Title: Harnessing bistability for directional propulsion of untethered, soft robots,
Abstract: In most macro-scale robotics systems , propulsion and controls are enabled
through a physical tether or complex on-board electronics and batteries. A
tether simplifies the design process but limits the range of motion of the
robot, while on-board controls and power supplies are heavy and complicate the
design process. Here we present a simple design principle for an untethered,
entirely soft, swimming robot with the ability to achieve preprogrammed,
directional propulsion without a battery or on-board electronics. Locomotion is
achieved by employing actuators that harness the large displacements of
bistable elements, triggered by surrounding temperature changes. Powered by
shape memory polymer (SMP) muscles, the bistable elements in turn actuates the
robot's fins. Our robots are fabricated entirely using a commercially available
3D printer with no post-processing. As a proof-of-concept, we demonstrate the
ability to program a vessel, which can autonomously deliver a cargo and
navigate back to the deployment point.