'Floating drive device, wave energy conversion system, Method for extracting energy from wave motion, Method for varying a hydrodynamic property of a floating drive device, Method for operating a wave energy conversion device '

摘要

A buoyant actuator (10) responsive to wave motion is provided. The buoyant actuator comprises a body (21) defining a chamber (23) for accommodating matter. A hydrodynamic property of the body is selectively variable by varying the matter within the chamber. The body comprises a wall structure (25) having a pliant outer skin (27) at a boundary of the chamber. The outer skin is adapted to deflect in response to a variation in matter within the body. The matter comprises a plurality of buoyant spheres (53) arranged to roll one against another, and the chamber is filled with the spheres so that the outer skin is drawn into a taut condition by the outward pressure of the spheres inside. This causes the actuator to assume a design shape, and the spheres are able to collectively maintain the shape of the actuator and roll against one another in response to outside forces on the actuator while still maintaining the shape of the actuator.