Urban Search and Rescue operations after a structure (e.g., a house or apartment building) collapse face complex layouts with unknown hazards, from fires to energized electrical wiring to the possibility of additional cave-ins. These unknowns and safety concerns lead to a slow and considered search process, even though time is one of the greatest predictors of success in rescue operations. Identifying areas where furniture or debris create “void pockets” for survivors and checking the safety of the structure for rescuers are some of the most laborious and time consuming tasks. Groups of robots with different abilities could reduce the areas to search and improve safety for human operators, significantly helping search efforts in these environments. This award supports research into the development of heterogeneous robot teams to aid in these search and rescue operations. The researchers will create methods for robots of different sizes, shapes, and abilities to physically work together in symbiotic teams and help each other move around collapsed environments. Small tennis-ball-sized robots that can fit through gaps will be delivered to important search areas by plant-inspired growing robots, and the smaller robot will help the larger growing robot steer, sense, and communicate. The lessons learned from building and studying this symbiotic robot team will help future designs for physically symbiotic robots and will serve as a starting point for developing new search and rescue tools. <br/><br/>This research investigates the development of symbiotic heterogeneous robot teams which use mutually beneficial physical interactions between team members to share existing capabilities and build new ones. The researchers will leverage two existing robot architectures, soft growing robots and microrobots, with complementary capabilities in the area of navigation and exploration of unstructured environments, and will study how physical interactions between these robots may be designed to create new symbiotic capabilities. While prior work has focused on how robots of differing capabilities can improve team performance compared to homogeneous teams, little work has demonstrated how heterogeneous robots may augment each other's capabilities when they function together. This project directly investigates how these symbiotic behaviors may be designed so that heterogeneous robot teams can be greater than the sum of their parts, with a specific target of creating teams to search disaster environments. In particular, the work will highlight how i) soft growing robots can serve as tethers and structures to extend the reach of microrobots and ii) how microrobots with different payloads can act as changeable actuation, sensing, and communication modules for expanding a growing robot’s range of motion and capabilities. The researchers will prototype and study a diverse range of potential interaction styles while identifying and designing those interactions that will best improve the ability of the team to move in simulated unstructured areas. Overall, the research investigates interactions between highly diverse soft and rigid robots, bridging the gaps between these fields to explore how benefits from each can be leveraged to create more effective robotic teams that can better move around the unstructured world. These results will build towards robot teams which can improve safety and success of search and rescue teams in collapsed buildings.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.