As we learned earlier this year, researchers at ETH Zürich's institute for Dynamic Systems and Control are looking at ways in which flying construction robots can be programmed to autonomously build tensile structures. Now it appears they've taken a significant step forward. Literally. The team has demonstrated a rope bridge built by drones that can support the weight of an adult human as they walk across it.
The ETH Zürich team is focused on leveraging the unique capabilities of drones to give rise to a new breed of architectural design. The researchers started making waves in this area in 2011, when they had drones use mathematical algorithms to translate digital design data into flight paths, neatly arranging 1,500 polystyrene bricks into a 6-meter (20-ft) tall tower. The work lies at the intersection of robotics and construction, but not construction as we have known it.
While overcoming their limited payload capacity is one factor that needs to be addressed, equally important is harnessing their agility and ability to zip in and out of hard to reach places and collaborate with one another on structures that cannot be built by a lone machine.
In this instance, a fleet of quadcopters equipped with motorized spools move autonomously between two scaffolds, laying out stretches of a light-but-strong rope made of Dyneema as they go. Dyneema is made from ultra-high molecular weight polyethylene and we've seen it used in everything from bulletproof blankets and whiteboards. The materials weighs just 7 g per meter (0.25 oz per 3.3 ft) and a rope 4 mm (0.15 in) in diameter can support 1,300 kg (2,866 lb), making it the ideal material for aerial construction.
The locations of the scaffold at either end of the bridge are measured manually prior to construction, but beyond this the quadcopters were responsible for constructing the entire structure without human intervention. This involved weaving knots, links and braids with 120 m of rope (394 ft) across nine segments for a total bridge length of 7.4 m (23 ft).
While a series of simulations were carried out before construction, a motion capture system allowed flight paths to be adjusted on-the-fly. This monitored vehicle position and, taking into account force applied to the quadcopters as the rope is deployed, computer algorithms then spat out commands and sent them to the drones over a wireless network. The researchers say this is the first time quadcopters have proven themselves capable of autonomously building load-bearing structures that can support a person.
You can see the drones work together to build their bridge to the future in the video below.
Source: ETH Zürich