Adaptive Control of Underactuated Underwater Vehicles

This paper deals with a control strategy for underactuated underwater vehicles whose target is trajectory tracking. A cascade approach is employed which brings to a control law consisting of: a) an outer loop, obtained from the vehicle kinematic model, which forces this model to track the reference trajectory; b) an inner adaptive control loop which forces the system to track the reference signals given by the outer control loop. Conditions for asymptotic tracking of the trajectory and boundness of the unactuated velocities are given. Simulation tests illustrate the proposed approach.