Effects of nonlinearity of restoring springs on propulsion performance of wave glider

Wave glider is an unmanned surface vehicle that can directly convert wave energy into forward propulsion and fulfill long-term marine monitoring. A previous study suggested the motion stiffness of restoring springs mounted on hydrofoil are main factors affecting performance glider. In this paper, dynamic responses nonlinear characteristics underwater mechanism considering investigated based a fluid–rigid body coupled model. Firstly, models with different kinds proposed, linear spring considered. Then, model developed by coupling rigid dynamics hydrodynamic Dynamic simulated numerical analysis method, illustrated time/frequency domain response phase diagram analysis. The effects excitation frequency, heights location connection point analyzed. results show multi-frequency occurred in system, provide larger moment to avoid excessive pitch angle more suitable for sea conditions, which provides reference developing mechanisms high complex environments.