Steering hierarchical formations of unicycle robots

In this paper a stabilizing control scheme to steer hierarchical formations of unicycle robots is proposed. Hierarchical formations are characterized by modular leader-follower units suitably interconnected. Robots linear velocity and trajectory curvature are forced to satisfy some given bounds. An original contribution of the paper is the study of the effect of these bounds on the admissible paths of the robots and the derivation of formulae. A peculiar feature of the proposed control strategy is that the position of the follower in the basic unit is not rigidly fixed with respect to the leader but varies in proper circle arcs centered in the leader reference frame. Simulation experiments illustrate the theory and show the effectiveness of the proposed design.