Control oriented modeling of a twin thruster autonomous surface vehicle

This work investigates and identifies a first principles maneuvering model for a small size robotic twin thruster autonomous surface vessel (ASV) that includes and explains the sources of nonlinearity and asymmetry of this class of robots. With respect to state of the art ASV models, the proposed one accounts for the effects generating a transverse thrust, explaining the asymmetric turning radii. The model also accounts for the need to adapt the hydrodynamic derivatives when the ASV performs large or tight turns. An experimental dataset has been acquired using the ULISSE ASV and it is used to support the proposed model in comparison to the “baseline” one often used in the literature. The improved precision of the proposed model in fitting experimental data is a necessary prerequisite to design model-based motion controller and navigation systems with enhanced performance.