Abstract: The present invention relates to a head positioning method and device for positioning a head to read information from disk media at prescribed positions using a rotary actuator, in which eccentricity errors of the rotary actuator are corrected. In a disk device having disk media, a head, a rotary actuator, and a control circuit, memory is provided to store eccentricity correction information for each region of a disk divided in the radial direction. Eccentricity correction information corresponding to the head position is read, and eccentricity correction signals are created. Optimal eccentricity correction corresponding to the position of the head on the disk is made possible, and rapid seeking is enabled.

Abstract: A head position control method performs virtual circular control which does not follow up the eccentricity of a disk, and implements high precision virtual circular control, even if the servo signals of an area demodulation method are used. The method performs virtual circular control by demodulating position signals in the area demodulation method and calculates the demodulation position with the velocity offset correction of 2-phase servo signals by using both the head velocity V of the virtual circular orbit reference and the relative velocity &Dgr;V of the virtual circular orbit and the position signal.

Abstract: A disk device that has displacement of servo signals in the circumference direction and radius direction between a plurality of disks, prevents a drop in performance due to the displacement when the heads are switched. To deal with the displacement in the circumference direction, the sector numbers on the disk are converted by a table for each head. Also the servo gate time is corrected by the table according to the eccentricity of the disk, so the servo signal detection accuracy improves. Also to deal with the displacement in the radius direction, the track numbers on the disk are converted by the table using the difference value based on the reference head.

Abstract: A disk device has eccentric misalignment between a plurality of disk surfaces. In order to prevent transient phenomena due to differences in the eccentric trajectories during head switching, a head position control method performs feed forward control for a plurality of disk surfaces by means of the eccentricity correction current of respective heads, and when switching heads, predicts the velocity fluctuation or current step differential between heads from the eccentricity correction current, and thus corrects the control system to eliminate velocity fluctuation and current step differential.

Abstract: This invention relates to a head-positioning method and device for positioning the head, that reads a disk medium, to a specified position. A disk device having a head, actuator and control circuit comprises: a demodulation unit for demodulating the demodulated position from the head output, a calculation unit for calculating the error between the demodulated position and target position, and a gain-correction unit for correcting the error with a gain. Since a relative position is used, it is possible to accurately detect the position error, for which the non-linear characteristics of the head sensitivity distribution have been corrected, at each offset position.

Abstract: Position information PosN and PosQ are compared and position information Pos1 and Pos2 in which influences of an error of a position sensitivity gain appear oppositely are calculated. Subsequently, a weight gain G1=M and a weight gain G2=(1−M) are obtained from the position information Pos1. A multiplication value obtained by multiplying the third position information Pos1 by the weight gain G1 and a multiplication value obtained by multiplying the fourth position information Pos2 by the weight gain G2 are added and synthesized, thereby calculating a decoded position.

Abstract: This invention comprises a head 3 for reading information from a disk storage medium 2, an actuator 5 for moving the head 3, and a control circuit 8 for calculating a control signal from the position signal, that was read by the head, using an eccentricity observer 21. The control circuit 8 selects a first eccentricity estimation gain during seek control and selects a second eccentricity estimation gain during following control. This makes it possible to perform seek control that is not affected by the eccentricity error.

Abstract: The present invention relates to a head positioning method and device for positioning a head to read information from disk media at prescribed positions using a rotary actuator, in which ch eccentricity errors of the rotary actuator are corrected. In a disk device having disk media (2), a head (3), a rotary actuator (5), and a control circuit (8), memory (11) is provided to store eccentricity correction information for each of the regions of a disk divided in the radial direction; eccentricity correction information corresponding to the head position is read, and eccentricity correction signals are created. Optimal eccentricity correction corresponding to the position of the head on the disk is made possible, and rapid seeking is enabled.

Abstract: This invention relates to head position control method for a disk device the uses a disk medium whose tracks have been formatted externally, and the disk device that effectively uses the range of motion of an actuator. In a disk device that has a disk medium (2), head (3), actuator (5), a control circuit (8), there is a conversion mechanism (31) that sets a data area in the writing range of the disk (2) that corresponds to the range of motion of the actuator, and converts a logical address to a physical address in the data area. This invention makes it possible to set a storage capacity that makes maximum use of the range of motion of the actuator for any device, even when there is position offset in the range of motion of the actuator.

Abstract: The present invention relates to a head positioning method, its and a disk device for positioning the head to read a disk medium at a predetermined position, which demodulates accurate demodulation positions even when the head is moving. In a disk device comprising a disk medium (6), a head (4), an actuator (3) and a control circuit (19), the demodulation result is determined from the position signal of the head and speed is corrected by a correction value which depends on the moving speed of the head. Since the speed is corrected, accurate positions can be demodulated even when the head is moving.

Abstract: In a head positioning method and device in which the position of position signals between heads is not uniform, it is aimed to reduce the time taken to find the position signals even when heads are switched. The storage disk device comprises a storage disk 1 with the position signal, a plurality of heads 3a through 3d that read the information from recording disk 1, an actuator 5 that moves the heads, and a control circuit 11 that positions the heads based on the position signals read from the recording disk by the selected head. This control circuit 11 comprises a synchronization circuit 6 that, in response to a head switching cue, synchronizes the time of the detection signal for detecting the position signal with the time of the position signal read by the head to which switching is directed, and a processing circuit 11 that reads the position signal for the head in response to the synchronized detection signal and positions the head in response to the position signal read.

