Origami-inspired soft twisting actuator

Soft actuators have shown great advantages in compliance and morphology matched for manipulation ofdelicate objects and inspection in a confined space. There is an unmet need for a soft actuator that can providetorsional motion to, for example, enlarge working space and increase degrees of freedom. Toward this goal, wepresent origami-inspired soft pneumatic actuators (OSPAs) made from silicone. The prototype can output arotation of more than one revolution (up to 435_), more significant than its counterparts. Its rotation ratio( = rotation angle/aspect ratio) is more than 136_, about twice the largest one in other literature. We describe thedesign and fabrication method, build the analytical model and simulation model, and analyze and optimize theparameters. Finally, we demonstrate the potentially extensive utility of the OSPAs through their integration intoa gripper capable of simultaneously grasping and lifting fragile or flat objects, a versatile robot arm capable ofpicking and placing items at the right angle with the twisting actuators, and a soft snake robot capable ofchanging attitude and directions by torsion of the twisting actuators.