Decentralized formation tracking of multi-vehicle systems with nonlinear dynamics

The problem of formation tracking can be stated as multiple vehicles are required to follow spatial trajectories while keeping a desired inter-vehicle formation pattern in time. This paper considers vehicles with nonlinear dynamics and nonholonomic constraints and very general trajectories that can be generated by some reference vehicles. We specify formations using the vectors of relative positions of neighboring vehicles and use consensus-based controllers in the context of decentralized formation tracking control. The key idea is to combine consensus-based controllers with the cascaded approach to tracking control, resulting in a group of linearly coupled dynamical systems. We examine the stability properties of the closed loop system using cascaded systems theory and nonlinear synchronization theory. Simulation results are presented to illustrate the proposed method.