Piezoelectric polymer actuators in a vibration isolation application

Abstract

We present results from development and testing of lightweight actuators made of the piezoelectric polymer PVDF. The prototype being developed is intended for microgravity applications in space and has been tested aboard NASA's Reduced Gravity Platform. The design has been driven by the requirements for a full three-dimensional (six-degreeof-freedom) environment. Incorporation of additional electrical leads into the actuators themselves may remove the need for a separate umbilical to the suspended experiment. Linear equations describing the displacement of piezoelectric bimorphs were developed and applied to the bellows actuator including the epoxy layer. Properties for the piezoelectric layers were obtained from the literature; properties for the epoxy layer were obtained through ultrasonic testing. To assess the validity of the assumed linearity of the actuator, we conducted nonlinear finite element analysis, which indicated a high degree of linearity on contraction and up to a maximum of 5% deviation on expansion to full deflection (about 6 mm). We have developed and tested a proportional-plus-derivative (PD) control system for use with the actuator in one dimension using a novel folded pendulum to simulate a zero-g environment. Passive and active characteristics are both in agreement with theoretical predictions.

Damping and electromechanical energy losses in the piezoelectric polymer PVDF

“…12. In this experiment, a bellows actuator was constructed from the 28 mm PVDF sheets (Bohannan et al, 2000;Mooibroek, 1998). A continuous 200 V was applied and the displacement without mechanical load was measured over time.…”

A Brief Review of Stimulus-active Polymers Responsive to Thermal, Light, Magnetic, Electric, and Water/Solvent Stimuli

“…All of these are responsible for the large electroactive effect. For practical applications, incorporation of defects into the polymers can significantly lower the transition temperature near to the room temperature, broaden the transition region, and eliminate the energy barrier in the transformation (Zhang et al, 1998;Bohannan et al, 2000;Xia et al, 2002;Huang et al, 2004b).…”

An investigation of the influence of substrate geometry and material properties on the performance of the C-shape piezoelectric actuator

“…In certain smart structure applications, the use of curved piezoelectric actuators is necessary. Active controls of satellite dishes or mirrors are examples of applications of curved piezoelectric actuators [1,2].…”