Vibration Energy Harvesting Using Multi-Stable Two Degree-of-Freedom Nonlinear Dynamics

In this research, we studied the integrated dynamics of a coupled linear oscillator-bistable energy harvester system. The method of harmonic balance together with perturbation analysis are used to predict the existence and stability of the bistable device interwell vibration. The influences of important parameters on tailoring the coupled system response are investigated to determine principles for improved energy harvesting performance. We demonstrate analytically that for excitation frequencies in a bandwidth less than the natural frequency of the linear oscillator, the additional linear system may substantially intensify the bistable harvester power generation as compared to a single bistable device. Moreover, the linear-bistable coupled system may introduce a stable out-of-phase dynamic between the linear and bistable elements around the resonance of the linear oscillator, enhancing the performance of the harvester by providing for a second interwell response. Key analytical findings are confirmed through experiments, validating the predicted trends and demonstrating the advantages of the coupled system for energy harvesting.