An in-pipe worm robot with pneumatic actuators based on origami paper-fabric composites

This article reports on the design, fabrication, and characterization of an in-pipe worm-like soft robot with pneumatic actuators based on origami paper-fabric composites in which the paper and fabric serve as the skeleton and skin of the robot, respectively. The robot is assembled with an extensor of a bellow-like structure for implementing peristaltic locomotion and a clamp fabricated using a Kresling crease pattern at each end of the robot for anchoring. The performances of the pneumatic actuators, as well as the worm robot, are characterized and their dependence on some material, structural, and pneumatic parameters are investigated. Stepwise inflation of the clamp actuator takes place as the pressurization duration increases. The extension ratio of the extensor has a nonlinear relationship with the pressurization duration. The higher rigidity of the paper with a high weight per unit area can facilitate faster retention near the end of the extension process for the extensor with a small number of creases, while it becomes a resistance for the extension of the extensor with a large number of creases. The softness, lightweight features, low cost, ease to fabricate, modular design, and mobility of the worm robot indicate it has potential to find application in pipeline inspection, etc.