An almost global tracking control scheme for maneuverable autonomous vehicles and its discretization

This technical note treats the challenging control problem of tracking a desired continuous trajectory for a maneuverable autonomous vehicle in the presence of gravity, buoyancy and fluid dynamic forces and moments. A realistic dynamics model that applies to maneuverable vehicles moving in 3-D Euclidean space is used for obtaining this control scheme. While applications of this control scheme include autonomous aerial and underwater vehicles, we focus on an autonomous underwater vehicle (AUV) application because of its richer, more nonlinearly coupled, dynamics. The desired trajectory and trajectory tracking errors are globally characterized in the nonlinear state space. Almost global asymptotic stability to the desired trajectory in the nonlinear state space is demonstrated both analytically and through numerical simulations.