Variable-Stiffness Tensegrity Spine
A novel robotic spine can transition from compliant to stiff mode and back. The artificial spine consists of a variable-stiffness tensegrity design inspired by the vertebrate spine and could be used as the backbone of safe robotic manipulators, or agile and strong robots.
Vertebrates, including amphibians, reptiles, birds, and mammals, with their ability to change the stiffness of the spine to increase load-bearing capability or flexibility, have inspired roboticists to develop artificial variable-stiffness spines. However, unlike their natural counterparts, current robotic spine systems do not display robustness or cannot adjust their stiffness according to their task. In this paper, we describe a novel variable-stiffness tensegrity spine, which uses an active mechanism to add or remove a ball-joint constrain among the vertebrae, allowing transition among different stiffness modes: soft mode, global stiff mode, and directional stiff mode. We validate the variable-stiffness properties of the tensegrity spine in experimental bending tests and compare results to a model. Finally, we demonstrate the tensegrity spine system as a continuous variable-stiffness manipulator and highlight its advantages over current systems.
This work was supported by the European Union and the Swiss National Science Foundation through the FLAG ERA RoboCom++ project, and by the SNSF Bridge project 20B2-1_180861.
Zappetti Davide, Roc Arandes, Enrico Ajanic, Dario Floreano (2020) Variable-Stiffness Tensegrity Spine. Smart Materials and Structures, https://doi.org/10.1088/1361-665X/ab87e0