US 8,134,797 B2Granted

Application of continuous position error offset signal to acquire servo track

AssigneeInternational Business Machines Corporation

InventorsNhan Xuan Bui, Randy Clark Inch, Eiji Ogura

Life of this patent

Estimating the term…

Loading patent…

Abstract

The method employs a servo system for positioning a head laterally to follow lateral motion of a longitudinal tape having longitudinal defined servo track(s), the servo system comprising a servo element configured to sense lateral position of the head with respect to an acquired servo track, a fine actuator configured to translate the head laterally with respect to the longitudinal tape, and a position error signal loop to operate the fine actuator to translate the head laterally to reduce position error. If the servo element is positioned away from the defined servo track(s), a continuous position error offset signal is applied to the fine actuator in a direction towards the defined servo track(s), whereby the fine actuator translates the head in accordance with the continuous position error offset signal; and, in response to the servo system acquiring the defined servo track(s), the continuous position error offset signal is discontinued.

Claims16

Dependent claims

In a servo system for positioning a head laterally to follow lateral motion of a longitudinal tape having at least one longitudinal defined servo track, said servo system comprising a servo element configured to sense lateral position of said head with respect to defined servo tracks, a fine actuator configured to translate said head laterally with respect to said longitudinal tape, a coarse actuator configured to translate said fine actuator laterally with respect to said longitudinal tape, and a position error signal loop configured to sense said servo element to detect servo signals and acquire at least one said defined servo track, to determine position error between said head and a desired position related to an acquired said at least one defined servo track, and to operate said fine actuator to translate said head laterally in a manner to reduce said determined position error, a method comprising:

if said servo element is positioned away from said at least one defined servo track, applying a continuous position error offset signal to said fine actuator in a direction towards said at least one defined servo track, whereby said fine actuator translates said head in accordance with said continuous position error offset signal;
and
in response to said servo system acquiring said at least one defined servo track, discontinuing said continuous position error offset signal;
wherein said applying step comprises integrating said continuous position error offset signal to operate said fine actuator to continuously translate said head laterally towards said at least one defined servo track.

1 more element

A servo system configured to position a head laterally with respect to at least one defined servo track of longitudinal tape, comprising:

a servo element for sensing lateral position of said head with respect to at least one defined servo track of said longitudinal tape;
a fine actuator configured to translate said head laterally with respect to said longitudinal tape;
a coarse actuator configured to translate said fine actuator laterally with respect to said longitudinal tape;
and
a servo control configured to sense said servo element;
to detect servo signals and acquire at least one said defined servo track;
to, if said servo element is positioned away from said at least one defined servo track, apply a continuous position error offset signal to said fine actuator in a direction towards said at least one defined servo track, operating said fine actuator to translate said head in accordance with said continuous position error offset signal;
and in response to said servo element acquiring said at least one defined servo track, to discontinue said continuous position error offset signal;
to determine position error between said head and a desired position related to said acquired at least one defined servo track;
and to provide signals to operate said fine actuator to translate said head laterally in a manner to reduce said determined position error;
wherein said servo control is configured to integrate said continuous position error offset signal to operate said fine actuator to continuously translate said head laterally towards said at least one defined servo track.

8 more elements

A servo control configured to operate a tape servo to position a head laterally with respect to at least one defined servo track of longitudinal tape, said tape servo comprising a servo element for sensing lateral position of said head with respect to at least one defined servo track of said longitudinal tape;

a fine actuator configured to translate said head laterally with respect to said longitudinal tape;
and a coarse actuator configured to translate said fine actuator laterally with respect to said longitudinal tape;
said servo control configured:
to sense said servo element to detect servo signals and acquire at least one said defined servo track;
to, if said servo element is positioned away from said at least one defined servo track, apply a continuous position error offset signal to said fine actuator in a direction towards said at least one defined servo track, operating said fine actuator to translate said head in accordance with said continuous position error offset signal;
in response to said servo element acquiring said at least one defined servo track, to discontinue said continuous position error offset signal;
to determine position error between said head and a desired position related to said acquired at least one defined servo track;
and
to provide signals to operate said fine actuator to translate said head laterally in a manner to reduce said determined position error;
said servo control configured to integrate said continuous position error offset signal to operate said fine actuator to continuously translate said head laterally towards said at least one defined servo track.

7 more elements

A data storage drive comprising:

a head configured to record and read data on a longitudinal tape data storage medium;
a drive configured to move said longitudinal tape data storage medium in the longitudinal direction with respect to said head, said drive comprising at least one flangeless tape guide at either side of said head in said longitudinal direction and configured to position said longitudinal tape data storage medium in proximity with respect to said head;
and
a servo system configured to position a head laterally with respect to at least one defined servo track of longitudinal tape, comprising:
a servo element for sensing lateral position of said head with respect to at least one defined servo track of said longitudinal tape;
a fine actuator configured to translate said head laterally with respect to said longitudinal tape;
a coarse actuator configured to translate said fine actuator laterally with respect to said longitudinal tape;
and
a servo control configured to sense said servo element;
to detect servo signals and acquire at least one said defined servo track;
to, if said servo element is positioned away from said at least one defined servo track, apply a continuous position error offset signal to said fine actuator in a direction towards said at least one defined servo track, operating said fine actuator to translate said head in accordance with said continuous position error offset signal;
and in response to said servo element acquiring said at least one defined servo track, to discontinue said continuous position error offset signal;
to determine position error between said head and a desired position related to said acquired at least one defined servo track;
and to provide signals to operate said fine actuator to translate said head laterally in a manner to reduce said determined position error;
wherein said servo control is configured to integrate said continuous position error offset signal to operate said fine actuator to continuously translate said head laterally towards said at least one defined servo track.

12 more elements

Dependencies are inferred from the claim text.