Multimodal Magnetic Soft Robots Enabled by Bistable Kirigami Patterns

Abstract

Creatures in nature have evolved to possess various modes of locomotion as a survival strategy. Drawing inspiration from nature, researchers have developed soft robots capable of achieving multiple modes of motion through multiple actuation controlling and structural reconfiguration. However, the complex control sequences and slow and tethered actuation limit their development. In this study, we introduce untethered soft robots capable of programmable multimodal motion by integrating bistable kirigami structures and hard magnetic actuations. By manipulating the external magnetic field, the soft robots not only undergo rapid transitions between different stable states but also exhibit distinct motions at each state, owing to variations in their geometric configurations and magnetization orientations. To understand the bistable transition behaviors, we develop a theoretical model based on the energy method, which is subsequently validated through finite-element analysis and experiments. Experimental results demonstrate the versatility of the bistable soft robots, including following “L”-shaped trajectories, displaying amphibious behaviors, and serving as recycle stents. The proposed bistable kirigami design and hard-magnetic driven methods open up possibilities for developing next-generation autonomous soft robots.