Fast Trajectory Tracking Control of Underactuated Autonomous Underwater Vehicles

The paper proposes a fast trajectory tracking control strategy for underactuated autonomous underwater vehicles (AUVs) moving in horizontal plane. By expanding the existing nonsingular terminal sliding mode control (NTSMC) approach, a fast NTSMC approach is developed to achieve precise and fast tracking, and meanwhile to afford a faster convergence rate for underactuated AUVs compared with the existing NTSMC approach. Simulations show the superiority of the presented control approach over the existing NTSMC approach in terms of convergence rate.

I. Introduction

Trajectory tracking is a typical task in the undersea applications of autonomous underwater vehicles (AUVs). It is considered as a more difficult control problem for engineers and researchers than path following, because it is concerned with development of controllers that can force AUV to arrive at and then follow a time-varying parameterized trajectory, which therefore requires strong constraints on time (fast response). Furthermore, most practical AUVs are underactuated, which means that the number of actuators is less than the degrees of freedom need to be controlled, exhibiting non-integrable acceleration constraints. This feature increases the difficulty of designing the tracking controllers for underactuated AUVs.