CORAL-AUV: CFD Oriented Reinforcement Learning for Autonomous Underwater Vehicles
This study addresses the poor sim-to-real transfer performance of conventional autonomous underwater vehicle (AUV) control methods, which rely on oversimplified hydrodynamic models and struggle to adapt to configuration changes and environmental disturbances. To overcome this limitation, the authors propose a novel framework that integrates computational fluid dynamics (CFD) with reinforcement learning. Specifically, high-fidelity yet computationally efficient surrogate drag models (SDMs) are constructed from CFD data and embedded within a six-degree-of-freedom simulation environment to train control policies. Remarkably, the resulting policy is deployed on a physical AUV without any fine-tuning—demonstrating, for the first time, zero-shot sim-to-real transfer. Compared to controllers based on simplified models, the proposed approach reduces energy consumption by 31%, increases waypoint-to-waypoint speed by 11%, decreases trajectory error by 19%, and is the only method to successfully generalize under parameter perturbations, substantially enhancing both robustness and task performance.