Xavier is a mobile manipulator developed at CMU that is being used for
research in robot learning and self-reliant autonomous operation.  It is
built on an RWI B24 base and includes bump sensors, a laser range sensor,
sonars, a color camera on a pan-tilt head, and an arm.  Control, perception
and planning are carried out on two on-board, multi-processing 486-based
machines.  The robot can communicate with humans both graphically and
through natural language.

The software controlling Xavier combines both reactive and deliberative
behaviours.  The reactive behaviours enable the robot to handle real-time
local navigation, obstacle avoidance, and emergency situations.  The
deliberative behaviours, which operate concurrently with the reactive
behaviours, maintain occupancy grid and topological maps, plan paths,
interpret visual information, and do task-level planning.  The behaviours
are integrated using the Task Control Architecture, which provides
facilities for scheduling and synchronizing tasks, resource allocation,
monitoring the environment, and handling exceptional situations.


In addition, Xavier has a detachable arm which can pick up boxes.
This arm has a large V-shaped end effector with roller bearings to
guide the box to the center, where two electromagnets were used to hook on
to metal plates mounted on the corner of the boxes.  The arm enables Xavier
to lift the boxes over its ``head'', simplifying planning of subsequent
movements.

This manual briefly reviews the physical components of Xavier, presents a
simulation environment, and introduces a programming tutorial and overview for
the novice roboteer. An index is included.