Drones are already being used for many purposes, such as aerial photography and land reconnaissance. A team of researchers is now presenting an invention that would make it possible to build entire houses in the future with the help of small aircraft. The method is based on wasps and swallows.
Drones can build large objects in layers in flight – like flying 3D printers. The method could be used in the future, for example, to create shelters in places that are difficult to access or after natural disasters, or to repair facades without scaffolding. A group led by Mirko Kovac from Imperial College London (Great Britain) presents their invention in the journal “Nature”.
3D printed houses already exist. Currently, ground-based robots and crane systems are mainly used for on-site construction, the researchers write. However, this construction technique is by no means suitable for all places and situations. When developing their method, Kovac’s team based it on wasps and swallows, which fetch their building material in flight.
When building with aircraft, two different types of drones are used: “BuilDrone” transports the building material and deposits it according to a construction plan. “ScanDrone” scans the building site after each applied layer; A 3D model is created with the data. If the construction deviates from the plan, feedback with BuilDrone ensures that the application of the material is readjusted. To increase accuracy, the scientists developed a system for fine adjustment of the nozzle head, which hangs below the drone. The system compensates for fluctuations in the drone’s trajectory and enables construction to be carried out with an accuracy of five millimeters.
To show how their technology works, the researchers had a construction drone and a scanning drone create a cylindrical object more than two meters high. To do this, they used a polyurethane-based construction foam that hardens very quickly. Because the building material must not be carried away by the wind caused by the propellers of the drones. A layer must also be stable quickly so that the next layer can be applied. The team of drones needed 29 minutes for the construction foam cylinder with a diameter of 30 centimeters.
Scientists also experimented with a more traditional, cementitious material. To make it lighter, they mixed it with xanthan gum, a polysaccharide, and hydroxyethyl methyl cellulose. The properties of these substances enabled the cementitious material to harden quickly. However, the drones needed more than two hours for an 18 centimeter high cylinder with an outer diameter of 33.5 centimeters.
Faster construction could be made possible by the coordinated use of multiple construction drones. The researchers showed that this works in principle with three drones, which they had built a dome-shaped object virtually (without building material). The trajectories could be tracked by light-emitting diodes. The highlight: The drones are programmed in such a way that they do not get in each other’s way. Ultimately, only one drone was used at the higher points with an ever-shrinking diameter of the object – without the scientists having expressly programmed this.
“We have proven that drones can build and repair buildings autonomously and in a network, at least in the laboratory,” Kovac is quoted as saying in a statement from Imperial College London. The researchers want to gradually improve their technology so that it can later be used in regular house construction. “We believe our fleet of drones could help reduce the cost and risk of building in the future compared to traditional manual methods,” says Kovacs.
