Revisiting UUV Dynamic Modeling Assumptions: A Critical Analysis of Added Mass, Damping Simplifications, and Their Operational Implications

Abstract

To enable real-time control and simulation, UUV dynamic models often rely on simplifying assumptions such as constant added mass, linear damping, and rigid-body approximations. This paper critically examines these assumptions, quantifying their impact on model fidelity and operational performance. Using sensitivity analysis, we identify scenarios—such as high-speed maneuvers, proximity to seabed, and strong current interactions—where simplifications lead to significant model-plant mismatch. The study introduces the “Fidelity-Latency Trade-off,” balancing model complexity against computational feasibility for onboard control. We discuss the implications of neglecting nonlinear hydrodynamic effects like vortex-induced vibrations and flow separation, which can degrade controller performance and mission safety. The paper advocates for hierarchical modeling approaches that adapt model fidelity based on mission phase and environmental conditions. This critical analysis provides guidelines for selecting appropriate modeling assumptions to ensure reliable UUV operation across diverse underwater scenarios.