Helical actuation on a soft inflated robot body

Continuum and soft robots can leverage routed actuation schemes to take on useful shapes with few actuated degrees of freedom. The addition of vine-like growth to soft continuum robots opens up possibilities for creating deployable structures from compact packages and allowing manipulation and grasping of objects in cluttered or difficult-to-navigate environments. Helical shapes, with constant curvature and torsion, provide a starting point for the shapes and actuation strategies required for such applications. Building on the geometric and static solutions for continuum robot kinematics given constant curvature assumptions, we develop a static model of helical actuation and present the implementation and validation of this model. We also discuss the forces applied by the soft robot when wrapped around an object that deforms the static shape, allowing a quantification of grasping capabilities.