Integral Line-of-Sight Guidance and Control of Underactuated Marine Vehicles: Theory, Simulations, and Experiments

TLDR

The study analyzes the integral line‑of‑sight guidance method for underactuated marine vehicles, extending from 2‑D surface vessels to 3‑D autonomous underwater vehicles to enable straight‑line path following under environmental disturbances. The authors develop a Lyapunov‑based closed‑loop analysis of the ILOS guidance, deriving explicit gain bounds for 2‑D sway dynamics and extending the framework to 3‑D kinematic and dynamic models with surge, pitch, and yaw dynamics, forming a cascade system. The integral action in the guidance law compensates for drift from currents, wind, and waves, guaranteeing uniform global asymptotic and local exponential stability, and simulation and experimental results confirm the theoretical predictions on a towing system vehicle and a light AUV.

Abstract

This paper presents an extensive analysis of the integral line-of-sight (ILOS) guidance method for path-following tasks of underactuated marine vehicles, operating on and below the sea surface. It is shown that due to the embedded integral action, the guidance law makes the vessels follow straight lines by compensating for the drift effect of environmental disturbances, such as currents, wind, and waves. The ILOS guidance is first applied to a 2-D model of surface vessels that includes the underactauted sway dynamics of the vehicle as well as disturbances in the form of constant irrotational ocean currents and constant dynamic, attitude dependent, and forces. The actuated dynamics are not considered at this point. A Lyapunov closed-loop analysis yields explicit bounds on the guidance law gains to guarantee uniform global asymptotic stability (UGAS) and uniform local exponential stability (ULES). The complete kinematic and dynamic closed-loop system of the 3-D ILOS guidance law is analyzed in the following and hence extending the analysis to underactuated autonomous underwater vehicles (AUVs) for the 3-D straight-line path-following applications in the presence of constant irrotational ocean currents. The actuated surge, pitch, and yaw dynamics are included in the analysis where the closed-loop system forms a cascade, and the properties of UGAS and ULES are shown. The 3-D ILOS control system is a generalization of the 2-D ILOS guidance. Finally, results from simulations and experiments are presented to validate and illustrate the theoretical results, where the 2-D ILOS guidance is applied to the cooperative autonomous robotics towing system vehicle and light AUV.