Harnessing bistability for directional propulsion of soft, untethered robots

TLDR

Soft robotics faces a major challenge in integrating sensing, actuation, control, and propulsion. We propose a material‑based approach for designing soft robots. Propulsion is achieved by bistable shape‑memory polymer muscles linked to paddles that amplify actuation forces. The resulting untethered soft swimming robots complete preprogrammed tasks without onboard electronics, can be programmed to follow routes, deliver cargo, and return to their deployment point, demonstrating broad impact for soft robotics based on programmed materials.

Abstract

Significance A major challenge in soft robotics is the integration of sensing, actuation, control, and propulsion. Here, we propose a material-based approach for designing soft robots. We show an untethered, soft swimming robot, which can complete preprogrammed tasks without the need for electronics, controllers, or power sources on board. To achieve propulsion, we use bistable shape memory polymer muscles connected to paddles that amplify actuation forces. As a proof of principle, we show that these robots can be preprogrammed to follow specific routes or deliver a cargo and navigate back to their deployment point. The proposed design principle can have a broad impact in soft robotics based on programed materials.