Ultrastrong and High‐Stroke Wireless Soft Actuators through Liquid–Gas Phase Change

Abstract

Abstract Soft actuators and robots, which depart from classical paradigms in rigid robot construction, increase the safety of robot–human and robot–environment interactions, bring superior adaptation capabilities, and extend the range of robotic operations to fragile and sensitive objects and environments. Pneumatic soft actuators are a key building block for soft robotics due to their inherent simplicity, high forces, and large strokes. However, pressure lines connected to large pumps, regulators, and valves put significant mobility limitations on these actuators. Recently, it has been demonstrated that by using phase changes of liquids, pumps can be eliminated in favor of on‐board pressure generation. Here, it is shown that power and control of soft actuators can be realized through phase change of liquids stimulated by inductor‐capacitor resonant receivers placed in an external magnetic field. The method requires no pumps, no external fluidic or electrical wiring, and no batteries on‐board, leading to the possibility of small and low profile wireless soft actuators and robots which can operate for long durations. The phase change enables ultrahigh forces and high strokes with a small volume of active material. An ultralow profile, strong and soft pneumatic bellows‐style actuator powered and controlled wirelessly demonstrates the potential of this technique.