  In recent years, autonomous mobile platforms are finding an increasing range
of applications in inspection or surveillance tasks, or to the transport of
objects, in places such as smart warehouses, factories or hospitals. In these
environments it is useful for the robot to have omnidirectional capability in
the plane, so it can navigate through narrow or cluttered areas, or make
position and orientation changes without having to maneuver. While this
capability is usually achieved with directional sliding wheels, this work
studies a particular robot that achieves omnidirectionality using conventional
wheels, which are easier to manufacture and maintain, and support larger loads
in general. This robot, which we call ``Otbot'' (for omnidirectional
tire-wheeled robot), was already conceived in the late 1990s, but all the
controllers that have been proposed for it are based on purely kinematic models
so far. These controllers may be sufficient if the robot is light, or if its
motors are powerful, but on platforms that have to carry large loads, or that
have more limited motors, it is necessary to resort to control laws based on
dynamic models if the full acceleration capacities are to be exploited. This
work develops a dynamic model of Otbot, proposes a plausible methodology to
identify its parameters, and designs a control law that, using this model, is
able to track prescribed trajectories in an accurate and robust manner.
