Re: [Paparazzi-devel] Re: Strong Wind

[Pascal Brisset]

Hi,

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)

--Pascal

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). 
>
> Regards,
>
> Christophe
>
> 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
>     environment.
>     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
>     aggressive
>     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,
>     Martin
>
>
>
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