Jumping dynamics of spherical shells driven by snap-through buckling

Soft robots can achieve complex and geometrically nonlinear deformation from simple energy inputs. Examples of energy resources are, for instance, air and complex fluids. The mechanisms behind their flexible deformation are compliant structures, such as elastomer and slenderness of structures. In particular, snap-through instabilities of slender structures enable us to design instantaneous and predictive motions of soft robots. Despite various different types of soft robots, predicting or optimizing their dynamic functionality are still challenging to date.

Here, as a simple model system, we study the jumping dynamics of a hemispherical shell on a rigid substrate driven by pneumatically-controlled snap-through buckling. We measure the jumping height of the shell experimentally, aiming to predict the performance of soft robots. We find that the jumping height depends on shell geometry and contact conditions, through scaling argument. Although the hemispherical shell has a seemingly simple geometry, its dynamical performance primarily relies on a complex interplay between the elasticity and geometry. Our predictive framework would pave the way for optimizing the performance of soft robots utilizing geometric nonlinearity.