Robotic arms built from stiffness-adjustable, continuously bending segments serially connected with revolute joints have the ability to change their mechanical architecture and workspace, thus allowing high flexibility and adaptation to different tasks with less than six degrees of freedom, a concept that we call malleable robots. Known stiffening mechanisms may be used to implement suitable links for these novel robotic manipulators; however, these solutions usually show a reduced performance when bending due to structural deformation. By including an inner support structure this deformation can be minimised, resulting in an increased stiffening performance. This paper presents a new multi-material spine-inspired flexible structure for providing support in stiffness-controllable layer-jamming-based robotic links of large diameter. The proposed spine mechanism is highly movable with type and range of motions that match those of a robotic link using solely layer jamming, whilst maintaining a hollow and light structure. The mechanics and design of the flexible spine are explored, and a prototype of a link utilising it is developed and compared with limb segments based on granular jamming and layer jamming without support structure. Results of experiments verify the advantages of the proposed design, demonstrating that it maintains a constant central diameter across bending angles and presents an improvement of more than 203% of resisting force at 180 degrees.

翻译：由刚度可调、连续弯曲的节段通过旋转关节串联构成的机器人臂能够改变其机械构型和工作空间，从而在少于六个自由度的情况下实现高灵活性和对不同任务的适应性，这一概念我们称之为可变形机器人。已知的刚性机制可用于实现这些新型机器人操作器的合适连杆，然而这些方案在弯曲时通常会因结构变形而性能下降。通过引入内部支撑结构，这种变形可被最小化，从而提升刚性性能。本文提出了一种新型多材料仿生脊柱柔性结构，用于为大直径的基于层叠阻塞的刚度可控机器人连杆提供支撑。所提出的脊柱机构具有高运动性，其运动类型和范围与仅使用层叠阻塞的机器人连杆相匹配，同时保持中空轻质结构。本文探讨了柔性脊柱的力学原理与设计，并开发了一个利用该结构的连杆原型，与基于颗粒阻塞和无支撑结构的层叠阻塞肢体段进行了比较。实验结果验证了所提出设计的优势，表明其在弯曲角度范围内能保持恒定的中心直径，并在180度时抗阻力提升超过203%。