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.
Untitled from Glider UAV on Vimeo.
Why an ATV?
- Wider search area
- More control (confidence) when further out
- Longer flight times, more searching
- Less effort / concentration
- More time to look around to find thermals (e.g. birds)
- Safety (failure transmitter / receiver)
- More efficient turning
- More efficient use of motor
- More options for trimming, mixing, speed, engine power
- Documenting flights, instructive
The unit can navigate in an circular area of 400 m in diameter. The model remains between 100 and 300 m altitude, using the engine if needed. The pilot can fly model until one releases the controls. In case of problems, including failure of the transmitter, the unit automatically land in the middle of the area.
An on-board camera allows video from the cockpit to be viewed after the flight. On the ground, I have a receiver that displays information about altitude, climb rate, airspeed etc. The data is also stored for later processing.
My goal is to develop techniques to have an e-glider autonomous fly as long and efficiently as possible. It is a challenge to make the electronics as small and simple as possible. My first goal was to have 100 m gain in a single autonomous flight using thermals, and I did.
I named my project ATV, which stands for Autonomous Thermalling Vehicle (and because I think the ESA variant is a wonderful piece of technology).
Height
The unit starts with the electric motor. It then climbs to 200m, then the engine is switched off while full throttle is still given on the transmitter. When the unit has dropped to 100m, this suppression of the engine will be lifted, and the engine will start again.
Navigation
Through four parameters, a semi circular area is defined within which the unit should remain. Once the aircraft is outside this area turns will be used to automatically bring it back in the area. It will only be flown within visual range.
Thermals
When the unit reaches 200 m, the motor will turn off and it will search for thermals. Only if there is good reception of the RC controller and GPS receiver is good and the height is between 100 and 300, there a right turn will be started as soon as rising air is detected.
Currently I fly with a Reichard Champion and a Topmodel CZ Fantasy . These models are just big enough for all the electronics to fit, and have decent performance. The heart of the autopilot is a micro-controller of Microchip, the PIC18F2550.
For the GPS receiver I have a GPS SkyTraq with updates every 1 second.
To measure the altitude and airspeed I use the VAT / VAM 300 with VAT GS by ELV.
I use an FMA CoPilot for stabilization.
I have two XBEEPRO modules for telemetry, which also supports a beep vario on the ground.
GliderUAV
Tags: atv, glider, thermalling, uav
Replies to This Discussion
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Permalink Reply by Adam French on -
Hi GliderUAV,
Thanks for posting your project. This is a cool algorithm - was it your idea? I really appreciate how lean it is.
Best,
Adam
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Permalink Reply by GliderUAV on -
Hi Adam,
Yes I did. I wrote it when I was still using pic16f88 devices, so it had to be small and simple. Glad you like it.
Looks like something like a uc could be added to the osd and telemetry systems more and more modelpilots are starting to use.
GliderUAV.
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Permalink Reply by Adam French on
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GliderUAV,
I've put it on my list to consider and evolve in my next slope-soaring setup. You'll get a credit in the comments.
What are you programming on now? I used an Arduino for my last project - an autopilot for my sailboat. I'm looking at the UAV DevBoard for my next.
Don't know what you mean by "like a uc could be added to..." in your reply. Do you mean you could use a matrix representation of the 2d space on the osd? Absolutely. Could look like "radar" on early videogames. Great idea.- Adam
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Permalink Reply by GliderUAV on
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Adam,
I'm sorry I was a little vague there. I like how you interpreted that, good idea really!
I ment to say this: I use a MicroController (some say uC), a pic18F2550 and program it with JAL v2.4O. It would be fun to take one of those low cost telemetry/osd sets and by adding a $3 chip turn them into an working autopilot....
I think You saw the ThermoPilot project by Jean-Louis Naudin? Be shure to checkout his work because he is working on slopesoaring as well.
GliderUAV
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Permalink Reply by John Campen on -
Have you though about adding hot air sensors somehow like thermal cameras can pick up? I'm also building a UAV but not for thermaling. My other hobby is paragliding and Ive always wondered about experimenting with using thermal goggles to find differences in air temperatures to find the thermals. Your project could be ideal to try this out with. Certainly if you can identify thermals would save a lot of time and energy searching for them randomly.
Lastly why not use solar film to recharge the batteries as well?. the whole wing could be covered in solar panel.
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Permalink Reply by GliderUAV on
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John,
Detecting the temperature of thermals would be challenging as thermals are only tenths of a degrees warmer than the surrounding air. Also some sort of depth percepion would be required, to know how far away the updrafts are. Maybe advanced videoprocessing combined with Schlieren technique or whatever could do this, but thats too much for me. That would be cool though...
Solarpanels could help to make real long flights, but for now, adding a litte battery capacity would buy a lot of extra flighttime for motorless flying.
Happy flying,
Glideruav.
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Permalink Reply by John Campen on
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Yes its certainly a challenge and Ill do some more researcher on it. I'm also thinking about how we fly looking for thermals by identifying terrain type. For example open fields generate more heat than forests. So perhaps the thermal camera could be looking at those and then calculate wind direction and drift to narrow down more likely areas for thermals.
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Permalink Reply by John Campen on
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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...
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Permalink Reply by danstrider on -
Nice auto-soaring results. Great to see others your interest and very glad to see you're having success.
Dan
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Permalink Reply by GliderUAV on
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Hi Dan,
Love what jou did with Aloft, is your record still standing?
Seems like http://soaring.goosetechnologies.com is dead. What url should I use to reference to Aloft, maybe http://www.rcgroups.com/forums/showthread.php?t=502046 ?
Meanwhile I am improving my ATV with a better microcontroller, sensors and software, but my main focus remains thermalling (better centering) and longer autonomous flights.
Regards,
GliderUAV
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