Re: [Paparazzi-devel] Reply to:"automated landing (address@hidden) (Marc)"

[Aka]

Ok,
you could try the descent control, but still 1m/s is quite a hard touchdown... 
And I´m not sure if the descent control by motor is fast enough. You should try 
at 50m altitude and see the log data :-) And please share!

Probably it would be a good idea to add a speed sensor and control altitude by 
elevator. This is much faster in response.

In the end without an additional sensor for altitude above ground it´s hard to 
get a good landing for higher wing loading planes (If you don´t have endless 
runway where you could program a descent at 10cm/s). It´s all about the timing 
of the flare out. Too early -> stall, too late -> hard landing... Been doing 
experiments on that with high precise systems (DGPS), and even then it is not 
easy.


If you look around at commercial UAS you can also see that landing is their 
biggest concern... All kind of complex solutions like parachutes, airbags, rope 
landing, deep stall.
And even big things like predator are often landed manually.


Marc



-------- Original-Nachricht --------
> Datum: Sun, 03 Jul 2011 23:12:57 +0300
> Von: Chris <address@hidden>
> An: address@hidden
> Betreff: [Paparazzi-devel] Reply to:"automated        landing 
> (address@hidden) (Marc)"

> I am flying a Thunder tiger Cessna 177 Cardinal.
> The normal way of landing has a problem when there is high wind.
> The plane just stalls before touch down because the motor is turned off 
> during the final phase
> (below 10m)
> <block name="final">
> <exception cond="ground_alt + 10 > estimator_z" deroute="flare"/>
> <go from="AF" hmode="route" vmode="glide" wp="TD"/>
> </block>
> <block name="flare">
> <go approaching_time="0" from="AF" hmode="route" throttle="0.0" 
> vmode="throttle" wp="TD"/>
> <attitude roll="0.0" throttle="0.0" until="FALSE" vmode="throttle"/>
> </block>
> 
> About the plane not shutting off it's motor if it touches down before 
> "TD" this cannot happen because
> when the plane touches down it still tries to maintain a -1 m/s climb 
> rate so when it sees that
> climb rate is 0m/s and not -1m/s it shuts down the motor in an effort to 
> increase the descent rate.
> Chris
> 
> 
> _______________________________________________
> Paparazzi-devel mailing list
> address@hidden
> https://lists.nongnu.org/mailman/listinfo/paparazzi-devel

-- 
NEU: FreePhone - kostenlos mobil telefonieren!                  
Jetzt informieren: http://www.gmx.net/de/go/freephone