A disk drive includes a disk, a head, a coarse actuator, a microactuator,
and a servo controller. The microactuator positions the head relative to
the disk. The coarse actuator positions the microactuator and the head
relative to the disk. The servo controller controls the microactuator in
accordance with a microactuator feedforward control signal that is
provided by the servo controller based on a plurality of microactuator
feedforward values. The servo controller tunes at least one microactuator
feedforward value of the plurality of microactuator feedforward values.
The servo controller scales the microactuator feedforward control signal
in accordance with a microactuator feedforward gain, and the servo
controller adjusts the microactuator feedforward gain based on a position
error signal that is determined during a seek operation.