  In this paper, we present a new leader-follower type solution to the
formation maneuvering problem for multiple, nonholonomic wheeled mobile robots.
The solution is based on the graph that models the coordination among the
robots being a spanning tree. Our decentralized control law ensures, in the
least squares sense, that the robots globally acquire a given planar formation
while the formation as a whole globally tracks a desired trajectory. The
control law is first designed at the kinematic level and then extended to the
dynamic level. In the latter, we consider that parametric uncertainty exists in
the equations of motion. These uncertainties are accounted for by employing an
adaptive control scheme. The proposed formation maneuvering controls are
demonstrated experimentally and numerically.
