New algorithm allows autonomous drones to work together to transport heavy and variable payloads

Scientists at Delft University of Technology in the Netherlands have developed a new algorithm that allows multiple autonomous drones to work together to control and transport heavy payloads, even in windy conditions. Drones are ideal for reaching and maintaining hard-to-access infrastructure such as offshore wind turbines. Often harsh weather, limited payload, and unpredictable contact with the environment make it difficult to operate current drones safely and effectively.

“The amount of cargo a single drone can carry is very limited,” explains Sihao Sun, a robotics researcher at Delft University of Technology. “This makes it difficult to use drones for tasks such as delivering heavy building materials to remote areas, transporting large amounts of agricultural produce in mountainous regions, or supporting rescue operations.”

To overcome these limitations, a team at Delft University of Technology designed a system in which multiple drones are connected to a payload via cables, thereby carrying much heavier loads. By adjusting their position in real-time, drones can not only lift and transport heavy objects, but also control their orientation, which is critical for precise placement in complex environments. The study was published in the journal Science Robotics.

quick adjustment

“The real challenge is coordination,” Sun says. “When drones are physically connected, they need to react to each other and to disturbances such as sudden movements of the payload. Traditional control algorithms are too slow and rigid for this.”

The new algorithm developed by the team is fast, flexible, and robust. It adapts to payload changes and compensates for external forces without requiring sensors on the payload itself. This is an important advantage in real-world scenarios.

Basketball obstacle course in the laboratory

“We built our own quadcopter and tested it in a controlled laboratory environment,” Sun says. “We tested dynamic responses using up to four drones at a time, adding obstacles, simulating wind with fans, and even using moving payloads like basketballs.”

The system passed all tests. Additionally, since drones are autonomous, you only need to specify a destination. They navigate independently and adapt to obstacles and disturbances along the way. “You just tell them where you’re going and they’ll take care of the rest,” Sun added.

Preparing for real-world applications

Currently, this system uses an external motion capture camera for indoor testing, so it is not yet useful in outdoor environments. The team hopes to prepare the technology for real-world deployment in the future, with potential applications in search and rescue, agriculture and remote construction.