Choosing the UAV model (characteristics)

Let's start working on the selection of the UAV model following this methodology:

Task 1.1 - Analysis of the main characteristics.

1. We are going from the work of André Noth in his Doctoral Thesis [3] that we have renamed as 3 -Conceptual_Design_of_Solar_Powered_Airplanes_for_continuous_flight.pdf"".
2. In chapter three of this Thesis, an analytical method is introduced to determine the viability of a solar UAV.
3. That method is implemented as a MATLAB program, which solves a third-degree polynomial equation to determine design feasibility. The code is comprised in the following files: Main.m, InitParameters.m, EvaluateSolution.m and MinimumPositive.m available in Deciding the model.
4. The first thing we will do is study both chapter three of the Thesis and the code (see the figure that describes the code below).   
5. In this course 2023 -2024, together with the third-year (junior) students, we decided to build a UAV with a wingspan of b=3m and an aspect ratio of AR = 10, for flying during July and August months.
6. We will do Task 1.1, which is stated in transparency 18 of the document  "UEMSolar - Work in progress V4.pptx". It is about studying the average solar energy available in July and August and determining the main design characteristics of the solar UAV.
7. To verify the solar energy available in Villa, we will use the Photovoltaic Geographical Information System tool (shown below). First, select the geographical location, then select the required month.                                                                                                                                     
8. Help for this tool is in the User's Manual.
9. The definitions of the different types of radiation can be found in the following documents:  FT Exploring: We Think. Therefore we Explore and Learn. and Solar radiation forecasting using ad-hoc time series preprocessing and neural networks.
10. For our work, we will take the global value (the maximum value of the global curve at 0º of inclination) and calculate day duration (hours) and then set these values in the variables I_max and T_day of the InitParameters.m file, 

Task 1.2.

The second part of this task is to use and modify the Noth's code for setting the parameters corresponding and components (batteries and cells) according to the figure shown below: 

 

You need to search and analyze the datasheets of these components and verify that the k_bat and k_sc data are correct as shown below. Some of the required data is available in  "UEMSolar - Work in progress V4.pptx".

We have noticed that Noth precisely uses P_elec_total, the electrical equivalent of P_lev (cruise power) for perpetual flight calculations. We are trying to over-dimension the power capacity using the "a" coefficient. When a=1 we are estimating that have that P_lev (cruise power) = Paverage (the average power used for calculating the possibility of the perpetual flight). When a=1.1, we over-dimension the UAV power capacity on a 7% approximately beyond P_cruise and therefore increase Paverage by 7%. This should give us a safety margin for perpetual flight, increasing the mass and the cruise velocity of the UAV.

To not disturb the operation of the algorithm too much, what we have done is to increase the aerodynamic coefficient a0 in the calculation of the P_lev and P_elec_total to oversize them and approximate them to the concept of average flight power Paverage. In the figure below, we can observe that a0 is multiplied by 1.10 (i.e.) in this calculation a=1.10

Results of the two tasks.

1. Report with the analysis of the design procedure and its relationship to MATLAB code.
2. Adjust all input parameters and execute the MATLAB code once for each "a" value.
3. Fill the table shown below (slide 30 of  UEMSolar - Work in progress V4.pptx") with the required results. 
4. Study how the meteorology and the selection of an average power affect the viability of possible UAV models.

All documents are stored in Deciding the Model.

Upcoming tasks:

• Design of the electrical system

References:

1. Oettershagen, P, Melzer, A, Mantel, T, et al. Design of small hand-launched solar-powered UAVs: From concept study to a multi-day world endurance record flight. J Field Robotics. 2017; 34: 1352– 1377. https://doi.org/10.1002/rob.21717
2. Zhao, X.; Zhou, Z.; Zhu, X.; Guo, A. Design of a Hand-Launched Solar-Powered Unmanned Aerial Vehicle (UAV) System for Plateau. Appl. Sci. 2020, 10, 1300. https://doi.org/10.3390/app10041300 
3. Noth, André, Design of Solar Powered Airplanes for Continuous Flight, PhD Thesis, Autonomous Systems Lab, ETH Zürich, Switzerland, December 2008.