Dynamic Modeling, Parameter Identification and Numerical Analysis of Flexible Cables in Flexibly Connected Dual-AUV Systems
Kuo Chen, Minghao Dou, Qianqi Liu, Yang An, Kai Ren, Zeming WU, Yu Tian, Jie Sun, Xinping Wang, Zhier Chen, Jiancheng Yu
TL;DR
This work tackles the nonlinear dynamics of flexibly connected dual-AUV towing systems by developing a lumped-mass cable model that couples axial elasticity, bending stiffness, buoyancy, added mass, and hydrodynamic forces with rigid-body AUV dynamics. A GA-based parameter-identification framework uses multi-configuration tension data from water-tank experiments to identify the equivalent Young's modulus $E$ and drag coefficients, ensuring predictive accuracy across operating conditions. Key contributions include a unified dynamic model, an effective identification procedure, and extensive simulations and experiments that reveal slack-taut transitions and boundary-load distribution under complex boundary conditions. The results provide a solid theoretical and practical foundation for towing-system design, control, and optimization in challenging marine environments, with implications for long cable deployments and multi-sensor configurations.
Abstract
This research presents a dynamic modeling framework and parameter identification methods for describing the highly nonlinear behaviors of flexibly connected dual-AUV systems. The modeling framework is established based on the lumped mass method, integrating axial elasticity, bending stiffness, added mass and hydrodynamic forces, thereby accurately capturing the time-varying response of the forces and cable configurations. To address the difficulty of directly measuring material-related and hydrodynamic coefficients, this research proposes a parameter identification method that combines the physical model with experimental data. High-precision inversion of the equivalent Youngs modulus and hydrodynamic coefficients is performed through tension experiments under multiple configurations, effectively demonstrating that the identified model maintains predictive consistency in various operational conditions. Further numerical analysis indicates that the dynamic properties of flexible cable exhibit significant nonlinear characteristics, which are highly dependent on material property variations and AUV motion conditions. This nonlinear dynamic behavior results in two typical response states, slack and taut, which are jointly determined by boundary conditions and hydrodynamic effects, significantly affecting the cable configuration and endpoint loads. In this research, the dynamics of flexible cables under complex boundary conditions is revealed, providing a theoretical foundation for the design, optimization and further control research of similar systems.