Performance evaluation of a two-directional energy harvester with low-frequency vibration

This study evaluates the power harnessing performance of a two-directional inertial pendulum energy harvester for miniature underwater mooring platforms (UMPs). This novel harvester can achieve a dominant rotational motion under different parametrical excitations. The two-directional energy harvesting performance is investigated through vibration platform experiments over roll-pitch coupling excitations. The frequency ratio between the pitch and roll motion is about 2 to 1, the roll excitation frequency is over the range of 0.2-0.3 Hz, and the pitch amplitude is much lower than the roll amplitude. Experimental results indicate that the inclination configuration of the harvester can improve two-directional energy harvesting performance significantly with low-frequency vibration. Geometrical tunability through adjusting inclination configuration for the harvester can enhance the two-directional energy harvesting apparently. Four prominent phenomena of the two-directional energy harvesting performance are observed with the increasing load resistance. The motion state transformation of the inertial pendulum can result in dramatical jumps or drops in two-directional energy harvesting.