Fabrication and Characterization of 3D Printed Out-of-Plane Torsional Comb-Drive Actuators for Microrobotics

This work presents 3D printed torsional electrostatic actuators in which a 3D design of circular combs and torsional springs enables an out-of-plane angular movement. The actuators were fabricated by a novel 3D printing process using two-photon polymerization (TPP) followed by sputtering and etch steps. The quasi-static behavior of the actuator was characterized with respect to applied voltage, and a maximum angular displacement of 13.8° was achieved at 190 V. Viscoelastic behavior of the 3D printed material was observed during actuation, but 10,000 cycles of repeated actuation were tested without failure. The 3D actuator design enabled pure rotary motion, with a linear correlation between the angular displacement and the square of voltage.