Hydrofoils in the left video moves like flapping creature. Flapping motion is common in nature creatures as birds and whales. Fully passive activation of a flapping hydrofoil turbine is a hot issue for increasing its power efficiency. 

  A mirror-type dual-flapping hydrofoil turbine with a new coupling mechanism have been developed in our group coworked with KIOST Pohang center. The developed system in the movie clip is fully passively activated by only flow energy wihtout any controller and also its power curve is regulated due to 90 degree phase difference between the two hydrofoils. 

  Supported from the recently-started project "turtle-mimicking tidal current turbine", a new dual FHT have been designed and its concept is being verified by using numerical tools. The coupling mechanism already utilized in the previous dual FTH is adopted for self-driven by flow like conventional rotary turibnes and a crank-locker mechanism is newly utilized for transmitting the flapping powers of the dual hydrofoils to a rotary shaft. 

  The working concept of the mechanisms is veried by animating the cyber model maded by Solidworks. The phase and distance etween both hydrofoils are determined by conducting parametric study with an in-house CFD tool. 

  The self-starting properties of the H-Darrieus turbines according to the change in solidity were investigated, and those of multiple-stage turbines were also analyzed. 

  As a result of the self-starting experiments, in the case of a large solidity, the incoming flow velocity that satisfies the self-starting criterion was low and the timing was fast, consequently self-starting properties were good. 

  Meanwhile, the self-starting properties of the multiple-stage turbines were poor because higher flow velocity and longer time were required as compared to the single-stage turbine. 

  The half model of the designed parallel-type dual FHT was fabricated for wind tunnel experiments. The self-starting fucntion by the coupling mechnism was worked well, and the flapping power of dual flappers was sucessfully transmitted to the rotor shaft by the crank-locker mechanism. The power transmission is operated like a two-cylinder engine. 

  We proposed a wheel-based Underwater Pole Climbing Robot(UPCR) platform, which was aimed at the inspection and maintenance of the substructures of the offshore wind turbines, with three advantages: high speed, good mobility and low power consumption. The results of this research show that the UPCR has basic moving capabilities required for the underwater work for substructures of the offshore wind turbine.