3D Path Following Control Method for Torpedo-Type Auvs with Uncertainty Terms in Their Dynamics

This paper presents a 3D path following control scheme for a class of torpedo-type autonomous underwater vehicles (AUVs) with uncertainty terms in their dynamics. For this kind of torpedo-type AUVs, there are only three control inputs, surge force, pitch and yaw moments, available for the vehicles' 6DOF 3D underwater motions. Therefore, it's a typical underactuated system. To tackle the 3D path following problem for this underactuated system, in this paper, we first introduce certain two spherical coordinate transformations so as to transform the vehicle's kinematics and dynamics model into three-inputs-three-outputs 2nd order strict-feedback form. Then, to avoid possible singularity problem in the recursive control design for this strict-feedback form of system, a similar asymptotic modification of orientation concept as in [1] is applied. In the case of uncertainty terms in the vehicle's dynamics, the proposed path following scheme can guarantee the uniformly ultimately boundedness (UUB) of closed-loop system in the spherical coordinate frame.