Finite Element Analysis of a Compound Device Integrated into a Piezoelectric Actuator and a Piezoelectric Harvester

A compound device integrated into a piezoelectric actuator and a piezoelectric harvester is developed. The device has sandwitch structure that is composed of a metal elastic body, a PZT element for actuating and a PZT element for vibration energy harvesting. The actuating PZT is bonded on the bottom surface and the harvesting PZT is bonded on the top surface of the metal elastic body, respectively. The electromechanical model is derived and the vibration characteristics and energy harvesting output characteristics of the piezoelectric device are simulated by using the finite element analysis method. The effects of the system parameters on the modal frequency, harmonic and transient performances are conducted. The developed device has modal frequency of 36.6 kHz, the vibration amplitude achieves 1.89um at the excited voltage of 67 V. The vibration dislocations in X, Y and Z directions reach a steady state at 1.5 ms. The harvesting voltage of each sector of the harvesting PZT is reaches 40V, which can provide electric power for low powered electronics devices. The developed device can be used for actuating and positioning the micro robot, as well as harvesting the vibration energy of the robot and converting it into electric energy.