Hello all.
I've been a long time lurker on this website, checking it almost daily. The last couple of months i was working on my bachelors project which consisted of designing from scratch an autopilot for a RC glider. During that time, this website proved to be invaluable and i would like to share my work hoping that, in return, it could help someone else.
The project was separated in two parts: a semester project which then continued as a bachelors project.
During the semester project, all the hardware was deigned, as well as the low level embedded programming.
During the bachelors project, an initial model of the aircraft was created in Simulink using XFLR5 and AVL.
Then using experimental data logs, I was able to determine simple transfer functions which were used to compute the different PID gains.
In parallel, I programmed a ground control station (Mission Control) which was greatly inspired from happykillmore's GSC (as you can probably notice).
The aircraft i used for the project was the AXN Floater from hobbyking. Here's a picture of the aircraft with the autopilot mounted:
For the final test flight, a small circuit was entered using the mission control application. The aircraft managed to complete two circuits before the battery ran out (it was the 8th test using the same battery). The two plots show the track the aircraft flew, and the pitch and roll closed loop angles:
For more details, you can download both reports here:
http://dl.dropbox.com/u/15692375/AXC-Glider%20Semester.pdf (Semester report)
http://dl.dropbox.com/u/15692375/AXCG%20Bachelor%20Report%20Public.pdf (Bachelor report)
If you guys have any questions / comments, or want more details feel free to ask :).
- Alex
Comments
First of all, nice work Alex.
I sum to Mark Colwell if we can check out your firmware code. I want to introduce the FreeRTOS to my ST32, at the moment my scheduler is static, and it would be nice if I can check it out.
Also I want to know if you have had large differents between your model from AVL and the real flights. I've read that the drag was not so much realistic.
In return I can help you to improve the next iteration of your HW, like improving the air-speed sensor (max 200km/h is useless xD), climb-rate sensor, or even AoA sensor, with not so much effort using the same sensors.
Thanks for sharing
thanks you all for the kind words.
Thanks again to Paul Mather for your gsc, as you can probably tell it helped speed things up quite a bit ;). As for selling the board, there are still small changes I'd like to make and features to add as well as trying to design a lower cost version, but if the interest is there i could always consider it a possibility.
As for the sys ident scripts, there aren't any really. you have to use the ident tool box and manually select the data you want to use etc. it's rather simple once you know how to use the tool box (and if you stick to simple linear SISO systems). if you need a more step by step guide of how to use it let me know.
great job
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