Robust nonlinear path-tracking control of vector-propelled AUVs in complex sea conditions

Abstract

Aiming to address the trajectory tracking problem of vector propulsion autonomous underwater vehicles (vector AUVs) under complex sea conditions, this paper proposes a dynamic control system based on vector propulsion (DS-Vector). The vector AUV has the vector characteristics of four tilt thrusters and is highly maneuverable. Based on the approximate kinematics and dynamics equations of the vector AUV under the action of current disturbance obtained through analysis, the proposed DS-Vector has a motion control module and force distribution control module. The motion control module adopts the control method by combining the nonsingular fast terminal sliding mode control based on an adaptive disturbance observer (NTSMC-ADO) and PID control law, while the force distribution control module selects the least square (LS) method. The effectiveness and robustness of the proposed DS-Vector are verified in an underwater visual simulation environment. To verify the superiority of the NTSMC-ADO designed in this paper, three other advanced control laws are used in DS-Vector for comparison. The results show that NTSMC-ADO has better anticurrent interference and better position tracking control response and is more robust than the other three advanced control laws.