A disk drive is disclosed including a disk having a plurality of tracks,
wherein each track comprises a plurality of embedded servo sectors. A
head connected to a distal end of an actuator arm is rotated about a
pivot by a voice coil motor (VCM) in order to actuate the head radially
over the disk. The actuator arm is unloaded onto a ramp by seeking the
head to a track near an outer diameter of the disk in response to the
embedded servo sectors, switching to a velocity control mode to unload
the actuator arm onto the ramp at a controlled unload velocity in
response to a back electromotive force voltage generated by the VCM, and
ramping a velocity command so that the velocity of the actuator arm when
contacting the ramp is less than half the maximum unload velocity while
traveling along the ramp.