Line-of-sight curved path following for underactuated USVs and AUVs in the horizontal plane under the influence of ocean currents

An essential ability of autonomous unmanned surface vessels (USVs) and autonomous underwater vehicles (AUVs) moving in a horizontal plane is to follow a general two-dimensional path in the presence of unknown ocean currents. This paper presents a method to achieve this. The proposed guidance and control system only requires absolute velocity measurements for feedback, thereby foregoing the need for expensive sensors to measure relative velocities. The closed-loop system consists of a guidance law and an adaptive feedback linearizing controller combined with sliding mode, and is shown to render the path cross-track error dynamics UGAS and USGES. Simulation results are presented to verify the theoretical results.