Simulation of an Autonomous Surface Vehicle With Colocated Tidal Turbine

Utility-class autonomous surface vehicles (ASVs) are small watercraft that can be equipped with environmental sensors used to collect data in coastal and marine locations. Their operation is constrained by energy storage limits, but with adequate resources, marine energy presents an opportunity to provide power in remote locations. To demonstrate the feasibility of using tidal energy to support ASV operations, we created a MATLAB-Simulink modeling tool. The model simulates an ASV performing surveys and charging at a nearby tidal turbine. Model components include the tidal turbine, generator, battery storage dynamics, ASV kinetics, and ASV control schemes. We refined the tool using experimentally collected data in the tidal-resource-rich Sequim Bay, which has been proposed for tidal energy testing, to empirically identify vehicle hydrodynamic drag and inertial coefficients. We then used the model to simulate a resource characterization survey in Sequim Bay under varying environmental conditions and survey parameters. Results indicated that a tidal turbine can support continuous ASV operation in low tidal or low target survey speed scenarios, and we suggest improvements to the model.