A two-step control strategy for docking of Autonomous Underwater Vehicles

This paper presents a novel integrated guidance and control strategy for docking of Autonomous Underwater Vehicles (AUVs). The approach to the base, and hence the control design, is divided in two steps: i) in the first, at higher speed, the vehicle dynamics is assumed to be underactuated and an appropriate control law is derived to steer the vehicle toward the final docking path, achieving convergence to zero of the appropriate error variables for almost all initial conditions; ii) in the second stage, at low speed, the vehicle is assumed to be fully actuated, and a robust control law is designed that achieves convergence to zero of the appropriate error variables for all initial conditions. Simulation are presented illustrating the performance of the proposed controllers.