A Compact and Flexible Nonbeam-Type Vibrational Energy Harvesting Device With Bistable Characteristics

摘要

Conventional beam-type vibrational energy harvesting devices suffer from poor low-frequency performance, stress concentration, and limited compatibility with other device structures. This paper proposes a vibrational energy harvester based on a novel bellows structure together with permanent magnets that exploits nonlinear bistability to enhance its performance at low frequencies. The device uses a flexible bellows tube that is compact and can also be used as an elastic unit instead of springs in other vibration-based devices. First, the structural configuration of a prototype device is described, after which the equations of motion are established to allow a bistability analysis of the device. Simulations and experiments are carried out to investigate the effects of various parameters on the bistability, including the distance between magnets, the excitation amplitude, and the excitation frequency. The performance of the proposed device is investigated experimentally for excitation frequencies from 2 to 15 Hz and is compared with the performance of a device without external magnets. This compact nonbeam-type bistable energy harvesting device represents a new design of bistable vibration energy harvester, which has the potential to provide higher output power at lower working frequencies.