A four bar mechanism as dynamic magnifier for improved performance of multi–modal piezoelectric harvester beams

Wireless sensors for structural health monitoring have gained significance because of low cost of installation. Vibration-based cantilevered piezoelectric energy harvesters have been found to satisfy the power requirements of remote sensors. Conventional piezoelectric vibration energy harvesters are designed to operate at their first mode. Multimode technique employs obtaining a larger number of peaks within the operating frequency range considered. This work involves the use of a novel rigid four bar mechanism to act as dynamic magnifier to amplify the output power from the harvester. Piezoelectric harvester beams of two different geometries are studied for their performance. The first harvester beam is fabricated using copper as substructure beam. Another harvester beam is fabricated by attaching two extended aluminum beams to the existing copper substructure beam at the tip end. Both harvesters are studied in standalone cantilever arrangement and in dynamic magnifier arrangement. In both cases, it is shown that with magnifier, the output voltage from the harvester has shown significant improvement when compared to a cantilever arrangement. Further, the superior performance of the proposed harvester with dynamic magnifier when compared to similar existing harvesters is also discussed