PRE2018 4 Group3

Group Members

Name	Student Id
Han Wei Chia	1002684
Niek Brekelmans	1017203
Floris Verheijen	0948592
Esmee Esselaar	0987206
Minjin Song	1194206

Problem statement

In the past few years beekeepers around the world have seen sudden dissapearances of wild and domesticated bees and a steady decline in the amount of honey bee colonies. According to research, causes of the observed decline can be found in the increase in pesticide use around the world and steadily increasing urbanization. Even climate change may be a factor that influences bee population decline.

Since around a third of the global food consumption depends on pollination by insects, of which the bee is a significant contributor, the decline or even extinction of these pollinators would have a large impact on our lives.

Besides proposed solutions to stop further decline of the bee population, there is a need to compensate the already occurred loss of pollinators. In this project, the intent is to research and design a replacement for bee pollination, in the form of a robotic and drone-like bee.

Objective

Our goal is to create a proof on concept of a drone that can collect and spread pollens of apple trees. Furthermore, we will give an advice / recommendation on how our proof of concept can be improved by making it autonomous (with image recognition) and a good way to deploy the drone with charging stations.

User, society and enterprise

Users

Due to decreasing population of honey bees in recent years, there has been impacts in beekeeping industries as well as in the rate of pollination by bees. Because significant proportion of food consumption in the world depends on pollination by insects, those who provide materials for food processors definitely needs replacements for the future. Those who are involved in food affected by pollination, such as beekeepers and large scale plant owners whose plants depend on pollination by insects, will be primary users who will definitely consider this solution to be feasible.

At this time, some beekeepers make a living by renting their bees to farms and municipalities that require more pollination. The jobs of those people will be complemented with robotic bees, so their job is saved, even if bees become extinct. Beekeepers will have to focus on repairing the robotic bee, rather than care for actual animals. If beekeepers can hande this shift in their business, they will not be affected by the robotic bee in a negative way.

Society

There are more honey bees in this world than any other type of bee and pollinating insects. This means that honey bees are the most important pollinators of our food crops. Approximately one third of our food relies on the pollination by bees. Without honey bees, we would have a global food crisis that would kill a lot of people. This food shortage in case of an extinction will be prevented if an artificial pollinator replaces bees in time. The protection of our food chain is essential and vital to humanity's survival.

Enterprise

Plants will be in trouble if pollinators die out. A lot of them would go extinct. This would lead to mass disruption of insect and wildlife life cycles. It would be hard to predict exactly what would happen, but there would be many negative impacts on user and society alike. There will be huge demand for other (Artificial) Pollination solution. Robotic bees could be the solution and be very beneficial for enterprises to invest in

Requirements

The things users will require the drones to meet are;

• The reusability of the drones
• Environment friendly materials need to be used, preferably bio degradable
• The drones need to be energy efficient so they last long enough on one charge, even though there is not a lot of battery capacity
• The flowers should not be damaged by the artificial pollination
• The drones need to be replaceable by one another like real bees are in a swarm
• The drones must be fully charged in a small time
• The drones must be able to reach a charging station in time
• The drones must hover over flowers to transport pollen for multiple flowers
• The pollen must be efficiently collected from and spread on a flower
• The drones need to be charged efficiently
• Charging should be safe
• Charging should work no matter the weather conditions

Approach

The following appraoch will be used to meet the requirements:

First a literature study will be done on the techniques and requirements described earlier. Next will be a literature study on the current state of the art of artificial pollination. We will reach out to a stakeholder to discuss the requirements of an artificial pollinator, and in what way our product would be useful for the stakeholder. When the research is done, a model and/or proof of concept will be build.

Milestones

Week	Milestones
1	-
2	Choosing a subject, define who the stakeholders are and finish the planning
3	concretely define problem and starting in-depth research into required recourses
4	Main part of research is completed Design
5	-
6	-
7	Finalize reasearch and design Finish prototype Finish wiki/report
8	Present
9	-

Deliverables

• Proof of concept drone
• Advice about deployment
• This wiki

Planning

Our up-to-date planning can be found with the following link: [1].

