A microactuator incorporated within an actuator assembly of a disk drive
is used as a detection element for rapid off track events that may occur.
Preferably, the microactuator employs one or more piezoelectric elements
used for purposes of secondary actuation. Uncontrolled movement of the
actuator across the disk results in the piezoelectric elements generating
a voltage spike or signal that is analyzed to determine whether a rapid
off track event has occurred. Rapid off track events are distinguished
from other possible events, such as shock events. If a rapid off track
event is detected, then remedial actions are taken to restore data
integrity, to include executing restore commands such as rewriting
selected data tracks. Dedicated piezoelectric elements may also be
provided for detecting rapid off track events wherein these elements are
not incorporated in the servo loop that controls positioning of the
actuator.