Abstract: This invention comprises a head 3 for reading information from a disk storage medium 2, an actuator 5 for moving the head 3, and a control circuit 8 for calculating a control signal from the position signal, that was read by the head, using an eccentricity observer 21. The control circuit 8 selects a first eccentricity estimation gain during seek control and selects a second eccentricity estimation gain during following control. This makes it possible to perform seek control that is not affected by the eccentricity error.

Abstract: A disk device includes a magnetic disk carrying servo information and rotatable about a rotational axis, a magnetic head for reading information from the magnetic disk, a positioning unit for positioning the magnetic head radially over the magnetic disk, and a control unit for controlling the positioning unit according to the servo information. The control unit separately measures a rotational frequency component of the magnetic disk and a high-order frequency component which has frequencies higher than the rotational frequency component, and thereafter controls the positioning unit so as to follow the rotational frequency component while eliminating the high-order frequency component. When the magnetic head is positioned along a circular pattern about the rotational axis of the magnetic disk, the magnetic head is prevented from vibrating while compensating for an eccentricity of the magnetic disk.

Abstract: A method for generating a reliable head position signal including track number validation. A head position signal is generated using two triangular signals PosN and PosQ having a phase difference of a 1/4 period, and a track number which is recorded on the medium. The track number is validated by comparing the relationship of the signs of the signals PosN, PosQ with the track number according to a predetermined rule. The track number may be a corrected if the track number was misread. Subsequently, a position signal generator demodulates the position signal on the basis of the absolute values of signals PosN, PosQ, the signs of the signals PosN, PosQ, and the track number. The accuracy of the head position signal is further improved using a conversion coefficient (position sensitivity factor) for correcting the amplitudes of the signals PosN and PosQ.

Abstract: A storage disk apparatus has a storage disk having servo information, a plurality of heads for reading information recorded on the storage disk, a plurality of first actuators for accurately positioning the heads with respect to the storage disk, a second actuator for coarsely positioning the heads with respect to the storage disk, and a control circuit for controlling the first actuators and the second actuator according to the servo information read by one of the heads. The control circuit supplies a drive current value depending on the servo information read by one of the heads to one of the first actuators to position the one of the heads, and also supplies the drive current value to the other first actuators to position the other heads. When one of the heads is positionally detected, all the first actuators, typically microactuators, are prevented from being vibrated and relatively displaced from the second actuator in a seek mode.

Abstract: An enhancement of the precision of the positioning of the head in a magnetic recording device having a magnetoresistive head is provided. The burst pattern stored in a storage medium is read by the head, and the two triangular waves are demodulated in the demodulation portion through the read/write portion. The actual head position signal generated in the head position signal generation portion is compared in the comparison portion with the target position generated in the target position generation portion. The deviation .DELTA.P as the output is controlled and calculated in the proportional and integral control portion, and the resultant output is compensated with regard to the reading gain difference of the head in the gain difference compensation portion. An arc-sine function transformation is carried out in the linearity compensation portion to compensate for the linearity. The position of the head is adjusted by the voice coil motor based on the signal after the compensation.

Abstract: A control system for a two-stage actuator for a disk drive, including a coarse actuator having a voice coil motor as a driving device mounted on a base of the disk drive, a microactuator mounted on the coarse actuator and carrying a head at a front end portion, a coarse actuator controller for controlling driving of the coarse actuator, and a microactuator controller for controlling driving of the microactuator. The control system further includes a feedback device for calculating a position error between a target position and an observed position of the head, and inputting the position error into the coarse actuator controller and the microactuator controller. The displacement of the microactuator relative to the coarse actuator is not input into the coarse actuator controller.

Abstract: A processing unit for effecting speed control in a drive control apparatus includes a storing unit having a first table which stores discrete values having exponential intervals, and a second table which stores multiples of normalized reference values having uniform intervals from each other and relating to a distance between a driven body subject to the speed control and a target position. The discrete values lie in a range over which the normalized reference values vary and are bound in a predetermined relation to a coefficient multiplied by the normalized reference values. The normalized reference values lie in the upper 1/2 range of said discrete values.A control target value generating unit calculates a control target value relating to a target speed of the driven body, by referring to the first and second tables.

Abstract: Disclosed is a head positioning control system for disk drives which enables fast access even when eccentricities of tracks defined with servo control information relative to the center of rotation are different among disks assembled after the servo control information is externally written on the respective disks. The head positioning control system is adapted to a disk drive comprising a plurality of disks each having a record surface on which servo control information indicating positions in a radial direction on a disk is recorded, and heads associated with the plurality of disk record surfaces and designed to detect information stored on the plurality of disk record surfaces. The servo control information includes position information in the radial direction on each disk record surface and defines servo-control circular trajectories.

Abstract: A storage device includes: a read/write mechanism which is actuated in accordance with a selected one of two or more sets of control data so that a read/write operation is carried out to read data from or write data onto a recording medium; a detection unit for detecting a source voltage from a host system, and for detecting whether one of source voltages from the host system has been switched to another source voltage; a control unit for controlling the read/write operation of the read/write mechanism in accordance with the detected source voltage; and a reset unit for resetting the control unit to an initial condition when the switching from the one of the source voltages to the another source voltage is detected as being in process, so that the controlling of the read/write mechanism is withheld until the end of the switching.