Appeal No. 1997-3923
Application 08/212,203
conventional profile velocity used to generate correction signals. Appellants base their calculation of the
correction signal on a "demand velocity" which is equal to the velocity from the velocity profile
increased by the scale factor. In this manner, "[t]he net result is that the seek phase will be carried out
using the maximum current available under existing circumstances to accelerate and decelerate the
transducers at a rate that will minimize the time for effecting the seek phase" (specification, page 10).
Representative independent claim 1 is reproduced below:
1. In a method for moving a transducer of a disc drive from an initial track on the surface of a
disc to a target track on the disc surface, the method including a seek phase wherein the transducer is
initially accelerated from the initial track and subsequently decelerated toward the target track in relation
to electrical currents supplied by an actuator driver to an actuator whereon the transducer is mounted
by adjusting the actuator current in each of a succession of time intervals in relation to a profile velocity
determined in relation to the distance between the transducer and the target track, the improvement
comprising the steps of:
for a seek having a length greater than a preselected minimum seek length, measuring
the actuator current during acceleration of the transducer for at least one time
interval selected to determine substantially the maximum current the actuator driver
can supply to the actuator;
generating a scale factor from said measured actuator current and a preselected
nominal actuator current, said scale factor increasing in a preselected relation to
the ratio of the measured actuator current to the nominal actuator current;
and
thereafter, in each of said time intervals, the steps of:
scaling the profile velocity with said scale factor to generate a demand
velocity;
determining the velocity of the transducer with respect to the disc surface;
generating a correction signal from the difference between the demand velocity
and the velocity of the transducer with respect to the disc surface; and
3
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