I graduated! After 3 years I am proud to say that I did my Bachelors of Honours at the Aerospace Engineering faculty of TU Delft.
Today my team and I have finished our final year project. After ten weeks of work we managed to present our design to a large crowd at the yearly DSE symposium. Our team was composed of 9 students and out of 26 teams we were ranked as having the 2nd best design by a jury of several European CEOs and professors form different universities. But what did we do?
Under the supervision of Christophe De Wagter we designed a pollinator drone. Why? Because of the need of artificial pollination. Bees are dying and a backup system needs to be set in place from an early stage. One third of your food relies on being pollinated by bees and if no solution mitigates the risk of hunger, people might die in less than 4 years.
We targeted the most profitable crop in the Netherlands, namely the tomato plant. This plant relies on self pollination, meaning that the pollen from the male part is in the same flower as the female part. This process makes the tomato flowers relatively easy to pollinate compared with the vanilla or the cucumber crop where cross pollination processes involve transporting the pollen from a male flower to a different female flower.
We started of with three concepts: a flapping wing, a small quad rotor and a big one. Trade-offs were evaluated in order to determine the best concept, and because of the high payload needed to be carried on board, the big quad rotor concept was chosen. Its name is APIS and it fits in a 30 by 30 cm box, with a weight lower than 250 g. It can fly autonomously for 10 to 12 minutes using the UWB (Ultra-Wide-Band) for indoor navigation, or the stereo vision for obstacle avoidance. The full system consists of 64 APIS and 8 ground stations and it is able to pollinate a 4 hectare tomato greenhouse every 3 days.
How can APIS pollinate like a bee? Well, it’s just inspired by bees. Studying them closely, we found out that the 100 Hz flapping frequency of a bee is enough to shake the flower and move the pollen to the right place. Therefore, we designed a blower that will target the flowers one by one with a 10 m/s air jet. This jet can induce vortex shedding to the stem of the flower and thus, vibrate it with the right frequency.
If you would like to dive more into the technical part of the detailed design and answer questions like how does the propeller wake interfere with the blower or what kind of electronics and algorithms can be used for the sensors and for navigating inside a crowded place like a greenhouse, then you can read the attached 150 page report made by our team: Greenhouse Pollinator Drone Final Report. Make sure you also check the design video below.
Vlad Petrescu 