Researchers at the University of Michigan have demonstrated an octocopter attaching asphalt shingles to roofs with a nail gun.

The UAS is autonomous, which means that it can position the nail gun on a nailing point, place the nail and move to the next point all without any human intervention needed.

“For me, the biggest excitement of this work is in recognizing that autonomous, useful, physical interaction and construction tasks are possible with drones,” says Ella Atkins, a professor of aerospace engineering and robotics.

Atkins adds that tasks that are considered “dull, dirty and dangerous” are best suited to robotization, which could potentially move the human workforce on to cleaner, safer and more interesting jobs.

Nailing down a shingle presents a number of challenges, including telling the UAS where the nails should go and triggering the nail gun. To enable the UAS to precisely locate itself in space, Atkins’ team used a system of markers and stationary cameras. This system was also used to tell the UAS where the nails should go.

To fire the nail gun, the team started by measuring the force needed to compress the point of the nail gun, which has to be done before a nail will deploy. After this, the team wrote software that would enable the UAS to apply that force.

Researchers note that the off-the-shelf version of this electric nail gun requires a trigger to be compressed as well, but the team turned that into a virtual switch, which activated when the octocopter was in position to place a nail.

According to the researchers, right now, the UAS is slow compared to human roofers.

“Initially, we tried using faster approach speeds to minimize nailing time. However, for those attempts, the nail gun tip often bounced off the roof, which meant it either wouldn’t trigger or it would trigger in the wrong place,” explains Matthew Romano, a robotics Ph.D. student and first author on the paper submitted to the International Conference on Robotics and Automation.

Atkins argues, though, that the UAS is already as fast as she and her spouse were when they put the first nails into the house that they re-roofed when they were graduate students.

“A novice roofer—who’s never climbed on a roof, who’s never used a nail gun—they start out slow. That learning process, the evolution from them being a complete novice to being successful, is something that we’ll need to see in this system as well,” Atkins says.

Researchers identified a few other areas of improvement for the UAS. For one, the UAS should be powered by tether instead of battery. The system can only run for a little more than 10 minutes at a time since batteries and nail guns are both heavy. A tether would allow the UAS to run indefinitely, and with an air line running alongside the power cable, the nail gun could be a more effective pneumatic model.

Additionally, a system of cameras and markers is more complicated than a roofing UAS would actually need, the researchers note. Shingles are marked with a shiny adhesive strip, and there is also a color difference between the exposed surface and the portion that lies beneath the next layer of shingles.

“It would be pretty easy to have a camera system mounted on the octocopter that understands both the orientation of the shingle and its position,” Atkins says.

The National Science Foundation funded this study.