Propulsion-Based Soft Robotic Actuation

The use of air propulsion to drive limb motion in soft robotics has been a largely untapped field even though the technology has been around since the 1700s. Air propulsion can generate greater degrees of motion in limb actuators compared to widely-experimented pneumatic actuators operating on expandable air channels, which are limited by air pressure input, minimum size and cyclic fatigue. To demonstrate the application of air propulsion in soft robotics motion, we developed a 3D-printed, tri-pedal, soft, air-driven robot that can perform biomimetic motions such as flexion and extension of limbs, crawling, rotation, grasping, kicking and picking of objects. To accomplish air-propelled actuation, milli-scale channels are incorporated throughout each limb that guides the pressurized air inflow to outlets of different directions. A Finite Element Model (FEM) approach to simulate the bending response of the limb due to varying pressure is proposed and evaluated. This study introduces the potential of using air propulsion as an alternate form of soft body actuation for longer cyclic lifespan and increased maximum air pressure input.