A structurally flexible humanoid spine based on a tendon-driven elastic continuum

When working in unknown environments, it is beneficial for robots to be mechanically robust to impacts. To obtain such robustness properties and maintain human-like performance, strength, workspace and size especially in the upper body, an elastic backbone approach is presented and discussed. Compared to the human spine stabilized by ligaments, intervertebral discs and muscles, we use a continuum mechanism based on silicone and tendons for actuation. The work presents the development of such a mechanism, that could be either used as neck or torso, but concentrates on the cervical part (neck). To prove functionality of the proposed concept, a planar setup was designed and experimental data regarding motion capabilities, robustness and dynamics are presented. With that knowledge, a modular multiple DOF prototype is built which can easily be equipped with different tendon routing and elastic continuum shapes. The results of that final setup will help the mechanical designer to choose the suitable solution for the robotic spine and provides a test bed to develop control strategies for such types of mechanisms.