Scaling Analysis of Large Stroke Piezoelectric Cellular Actuators

This paper presents a scaling analysis for a novel method of amplifying the motion of piezoelectric stack actuators. The amplification method involves nesting, or layering, of individual flexure mechanisms atop piezoelectric stacks to create a large stroke actuator subunit. A single subunit is referred to as an actuator cell. First, we develop an augmented kinematic model and a deterministic design process to arrive at closed form equations of cell performance. We then describe performance metrics that are used to evaluate the cell design as the size of the piezoelectric stacks is varied. For each performance metric, we provide numerical scaling contours that are determined using only mild design assumptions and realistic manufacturing constraints. With respect to maximum work density and cell packing efficiency, we find that there exists an relatively narrow optimal scale region for the cell designs.