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        Discussion AP UAV methodology.

#1 vintage1 Aug 25, 2008 08:14 AM

AP UAV methodology.
 
Someone asked somewhere else what would be neded to get a model to fly a preplanned course at a given altitude, stabilize and take an aerial survey set of pictures.

I decided that some sort of two axis gyro and a GPS system,plus some microcontroller smarts was what would be needed.

What is available to do the GPS? a module or chipset that you can read from a PIC or similar and determine position and altitude?

And how do you determine heading? Or is it a question of simply working it out from repeated position measurements..I know that standard GPS is only accurate to a few meters, but does it have enough resolution to detect a position CHANGE to less then that?

#2 nagyizee Aug 25, 2008 09:18 AM

NMEA messages from GPS module already contain the heading and speed. The GPS module calculates these parameters from successive position measurements. The positioning accuracy is a couple of meters but the difference between two position measurement has only a little error (couple of cm) so the speed and heading is decently accurate. Heading is more accurate with higher speed.
For an integrated GPS/3xGyro/Accelero module I would recommend to look at:
http://www.xsens.com/en/products/mac...otion/mtig.php

#3 aaronbeekay Aug 25, 2008 12:39 PM

Take a look at the fantastic work being done here:

http://diydrones.com/profiles/blog/s...ogPost%3A44814

That's the page for one of their products. I know they have several other versions, as well as a blimp, and the site is just chock-full of fascinating information and brilliant work.

#4 vintage1 Aug 25, 2008 02:24 PM

Now we are talking..I wasn't aware that work had progessed that far....

If that module can control a rudder, and throttle, then a gyro for the elevator and ailerons should keep all steady enough.

#5 aaronbeekay Aug 25, 2008 05:32 PM

The guy who runs that project is editor in chief of Wired Magazine, and they've done some pretty incredible things. Check out the BlimpDuino for an example-- a fully autonomous helium blimp, with thrust vectoring on two axes and the ability to follow waypoints and find IR beacons.

The ArduPilot Pro, on the same site, integrates full attitude control and stability (4 channels, I believe) with two CPUs, but it's not as far along as the ArduPilot, which is nearly in production.

They recommend the FMA Co-Pilot for stability control, but I'm not familiar with it. YMMV.

Quote:

Originally Posted by vintage1
Now we are talking..I wasn't aware that work had progessed that far....

If that module can control a rudder, and throttle, then a gyro for the elevator and ailerons should keep all steady enough.



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