Theoretical analysis and experimental verification for improving energy harvesting performance of nonlinear monostable energy harvesters

Theoretical analysis and experimental verification of nonlinear monostable energy harvesters are presented to enhance energy harvesting performance from low-level ambient vibrations. Harmonic balance analysis of these harvesters demonstrates that there are two stable orbits (high-branch orbit and low-branch orbit) in a specific multi-solution range when the excitation level is larger than a threshold. Under the same excitation, these nonlinear harvesters may finally vibrate at different orbits depending on different initial conditions or disturbances. The energy harvesting efficiency will be greatly improved if high-branch oscillations could be induced in the multi-solution range. Numerical investigations into the influence of a disturbance method and initial conditions on high-branch oscillations are performed for energy harvesting enhancement of nonlinear monostable energy harvesters. Experimental results verify the effectiveness of adding disturbances by using an impact method for improving energy harvesting performance and the capability of nonlinear monostable energy harvesters in maintaining high-branch oscillations at low-level vibrations.