Dynamics and power performance of a novel wave-powered unmanned surface vehicle.

Unmanned surface vehicles (USVs) are playing a significant role in the marine science and engineering field, e.g., they have been widely used in measuring ocean waves and currents. However, their operation time and range are limited by the energy carried by internal batteries, and this challenge needs to be urgently addressed. In this study, a novel USV concept that can harvest vibration energy excited by ocean waves in the heaving and pitching direction is presented, which provides a sustainable and continuous power supply. A fully coupled wave-to-wire model that considers the viscous damping force is developed to investigate the dynamics and electric power performance of this novel device under site-specific realistic wave climates, with the external electric load optimally tuned for each sea state. Besides, the influence of the forward speed, geometric size, mass ratio and end-stop spring is studied. Numerical results show that the proposed USV in a freely floating situation can efficiently capture and convert harvested energy into electricity with a wave-to-wire efficiency of up to 20. 21 %. Additionally, it can generate an annual mean electric power of 29.73 W, under the wave climates of the national wave energy test site in China. • A novel wave-powered unmanned surface vehicle is designed. • A fully coupled wave-to-wire model is developed. • A high wave-to-wire efficiency up to 20.21% is obtained. • An annual mean electric power of 29.73 W is achieved by the USV. [ABSTRACT FROM AUTHOR]