Origami-inspired dual-mode wave energy harvesting for ocean buoys

In-situ wave energy harvesting is a promising technology for supplying sustainable energy to ocean buoys. The energy harvester operates based on the response of excitations and generates more power with stronger resonance. However, when faced with high sea conditions, severe shocks or collisions inside ocean buoys can lead to dysfunction. This work proposes a dual-mode wave energy harvesting method and designs a foldable mechanism inspired by conical Kresling origami with a pendulum-based wave energy harvester, which can work under various sea conditions. In harvesting mode, the energy harvester attains excitations and transmutes wave energy to electricity. In protecting mode, the energy harvester has a compact structure with high reliability and maneuverability. To enhance the powering ability in the harvesting mode and maintain greater stability in the protecting mode, a foldable mechanism is designed with a high compression ratio of approximately 4:1. Theoretical analyses are implemented to design and optimize the foldable mechanism, and a proof-of-concept prototype is fabricated to evaluate the proposed method. Laboratory experiments are set up to evaluate the energy harvesting ability and hydrodynamic stability of these materials. Verified by the sea trial, the results show that the prototype can harvest wave energy in the harvesting mode and maintain greater stability in the protecting mode, demonstrating the efficacy and reliability of the proposed concept.