Pneumatically Actuators with Electronics-Free Sensing and Control

In soft devices, most pneumatic actuators are controlled by hard electronic valves and microcontrollers. The emerged soft oscillators typically lack feedback for enhanced adaptability. Meanwhile, most embedded soft sensors are based on electric or optical principles, while soft fluidic sensors received less attention. Here, we fabricate all-fluidic untethered soft robots with all pneumatic sensors, valves, and actuators. The strain sensor is easily made of a low-cost elastic tube, which provides proprioception as the feedback. The pneumatic valve transforms the continuous inflow into cyclic activation, and controls the soft actuators bending and recovery as a result of the feedback signals. Our fluidic system enables fully untethered control of soft robots without using electronics. Future integration of multiple actuators could potentially lead the way toward fully autonomous soft robots in an unpredictable environment.