Design and analysis of a microminiature omnidirectional wave energy-harvesting device based on a spatial slider–crank mechanism

Energy-harvesting devices using wave energy and ocean current energy can provide higher endurance and operation capacity for small floating or mobile equipment in offshore operations. In this paper, a microminiature omnidirectional wave energy-harvesting device based on a spatial slider–crank mechanism was designed for equipment whose length is less than ordinary ocean wavelength. It can harvest the ocean wave energy from the omnidirectional swing of the buoy and convert the reciprocating swing motion of the buoy into the unidirectional rotation motion of the generator to improve the energy conversion efficiency. The dynamic model and equivalent circuit model of the energy-harvesting device were established by the Lagrangian method and circuit-based analysis method, respectively. The model was simulated, and the effects of parameters such as crank length, wave period, etc. were investigated. The results showed that the device has good energy-harvesting performances, especially in medium and low sea conditions. In addition, the performance of the device can be improved by adjusting the length of the crank and rod.