A Compact Thermofluidic Soft Actuator

Abstract

A compact thermo-fluidicactuator

Objective: Soft actuators producing large motion in a short time is mainly based on stretchable polymers actuated by pneumatic pressure. But such systems consist of bulky components like motor, pump/compressor, tubes and valves. Here, we developed a fast-responding large-amplitude soft actuator based on a liquid-gas phase transition, resulting in a compact system.  Methods: The required pressure is generated solely by the electrically induced phase transition of a fluid in a cavity. We pay special attention to design variables to improve the response time and propose a new design for the electrodes which are the most critical components.  Results: Our bending actuator produces large motion in less than 7 seconds using a low voltage source (less than 50V), which is much faster than previously reported soft actuator based on phase transition.