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Old Nov 23, 2009, 06:54 AM
Graham Dyer
pardus's Avatar
Johannesburg, South Africa
Joined Jul 2003
702 Posts
Question
Recommend Autopilot syetm

(sorry - "system")

I have an ArduPilot that I've been having fun with but am now looking for some more developed/mature/professional without breaking the bank?

I need an autopilot that can fly a model aircraft in a grid pattern and then return to launch. The grid has to be fairly precise as does the altitude hold as this is for photo and geo surveys. Telemetry is also required & "plug and play" would be nice.

Can someone with experience with what available advise as to what would work well? Others I've seen but don't know much about are Paparazzi and Attopilot. I don't want something that is still having major development on it, it must be proven with possibly only minor enhancements.

Thanks

Graham
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Old Nov 23, 2009, 08:30 AM
Registered User
brakar's Avatar
Asker, Oslo, Norway
Joined Feb 2009
425 Posts
Besides the systems allready mentioned, you could also have a look at the Picopilots and FlexiPilot/EasyUAV. (I have one EasyUAV and intend to use it for about the same reasons as you describe).

However, the only advice I want to give is to look closer to the various systems first - and then to ask more specific questions about each of them. There might also be some issues related to availability and export out of the US.

Good luck,

brakar
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Old Nov 24, 2009, 01:02 AM
Graham Dyer
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Johannesburg, South Africa
Joined Jul 2003
702 Posts
Thanks brakar, the systems you mentioned are pretty pricey though and I need to find a balance, 1000 Euro seems a bit much, anyone know of other comparable systems around?
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Old Nov 24, 2009, 03:53 AM
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kbosak's Avatar
Wrocław, Poland
Joined Jun 2007
696 Posts
Quote:
Originally Posted by pardus View Post
Thanks brakar, the systems you mentioned are pretty pricey though and I need to find a balance, 1000 Euro seems a bit much, anyone know of other comparable systems around?
pardus, it depends on what do you really want to achieve.
EasyUAV is 1200EUR, but this is ready to fly system.
Even when counting your time as 0USD/hr,
you realistically cannot have popular or even open-sourced thermopile UAV system installed and tested within that budget, mainly because you would need a lot of electronics infrastructure, or a commercial autopilot plus the platform integration time with all additional expenses included.
FLEXIPILOT is 6DOF IMU (inertial-guided), this means all weather (main limitation that remains is winds speed what is platform specific and is a limitation indeed, up to some 20km/h, but IMU systems are independent on rain/fog/clouds).
The IMU autopilots are inherently much more complex as they present development pitfalls that only manifests inflight, therefore the development is very costly. This is contrasting thermopile autopilots, which in acceptable weather conditions, allow easy drive of unstable, vibrating airframes. The limitation of thermopiles is size (distributed elements), cables running around, sometimes the need for calibration pre-takeoff, and the fact that the single water droplet on 3x3 mm thermopile might be immediately fatal for that flight. It is not a problem that thermopiles need good weather, the problem is that the definition of good weather is uncomfortably blurred. Also maximum wind speed is a severe limitation for autopilot without gyro, therefore, you can afford relatively slower flight with IMU autopilot.
Regarding repeatability, I would like to point out that endurance testing I can do on the local field without even looking at the airframe, it did around 10 flights taking off in the night, automatic landing in the night, one of the flights ended in slight rain.
Take a look at T3-3 contest, where EasyUAV lands well after sunset.

The main system limitation is that all spare channels have been dedicated to photo triggers - as a result only rudder+elevator platforms are supported.
What really matters is if you are ready for the next step, or if you want to invest months in debugging 'gaining personal achievement points'.
EasyUAV I am using for endurance testing are achieving 1:1 maintenance time to flight time ratio (basically charging the battery and replugging payload) - I believe the users can get there after a few months of experience using it. This opens the chance for doing a little more with your UAV than 'just flying'. There is no fun in UAV if you cannot share the results.
I have started main thread here:
http://www.rcgroups.com/forums/showt...hlight=easyuav

Concering the price, next possible competitor for EasyUAV is Cropcam (with better endurance, groundstation, but similar payload and significantly higher maintenance time).
For Flexipilot, it would be any of the 6DOF IMU autopilots.
Note there are plans for IMU autopilot for every hand-made or open-source autopilot I have seen, since many years. However such autopilots are most often beyond skills of a single person (what stops most amateurs) and are beyond determination for most open communities (which notoriously stumble into thermopiles for good, 'because it works' - when it works, then the inertia comes into play). IMU autopilot is also usually more difficult to tune for a platform (when you need it) therefore it is normal for amateurs to stay around thermopiles. The reason for IMU tuning difficulties are mainly its sensitivity to several modes of aerodynamic oscillations and chances for buildup of estimations errors (besides feedback overshots) if somebody uses overly aggressive settings - on the other hand you can shift original feedback settings from EasyUAV +/-50% and it will fly in predictable way.
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Old Nov 24, 2009, 05:41 AM
Graham Dyer
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Johannesburg, South Africa
Joined Jul 2003
702 Posts
Thanks Krzys, appreciate all the info. I've seen the UAV DevBoard fly and was very impressed with it so may look into that first as my budget is fairly tight. I want to use my own design aircraft and power system, which has a fairly high payload capability, plus duration but size is not really a limiting factor so will develop that part myself. If i don't come right I may consider the EasyUAV.
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Old Nov 24, 2009, 08:31 AM
Lift is cheap - Drag sucks
Tom Harper's Avatar
Socorro, NM
Joined Jul 2004
3,664 Posts
Hi Graham!

There are two PicoPilots on eBay.

Tom
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Old Nov 24, 2009, 12:24 PM
Graham Dyer
pardus's Avatar
Johannesburg, South Africa
Joined Jul 2003
702 Posts
Hi again Tom, thanks I'm looking at them. Their website isn't very good, one of the things they say is "- 1 axes control: Aileron or Rudder", does that mean that there's no altitude hold or that there's no control over throttle or elevator?
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Old Nov 24, 2009, 03:15 PM
Lift is cheap - Drag sucks
Tom Harper's Avatar
Socorro, NM
Joined Jul 2004
3,664 Posts
Sorry, I don't know that much about PicoPilot and I'm not yet willing to part with $300 (or whatever it goes for) to find out.

Tom
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Old Nov 24, 2009, 06:21 PM
Chris Anderson
San Francisco/Bay Area
Joined Mar 2007
940 Posts
Pardus,

If you're comfortable using Linux, Paparazzi is the best choice. Normally I would recommend AttoPilot, but I don't think Dean is shipping internationally right now (if I'm wrong, you should definitely consider that). EasyUAV looks terrific and Kbosak has done a great job of community participation so I think you'd be in very good hands there, too, but I don't have any first-hand experience with it.

the UAVDevBoard works great, but it's similar to ArduPilot in the sense that you need to be comfortable with a programming-led environment.

Chris
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