In the future, will flying robots replace firefighters in the riskiest fire-fighting operations inside buildings? According to a Japanese study, research is heading in this direction, exploring techniques to enable robotic units aerial, equipped with onboard fire engines and nozzles

There are essentially two challenges that robotic approach to fire emergency management faces today. The first involves designing robots for firefighting in buildings capable of extinguishing flames in increasingly rapid and precise ways. The second challenge involves these robots replacing firefighters in the most dangerous operations, thereby keeping them away from hazards such as the risk of being trapped in a structural collapse or inhaling toxic gases.

Over the last two decades, various firefighting solutions have been developed by robotic engineering. To name just a few, there’s the prototype of the “snake-like  firefighter“, a cable-like robot that slithers, guided by water pressure. Created in 2008 by a Norwegian team, Anna Konda – its name – was designed to extinguishing fires in particularly tight spaces, including tunnels. And eleven years later, in 2019, came Colossus, a mobile, tracked robot equipped with a water jet and remotely controllable, capable of navigating uneven terrain. These are just two of the many examples.

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Takeaway

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Building Firefighting Robots: From Ground-Based to Aerial Interventions

In recent years, drones have been employed in firefighting roles, particularly in combating forest fires. Some companies have even developed drones for extinguishing flames in very tall buildings. However, especially in confined spaces, the water hose connected to the aircraft could interfere with objects inside, creating the dreaded “dragging effect,” as observed by the authors of the study presented in “Development of a remotely controllable 4 m long aerial-hose-type firefighting robot“, published on December 23, 2023, in Frontiers in Robotics and AI.

In particular, the article by the research group – from the Japanese Universities of Akita, Tohoku, and Osaka – describes how they combined the features of a building firefighting robot with those of a drone designed for fire extinguishment. They designed a machine capable of flying and smoothly introducing water hoses into structures of any type and size, to extinguish fires as quickly and safely as possible.  Let’s explore what this entails [for further details, we recommend reading our guide to robotics, which explains how it works and what the application examples are – ed].

How the Dragon-Shaped Flying Firefighter Works

In the field of building firefighting robots, the work of Japanese researchers has focused on creating a flying machine with an elongated, lightweight, and flexible body, allowing it to move easily in any physical space.

However, unlike past firefighting robots and drones, the water hose of this flying firefighter needed to have characteristics that allowed it to be manipulated using sets of nozzles distributed along its entire structure, to enable it to spray water through building windows. Furthermore, the robot needed to be capable of lifting off with enough thrust to support the entire load of a fire engine.

This led to the development of the aerial firefighting robot with a mobile base, known as Dragon FireFighter. This 3.6-meter-long “dragon firefighter” comprises a long water hose equipped with two sets of nozzles (one in the middle and one at the head), a wide-angle camera, and a thermal camera. These last two devices are crucial for pinpointing the exact location of the fire, to accurately direct water at its source.

The “flying dragon” was recently tested during a small-scale firefighting demonstration – with a burning area of about 3.27 square meters – at the ImPACT Tough Robotics Challenge, a Japanese project-event dedicated to robotic technologies applied to emergency and national disaster preparedness and response.

“The fire simulation required the flying dragon to pass through a 1.5-meter high gap, corresponding to a window frame, to extinguish the flames beyond it. Although the test showcased the potential of the developed robot, the system is not yet complete, as it lacks remote operation and control“, the research group notes.

Building Firefighting Robots: Working Towards Remote Operation

In the realm of building firefighting robots, the system devised by Japanese researchers is designed for remote initiation and management, allowing operators to tackle flames from any location by simply triggering a series of automated mechanisms. They particularly emphasize:

“By activating appropriate postures of the nozzle units, different and optimized performances of the Dragon FireFighter are achieved. For instance, during the demonstration, the robot-dragon performed better when the roll positions of the nozzles were set to zero during flight”.

However, in the future, the team plans to modify the shape of the dragon’s body to achieve optimal postures for the central nozzles, depending on the required positions of the robot’s head nozzles.

Another aspect concerns the adjustment of the flight mechanism, which will eventually need to utilize “more advanced controllers to dampen oscillations of the dragon’s body, replacing its passive mechanism.”

The authors explain that the “passive damping” mechanism effectively stabilizes flight, but its adjustment is time-consuming. To speed up the process, it has been determined that both flowing water and disturbance rejection controllers are capable of dampening higher modal oscillations.

Future Research

The Dragon FireFighter system is just an initial model of a flying robot – distinct from ground robots and drones – designed for firefighting operations in buildings. Therefore, it is subject to refinement and improvements in both its structure and functionalities.

For instance, it has been observed that the physical properties of the water hose body change according to thermal condition variations. During the fire demonstration at the ImPACT Tough Robotics Challenge, the dragon firefighter was unable to take off while maintaining the same shape it had during laboratory tests, despite the same commands being used.

This phenomenon – the research team comments – is linked to the overheating of the material used for the hose, due to direct sunlight during the long waiting period before the demonstration. The result was plastic deformation of the body, which in turn altered its physical properties. In the future, this issue will need to be addressed by selecting a less thermosensitive material, concludes the research group.

Building Firefighting Robots: Preview of Potential Scenarios

In the next twenty years, a flying robotic system like the one described, appearing near burning buildings to tackle fires, won’t replace professionals such as firefighters. Instead, it will protect them from dangers and streamline their workload. This is the goal.

The future scenarios we can envisage in 2024 lead us to imagine fleets of flying firefighter robots, engaged in extinguishing fires in a variety of indoor environments where drones cannot enter due to obvious structural limitations.

Moving beyond firefighting, we can think also about other types of emergencies and disasters, including earthquakes, and envision flying robots capable of intervening remotely to save human lives.