US 4,544,968 AGranted

Sector servo seek control

AssigneeInternational Business Machines Corporation

InventorsTodd B. Anderson, Thomas W. Glaser, John J. Neesz

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Abstract

A sector servo seek control samples each sector to obtain sector time, the track identification within a sequence of track types and a position error signal for a track location to track location seek. The device during each sector determines the actual transducer track location and the next sector projected track location with respect to the sequence of track types. The projected track location is corrected using the error signal to find the actual location, but if a sector signal is missing or erroneous, the projected location is used as the actual location, permitting a composite correction to be made when a correct sector signal is obtained. The seek time is minimized by using maximum acceleration followed by maximum deceleration while not exceeding a velocity value that would cause the device to overshoot the target track using full deceleration.

Claims5

Dependent claims

In a data storage device wherein information is retained on tracks formed of sectors containing servo data that defines sequences of track types that form a capture area and are accessed by a transducer assembly driven by an electromagnetic actuator, position control means for moving said transducer assembly from one track location to another track location during a seek operation comprising:

a first continuous sequence of selected velocity values adjacent to, but continuously less than a second sequence of the highest velocity values with respect to which maximum deceleration will permit the selected terminal track position to be approached without overshooting;
drive means for applying forward direction drive, reverse direction drive or no drive to said transducer assembly;
acceleration means for applying said drive forward direction drive until a velocity is achieved approaching the value of said first sequence of velocity values;
and
deceleration control means for effecting deceleration by using said drive means to induce said transducer assembly to follow said first sequence of velocity values without exceeding said second sequence of velocity values;
said deceleration control means including a continuous range of velocity values adjacent to and including said first sequence of velocity values, but less than said second sequence of velocity values, during which said drive means applies no drive to said transducer assembly whereby a dead band occurs wherein said transducer assembly is allowed to coast.

3 more elements

Dependencies are inferred from the claim text.