Hierarchical LOS-Based Control in Polar Coordinates with Dynamic Feedback Compensation for a Differential USV

This work presents a hierarchical control strategy for a differential-thrust Unmanned Surface Vehicle, integrating a polar Line of Sight guidance law with a dynamic feedback compensation layer. The kinematic controller is formulated in polar coordinates and ensures convergence to predefined waypoints. Local asymptotic stability of the closed-loop kinematic system is established via Lyapunov analysis. The dynamic layer uses model inversion based on a simplified three-degree-of-freedom model structured according to Fossen's canonical formulation. Control efforts are mapped into actuator-level commands consistent with the vehicle's propulsion layout. The proposed strategy is validated both on a physical prototype, IAcquaBot, and in IAcquaBotSim, a digital model of the real platform implemented in a virtual simulation environment. Experimental and simulated results confirm the effectiveness of the control scheme in achieving accurate and stable waypoint tracking.