Sea-state Interaction based Lagrangian Dynamic Model of the Liquid Robotics Wave Glider Platform

The Liquid Robotics Wave Glider is an unmanned marine research vessels that makes use of wave propulsion to minimise energy requirements during voyages. Models of these hybrid sea-surface and underwater craft must incorporate the platform's interaction with the sea state to allow for more accurate navigation and path planning. This paper describes the multi-body Wave Glider system using Denavit-Hartenberg parametrisation, with a Lagrangian approach used to generate the equations of motion for the body. Physical dimensions and hydrodynamic factors were derived from both platform measurements and a SolidWorks model of the system. The model's propulsion is dependent on the sea state by virtue of the characterisation of the hydrofoil motion and the hydrodynamic forces on the hydrofoil. The model is simulated for various sea states to investigate the performance.