Bio-Inspired Tensegrity Building Block With Anisotropic Stiffness for Soft Robots

Rigidity and softness are contradictive but critical to empowering soft robots with the versatility needed to cope with diverse complex scenarios. However, current soft robots consistently encounter a limitation, being confined to either soft or rigid states, thereby lacking the capability to incorporate both properties within a unified paradigm. Herein, we developed a simple yet versatile building block constructed by tensegrity structures, showing anisotropic deformation characteristics analogous to seahorse tails. Due to the disparity in bending stiffness between the ventral and lateral directions, the tensegrity building block presents notable advantages in the creation of robotic paradigms with anisotropic behavior, which enables soft robots created by it to show customizable responses. Then, we implemented the construction of two distinct soft robots based on the building block, i.e., continuum robots and robotic grippers. These typical applications serve to exemplify how the anisotropic properties bestow upon soft robots the capability for programmable mechanical responses and versatile capabilities. This interdisciplinary investigation represents a noteworthy progression in the development of readily adjustable building blocks for soft robots.