Formation Tracking Based on Approximate Velocities

This paper analyses the formation tracking of groups of mobile robots moving on the plane. A leader robot is chosen to follow a prescribed trajectory whilst the rest, considered as followers, are formed in an open-chain configuration. Two formation-tracking control laws using approximate velocities are proposed, in which some velocities must be communicated between robots in order to ensure the simultaneous preservation of the formation and the following of the group path. The main result is analysis of the convergence of the two proposed control laws. The restriction of inaccurate information occurs in decentral-ized multi-robot platforms, in which the mobile agents are only able to measure positions and the velocities’ functions are estimated using online numerical methods. A numerical simulation of both controllers in the case of omnidirec-tional robots is shown. For the case of the unicycle-type robots, real-time experiments of both controllers were implemented and tested.