An Unbreakable Drone ?
” Anyone who’s ever flown a drone of any sort will tell you that sooner or later, you’re going to crash it. The question is how exactly you will go about doing this, and how much of the drone will be functional after it’s happened. Most flying animals somewhat frustratingly don’t have this problem: Birds and insects run into things occasionally (or all the time, for small bugs), and just shrug it off and keep on going, thanks to their biological design, which includes both stiffness and flexibility. Now roboticists at the EPFL, in Lausanne, Switzerland, are relying on these same qualities to design a highly resilient quadrotor that’s impressively difficult to destroy.
There are three primary strategies for designing drones with impact resistance. The first is to just protect the propellers by surrounding them with the frame of the drone or with individual propeller guards. Most commercial drones have something like this. With this level of protection, you’re less likely to injure people, but since the prop protection is rigid, you’re more likely to injure the drone itself if (I mean, when) you crash it.”
” The second level of impact protection is to design your drone in a way that it can absorb energy from the crash without breaking into pieces. One way of doing that is to decouple the frame of the drone by, say, using flexible, elastic couplers. This gives you a “squishy” drone, which is very effective at handling impacts, but it’s also squishy in-flight, which causes all kinds of structural and stability problems.
The most impressive level of impact protection that we’ve seen in drones is the brute force approach of just surrounding the entire thing with a flexible, rotating cage. Flyability has made a compelling business case for using drones with protective cages, and for some applications, it’s fantastic. You do, however, pay a penalty, since the cage can increase the overall size of the drone by upwards of 60 percent, meaning that it’s safer to run into things, but you’re also much more likely to run into things. The cage adds mass as well, leading to a drone that can’t lift as much or fly as far.”