The present invention is an apparatus and method for automatically
realigning an end effector of an automated equipment after an undesired
contact of the end effector to prevent a crash of the end effector. The
present invention includes a plurality of contact detectors, and each of
the contact detectors is disposed at a respective location with respect to
the end effector. In addition, each of the contact detectors generates a
respective signal for indicating direction of force on the end effector
that results from the undesired contact. Furthermore, the present
invention includes an end effector controller that is coupled to the
plurality of contact detectors and to the end effector. The end effector
controller causes the end effector to move to a reset position after the
undesired contact when any of the respective signals from the plurality of
contact detectors is greater than a predetermined level. The reset
position includes a respective positional off-set that corresponds to the
direction of the force on the end effector that results from the undesired
contact as indicated by which of the respective signals is greater than
the predetermined level. In one aspect of the present invention, a carrier
holds the end effector and allows movement of the end effector along the
direction of the force on the end effector from the undesired contact.
Such movement minimizes the stress of force on the end carrier and on the
part with which the end effector has made undesired contact. In that
aspect of the present invention, the direction of the force on the end
effector is determined from direction of the movement of the end effector
during the undesired contact. By automatically realigning the end effector
after an undesired contact, a crash of the end effector is prevented.