## Wind drone simulator, EASY and open source

I finally found the time to upload my wind drone simulator. After a researcher from Politecnico di Milano asked it to me, I decided to make it available to anyone. I hope you like it and I wait for your feedback!

I finally found the time to upload my wind drone simulator. After a researcher from Politecnico di Milano asked it to me, I decided to make it available to anyone. I hope you like it and I wait for your feedback!

## Getting started

Extract file from the rar archive and run the file

**MAIN_wind_drone_RUN_THIS.m**in Matlab.## Wind-polar coordinate system

The wind drone position and attitude is fully defined by the length of the cables $L$, the orientation angle $\psi$ and the spherical

angles $\theta$ and $\varphi$. The wind-polar coordinate system [1] can be described with rotations as follows: starting with the cables along the $x$ axis and the wind drone pointing upwards, the first rotation has amplitude $-\psi$ around $x$, then $-\theta$ around $y$ and finally $+\varphi$ around $x$ again. Three examples of wind-polar coordinates are shown in the figure below.

A full description of the simulator can be found in [2].

angles $\theta$ and $\varphi$. The wind-polar coordinate system [1] can be described with rotations as follows: starting with the cables along the $x$ axis and the wind drone pointing upwards, the first rotation has amplitude $-\psi$ around $x$, then $-\theta$ around $y$ and finally $+\varphi$ around $x$ again. Three examples of wind-polar coordinates are shown in the figure below.

A full description of the simulator can be found in [2].

Examples of wind-polar coordinates. Positive wind-polar coordinates ($\psi$,$\theta$,$\varphi$) are indicated by the black arrows. Blue arrows show the kite cartesian reference frame. By definition, the wind window has the wind going towards the screen, in x direction.

The transformation from wind-polar to cartesian position is therefore:

**References**

[1] M. Erhard and H. Strauch, “Theory and experimental validation of a simple comprehensible model of tethered kite dynamics used for controller design,” in Airborne Wind Energy, U. Ahrens, M. Diehl, and R. Schmehl, eds., ch. 8, pp. 141–165, Springer, Berlin, 2013

[2] Antonello Cherubini, Giacomo Moretti, Marco Fontana, "Dynamic modeling of floating offshore airborne wind energy converters", Accepted for publication in the second edition of the Airborne Wind Energy Book, 2016