Gray-box dynamic model for wave glider driven by a hybrid of deep learning and physics-based models

Yuanhui Wang, Hui Wang, Yongkuang Zhang, Mingze Xie,
Gray-box dynamic model for wave glider driven by a hybrid of deep learning and physics-based models,
Engineering Applications of Artificial Intelligence,
Volume 162, Part E,
2025,
112730,
ISSN 0952-1976,
https://doi.org/10.1016/j.engappai.2025.112730.
(https://www.sciencedirect.com/science/article/pii/S0952197625027617)
Abstract: Wave gliders, a widely used type of unmanned ocean robot, leverage wave and solar energy to achieve near-unlimited endurance, making them ideal tools for ocean monitoring and meteorological observations. However, existing more accurate wave glider modeling often requires computational fluid dynamics (CFD) calculations, especially considering the complexity of tandem hydrofoils. The computational cost is very high, making them unsuitable for real-time control applications. Therefore, this paper proposes a gray-box dynamic modeling approach that balances model accuracy and computational efficiency by integrating deep learning with traditional physical models. The gray-box model consists of a deep learning-based surrogate model and analytical dynamic equations, with the surrogate model replacing the CFD simulation process for the hydrofoils in the wave glider's dynamic model to improve the overall computational efficiency. After comparing the predictive performance of various deep learning models, this paper ultimately selects the Gated Recurrent Unit-Fully Convolutional Network (GRU-FCN) as the surrogate model. Validation of the proposed gray-box dynamic model under both regular and irregular wave conditions demonstrates excellent agreement with experimental data and CFD results. Furthermore, the gray-box dynamic model significantly improves computational efficiency, offering a reliable dynamic model reference for the real-time control of the wave glider.
Keywords: Wave glider; Gray-box dynamic model; Deep learning; Surrogate model; Dynamic modeling