Origami-based cable-driven shape-changing robot

Abstract

This article presents a cable-driven design for shape-changing ground robots, inspired by the miura origami fold (miura-ori). We focus on a triangular miura-ori shell (tri miura-ori) implemented as a finite-thickness, three layers module. Currently, shape-changing robots face significant challenges, including payload, complex control systems, and intricate manufacturing processes. Our origami-based design addresses these issues through a mechanically coupled cable transmission with one independently commanded actuation input that can be fabricated using two-dimensional prototyping techniques combined with lamination, ultrasonic welding, and subsequent system assembly. The robot, powered by a single encoder motor-cable system and manipulated via eight cables, coordinates the folding of four modules. Loading experiments have demonstrated that across five independently fabricated modules, the stabilized peak compressive force was 37.5 N and a load-to-weight ratio of 12.9. It achieves a fold-to-deploy ratio of 44.4%. Taking advantage of these characteristics, we prototyped this origami design as a shape-changing robot. The ability to change shape enables the robot to reduce its characteristic diameter from 75 cm to 50 cm in a qualitative constrained-access demonstration. It has potential for logistics transportation and ground rescue operations. This research contributes to the field of robotics by integrating Miura-ori geometry, finite-thickness multilayer fabrication, and common cable actuation in a mobile robotic platform.