Multi-Directional Vibrational Energy Harvester with In-Plane Motion

Abstract

A novel multi-directional piezoelectric vibrational energy harvester (PVEH) is proposed that can harvest from excitation angles in the XY-plane. The design is a parallel three-chain rotationally symmetric folded-flexure (3CR-FF) topology with a PZT-5H patch on each arm, that achieves multi-directionality utilising degenerate in-plane translational modes. Finite-element modelling guides the geometric design, system identification with a single-degree-of-freedom fit determines the near-optimal load, and the prototype is then evaluated experimentally at 15◦ angular increments in the XY- plane. The 3CR-FF prototype delivers an angle-averaged peak acceleration-normalised power of 1.35 ± 0.23 µW/mg^2 at 43.48 ± 0.12 Hz, with a localised performance dip between 330◦ and 15◦. Its performance is benchmarked against an array of three equally spaced cantilever beams (3TC) of equal total proof mass, which achieves roughly three times lower mean peak power and a wider frequency spread across angles (±0.45 Hz).