A method and system can align a robot arm with a payload station. A probe
and a contact detector may be positioned on the robot arm and three pins
may be placed on the payload station. A controller may move the robot arm
in a pattern over the payload station until contact may be made between
the probe and one of the pins. A search about the contact location may be
performed to obtain additional contacts. The search may be interrupted
when contact is made between the probe and one of the pins. The position
of the pin may be calculated from three such contacts on the spherical
portion of the pin. The location of the probe at the time of contact may
be stored and a localized search about the pin location may be performed.
If the position of the pin cannot be resolved from three contacts,
additional contacts may be made until a combination of three contacts
does provide a solution. Three such pins may be so located such that the
robot arm may learn the position of the payload station without operator
intervention.