Assumptions

For our project on robotic bees we decided to narrow down the research and design by focussing on the pollination of apple trees. This was decided since there exist around 300.000 species of flowering plant in the world, making the design a robotic bee suited for all species of flowers too complicated to achieve.

The apple tree was chosen since the apple is the most eaten fruit in the Netherlands, as well as an important export product. Furthermore, when it comes to pollination, the apple tree is self-incompatible, which means that it must be cross-pollinated to bloom. This would accomodate the testing of a prototype of robotic bee, since the self-incompatibility helps to ensure that the bee is the only pollinator.

Furthermore, since appleblossom grows all around the branches and thus also face towards the ground, the drone cannot land on all of the flowers in order to pollinate them. Therefore it was decided to focus on a drone that only hovers over the flowers while pollinating or collecting pollen.

State of the Art

PRE2018_4_Group3_Literature

Recommendations

Charging stations

The 10x10 drone uses approx. 25W as calculated in Wireless charging possiblities and can fly around 600 seconds with a maximum speed of 7.75 m/s. As it will not fly in a straight line, but must pollinate the tree flowers in the mean while, we assume that the average speed equals half the maximum speed, 3.88 m/s. This means it can fly around 2.3 kilometers.

A charging station needs to be able to power many drones simultaneously. If there is a charging station every kilometer in the area, drones will not have to fly more than 2 times that distance before reaching the next station, so 2 kilometers. This gives our drone some margin distance, so it can divert from its course a bit more for pollination and handle bad weather circumstances, like headwinds.

The 10x10 drone has a LiPo battery with a capacity of 1100 mAh.

Solar power

One of the possibilities to keep the charging stations energy efficient is to power them using solar panels. Solar panels cost quite some space. The standard solar panel has an input rate of around 1000 Watt per square meter, but you will only gain roughly 15-20% efficiency at best. A solar panel of one square meter with an efficiency of 20% will therefore be approximately 200 Watt. A day has approximately 5 sun hours, so the solar panel will produce around 1 kWh per day. This energy production depends on the weather of course. Because of this, solar power alone is not very reliable. The charging stations will still need power from other sources to ensure that the drones can always be charged. 1 kWh per day corresponds to 41.67 W, which is not enough to charge multiple drones at once.

As the charging stations are not that far apart, we will try to keep the solar panels small, which is why the solar panels will not be a lot larger than 1 square meter. The rest of the energy comes from the grid.

Pollen collection

Study shows that the density and length of the bees hairs is an important factor in the adhesion of pollen; the relation between the diameter of the pollen and the spacing of the bee's hairs defines the difficulty of removal. When the diameter of the pollen is significantly smaller than the spacing of the hairs, the pollen settles deeply into the hairs. However, as the diameter/hair-spacing ration increases, the pollen are suspended between the hairs, which better facilitates the removal of the pollen.

The ratio of hair-spacing to pollen diameter should be 1 for optimal pollen adhesion. However, apple pollen have an elliptic form, of on average 45 by 25 micrometer, and will therefore never exactly fit into an evenly spaced grid of hairs. Consequently, a hair spacing of 35 micrometer would be an acceptable average.

Replacing functionalities

Since our objective is to develop a proof of concept of a drone attachment that will collect and transport pollents, we need to discuss how the attachment affects the performance of the drone that will carry the attachment. Because the drone will hover over apple tree flowers to collect and deliver pollens, the drone will not be similar in terms of its size, carrying capacity, and travel distances. Rather, the drones will transport pollen within the range of the charging station acting as hives for the bees and cover multiple apple tree flowers. The drones will not be able to land on the flower due to the size that is needed to carry large amount of pollent for multiple flowers.

References