An Electrostatic Linear Film Actuator with Passive Phase Switching

Abstract

Artificial muscles for soft robots and human-interactive machines must deliver high force, fast dynamics, and large stroke (tens of percent strain) while remaining mechanically compliant. Sliding electrostatic film actuators enable compact multilayer integration without lateral expansion and provide large stroke (≈40% contraction) by generating shear forces between ultrathin (≈50–150 µm) slider and stator films. However, in multi-stack configurations, force additivity degrades under curvature or misalignment due to uneven electrode overlap. Here, we introduce an electrostatic linear film actuator with passive mechanical phase switching via patterned brush contacts. As the slider moves, each stator electrode is locally assigned HV or ground at the correct position, maintaining force direction under bending and stretch, and enabling operation from a single DC source.