For the last few years, Italian engineers have been working on a humanoid robot for emergency response applications. The iRonCub3 has jets on its back and fire-breathers on its arms, and has now achieved stable take-off and hover for the first time.
Editor's note: Readers often ask us for follow-ups on memorable stories. What has happened to this story since publication? This article was originally published last year but has been re-edited and updated with new information current as of June, 2025. Enjoy!
The project from the Artificial and Mechanical Intelligence group at the Italian Institute of Technology (Istituto Italiano di Tecnologia) has taken a child-like biped designed for AI research – the iCub – and aims to get it off the ground using jet power.
As well as strapping a twin-jet pack to its back, the team also sacrificed the original robot's flexible human-like hands in favor of more fire-breathing JetCats. Thrust is said to max out at 1,000 N (around 225 lbf) and exhaust temperatures can get as high as 800 °C (1,472 °F).
"iRonCub3 represents a major leap forward from earlier versions of the iRonCub project," the engineers told us. "While the original versions were used to develop and test components in isolation – such as jetpack design, estimation algorithms, or aerodynamic learning – iRonCub3 is the first complete system to integrate all those elements into a fully functional flight-capable humanoid robot."
The Tony Stark-inspired iRonCub3 has been treated to a newly developed titanium spine to help it cope with the forces at play, and has had heat-resistant covers applied instead of the funky outer suit on earlier prototypes. New electronics were designed, force-torque sensors installed in the jetpack and components removed to make way for the updated system. The team told us that its forearms have been "carefully engineered using FEM analysis to support realistic flight dynamics" and that the humanoid also features "an advanced multi-rate control architecture, including a Model Predictive Controller tailored to the nonlinear and multi-frequency actuation of jets and joints."
As of August last year, the jet-powered humanoid had been tested in a wind tunnel to validate aero simulations, and the jets had all been successfully powered up a number of times. The team has since developed "an advanced control model for systems composed of several interconnected parts" as well as AI-based models for real-time estimation of aerodynamic forces.
As you can see in the video above, the iRonCub3 prototype – which weighs in at 70 kg (154 lb), including the jets – managed to achieve stable lift-off and relatively stable hover, though its time aloft during each test was quite short.
The researchers certainly haven't made it easy for themselves, with the multiple shapes of the robot's body and its moveable arms adding complexity to the AI-based flight control systems. "Our models include neural networks trained on simulated and experimental data and are integrated into the robot’s control architecture to guarantee stable flight," revealed the team's Antonello Paolino, first author of a paper on the recent developments.
The humanoid, its onboard sensor suite (an inertial measurement unit, force-torque sensors and a RealSense depth camera) and its control systems are reported robust enough to handle extreme operating environments. The team says that this combination should also allow the robot to "maintain posture and stability even during non-stationary maneuvers, such as sequential engine ignition or changes in body geometry."
But that's something for the future. Up until now, the project has undertaken development and flight testing at a small area within the Italian Institute of Technology campus. But as work progresses, the project will need a larger space for experimentation – and that's been made possible thanks to a collaboration with Genoa Airport.
"This research is radically different from traditional humanoid robotics and forced us to make a substantial leap forward with respect to the state of the art," explained team lead, Daniele Pucci. "Here, thermodynamics plays a pivotal role – the emission gases from the turbines reach 700 °C temperature and flow at nearly the speed of sound. Aerodynamics must be evaluated in real-time, while control systems must handle both slow joint actuators and fast jet turbines. Testing these robots is as fascinating as it is dangerous and there is no room for improvisation."
The eventual aim is to have humanoids that can fly to a disaster/emergency site to perform aerial inspections or provide remote personnel with key data. But it will also be able to land and walk around, move over obstacles, climb stairs, open doors and so on. This adaptability could be useful for inspecting dangerous buildings or infrastructure.
Source: Italian Institute of Technology
A version of this article was originally published in 2024.
