The first team with a humanoid and a drone for rescue missions

The world of robotics is witnessing a historic milestone. Researchers from the California Institute of Technology (Caltech) and the Technology Innovation Institute (TII) in Abu Dhabi have unveiled X1, the world's first multi-robot system that combines a humanoid robot and a transformable drone. This "dream team" is designed to intervene in environments that are too dangerous or chaotic for human rescuers, leveraging the advantages of walking, flying, and driving in a single integrated package.

Photo: Caltech

The X1 system solves one of the biggest dilemmas in modern robotics: how to overcome the limitations of individual types of movement. Humanoid robots excel at walking up stairs and narrow corridors, drones quickly fly over obstacles, and wheeled robots are most effective on flat surfaces. The X1 robot combines these three modalities into a cooperative whole. The central part of the system is a customized humanoid robot, the Unitree G1, which serves as a mobile platform and carries another robot on its back like a backpack.

This “backpack” is no ordinary piece of equipment, but the M4 (Multi-Modal Mobility Morphobot), Caltech’s groundbreaking shape-shifting robot. The M4 can instantly transform from a quadcopter drone to a wheeled vehicle or even a robot that stands on two wheels for better visibility. During a demonstration on the Caltech campus, the X1 humanoid robot confidently walked its way through the library and laboratories until it reached an elevated point. There, it leaned forward, allowing the M4 robot to take off directly from its back.

The key to the X1 system’s success is not just in the hardware, but in its advanced artificial intelligence and physics models. Project leader Professor Aaron Ames explains that the robot does not rely solely on recorded human movements, but “learns to walk as physics dictates”. This allows it to walk stably on uneven terrain and stairs, even when carrying a heavy load. TII has contributed key components for safe autonomous navigation and real-time data processing, allowing the robot to make decisions without direct human guidance, even when communication networks are down.

The X1 system measures approximately 130 cm in length (humanoid height), while the M4 drone is compact enough not to interfere with walking stability. This tandem represents the future of rapid response to emergencies. The humanoid can carry the drone over long distances and obstacles where the drone would consume too much energy, while the M4 can then perform rapid aerial reconnaissance or deliver emergency medical assistance to otherwise inaccessible locations.