Method for adapting seeks of a disc drive transducer to the maximum actuator current available to accelerate and decelerate the transducer

Claim 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 transmitting the correction signal to the actuator driver to control the current supplied to the actuator.