Bilateral multi-impact oscillators for cantilever energy harvesting enhancement

This paper presents an enhancement energy harvesting in a cantilever system using bilateral multi-impact oscillators with nonlinear magnetic flux for a broad bandwidth frequency. Two nonlinear oscillators with low resonant frequency provided bilateral multi-impacts onto a cantilever beam in different positions. The nonlinear electromagnetic distribution around the coil placing the tip of the cantilever beam produced the Lorenz force along with the motion during the system in operation. The response frequencies of the cantilever beam were no longer near its resonance frequency due to the bilateral multi-impact oscillators. The strong impacts and nonlinear Lorenz force affected the entire system, which reduced power harvesting enhancement with a large response frequency range from the oscillator's natural frequency (12 Hz) to several times its frequency (39 Hz). It was also observed that the numerical simulations of the obtained power of the cantilever beam were a good agreement with the experimental results. Moreover, the two magnets placing the top and bottom of the tip cantilever beam in repulsion had a much higher voltage response due to the strong nonlinear transient magnetic flux, which resulted in similar to 4 times more power in the bilateral multiple impacts system.