Decentralized formation trajectory tracking control of multi-AUV system with actuator saturation

This paper focuses on the three-dimensional (3-D) formation tracking of multiple autonomous underwater vehicle (multi-AUV) system in complex ocean environments. An observer-controller scheme based on decentralized estimation and control is designed. Develop an observer for each AUV to estimate the overall state of the system, then integrate it with collective task variables to produce the control inputs. It enables the multi-AUV system to perform formation trajectory tracking tasks that depend on global information. In the design stage, utilizing hyperbolic tangent function reduces the risk of actuator saturation, and the measurement noise and nonlinearities of the system are addressed. Next, under the connected undirected topology, as well as for the cases of unsaturated and saturated control inputs, the stability analysis based on the Lyapunov method proves the convergence of estimation errors and task errors. Simultaneously, sufficient conditions for the formation tracking convergence are given. Finally, the simulation results in different cases demonstrate the effectiveness of the proposed method.