A Hybrid Dynamical Model for Robotic Underwater Vehicles when Submerged or Surfaced: Approach and Preliminary Evaluation

This paper reports a numerical method for mod- eling underwater vehicle (UV) interactions with the free surface using a finite-dimensional dynamical plant model. Although finite-dimensional plant models of fully submerged UV behavior are well-established, they are unable to model the ubiquitous condition of a UV operating at or near the free surface. We report a Monte Carlo-based hybrid model approach for calculating the buoyancy and righting moment of a partially or fully submerged UV in order to model interactions with the free surface. We also report a preliminary evaluation of the hybrid model in numerical simulations, comparing the hybrid model’s performance to that of a model for fully submerged UVs and to the experimentally observed behavior of an actual vehicle while fully submerged and while interacting with the free surface. The results of this preliminary study suggest that the proposed hybrid approach may offer a simple and practical method for modeling UV behavior when submerged or interacting with the free surface.