Line-of-sight guided time delay control for three-dimensional coupled path following of underactuated underwater vehicles with roll dynamics

This paper addresses the problem of three-dimensional (3-D) coupled path following control for a six-degrees-of-freedom underactuated underwater vehicle. To compensate for nonzero roll angle, an improved 3-D line-of-sight guidance law is proposed in the kinematic layer. Especially, this novel guidance law can be applied to not only actuated but also underactuated underwater vehicles in roll, by assigning the desired roll angle. Subsequently, a simplified time delay controller is designed in the dynamics layer to robustly track the desired guidance angle, such that the entire path following errors are bounded. Finally, comparative numerical simulation results among different following paths, initial states and controllers are provided to show the outperformance of the designed 3-D coupled path following controller.