We have seen fixed-wing drones pull off some impressive maneuvers, with versions that dive like a seabird, land like a perching bird and even using shape-shifting wings to soar through the air like one. But landing on and taking off from vertical surfaces? A team from Sherbrooke University has crafted an autonomous aircraft that can do just that.
The drone is called S-MAD (Sherbrooke's Multimodal Autonomous Drone) and was presented by the researchers at the Living Machine 2017 conference last week, where it won the "Best Robotics Paper Award." The team was inspired by the ability of birds to adjust their flight path with a last-minute upward thrust as they close in on perching locations.
So it set about recreating this ability in an autonomous fixed-wing drone. This was far from straightforward, however, with the team first running thousands of aerodynamic modelling simulations before finally getting the thrust and pitch of the drone's approach just right.
Here's how it does it. The drone flies horizontally towards the oncoming wall at a speed of 7 to 9 meters per second. A laser sensor then detects the wall and feedback control slows the aircraft down to 1 to 3 meters per second, as it tilts the drone upwards. Thrust increases meanwhile to hold its vertical position as it closes in on the wall.
Microfiber feet then latch onto the wall and suspension absorbs the kinetic energy from the impact as the propellor is switched off. The team says these feet will engage any rough surfaces, including bricks, concrete and stucco. With the drone settled on the wall, it can apparently remain there until it is time to take off again, at which point it fires up the propellor and leaves its perch behind.
The team imagines that these types of drones could be used to carry out extended missions, stopping to take a break and saving energy in places regular drones could not. For this reason, they could find use in long-term surveillance operations, but with the ability to perch on vertical surfaces they could also conduct building inspections or be deployed in disaster zones, for example.
You can see the S-MAD drone do its thing in the video below, while the team has also written a conference paper describing its research.