On-Demand Assembly and Disassembly of a 3D Swimming Magnetic Mini-Propeller With Two Modules

Abstract

Various morphologies and motions have been investigated extensively for robots on substrates or interfaces. However, the locomotion of modular robots in 3D free spaces remains challenging owing to zero dependence on boundaries, in particular at small scales. Here we propose simply modularized miniature propellers (mini-propellers) with vertical mobility. These mini-propellers perform directional self-assembly and on-demand disassembly for increasing adaptability in complex environments. They can travel through a 3D maze, and the 3D locomotion is realized by regulating programmable magnetic fields. Furthermore, the mechanism of vertical swimming and disassembly is theoretically analyzed and experimentally verified. We find that the mini-propeller in critical poses is capable of swimming upstream against flows. Optimal actuation conditions for conducting effective upstream motion are determined. Mini-propellers may help exploit more off-boundary swimming behaviors, and the simple assembly and disassembly strategy is anticipated to be a useful and scalable method to develop small-scale modularized robots for versatile functionalities.