Which is better: one large and durable robot, or many small disposable robots? Nature has proven how robust a swarm can be time and time again. A colony of ants might have less combined mass than a small mammal, but it would be virtually impossible for that mammal to eradicate the entire colony—some survivors will always remain to rebuild. The same idea was the basis for Michael Crichton’s novel Prey, in which swarms of nanorobots become almost unstoppable. Swarms can also be used for good, as proven by this fleet of tiny drones developed by researchers from the Delft University of Technology, University of Liverpool, and Radboud University of Nijmegen.
The benefit of a drone swarm over a single, more capable drone is in redundancy and work distribution. You could build one drone that is faster and more agile than any individual drone in a swarm. It could also have a higher payload and carry more sensors. But any fault with that drone brings your operation to a halt. A swarm of drones, on the other hand, could lose numerous individuals and still continue on with the job. The swarm is also able to explore more area in a given amount of time, making it ideal for situations where time is limited, such as during search and rescue operations.
The challenge with a swarm, however, comes from the fact that each individual drone is limited in its capability. To keep the drones small and inexpensive, they can only carry the bare minimum of sensors and navigation equipment. These researchers overcame that challenge with inspiration from nature. Each of the drones is equipped with a camera and a WiFi chip. The video feed from the camera is used to locate survivors in a search and rescue operation, while the WiFi chip is used for navigation.
An individual in the swarm can recognize the strength of its neighbors’ WiFi signals in order to avoid collisions. It can also use the WiFi signal from a base station to find its way “home.” Each drone only needs to be given a direction to move towards, and it can keep going until it runs into an obstacle, finds a survivor, or is given the command to come home—similar to how ants explore. Because they’re not building real maps of the environment, the drones don’t need to have much processing power or any expensive sensors. A swarm like this could explore an entire building far more quickly than any single drone, and wouldn’t necessarily cost more money.