Design of vibration energy harvesters with customized nonlinear forces

Abstract

Nonlinear forces have been widely introduced into vibration energy harvesting to improve its performance. Generally, sources of nonlinearity include magnet forces, spring forces, geometric and material nonlinearity, etc. However, these nonlinear forces cannot be manipulated arbitrarily. It is very promising if the nonlinear forces can be customized according to requirements, in which the performance of the energy harvester can be further optimized. Therefore, the purpose of this study is to develop a kind of vibration energy harvester (VEH) that can customize the nonlinear forces. The nonlinear force customization device consists of a pre-compressed spring, a miniature bearing, and a raceway, which are designed according to the nonlinear forces. As an example, the device is installed at the end of a piezoelectric cantilever beam, and mono-stable, bi-stable and tri-stable energy harvesters are customized, respectively. Simulation and experiments prove its effectiveness. The nonlinear force customization device enables designers to obtain the desirable nonlinear forces for the vibration energy harvesters.