A disk drive is disclosed comprising a disk having a plurality of tracks,
an actuator arm, a head connected to a distal end of the actuator arm,
and a voice coil motor (VCM) for rotating the actuator arm about a pivot
to actuate the head over the disk. A driving current is applied to the
VCM to control the motion of the actuator arm. A back EMF voltage
generated by the VCM is detected, and a velocity of the VCM is estimated
in response to the back EMF voltage. The estimated VCM velocity is
compared to a target velocity in a velocity profile, wherein the velocity
profile comprises at least an acceleration component and a coast
component. The driving current is adjusted in response to the comparison
so that the velocity of the VCM substantially follows the velocity
profile.