEMS (20,2020) IN DATA STORAGE DEVICES (10,2010). A DETECTION TECHNIQUE IS PROVIDED WHEREIN A DETECTION FILTER (40,50,140,240,2040) IS CONFIGURED TO SCAN A POSITION SIGNAL OF THE SERVO SYSTEM ACROSS A RANGE OF FREQUENCIES, AND, AT EACH RESPECTIVE SCANNED FREQUENCY, RECORD AN AMPLITUDE ASSOCIATED THEREWITH. THE RECORDED AMPLITUDES ARE EXAMINED TO DETERMINE WHETHER ANY EXCEED A THRESHOLD, THEREBY LOCATING A PEAK FREQUENCY OF THE VIBRATION. USING THE DETECTED PEAK FREQUENCY OF THE VIBRATION, A CORRECTIVE FILTER IS CONFIGURED TO OPERATE ABOUT THE PEAK FREQUENCY OF VIBRATION, THEREBY REDUCING ITS IMPACT ON THE POSITION SIGNAL IN THE SERVO SYSTEM. OPTIMUM DETECTION AND CORRECTION FILTER STRUCTURE ARE DISCLOSED, AS ARE TECHNIQUES FOR ADDRESSING FILTER STATE VECTORS AS INITIAL CONDITIONS AS THE CORRECTIVE FILTERS ARE REPEATEDLY ENGAGED DURING SUCCESSIVE SETTLE-OUT AND TRACK FOLLOW CYCLES (BETWEEN SEEKS), AS ARE CONTINUOUS ADAPTATION TECHNIQUES FOR CHANGING VIBRATION ENVIRONMENTS.FIGURE 7B

公开(公告)号：JP2003151229A

公开(公告)日：2003-05-23

申请号：JP2001343822

申请日：2001-11-08

Applicant: IBM

Inventor： TOKIZONO AKIRA ,  AONO SHIROO ,  OTA SHUNICHIRO ,  UNOKI TOSHIRO ,  HASHIMOTO MINORU

IPC: G11B21/21 ,  G11B5/55 ,  G11B21/08

Abstract: PROBLEM TO BE SOLVED: To prevent undulation of a lubricating film on a magnetic disk and to decrease the writing defects occurring in this undulation. SOLUTION: The hard disk drive which reads out or writes data by a magnetic head 4 from the magnetic disk 2 rotating in accordance with a command from a host computer detects the moving quantity in the radial direction of the magnetic head 4 within a prescribed period and seeks the magnetic head 4 by the prescribed quantity when the detected moving quantity is small.

公开(公告)号：JP2002032970A

公开(公告)日：2002-01-31

申请号：JP2000207565

申请日：2000-07-07

Applicant: IBM

Inventor： TOKIZONO AKIRA ,  KAGAMI NAOYUKI ,  UCHIDA HIROSHI ,  KURODA TAKASHI

IPC: G11B21/08 ,  G11B5/012 ,  G11B5/54 ,  G11B5/596 ,  G11B19/04 ,  G11B21/02 ,  G11B21/10 ,  G11B21/22 ,  G11B27/30 ,  G11B27/36

Abstract: PROBLEM TO BE SOLVED: To provide a technique for attempting to maintain a servo lock state and to restore to a normal readout state even when a servo address mark(SAM) can not be detected. SOLUTION: In this device, when the SAM can not be detected, a dummy SAM is generated in timing when a servo lock is not released. When servo control processes in which the dummy SAM is used exceeds a fixed frequency by performing a servo interrupt control normally, the device starts its urgency brake control. In the urgency brake control, the moving direction of an arm is judged and current is made to flow through a VCM(voice coil motor) so that the arm is driven in a reverse direction. Moreover, feedback control is performed by using the output value of a back emf(electromotive face) circuit which is used in a loading/unloading mechanism.

公开(公告)号：JP2000137961A

公开(公告)日：2000-05-16

申请号：JP30917498

申请日：1998-10-29

Applicant: IBM

Inventor： UCHIDA HIROSHI ,  TOKIZONO AKIRA ,  KAGAMI NAOYUKI

IPC: G11B5/55 ,  G11B21/08 ,  G11B21/10

Abstract: PROBLEM TO BE SOLVED: To provide initial value compensation by a writing operation in an initial value compensating method at the time of the head positioning of a hard disk drive even when a distance L between a head starting position and a target position is larger than a specified value. SOLUTION: In the control method of a data recording device for using plural control operation modes during the operation of positioning a reading/ writing head from a starting position to a target position, investigation is made as to the starting time of one control operation mode among the plural control operation modes (S54). Then, in response to the starting time of one control operation mode, determination is made as to whether processing is a writing or reading operation (S55). In response to a writing operation, the processing operation makes investigation as to whether a distance between the starting and target recording positions of the reading/writing head is equal to a specified value or lower and, in response to the determination that the distance between the starting and target recording positions of the reading/writing head is lower than the specified value L1, compensation is performed by an initial value compensating method, and one control mode of the writing operation is executed.

公开(公告)号：JP2000137939A

公开(公告)日：2000-05-16

申请号：JP30821898

申请日：1998-10-29

Applicant: IBM

Inventor： SAKAI TATSUYA ,  TOKIZONO AKIRA ,  KAGAMI NAOYUKI ,  KURODA TAKASHI

IPC: G11B21/08 ,  G11B5/596 ,  G11B19/28 ,  G11B21/10 ,  G11B27/30 ,  G11B19/02 ,  G11B19/247

Abstract: PROBLEM TO BE SOLVED: To provide a disk drive device, a servo controller and a control device, which are capable of contributing to the improvement of performance of the disk drive device. SOLUTION: When data for showing the reproduction level of a servo pattern are supplied from a channel 5 through a servo control part 21, the calculation for the servo control is executed by an SA(servo assist) 23 independently of an MPU 12 and the calculated result is supplied to a VCM(voice coil motor) driving part 6 through a SIO(serial I/O) 22 to drive a head arm 3. The selection is made by an interruption generating part 26 with regard to whether the interruption against the MPU 12 is generated for every reproduction of the servo pattern or the interruption against the MPU 12 is generated based on condition signals from the SC(servo control part) 21, SA 23 and DC(drive control part) 25, according to the selection from the SA 23 or MPU 12.

公开(公告)号：JP2000132932A

公开(公告)日：2000-05-12

申请号：JP30354398

申请日：1998-10-26

Applicant: IBM

Inventor： KAGAMI NAOYUKI ,  TOKIZONO AKIRA

IPC: G11B21/10 ,  G05B11/36 ,  G05B13/02 ,  G05D3/12 ,  G11B5/596

Abstract: PROBLEM TO BE SOLVED: To improve stability of head positioning servo to reduce fluctuation of head by including a step to compensate for a position detection signal gain depending on a cyclic loop gain and adequately compensating, not depending on the head, for inclination of PES at the center of MPES and SPES. SOLUTION: PES gain H(x) is read to a PES gain table within a memory. A MPES/SPES calculating means 8b calculates a main position detecting signal using PES gain H(x). Noise is respectively set to a noise table and sine table or the like reserved in the memory. A cyclic loop gain of head is obtained, the PES gain (inclination of PES) itself is compensated depending on deviation from the standard value (average value) of cyclic loop gain and moreover the Cont gain of a servo loop having a large cyclic loop gain is also compensated. Thereby, gradient of PES may be set identical for any head.