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Re: [Paparazzi-devel] Re: Strong Wind

From: Pascal Brisset
Subject: Re: [Paparazzi-devel] Re: Strong Wind
Date: Mon, 13 Apr 2009 18:35:23 +0200
User-agent: Thunderbird (X11/20090318)


thanks Christophe for your contribution. It should probably be included in the main code. I've just committed
related misc changes:
- -DWIND_INFO flag is now the default in SITL simulation (conf/autopilot/sitl.makefile) - I moved the heading estimation (estimator_psi) from fw_h_ctl.c to estimator.c (computed when a GPS message is received) - this heading is now correctly displayed by the GCS (new field in the FLIGHT_PARAM message) - the angles of the ATTITUDE message are now in radians (airborne and ground conversions removed). There are still displayed (in Messages and Plotter) in degrees thanks to the alt_unit_coef specification (messages.xml)


Christophe De Wagter wrote:
Hi Martin,

I added the STRONG_WIND-code to the SVN. The code is in fw_h_ctrl.c. Just call it with the extra -DWIND_INFO and -DSTRONG_WIND flags. If you don't thrust the automatic wind, use the wind.xml setting file (very useful for auto-takeoff) and remove the periodically send wind flag in the GCS.

In the sim, gradually increase the wind once the aircraft has a rough wind estimate and the aircraft will fly backward like in the included picture. By playing with the airspeed you can make the plane hover when the wind speed is within the flight envelope. Unfortunately the paparazzi GCS aircraft symbol does not show the heading of the aircraft but the direction of motion. (Should be easy to change but the GCS is still a big mystery to me as we use our own GCS.)

So I hope your aggressive climb can be as aggressive as the funjet can handle again and maybe even climb almost vertically on windy days. (make sure to program the DASH button in case the altitude wind is higher than cruise speed).


PS: The code helps for the landings as the ground speed is often (much) lower but for landings at EMAV08 we also used an airspeed sensor in the vertical control loop. I will see if I can add the airspeed stuff too if anyone is interested

On Thu, Apr 9, 2009 at 1:14 PM, <address@hidden <mailto:address@hidden>> wrote:

    Hi Christophe,

    thanks! It was a great time being there and flying in that
    Happy to see you in chat watching the flights.

    There are issues with slow flying in regard to the ground. You can see
    that in the youtube video when we go from the 150m circle to
    climb. The nav/roll loop starts oscillating. What we did was manually
    reducing the (aggressive climb) pitch angle. That of course
    limited the
    possible climb rate.

    We would like to test the code. Think you were talking about the code
    change at EMAV2008 - your landings were much better than from anyone
    else using Paparazzi. As we are flying circles in the meteo
    flights the
    wind is usually well predicted - we did some comparsions with tethered
    balloons flying right next to the aircraft.

    Looking forward to EMAV2009 in Delft.

    Best regards,



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