Nonlinear behaviour of a micromachined SOI device for energy harvesting application

This paper reports a novel nonlinear MEMS mechanism for energy harvesting applications based on vibrating source. The typical mechanism to harvest energy is based on resonance mechanical bodies (linear systems) that enable collecting energy through self-generating materials and tuned close to the resonance spike. Moreover, it must be observed that in the vast majority of cases the ambient mechanical vibrations come in a vast variety of forms and having the energy distributed over a wide spectrum of frequencies. For this reason the novel approach proposed concerns a nonlinear vibrating system based on a switching mechanism around two stable states. A wider spectrum is predicted for these nonlinear oscillators, so more energy can be saved adopting a bistable dynamic. An U-shaped BESOI (Back Etched SOI) cantilever has been designed and simulated and an experimental campaign validates the principle.