New Algorithm Allows a Swarm of Mini Drones to Fly Together

Named the Crazyflies, these miniature drones may be able to assist in real-world environments.
Fabienne Lang
A swarm of Crazyflie miniature dronesMcGuire et al./Science Robotics 4, eaaw9710 (2019)

You've seen regular sized drones swooping over your head, probably on a mission to entertain their owners by capturing impressive images from above. But have you ever seen a swarm of them buzzing from high above? 

Probably not. Now imagine an entire grouping of miniature drones flying together on a mission to find someone lost in the brush.


A team of engineers from the Delft University of Technology in the Netherlands has just created a new algorithm that allows a swarm of miniature drones to operate and work together seamlessly. 

The study was published in Science Robotics.

A new algorithm to tackle complex tasks

A swarm of miniature flying robots just completed a task that required them to navigate a real-world environment in a search and rescue style mission. This type of task would usually only be possible for larger robots that are equipped with higher computer processing power and sensors. 

New Algorithm Allows a Swarm of Mini Drones to Fly Together
One of the Crazyflies in action. Source: McGuire et al./Science Robotics 4, eaaw9710

The reason the mini drones were able to complete their task was thanks to a new algorithm created by Delft University of Technology engineers led by Kimberley McGuire.

The algorithm allows the drones to have a basis for understanding navigation problems as a pack — for instance, team coordination and obstacle avoidance. 

Why is this algorithm so interesting? 

The reason this new algorithm is useful is because these small swarms of flying robots could prove helpful in surveillance matters, tracking stock in large warehouses, or keeping an eye on fields and industrial plants, for example. 

New Algorithm Allows a Swarm of Mini Drones to Fly Together
A swarm of four Crazyflies in action. Source: McGuire et al./Science Robotics 4, eaaw9710

You may be wondering what the difference is between a swarm of small robots and one large drone doing the job. 

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Larger drones that already operate in such a manner are typically quite big and require a number of security measures. The smaller the drone, the safer it is for humans when they are flying above them. 

Furthermore, like a swarm, these drones may be able to tackle more complicated issues — you could liken them to colonies of ants or swarms of bees working together. 

New Algorithm Allows a Swarm of Mini Drones to Fly Together
Swarm of Crazyflies going through a doorway. Source: McGuire et al./Science Robotics 4, eaaw9710

What are the challenges of creating such small bots? 

The team's big challenge was to create small flying robots that operate with much less speed and memory space, to navigate much like larger drones. 

McGuire and her team created the SGBA, or "bug algorithm." This algorithm enables the mini-drones to navigate without a mapping system by using continuous motion detection and "wall following" (when robots follow the contours of a wall until they find a free space).

New Algorithm Allows a Swarm of Mini Drones to Fly Together
One Crazyflie hovering. Source: McGuire et al./Science Robotics 4, eaaw9710

The team tried the SGBA on swarms of two, four, and six drones, known as Crazyflies. These Crazyflies only weigh around 30 grams and fit in the palm of your hand. 

Each of the drones is equipped with a microprocessor and small sensors. 

When put through 15 tests, the Crazyflies were able to navigate together through an office space, without colliding into each other or the walls (except for one instance), and returning to their base when the battery power was running low.