Distributed Two-Layered Leader–Follower Affine Formation Control for Multiple AUVs in 3-D Space

This article focuses on addressing the distributed three-dimensional (3-D) formation maneuver control problem of multiple autonomous underwater vehicles (AUVs) in undersea exploration. The 3-D affine formation maneuver strategy by fusion of the stress matrix is employed to maneuver the multi-AUV formation for the sake of achieving the formation pattern maneuver transformations (e.g., rotation, scaling, shear, coplanarity, collineation, etc.). The desired yaw angle of each AUV is calculated in real time on the basis of its individual desired trajectory, which can guarantee the attitude configuration for the multi-AUV formation. Meanwhile, the two-layered leader-follower framework is employed to guarantee the flexible maneuvers, in which the AUVs are divided into three layers: 1) first leader AUV; 2) second leader AUV group; and 3) follower AUV group. The desired formation maneuver information only needs to be known by the first leader AUV. For the second AUV group, the formation maneuver information is estimated by the designed distributed estimators to acquire their desired reference trajectories. The follower AUV group only needs to track their desired trajectories affinely localized by the leader AUVs. Furthermore, the adaptive fast nonsingular integral terminal sliding-mode controllers are designed for the leader layers and follower layer to guarantee the fast and accurate tracking of their desired trajectories, such that the multi-AUV formation system is able to realize the precise maneuvers. Finally, the effectiveness of the proposed control strategy is verified by the high-fidelity simulations with real water current disturbances.