High-speed drone lands on a moving car at 110 km/h

Scientists at the University of Sherbrooke in Canada have developed the experimental drone DART (Direct Approach Rapid Touchdown), which can land on vehicles traveling at high speed using a special landing gear. The drone system combines a special landing gear with sophisticated control of the landing process.

Landing on flat ground is not particularly challenging for drones. However, if the landing surface moves, landing is no longer so easy because the drone has to slow down sharply from a forward motion and absorb the remaining kinetic energy to make a soft landing on a moving object.

The researchers at the University of Sherbrooke have identified two problems in particular: firstly, the drone has to tilt forward considerably in fast flight due to the air resistance. There is a high risk of the rotor blades touching the land surface during a landing and the drone crashing. Secondly, the kinetic energy of the drone must be absorbed as quickly as possible so that the quadrocopter does not bounce off the landing surface when it lands.

The scientists are tackling these two issues with what appear to be relatively simple solutions: reverse thrust and a landing gear with friction shock absorbers. They have summarized their research results in the study “Friction Shock Absorbers and Reverse Thrust for Fast Multirotor Landing on High-Speed Vehicles,” which has been published in the Journal of Field Robotics.

Electromotive adjustable landing gear

The DART drone lands on moving objects by descending quickly and aggressively. This helps to minimize the need to fight gusts of wind. Shortly before landing, the drone automatically performs a quick leveling maneuver. During this maneuver, the drone straightens up from its inclined flying position. A landing gear equipped with friction shock absorbers absorbs the kinetic energy. This also prevents the drone from tipping over.

The landing gear is designed in such a way that the impact energy of a drone weighing around 2.4 kg can be absorbed at an impact speed of 4 meters per second. To achieve this, the researchers use several thin discs in the landing gear, which are moved together by an electric motor via a gearbox and generate different levels of damping due to the resulting friction. The damping can thus be adjusted to the respective impact speed. In addition, a reverse thrust is initiated to press the drone against the landing surface when it lands.

In their experiments, the scientists found that the combination of landing gear with friction shock absorbers and reverse thrust increases the flight range by a factor of 38 compared to a conventional landing gear without shock absorbers. The drone can therefore land safely from various different flight positions.

The researchers tested the landing capabilities of the DART drone using a moving pickup truck as a landing platform. During the tests, the truck traveled down a straight road at speeds of up to 68 mph (around 110 km/h). The drone managed to land safely on the roof of the truck 38 times, succeeding at different speeds.

The researchers also provide a suitable application for the technology: drones could be used to land on moving speedboats or moving emergency vehicles, for example. Overall, the combination of the electrically adjustable landing gear and the use of reverse thrust improves the landing behavior of the drone wherever landing conditions are difficult.

(olb)