A new piezoelectric actuator using a feed-screw for quasi-static motion accumulation - Part I: Experimental development

Piezoelectric materials' excellent dynamic performance, high energy density, and incremental positioning capability have motivated their use for solid-state actuation. However, harnessing a piezoelectric material's low-displacement and high-force electric field-induced mechanical output to perform large-displacement actuation is a significant challenge. Despite recent advances toward addressing this challenge, issues including long term reliability, high fabrication cost, and large power electronics remain obstacles for widespread application of piezoelectric actuators. This study proposes a new piezoelectric actuator design that achieves high performance actuation while making strides toward addressing the drawbacks of existing piezoelectric actuators. The new actuator's operation involves intermittent rotation of two nuts on a feed-screw to achieve quasi-static piezoelectric motion accumulation. Merits of the feed-screw concept include its reversible, robust, and high force actuation; simple power electronics; insensitivity to wear; and a rigid power-off self-locking state. The significance of this design is experimentally demonstrated by the fabrication of three prototype actuators, the best of which exhibited a 1235lb blocked force, 29 W peak power output, and 6.1 W/kg specific power.