Twirlbot: Tumbleweed-inspired rolling robot.

Abstract

Omnidirectional locomotion offers superior adaptability and maneuverability over uni-/bidirectional movement, with spherical structures being ideal due to their zero turning radius and geometric stability on complex terrains. However, existing spherical robots rely on embedded control components and onboard power sources, inevitably increasing design complexity, weight, and cost. Herein, we developed a tumbleweed-inspired rolling robot (Twirlbot) to achieve the hollow spherical architecture by weaving photoactive/passive bilayer strips. The Twirlbot demonstrated autonomous rolling under constant light, enabling multiple functionalities, including omnidirectional locomotion, slope climbing, trampling resistance, cargo transport, self-correction, wind resistance, and adaptation to diverse terrains and environments. These features endowed the Twirlbot with great potential for real-world applications, such as self-sustained seed-sowing, daylight-driven commuting, and autonomous underwater wiring. Notably, the structural design was generalizable to other systems, including commercial materials, enabling substantial cost reduction (less than one-tenth that of existing autonomous untethered robots) and thereby presenting a promising route toward next-generation untethered, self-sustained robotic systems.