A novel piezoelectric power generator integrated with a compliant energy storage mechanism

One of the practical solutions for low-power wireless wearable devices is to use mechanical energy harvesting devices to supply uninterrupted power. A device for harvesting mechanical energy from human movement can convert the energy into electrical energy which can supply microelectronic device. Although foot impact energy is the most easily utilized mechanical energy, there is a large damping loss during the conversion process due to its short duration of action on the energy harvesting device. It is necessary to design a transient elastic energy storage device for storing mechanical energy during periods of no impact load. In this study, a spring energy storage device consisting of a crank rocker mechanism and a compliant spring was integrated in a mechanical energy harvesting system. The system can store and release instantaneous footstep energy to drive piezoelectric energy harvesters to generate electricity. The performance of the energy storage device was evaluated by finite element analysis and topology optimization design. Finally, a prototype was made and proven to work effectively. (paper)