Path Following Control for Static Docking Recovery of an Underactuated AUV in the presence of Ocean Current Disturbances

Abstract

The problem of static docking and recovery of an underactuated AUV in the presence of ocean current disturbances is addressed in this paper, and according to the planned recovery path, a novel path following control algorithm is proposed. Firstly, the path following control for the static docking and recovery of an underactuated AUV in the presence of ocean currents is formulated, and tracking errors are designed in Serret-Frenet coordinate system. Meanwhile, the ocean current relative coordinate system and ocean current relative velocity are designed, in order to integrate the ocean current disturbance into the kinematic and dynamic equations of the AUV. Secondly, an improved line of sight virtual guidance law for heading control is proposed, and the longitudinal position error and lateral position error are both introduced into the guidance law. Thirdly, in order to simplify the underactuated AUV path following control system, a virtual velocity in the tangent direction of the planned path to be followed is designed, and the inspiration comes from the virtual design of nonlinear backstepping method. Stability of the control laws designed is prove by Lyapunov stability theory, then simulation experiments are carried out on semi-physical simulation platform in our laboratory in order to show the effectiveness and reliability of the control algorithm designed.