A.T.V. Autonomous Thermalling Vehicle

"Cruise control" for an e-glider.

I am building an e-glider that is controlled normally until you release the sticks. Then the autopilot kicks in and keeps the model around and starts looking for thermals or starts the motor when the glider is too low. No waypoints, its all about finding thermals.

Here is a video of my first long autonomous flight.

Reichard Champion ATV 2011 from Glider UAV on Vimeo.

2013 Update

Finally, an update about my project:

I have converted the telemetry log into subtitles, so You can see what's going on. This video explains a "Thermalling method for Model Glider Autopilots" in more detail.

I am gradually replacing my autopilot code with MatrixPilot. Please have a look and feel free to comment.

2014 Update

Local Endurance Thermalling mission in MP

Currently I fly with a Topmodel CZ Linea with an Auav3 autopilot and a Topmodel CZ Fantasy with a UDB5 autopilot board.

Recently I removed my "ATV autopilot pic-chip", so that I now have a 'MatrixPilot only' solution.
I wrote a LOGO script and some extra commands.

!!!!! The code is public and free to use !!!!!

I posted al the needed code and mods here: (May 24 '14)

"Support for (E-)Glider local endurance thermalling mission in MP"
Post on MatrixPilot forum

Special thanks to the MatrixPilot development team.

GliderUav

2015 Update

MatrixPilot got upgraded with the helical turn method. I changed my code to follow this development.
To add the auto land function, i needed better brake control. After that i created the auto landing script.
The codebase has moved to Git. My code is here: https://github.com/KeesGuijt/MatrixPilot.

2016

2017

Hi,

I received a question about how I wrote my navigationcode.

1. I store the GPS position when I start the motor for the first time

2. A fixed value is coded to limit max distance to the centre

3. Every second, the distance North/South and East/West between the startuppoint and the current location is calculated.

4. the two distances are devided by the fixed factor (2) to form x and y coordinates for an array

5. a lookup is performed in this array:

-- aimed right of centre, for left turns
const byte NavMatrixSoft[]= --
{
30, 30, 22, 22, 22, 7, 7, 7,165,165,
30, 30, 22, 0, 0, 0, 0, 7,165,165,
68, 68, 0, 0, 0, 0, 0, 0,142,142,
68, 0, 0, 0, 0, 0, 0, 0, 0,142,
68, 0, 0, 0, 0, 0, 0, 0, 0,142,
52, 0, 0, 0, 0, 0, 0 ,0, 0,157,
52, 0, 0, 0, 0, 0, 0, 0, 0,157,
52, 52, 0, 0, 0, 0, 0, 0,157,157,
75, 75,105, 0, 0, 0, 0,112,120,120,
75, 75,105,105,105,112,112,112,120,120
} -- headings / 2

6. If the found value is 0 then no action is taken. If the value is not 0 then the value is multiplied by two, and the autopilot will turn to this new heading, bringing the aircraft back in the area.

This method is simple, has a small footprint and is low on CPU-load. I found the aircraft will fly a random pattern in the area, so few spots are missed in search for updrafts.

Replies

GliderUAV September 13, 2013 at 2:24pm

Hi,

Finally, an update about my project:

I have converted the telemetry log into subtitles, so you can see what's going on. This video explains a "Thermalling method for Model Glider Autopilots" in more detail.

<video>

I am gradually replacing my autopilot code with MatrixPilot. Please have a look and feel free to comment.

Cheers, GliderUav
danstrider February 13, 2012 at 5:40pm

Nice auto-soaring results. Great to see others your interest and very glad to see you're having success.

Dan
John Campen October 13, 2011 at 3:44pm

Something to keep an eye on is Sliver solar technology where the solar cell can be made into a very thin flexible film which would be ideal for aircraft wing skins. The cells also have nearly double the power capacity and can still generate power in much lower light conditions than conventional solar voltaic cells http://solar.calfinder.com/blog/news/boise-city-to-build-thinnest-s...
GliderUAV June 5, 2011 at 6:10am

Hi,

I received a question about how I wrote my navigationcode.

