Tumbleweed-inspired robots with hybrid mobility for terrestrial exploration.

We present a tumbleweed-inspired rover that integrates passive wind-driven mobility with selective active control, creating a hybrid system capable of carrying heavy payloads while consuming less energy. By analyzing airflow over natural tumbleweeds and solid spheres, we found that the porosity gradient and resulting wake dynamics in tumbleweeds substantially enhance aerodynamic drag and mobility relative to solid forms. Following these findings, we fabricated a bio-inspired spherical shell with a tumbleweed-mimicking porosity profile to enable passive, wind-driven locomotion. When passive motion stalls due to insufficient wind or obstacles, mobility was maintained through an embedded quadcopter, enabling active maneuvers like tumbling, spinning, gliding, and flying. This hybrid approach allows the system to remain primarily passive while activating propulsion only when necessary, reducing energy expenditure. Furthermore, we deployed a mesh network of multiple such rovers to generate spatially distributed environmental maps, with each unit functioning as both transmitter and receiver to ensure reliable data relay even as nodes drift apart. Extensive laboratory and field testing validated the applicability and effectiveness of this hybrid approach, establishing a foundation for unmanned, energy-efficient terrestrial exploration.