Disk apparatus, head retracting method and head actuator control circuit
AssigneeFujitsu Limited
InventorNobuyuki Suzuki
Life of this patent
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Abstract
A head retracting method retracts a head to a retract position which is different from a disk to perform a stable unload operation when a power supply failure occurs, regardless the position and the velocity of the head. When the power supply failure occurs, controller controls that the head reaches the inner stopper, which is at a predetermined position in an opposite direction from the ramp, so as to stop at the inner stopper at a predetermined position without receiving impact shock, regardless of what position the head is and regardless of what velocity the head is moving. The head is unloaded from the predetermined position by constant voltage driving, so the head contacts the ramp and climbs onto the ramp at a predetermined velocity.
Claims19
A head retracting method for retracting a head which at least reads information for an information recorded disk to a retract position according to the power supply failure, comprising:
- a first step of moving-controlling said head to a predetermined position contacting a stopper in an opposite direction from said retract position such that the velocity of said head becomes constant in the vicinity of said predetermined position;
- a second step of moving-controlling said head to said retract position after said head reaches said predetermined position such that the velocity of said head becomes constant in the vicinity of said retract position;
- and
- a third step of monitoring the velocity of said head after said movement control of said first step and shifting to said second step when the velocity of said head is a predetermined velocity or less for a first predetermined period of time while said head is in contact with said stopper,
- wherein the velocity of said head is monitored by detecting a back electromotive force of an actuator for moving said head.
A disk apparatus for retracting a head which at least reads information for an information recorded disk to a retract position according to the power supply failure, comprising:
- an actuator for moving said head;
- and
- a control unit which moving-controls said head to move to a predetermined position contacting a stopper in an opposite direction from said retract position such that the velocity of said head becomes constant in the vicinity of said predetermined position, and moving-controls said head to said retract position after said head reaches said predetermined position such that the velocity of said head constant in the vicinity of said retract position;
- wherein said control unit monitors the velocity of said head after said movement control to said predetermined position, and shifts to the movement control to said retract position when the velocity of said head is at a predetermined velocity or less for a first predetermined period of time while said head is in contact with said stopper, and
- wherein the velocity of said head is monitored by detecting a back electromotive force of an actuator for moving said head.
A head actuator control circuit for retracting a head which at least reads information for an information recorded disk to a retract position according to the power supply failure, comprising:
- a power monitoring circuit for detecting said power supply failure;
- and
- an actuator control circuit which moving-controls said head to a predetermined position contacting a stopper in an opposite direction from said retract position such that a velocity of said head becomes constant in the vicinity of said predetermined position according to the power supply failure detection of said power supply monitoring circuit, and then moving-controls said head to said retract position after said head reaches said predetermined position such that the velocity of said head moving to said retract position becomes constant in the vicinity of said retract position,
- wherein said control unit monitors the velocity of said head after control of movement to said predetermined position is performed, and shifts to the control of movement to said retract position when the velocity of said head is at a predetermined velocity or less for a first predetermined period of time while said head is in contact with said stopper, and
- wherein the velocity of said head is monitored by detecting a back electromotive force of an actuator for moving said head.
Dependencies are inferred from the claim text.