A Vibration Energy Harvesting Structure, Tunable Over a Wide Frequency Range Using Minimal Actuation

This paper introduces a novel vibration energy harvesting structure with a resonance frequency that is tunable over a large range using a simple compact mechanical adjustment that alters the structural stiffness. The frequency tuning requires minimal actuation that can be “turned off” while maintaining the new resonance frequency. Testing shows that the natural frequency can be adjusted from 32 Hz to 85 Hz. The structure is coupled with an electromagnetic transducer to generate power. Test results at varying excitation frequencies and amplitudes demonstrate tunable power generation over a very wide bandwidth. In addition to frequency tunability, the structure is a nonlinear softening spring, which provides the added benefit of a passively wider bandwidth for specific ranges of the design parameters.