I was going to call it 2.6.3, but so many changes have been made, updates added, I think it requires a full point. Also, the header file has been streamlined a bit and some defines have changed. The PID gains have not, so if your plane flew well with 2.6 it will fly well, or even better with 2.7. BTW, this is the first release that has only been tested via HIL. I've never flown it for real because of the strong winds in the bay area right now. We'll see, but I think this will be the most stable release yet.

What's changed:

I've included a folder for connecting your ardupilot hardware to X-Plane. There are PNG files showing the configurations to make in the menus.

X-Plane supplies IMU data and airspeed data to Ardupilot so you must select the GPS_IMU option to connect.

New altitude estimation - Thanks to Ryan Beall for this one. This smooths out noisy altitude readings from GPS.

Takeoff and landing are now full features. Their use has been simplified and are assigned full flight modes which can be seen with a ground station.

New Fly by wire throttle command by Christof Schimd.

Updates altitude hold for those with airspeed sensors. Airspeed is now recorded in m/s instead of air pressure value. Since calibration for your particular pitot tube setup could be needed there is now a calibration value in the header file.

Improved stick mixing response for all modes.

Waypoints will be skipped if you miss them after one loop around. The number of degrees can be changed in the code so let me know how many is good.

Loiter hold has been improved.

Cross track gain now on by default.

Numerous bugs are gone.
Old, unused code and vars have been removed. Code has been reformatted and commented.
If you have any issues, please comment here and I'll get them fixed in the final release.


Views: 1155

3D Robotics
Comment by Chris Anderson on July 23, 2010 at 11:41pm
Sweet! Will try to fly it this weekend.

I'll also try the HIL sim, and once I get it working, I'll add it to the manual.

Comment by Ryan Beall on July 24, 2010 at 12:15am
Your read airspeed subroutine could be written slightly different such that it ouputs negative airspeeds. That way you see which side of the offset you are on and offers more intel as to what the sensor is seeing. Could also include math for the "ratio" so user's can see what is going on. At least in the setup so you can change the density directly instead of having to run through all of the calcs. Less confusing and more tunable.

Just my 2cents - Great work. I'd also change up the alt_estimator a little. IE all of the constants should be in the config file because average aoa may vary significantly and for use in faster GPS's the algorithm gain time constant may also want to be fiddled with.

if (d_press < 0)
airspeed = -sqrt(-2*d_press*144/density); //airspeed in fps
airspeed = sqrt(2*d_press*144/density);

Comment by Nathaniel Caner on July 24, 2010 at 8:12am

What happened to the following:

#define THROTTLE_IN 1 // (boolean) Disables throttle input when set to 0
#define THROTTLE_OUT 1 // 1 = throttle, 0 = no throttle output at all! (good for saving fingers on the bench.)

Has it moved elsewhere ,names changed, been eliminated, or missed? It was quite useful for bench testing.


Comment by Jason Short on July 24, 2010 at 8:59am
Hi Nathaniel,

Now that the throttle pin issue is solved, I made throttle in permanently on. This was to simplify a lot of the code. 

I took throttle_out, out well but I cam add that one back in. I forgot that it was useful for testing.

Comment by Mark Colwell on July 24, 2010 at 9:29am
Very nice work! I really look forward to flying with m/s airspeed and smoothed altitude hold..
This version deserves a new 2.7 just for X_plane SIM, and the flight testing of FBW mode.

Comment by Nathaniel Caner on July 24, 2010 at 1:56pm

That makes perfect sense to remove the throttle_in, and having the throttle_out would be a good safety measure for bench testing (providing I can remember to set it!).

Thanks for all the great work you have done bringing this version to fruition, and thanks goes out to all the other contributors who help make Ardupilot the great open source platform it has become. A special thanks goes out also to Christof Schmid for his extensive testing on 2.6 with his informative and well presented testing reports.


Comment by Christof Schmid on July 24, 2010 at 3:16pm
Hi Jason

I am looking forward to fly the 2.7. after my vacation. Thanks for the great work.

Comment by Christof Schmid on July 24, 2010 at 3:24pm
Oh, it would be great if you could open the 2_7 SVN and maybe set the 2_6_2 to the latst release of 2_6_2

Comment by Christof Schmid on July 25, 2010 at 2:25am
Thanks for the SVN


3D Robotics
Comment by Chris Anderson on July 25, 2010 at 10:59am
With Airspeed Sensor = 1, I get a compile error:

'alt_energy_error' was not declared in this scope In function 'void read_control_switch()'


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