Heat-resistant drone locates fire survivors

Scientists at Imperial College London and Empa in Switzerland say they have developed a heat-resistant drone that could be used to scope out and map burning buildings and wildfires. It’s hoped that the FireDrone prototype will provide crucial first-hand data from danger zones. I’ve been speaking to Mirko Kovac from the Aerial Robotics Lab at Imperial College London and the Laboratory of Sustainability Robotics at Empa…

Mirko - In 2017, there was this terrible incident, the Grenfell Tower fire that killed at least 72 people. I used to live close to this tower and used to drive by in the morning, and I was really shocked by this. At the same time, people used to ask me whether I have a drone that can fly inside and kind of look for survivors and so on. And this came out of the Imperial College lab that I'm running on aero robotics. And at that time I didn't have that. And really the technology was not there to have something that can fly inside of hot environments and take relevant data.

Chris - At the moment, I suppose what we have to do is send in firemen.

Mirko -
Yes. The problem is really that the firemen are human beings and they really shouldn't go into areas that are very toxic, very hot, very dangerous. So the fire drone is a tool that can get the information more quickly to them. And like this helps in rescue efforts, the basic idea is to have a drone that can fly in hot environments and also in cold environments. So we call it a temperature agnostic drone that can survive for a longer time and collect data, pictures, thermal images of those environments to then inform the rescue efforts.

Chris - Presumably there are quite a few problems you have to solve in realising that goal because you've got a navigational problem, you've got a visual problem, seeing where you're going, a control problem, getting signals through, and then obviously getting the thing to resist a very harsh environment. So how have you solved all that?

Mirko - Yes, it's really a problem that is very multidisciplinary going from materials to control systems to system designs and operations autonomy. And in 2019, I set up a collaboration between Imperial College in London and the Empa Material Science Institute in Switzerland. Together we have developed this drone that uses a specially developed aerogel material that allows the drone to fly in very hot environments for prolonged periods of time.

Chris - How hot can it withstand?

Mirko - It is designed to operate at 200 degrees centigrade for 10 minutes. But this is really difficult to actually define as a number or duration because it's about flying close to fire in hot burning environments for several minutes to collect the data compared to current drones, which can really survive only a few seconds in those types of environments.

Chris - One of the big challenges in aviation is weight. So how do you get around the constraint that you're adding something to a craft where weight really matters?

Mirko - Yes, this was a major effort of this work and in fact, aerogel is a very good material for that. Aerogel, in case you're not familiar with this, is a material that consists up to 99.98% of air. So it's a material that has air bubbles or pores inside of it. And because this can be an extremely strong thermal insulator, it is used in space applications, in facade insulation and so on. And we are now here developed a particular aerogel that has glass fibers embedded in it, which allows it to be a structural material that can be used for the robot body while at the same time providing the insulation. We also have integrated other methods of heat, insulation and management, including a face transition mechanism with a compressed gas capsule and an arrangement of the motors that is accordingly to optimise the overall design.

Chris - What does the drone look like that you've built and how big is it?

Mirko - It's basically a flying sphere that has four arms with propellers at the end, the motors are inside of the sphere so that they're heat protected and the choice of going for a sphere shape is also inspired from animals that have this spherical arrangement to have a better heat protection. So like this, you can imagine it has several cameras and can fly safely inside of different environments and take pictures, map the environment and provide the data very quickly.

Chris - The idea being then that you would deploy this into a burning building and.. What? Would it be autonomous, can it get itself out of trouble or have you always got to have somebody on the end of a controller watching where it's going, guiding it, and then hopefully getting data back in real time?

Mirko - The concept is something we call shared autonomy, where the vehicle itself has some level of autonomy such as being able to stabilise even in gusty environments or fly a certain trajectory or fly close to walls while keeping a certain distance. While at the same time there is a mission level control and operation from a human operator who might have, let's say a headset, virtual reality interface to then be able to have these remote presence in those type of hazardous and hot environments. So it's really sharing the autonomy on the vehicle with the operational control and mission planning of the human.

Chris - So can you take us through a scenario as though this were being deployed into a situation? What would it do and how would it help?

Mirko - So imagine there's a fire in a building and the firefighters would want to see whether there's a survivor or somebody trapped inside of the building. So instead of trying to go inside physically by themself, which is very dangerous, and also not just because of the fire, but also because of the collapse of the structures. Instead of that, they could deploy a handheld sized flying robot into the building that would fly autonomously and map the internals, get temperature signatures of the environment to identify heat sources and also see whether there are any survivors or people inside of the building. Such an operation could take a couple of minutes compared to a longer duration of time, which would be needed for a human to go inside safely.