Distributed formation control of autonomous underwater vehicles without velocity measurement

This paper addresses the distributed formation control problem of autonomous underwater vehicles moving in horizontal plane without velocity measurement. A novel output-feedback formation protocol is proposed based on leader-following strategy while assuming that only a subset of followers know the information of leader. First, a distributed observer is designed for each follower to estimate the information of the leader and extended state observers are designed to estimate the unmeasured velocities as well as to recover lumped uncertainties induced by parameter perturbations and external disturbances. Based on the observation results, the formation tracking laws are proposed in kinematic and dynamic level, while desired tracking performance and robustness are guaranteed. It is proved that estimation errors and formation tracking errors converge to an arbitt-atily small neighborhood of zero. Simulation results are finally presented to validate the effectiveness of proposed strategy.