A fire ripped through the architectural building at Delft University of Technology (TU Delft) in the Netherlands, in 2008. The school wanted to know if any furniture was salvageable, even though the firefighters got the blaze under control. An associate professor of aerospace engineering, flew a drone around the building to survey the damage. However, he didn’t get too close, de Croon worried that if the remote-controlled drone lost signal, it would drop, irretrievable, into the wreckage. The swarm robotics approach is different than the singular, camera-equipped drone that de Croon used in 2008. However, it ultimately proved effective in exploring places that might be difficult or dangerous for humans to traverse on foot. The team of engineers has created an algorithm that lets a swarm of small search and rescue drones explore new spaces without a human controller or even GPS technology.

swarm of drones
A swarm of Crazyflie 2.0 drones

Like Honeybees?

The team started with a palm-sized microdrone that weighs in at just over an ounce (28 grams). The drone called the Crazyflie 2.0 has now evolved into the second generation Crazyflie 2.1. What Croon said was something very different from usual answers. “If you look at insects, that’s not how they navigate,” he says. Thus, the Carzyflie drones are so small and lightweight that they almost have no memory. They are very similar to the way honeybees navigate. “It’s only very short-term,” he says. “They’re not looking at the environment. Although bees do note some of the landmarks around them when they fly, these bots are like an even simpler, more stripped-down version of the bugs.”

The bots don’t have a GPS but a small sensor to tell how far it is from the others. Exploring the boundaries of the room is thus easier when there is no GPS. Then, when their batteries drain to 60 percent, the drones fly back to the beacon, following the signal’s strength.

Furthermore, in case of disasters, Croon says that the bots don’t need to return for the search to be effective. “It’s a calculated risk, some of them just won’t come back,” he stated. “Much like honeybees, casualties will happen as members of the swarm go out to collect pollen. But even if a few disappear, the queen bee can still keep her hive alive and running.”

Not only can these drone swarms be used for search and rescue operations but also for monitoring greenhouses. “They’re so lightweight and safe that the people, don’t really have to adapt,” However, due to their light-weight, they cannot carry medicines or heavy things at all.