Programmable inflatable origami

Origami is a practical approach for developing soft robots and deployable structures. If the folding and stiffness are actively adjustable, we can program the motion of the resulting origami structure. Here, we propose an entirely soft inflatable origami actuator with variable stiffness and multimodal deformation. The programmable inflatable origami consists of a prismatic chamber based on the Kresling pattern with miniature fluidic channels at the mountain folds. Applying a vacuum to the central chamber provides the main actuation force, while the selective inflation of the fluidic channels controls the motion and changes the stiffness. We formulated a geometric description for the origami module to optimize the design parameters. Then, we fabricated the origami actuators from elastomeric rubber using a multistep single-material fabrication technique. Finally, we characterized the axial contraction and rotation angle and demonstrated variable stiffness and omnidirectional bending. Our work imbues origami actuators with embodied behavior presenting an integrated versatile soft robotic building block applicable to manipulation and locomotion scenarios.