Untethered soft robot capable of stable locomotion using soft electrostatic actuators

This paper reports an untethered soft robot using soft electrostatic actuators. The robot consists of a deformable body driven by dielectric elastomer actuators, and two paper-based feet driven by electroadhesion actuators. The use of light-weight batteries and small-volume amplifiers contributes to the development of this untethered soft robot. Inspired by inchworms, this untethered soft robot can achieve locomotion through alternate expansion/contraction of its deformable body and adhesion/detachment of its two paper-based feet. The strong electroadhesion ensures a stable locomotion, and the large voltage-induced deformation and fast response of the robotic body leads to a velocity of 0.02 body length/s. This velocity is higher than that of untethered soft crawling robots based on pneumatic actuators or ionic polymer metal composites. The deformation of the robotic body is studied through finite element analysis. Compared to traditional hard robots, soft robots are found to be more susceptible to dissipative processes, including charging/discharging the actuators, dielectric relaxation and viscoelastic effects. These dissipative effects on this untethered soft robot are also investigated in this paper.