Origami structures have been widely explored in robotics due to their many potential advantages. Origami robots can be very compact, as well as cheap and efficient to produce. In particular, they can be constructed in a flat format using modern manufacturing techniques. Rotational motion is essential for robotics, and a variety of origami rotational joints have been proposed in the literature. However, few of these are even approximately flat-foldable. One potential enabler of flat origami rotational joints is the inclusion of lightweight pneumatic pouches which actuate the origami's folds; however, pouch actuators only enable a relatively small amount of rotational displacement. The previously proposed Four-Vertex Origami is a flat-foldable structure which provides an angular multiplier for a pouch actuator, but suffers from a degenerate state. This paper presents a novel rigid origami, the Self-Lock Origami, which eliminates this degeneracy by slightly relaxing the assumption of flat-foldability. This joint is analysed in terms of a trade-off between the angular multiplier and the mechanical advantage. Furthermore, the Self-Lock Origami is a modular joint which can be connected to similar or different joints to produce complex movements for various applications; three different manipulator designs are introduced as a proof of concept.

翻译：折纸结构因其诸多潜在优势在机器人领域得到广泛探索。折纸机器人可高度紧凑，且制造经济高效。特别地，利用现代制造技术能以平面形式构建折纸机器人。旋转运动对机器人技术至关重要，文献中已提出多种折纸旋转关节。然而，其中鲜有关节能实现近似可平面折叠。实现平面折纸旋转关节的一个潜在方案是引入轻量化气动气囊以驱动折纸折叠；但气囊致动器仅能实现较小角度的旋转位移。先前提出的四顶点折纸结构是一种可平面折叠结构，可为气囊致动器提供角放大倍率，但存在退化状态问题。本文提出一种新型刚性折纸结构——自锁折纸，通过略微放宽可平面折叠假设消除了这一退化性。本文从角放大倍率与机械增益的权衡角度分析了该关节。此外，自锁折纸是一种模块化关节，可与相同或不同类型的关节连接以实现复杂运动，适用于多种应用场景；作为概念验证，本文介绍了三种不同机械臂设计方案。