Abstract
A Variety of different concepts of multi-axis wave conversion devices, most of which belongs to the so-called point absorber wave energy converters, have been proposed over the years aiming to harvest more wave energy and improve the efficiency. This paper considers a multi-axis concept device named TALOS that has been initially proposed and developed by Lancaster University. TALOS is a point absorber wave energy converter, with a fully-enclosed hull containing all the internal reaction mechanisms. The internal power take-off system consists of an inertial mass with secondary transmission mechanism, which can be hydraulic cylinders or other types of components, connecting the mass to the solid outer hull. In this paper, a full-scale device (based on a sea trial prototype width of 3 m, expected to be deployed in the East China Sea) is studied numerically and a 1/4th scale model is tank tested at Zhejiang University. A new form of power take-off (PTO) design is introduced, which is that the inertial mass is connected to rotary DC generators by screw drive mechanisms. A numerical model is firstly built with the help of open-source software WEC-Sim and is used to estimate the system's dynamics. Subsequently, further tank tests are carried out to obtain experimental results. Also, based on the current research progress, some design that can be improved in the future are summarized and introduced.