Chinese researchers have created a prototype drone powered by a laser beam; he would therefore never need to land… in theory.
In recent years, individuals have been able to afford increasingly sophisticated drones that were long reserved for wealthy professionals. But these machines still suffer from a universal limit: autonomy, which remains limited because of the weight of the batteries. A team of Chinese researchers wants to change that. In work spotted by the South China Morning Post, its members presented a concept that could allow a drone to fly ” indefinitely “.
To achieve this, Li Xuelong and his colleagues at Northwestern Polytechnical University (NPU) relied on laser-based technology. A bit surprising, knowing that these beams are rather used to destroy unwanted quadcopters. In this specific case, the researchers want to use it to directly power a drone in full flight.
For this, the machine was equipped with a photoelectric conversion module. It is a component that transforms the energy transported by an electromagnetic wave, such as laser light, into electricity that can be used directly by the device. In theory, the latter could therefore fly indefinitely, at least as long as the laser beam is maintained.
This is a concept that has already been explored in different contexts, particularly in the military sector. This Popular Mechanics article also describes a comparable system designed by the US Army. But for now, no one has yet managed to bring this technology to maturity.
A light-based umbilical cord
This is mostly because of two main limitations. The first is tracking capability. In fact, to power a drone, the laser must be aimed permanently at the conversion cell. And that’s easier said than done, because systems like this can easily go off the rails as soon as they encounter an unfamiliar situation.
To circumvent this obstacle, Chinese researchers have written a predictive algorithm that tries to guess the next movement of the drone constantly. Although not stated explicitly, the wording suggests that it could be an AI-based system.
Apparently it performs quite well, even in less than ideal conditions. The authors explain that it displays a ” good tolerance at different light levels in any environment.
From there, the researchers were able to tackle the second, even more difficult problem: the transmission of energy. Because even if a laser beam actually conveys a certain energy, the performance is not perfect. Not all of the energy supplied to the device ends up transmitted entirely to the beam. And when the latter crosses a medium, part of the energy of the laser will be lost because of the diffraction phenomenon. This is called a mitigationand this means that the energy will be less at the end of the beam than at the origin.
A working proof of concept
To provide a sufficient amount of energy to the drone, the researchers had to reduce this attenuation as much as possible. They have therefore developed a solution which makes it possible to adapt the shape and power of the beam in real time. This reduces the negative impact of atmospheric turbulence on the beam. And, by extension, to improve the transmission of energy.
They also added a security system. If another object such as a bird passes between the drone and the laser source, the intensity will be adjusted immediately to avoid damaging it.
According to the South China Morning Post, these two elements have been integrated into a prototype. The latter managed to stay in the air for an extended period of time. The authors consider that this proof of concept “ demonstrates potentially unlimited range for optically powered drones (or ODD, for optics-driven drones).
Unfortunately, there remains several size unknowns. For example, the authors did not indicate how long the machine had been able to stay in the air. And above all, they remained very discreet about the characteristics of the conversion cell. We don’t know how far it can work or what its performance is. Nothing surprising, knowing that these are technologies likely to be used in a military context.
A military, industrial and civilian interest
In this area in particular, the fact of being able to fly drones permanently would indeed be very interesting. This particularly concerns monitoring. The authors explain that this system could also work wonders during relief operations. ” In very long missions, such as searching for tourists trapped by floods, continuous flight will save valuable time “, explain the authors of the work.
They also suggest that these SDGs could play a determining role in the logistics of tomorrow. And this concerns both industry and communities. ” Optical drones could have a profound impact on traffic control, security patrols, contactless logistics… “, enumerate the researchers. We can also imagine drone relay which would allowthus conveying energy over long distances, and without cables.
They also discussed the future of this technology in the field of transport. ” Large drones could be transformed into real aerial buses to build a three-dimensional transport network “, they indicate. They go even further. According to them, this technology would even make it possible to create a “ low altitude satellite ” or a “ artificial moon “. But before we get there, we’ll probably have to make a lot of progress in terms of yield.
In the meantime, it will already be interesting to see in which contexts this technology can be useful as it is. Unfortunately, it is impossible to offer leads at this level without knowing the yield of the conversion. The weaker it is, the more the SDGs will be reserved for rich and powerful institutions, especially on the military side. Even if this technology eventually takes hold, it will probably take a few more years to see consumer applications appear.
