Robot Links: Towards Self-Assembling Truss Robots

Today's monolithic robots act as closed systems that cannot absorb more material to keep operating after or recover from significant structural damage during their lifetime. Modular, reconfigurable robots offer a potential solution by discretizing the robot into replaceable and often identical modules that can self-assemble and self-rearrange. We introduce the Robot Link, a novel truss-robot module with magnetic connectors capable of self-assembly and re-forming broken connections. Each Robot Link can connect up to nine other Robot Links on either side and can thus form polygons and triangular lattice structures when combined with other Robot Links. Robot Links can crawl forward and backward, which allows them to move towards and connect to other links. We demonstrate a self-assembly sequence that shows individual Robot Links combining and transforming to form a tetrahedron, thereby demonstrating the first transformation of independent truss-robot modules that are limited to one-dimensional locomotion into a fully actuated, three-dimensionally maneuverable robot. Experiments revealed that Robot Link structures can reform broken connections, mimicking cells with reformable bonds. We demonstrate that three different robot topologies recover from separation after impact. This work contributes to developmental robotics by introducing a robotic substrate that enables robots to “grow” by integrating more material, self-improvement, and self-repair within their lifetime.