This is what happens:
This is the Flight Assembled Architecture, an installation that opened yesterday near Paris and is still going up as I write this. It's the result of a collaboration between ETH Zurich roboticist Raffaello D'Andrea and architects Fabio Gramazio and Matthias Kohler, also from ETH.
D'Andrea, an IEEE Fellow and IEEE Spectrum editorial board member, is known for his amazing robotic sculptures and flying robot stunts, and Gramazio and Kohler, who run their own design studio, are pioneers in bringing together robotics and architecture. But for an installation at the FRAC Centre, in Orléans, near Paris, they wanted to do something entirely new and bold.
How about using a fleet of quadcopters to build a 6 meter (20 feet) twisting tower out of 1500 foam bricks? Sure!
D'Andrea tells me they're using four flying robots at the same time. First, the robots grab foam bricks from a special brick dispenser on the ground. Next the quadcopters receive the exact coordinates of where the bricks should go based on a detailed digital blueprint of the tower. Then they fly off.
The robots fly autonomously, but they get help from the environment: The ceiling of the room where the assembly is taking place was equipped with a motion-capture system. A computer uses the vision data to keep track of the quadcopters and tell them where to go -- the same approach used at ETH's Flying Machine Arena. (More technical details here.)
When a robot's battery runs low, it automatically lands on a charger and a new quadrotor takes its place. The assembly is happening at a pace of one brick per minute on average, D'Andrea says. Glue on the bottom of the bricks keeps them in place (the installation will become part of FRAC's permanent collection).
The foam tower is actually a 1:100 model of a "vertical village" conceived by Gramazio and Kohler. It would have a height of 600 meters and living space for 30,000 people, with each "brick" housing multiple apartments.
This week, after some test runs in Zurich, D'Andrea, Gramazio, and Kohler gathered their teams, packed their robots and bricks, and started the setup at the FRAC space. Last night, the museum opened its doors, and a crowd filled the room, letting off "lots of oohs and ahhs," reports Markus Waibel, a member of the D'Andrea team.