Double-body coupled heading manoeuvrability response model considering umbilical lag of unmanned wave glider

Abstract

The unmanned wave glider (UWG) comprised of an underwater glider (Glider), a surface float (Float) and an umbilical cord (Umbilical) is an energy-saving marine vehicle. Currently, its heading manoeuvrability models is cumbersome and its parameters is difficult to accurately estimate; while this is suitable for theoretical analysis, it is insufficient for motion control and forecasting. In this paper. From the point of view of motion response, the double-body coupled heading manoeuvrability response model (HMRM) is established based on the first-order nonlinear KT equation. On the basis of reasonable assumptions, combined with the unique motion characteristics of the UWG, a step-by-step identification method of model parameters is designed under the condition that the Float is equipped with only a single heading sensor. The umbilical lag time is introduced into the HMRM as an important parameter. The experimental results show that the deviation of the model which does account for Umbilical lag (ULM) is the smallest when the time lag is 4.6 s. In different working conditions and different periods, taking the heading deviation of the model which does not consider Umbilical lag (NULM) as the standard, the reduction rate of the heading deviation of the ULM ranges from 20.79–79.21%. Thus, the ULM greatly improves the description accuracy of the heading motion of the UWG compared to the NULM, as well as the generalization. Therefore, compared to the NULM, the ULM is better suited for heading manoeuvrability prediction and motion control of the UWG.