Methods and systems for improved deceleration control for a disk drive
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorFred R. Hansen
Life of this patent
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Abstract
Improved deceleration control for a disk drive is provided. A deceleration profile is selected based on a present velocity (vi), a present position (xi) and a BEMF constant associated with a voice coil motor (VCM). A control signal is supplied to a VCM driver in an attempt to have a read/write head follow the selected deceleration profile. As new present velocities and new present positions are obtained, these steps are repeated until the seek operation transitions from the deceleration phase to a settle phase. This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures and the claims.
Claims58
For use in a disk drive system including a read/write head, an actuator assembly including a voice coil motor (VCM) that is used to control movement of the read/write head, and a VCM driver that drives the VCM, wherein the VCM has an associated back electromagnetic field (BEMF) constant,
- a method for controlling the deceleration phase of a seek operation that is used to move the read/write head to a desired velocity and a desired position in phase space, the method comprising:
- (a) obtaining a present velocity (vi) and a present position (xi) of the read/write head;
- (b) selecting a deceleration profile, based on the present velocity (vi), the present position (xi) and the BEMF constant, wherein the deceleration profile defines a path in phase space from the present velocity and the present position to the desired velocity and the desired position;
- and
- (c) supplying a control signal to the VCM driver in an attempt to have the read/write head follow the selected deceleration profile.
For use in a disk drive system including a read/write head, an actuator assembly including a voice coil motor (VCM) that is used to control movement of the read/write head, and a VCM driver that drives the VCM, wherein the VCM has an associated back electromagnetic field (BEMF) constant,
- a method for controlling the deceleration phase of a seek operation that is used to move the read/write head to a desired velocity and a desired position in phase space, the method comprising:
- (a) obtaining a present velocity (vi) and a present position (xi) of the read/write head;
- (b) selecting a deceleration profile, based on the present velocity (vi), the present position (xi) and the BEMF constant, wherein the deceleration profile defines a path in phase space from the present velocity and the present position to the desired velocity and the desired position;
- and
- (c) supplying a control signal to the VCM driver, wherein the control signal is a function of the selected deceleration profile, the present velocity, the present position and the BEMF constant.
A method for controlling the deceleration phase of a seek operation that is used to move a read/write head to a desired velocity and a desired position in phase space, the method comprising:
- (a) obtaining a present velocity and a present position of the read/write head;
- (b) selecting a deceleration profile, based on the present velocity, the present position and a BEMF constant associated with a voice coil motor being used to move the read/write head, wherein the deceleration profile defines a path in phase space from the present velocity and the present position to the desired velocity and the desired position;
- and
- (c) using the selected deceleration profile to control movement of the read/write head toward the desired position.
A disk drive system, comprising:
- a rotatable disk including at least one surface to store information;
- a read/write head to read from and write to the disk;
- an actuator assembly including a voice coil motor (VCM) that is used to control movement of the read/write head, wherein the VCM has an associated back electromagnetic field (BEMF) constant;
- a VCM driver to drive the VCM;
- and
- a deceleration controller to control a deceleration phase of a seek operation that is used to move the read/write head to a desired velocity and a desired position in phase space,
- wherein the deceleration controller is configured to select a deceleration profile, based on a present velocity (vi) and a present position (xi) of the read/write head and the BEMF constant, wherein the deceleration profile defines a path in phase space from the present velocity and the present position to the desired velocity and the desired position;
- and
- wherein the deceleration controller is further configured to supply a control signal to the VCM driver in an attempt to have the read/write head follow the selected deceleration profile.
A disk drive system, comprising:
- a rotatable disk including at least one surface to store information;
- a read/write head to read from and write to the disk;
- an actuator assembly including a voice coil motor (VCM) that is used to control movement of the read/write head, wherein the VCM has an associated back electromagnetic field (BEMF) constant;
- and
- a deceleration controller to control a deceleration phase of a seek operation that is used to move the read/write head to a desired velocity and a desired position in phase space,
- wherein the deceleration controller is configured to select a deceleration profile, based on a present velocity (vi) and a present position (xi) of the read/write head and the BEMF constant, wherein the deceleration profile defines a path in phase space from the present velocity and present position to the desired velocity and the desired position;
- and
- wherein the deceleration controller is further configured control movement of the read/write head using the selected deceleration profile.
Dependencies are inferred from the claim text.