Decentralized time-varying formation control for multi-robot systems

In this paper, a distributed controller–observer schema for tracking control of the centroid and of the relative formation of a multi-robot system with first-order dynamics is presented. Each robot of the team uses a distributed observer to estimate the overall system state and a motion control strategy for tracking control of time-varying centroid and formation. Proof of the overall convergence of the controller–observer schema for different kinds of connection topologies, as well as for the cases of unsaturated and saturated control inputs is presented. In particular, the solution is proven to work in the case of strongly connected topologies, in the case of non-switching topologies, and with balanced strongly connected topologies, in the case of switching topologies. In order to complete the work, the approach is validated by experimental tests with a team of five wheeled mobile robots