1. I store the GPS position when I start the motor for the first time

2. A fixed value is coded to limit max distance to the centre

3. Every second, the distance North/South and East/West between the startuppoint and the current location is calculated.

4. the two distances are devided by the fixed factor (2) to form x and y coordinates for an array

5. a lookup is performed in this array:

-- aimed right of centre, for left turns
const byte NavMatrixSoft[]= --
{
30, 30, 22, 22, 22, 7, 7, 7,165,165,
30, 30, 22, 0, 0, 0, 0, 7,165,165,
68, 68, 0, 0, 0, 0, 0, 0,142,142,
68, 0, 0, 0, 0, 0, 0, 0, 0,142,
68, 0, 0, 0, 0, 0, 0, 0, 0,142,
52, 0, 0, 0, 0, 0, 0 ,0, 0,157,
52, 0, 0, 0, 0, 0, 0, 0, 0,157,
52, 52, 0, 0, 0, 0, 0, 0,157,157,
75, 75,105, 0, 0, 0, 0,112,120,120,
75, 75,105,105,105,112,112,112,120,120
} -- headings / 2

6. If the found value is 0 then no action is taken. If the value is not 0 then the value is multiplied by two, and the autopilot will turn to this new heading, bringing the aircraft back in the area.

This method is simple, has a small footprint and is low on CPU-load. I found the aircraft will fly a random pattern in the area, so few spots are missed in search for updrafts.
Ryan Johnston May 22, 2011 at 4:20pm

Hi there! Im a mechanical engineering student, and im doing a project very similar to this. Neat to see that there other people who think this is worth perusing. I live in New Zealand.

Im in the very early stages of my project. Iv just received my APM unit so i can finally get started! Im using a radian for my airframe. I suspected that the wingspam (~2m) was too small, but it looks like you have achieved a working prototype with a similar size model.

Im happy to find that there are others apart from nasa developing these, it certainly makes it a little less intimidating! It looks like theres a small autonomous soaring community starting to develop.
Mark Sutton April 28, 2011 at 7:50pm

Thermal Soaring is very interesting and enjoyable. Living in north Texas we don't have much slope lift so Thermal Soaring is how we do it. Once you learn to Find lift then you learn to get in it and ride it. If the lift is good and you can stay Centered in the bubble which is drifting with the wind you can go way up even out of sight in very short time, minutes. The nest trick is learning to Bail Out. This is not as easy as you may think because thermals are like vacuums and will suck you into the cloud above them. This happened to me when I first started flying sailplanes and I never say that Gentle Lady again. Needless to say I was hooked on Thermal Soaring. It is very easy to get flight times of 45 minutes to over an hour when conditions are right. I even thermaled In the rain with a 200 ft. cloud ceiling once for about ten minutes and the hard part was staying below the clouds or fog. Thermals are bubbles of warm air that leave the ground about every 5 minutes and you can see them and feel them. As they leave they drift downwind as they rise upward. In a strong one you can stand a sailplane on one wing tip and almost spin your way right up. So when you get your thermal tracker working and start catching lift you then need to have a way to bail. This is a problem you want to have, right? One other thing, thermals are addictive. l started chasing free flight models when I was a child hundreds of years ago and still love it. You should always put your contact info on your model in case you loose it and someone finds it before you do. Gotta love it.
Bryan Cuervo April 23, 2011 at 4:51am

Here is a picture of the 270 deg. thermalling technique used by full scale pilots.....
Ritchie April 22, 2011 at 2:35pm

Very interesting. Nice little project and clear concise goals. Please bring your thought to light here as I'm sure many will want to help you in this endeavour. Also a pic of your airframe would inspire imaginations :)
by.charly April 22, 2011 at 12:09pm

Very interesting project!

Estaré pendiente de tus futuras publicaciones.
Developer

Doug Weibel April 22, 2011 at 9:02am

Nice project!

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A.T.V. Autonomous Thermalling Vehicle

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