Robust Formation Control of Underactuated Autonomous Underwater Vehicles with Disturbances under Input Saturation

We investigate the leader-follower formation control of underactuated multi autonomous underwater vehicles (AUVs) with unknown bounded time-varying disturbances and input saturation in this paper, where the non-diagonal mass and damping matrices are considered. A virtual vehicle is constructed to define the formation between leader and follower. Additional control is employed to handle the input saturation and underactuation of AUV. Based on the additional control, the leader-follower formation control law is designed by incorporating disturbance observer with backstepping method. The disturbance observer is constructed to provide the estimates of unknown time-varying disturbances. The stability analysis indicates that proposed formation control law can make AUVs achieve the desired formation and guarantee uniformly ultimate boundedness of all signals of the AUVs formation closed-loop system. Simulation results on three AUVs demonstrate the effectiveness of the proposed formation control law.