Modeling, Fabricating, and Evaluating Synergistic Soft‑Rigid Actuators

Soft actuators offer lightweight, compliant, and safe alternatives to traditional mechanisms, but they often incur complicated actuation schemes, bulky support systems, and limited functionality when made solely from soft materials. Soft‑rigid designs that integrate rigid elements into primarily soft bodies are common, yet the potential of those rigid parts to shape actuation behavior without compromising the overall softness remains underexplored, and fabrication practices often lack reproducibility. In this talk, I will present two case studies of synergistic hybrid actuation systems that utilize the complementary roles of soft and rigid components to dictate temporal and spectral behavior in response to simple input commands. The first case study implements a soft-active/rigid-passive approach for the medical robotics application of endoluminal locomotion. A thin hyperelastic balloon encased in an inextensible sleeve is coupled with a thicker, non-encased balloon on a single fluid supply to serve as front and rear anchors, respectively. The second case study applies a soft-passive/rigid-active strategy in the domain of fingertip haptic actuation. A silicone sheath with embedded miniature magnets, excited by a single air‑core coil, produces localized, rich vibrotactile feedback. Together, these studies provide design rules, a simulation-fabrication-validation workflow, and reproducible fabrication practices for soft-rigid hybrid actuators that realize desired mechanical outputs from minimal actuation commands.