A fabrication strategy for millimeter-scale, self-sensing soft-rigid hybrid robots
Hun Chan Lee, Nash Elder, Maisa F.M. Leal, Sarah Stantial, E. Martinez, Sneha Jos, Hyunje Cho, Sheila Russo
Abstract
Soft robots typically involve manual assembly of core hardware components like actuators, sensors, and controllers. This increases fabrication time and reduces consistency, especially in small-scale soft robots. We present a scalable monolithic fabrication method for millimeter-scale soft-rigid hybrid robots, simplifying the integration of core hardware components. Actuation is provided by soft-foldable polytetrafluoroethylene film-based actuators powered by ionic fluid injection. The desired motion is encoded by integrating a mechanical controller, comprised of rigid-flexible materials. The robot’s motion can be self-sensed using an ionic resistive sensor by detecting electrical resistance changes across its body. Our approach is demonstrated by fabricating three distinct soft-rigid hybrid robotic modules, each with unique degrees of freedom: translational, bending, and roto-translational motions. These modules connect to form a soft-rigid hybrid continuum robot with real-time shape-sensing capabilities. We showcase the robot’s capabilities by performing object pick-and-place, needle steering and tissue puncturing, and optical fiber steering tasks. This work introduces a fabrication method for mechanically controllable, self-sensing soft-rigid hybrid robots. Translational, bending, and roto-translational modules are designed and assembled as a continuum robot with real-time shape-sensing.