Robust Orientation-Sensitive Trajectory Tracking of Underactuated Autonomous Underwater Vehicles

Orientation-sensitive trajectory tracking (OSTT) claims that both position and orientation of the autonomous underwater vehicles (AUVs) are regulated to the reference. This article addresses the OSTT controller design problem for AUVs with separate forces or torques for surge, heave, roll, and yaw, in the presence of hydrodynamic uncertainties and external disturbances. In the kinematic stage, these AUVs are capable of moving sideways by exploiting the nonzero angle of the roll, so that the position tracking can be handled while the steering tracks the referenced yaw angle. As for the kinetic stage, a robust nonsmooth controller is implemented to guarantee the exponential convergence of velocity tracking errors. Trajectories are planned for the docking task and bridge pier inspection task. It is shown that the position tracking error can converge to a neighborhood about zero, and the yaw angle tracking error converges to zero exponentially as well. The effectiveness of the proposed method is illustrated by both simulation results and experimental results.