Vibration energy harvesting from a helicopter transmission using Mn-doped relaxor ferroelectric single crystal

A multi-modal vibration energy harvester has been developed for use on a helicopter transmission. The harvester is based on a topology optimised spring-steel cantilever-beam, with a pair of [011] poled Mn-PMN-PZT relaxor ferroelectric single crystal (RFSC) disk transducers. Finite element modelling is used optimise the position and crystal orientation to maximise the harvester output. The harvester is applied to a Bell 206-B Kiowa helicopter main rotor transmission, which has three main vibration components at 1900 Hz, 2300 Hz, and 2500 Hz. Superposition of the three vibratory components produced maximum measured peak accelerations of 100g (where g is 9.81 m s
^-2
). The harvester was mounted on the transmission and tested under near-operational conditions, with the transmission oil temperature reaching 86 degrees Celsius. During testing the harvester typically produced peak open-circuit output voltages of 12.8 V and 10.6 V for the left and right RFSC transducers respectively. With an optimised resistive load of 60,000 Ohms, the harvester generated a peak power of 2.37 mW from the multi-component vibrations present on the transmission casing.