Nonparametric Identification Model of Coupled Heave–Pitch Motion for Ships by Using the Measured Responses at Sea

In order to simulate or control the coupled heave–pitch motion of ships in waves as realistically possible, an appropriate mathematical model must be established advance. this paper, a nonparametric identification method, based on combination random decrement technique (RDT) and support vector regression (SVR), was proposed by only using measured responses at sea. First, describe irregular waves. Second, equation signatures were obtained RDT. Third, damped frequency motions analyzing signatures. Fourth, SVR applied identify unknown hydrodynamic functions model. The applicability validity method verified case studies which designed simulated data test data, respectively. Results study showed that can