Abstract
This paper introduces a simulation framework and a corresponding Robust Optimal Control (ROC) for docking Unmanned Underwater Vehicles (UUVs) that leverages Marine Renewable Energy (MRE) for improved autonomy in docking and charging operations. The proposed simulation framework integrates the dynamics of the Wave Energy Converter (WEC), docking station, and UUV within a unified system. Utilizing the WEC-Sim for the hydrodynamic modeling and MoorDyn for mooring dynamics, and in-house UUV dynamics in Simulink, the simulation effectively accounts for complex interactions under dynamic ocean conditions. The ROC docking controller, consisting of a Linear Quadratic Regulator (LQR) and a Sliding Mode Control (SMC), is designed to enhance robustness against environmental disturbances and system uncertainties. This controller utilizes input-output linearization to transform the nonlinear dynamics into a manageable linear form, optimizing docking performance while compensating for disturbances and uncertainties. The combined simulation and control approach is validated under various ocean conditions, demonstrating effective docking precision and energy efficiency. This work lays a foundational platform for future advancements in autonomous marine operations for UUV docking systems integrated with WEC. In addition, this work also demonstrates the feasibility of using MRE to significantly extend the operational duration of UUVs; such a platform will be leveraged for further development of structural health monitoring and fault diagnosis techniques for offshore structures such as WECs and Floating Offshore Wind Turbines.