At the University of Leuven (KU Leuven) we are working hard on improving performance of multi-rotor UAVs in terms of flight speed, endurance and possible payload, with the application of automated aerial transportation in mind. Our approach is to add wings to a multi-rotor and make a transition between hover and cruise flight in order to decrease the required power for flying at high speeds. In order to reduce the number of moving parts, and therefore extra weight and points of failure, we only use differential thrust for controlling the UAV throughout all flight phases
In the summer of 2014, our first prototype was presented, the “ VertiKUL "
This UAV made a transition of 90°, producing 100% of its required lift from the wing in cruise flight. Also see this post. We noticed that flying in windy conditions, however, was challenging. Especially the automated landing was hard. Therefore we decided to improve the wind resistance of the UAV by reducing the wing size. Therefore, part of the required lift in cruise flight is still produced by the propellers that now operate at 45° with respect to the direction of flight. The result is a very wind tolerant, efficient and fast multi-rotor: VertiKUL2
- 5kg total mass
- 60 to 70km/h cruise flight
- + 25km of range (we still have to validate this)
- Pixhawk flight controller with adapted ArduCopter 3.2.1 firmware
- 1kg of payload possible (20x15x10cm)
Because of the transitioning, it was hard to include a landing gear to land on a flat surface. Therefore we decided to land on an inclined surface, or a box as in the video.
We developed a new approach for controlling these transitioning VTOL UAVs with promising results and applicable on a wide range of VTOL UAV designs that are controlled by differential thrust as multi-copters. More info will follow…