Drone aircraft are becoming less expensive and more capable with each passing year. And with laws for commercial usage being loosened, the sky could soon be teeming with semi-autonomous robots. What happens if something goes wrong, though? An Amazon delivery drone carrying a box of junk could do some damage when it spirals to the ground below. A team of researchers from the University of Zurich are working on a system that makes drones able to regain stable flight after losing control.
The system was designed and tested with small quadrocopter-type drones, each one equipped with a single downward-facing camera, an inertial measurement unit (IMU), a distance sensor, an accelerometer, and a gyroscope. It uses the camera to identify landmarks while in stable flight, with help from the distance sensor, which it then uses when tragedy strikes. All the coordination of these sensors is handled by an on-board smartphone processor.
This system should snap into action instantly when these sensors detect the drone is in freefall. If there’s a collision, a strong gust of wind, or a troublesome engineering student with a stick, the drone can use the camera to look for landmarks to figure out what’s up and down. It then stabilizes its flight at the same height it was previously at based on data from the distance sensor. Once it has righted itself, the drone can compensate for wind or other outside forces until it receives new instructions.
Recovering from unexpected failure isn’t the only use for the system developed at the University of Zurich. There’s also the possibility of easier drone launching and improved indoor reliability. The team has created an entertaining video detailing how a drone might recover from being tossed into the air as a means of takeoff. This isn’t just a gentle toss, either, as you’ll see — the researchers really hurl that thing. Once the drone realizes it’s in freefall, it only takes a second for it to right itself. This happens so fast it could make drones safer for indoor use where there are more obstacles and less vertical space.
What if the drone can’t continue flying? Maybe it’s running low on battery or there’s a mechanical failure. In that case, the system can find a safe landing zone free of obstructions and (hopefully) people. The landmark-tracking camera is continuously creating a 3D map of its surroundings. That’s perfect for finding a safe emergency landing zone, which the drone can do autonomously.