Adaptive line-of-sight guidance law for synchronized path-following of under-actuated unmanned surface vehicles based on low-frequency learning

This paper presents a guidance law design for synchronized path-following of multiple under-actuated unmanned surface vehicles (USVs) in the presence of unknown sideslip. The sideslip can be caused by wind, waves, and ocean currents, or arise when following a curved path. An adaptive guidance law is proposed based on a line-of-sight (LOS) guidance principle and a low-frequency learning scheme. By using this guidance law, the undesired high-frequency transients existing in classical adaptive LOS guidance law can be eliminated, and aggressive maneuvers for USVs can be avoided. The global uniform asymptotic stable (GUAS) of closed-loop guidance system is established. Simulation results are given to demonstrate the effectiveness of the proposed adaptive guidance law for synchronized path-following.