This study presents a new origami joint design for self-folding or self-assembling robots. The concept of a self-assembling robot has attracted attention for future robotic applications, and origami has emerged as a promising approach, dramatically simplifying joint structures through material bending. However, despite its potential, the practical application of origami design in robotics has been limited by inherent challenges. One is a joint slack problem. Material bending necessitates a gap between links, which creates slack and causes undesired motion, hindering reliable, efficient behavior. This has long been a vexing problem for origami robotic designers and has posed a significant barrier to the adoption of origami design methodology in robotics.

We propose an alternative approach to this issue. Our method uses torsion rather than bending for folding, achieving performance comparable to the ideal pin joint while endowing the structure with inherent elasticity without the need for additional springs or elastomers. This simple, efficient design enables complex self-folding mechanisms, which we validate through the development of a self-assembling robotic arm.