Design, Dynamics Modeling, and Experiments of a Vibration Energy Harvester on Bicycle

Harvesting vibration energy during riding for powering on-board appliances has been demanded. However, few vibration energy harvesters on bicycle have been reported and the output power can hardly satisfy the requirement. A vibration energy harvester for bicycle is proposed based on a directional variable inertia flywheel and coaxial mechanical motion rectifier, in order to improve the output power and stability via improving the ratio of inertia and damping. The coaxial mechanical motion rectifier is designed to convert reciprocating rotation to unidirectional rotation, and the directional variable inertia flywheel is designed to extend the overrunning phase. Dynamic modeling with two-degree-of-freedom is proposed with the consideration of the nonlinear velocity response in the overrunning phase. The input force and output voltage are simulated with different input signals and external resistances. Lab tests demonstrate that the directional variable inertia flywheel is beneficial to increasing the output power, and maximum output power of 1.73 W is achieved. Finally, road tests of applying the vibration energy harvester on a bicycle are carried out, and average output power of 2.11 W and maximum power of 9.77 W are achieved.