Modeling and Analysis of a Piezoelectric Stick-slip Energy Harvester

This study presents a dynamical modeling and analysis of a piezoelectric energy harvester which converts a translational motion into sustained vibration via stick-slip motion. The presented device consists of an Lshaped cantilever oscillator with a piezoelectric transducer (macro-fiber composite) glued on it. When its tip is rubbed by a linearly moving friction pad, a friction-induced vibration yields a power flow from the mechanical work applied to move the friction pad to the piezoelectric transducer. In this study, the oscillator was modeled as a 2-DOF system, and the equations of motions were derived via the Lagrange equation of motion. A preliminary study suggested that there were several typical modes of tip motions, including one always kept contact with the surface of the friction pad, and another one kept hopping-like motion on the surface. Numerical simulations were conducted to find the underlying physical mechanism of the behavior of those tip motion. As the results of the numerical simulations, the former motion mode was successfully reproduced, while the latter motion mode was not sufficiently reproduced, which may require another degreeof-freedom to represent the higher vibration mode of the oscillator.