Re: [Paparazzi-devel] Auto landing

[Pascal Brisset]

Hi,

Daniel Morgan wrote:
>    <block name="land">
>       <call fun="nav_compute_baseleg(WP_AF, WP_TD, WP_BASELEG, 
> nav_radius)"/>
Computes the location of the BASELEG waypoint in order to have a circle 
of radius nav_radius tangent to the segment AF-TD (Approach Fix, Touch 
Down) in AF. Computes also baseleg_out_qdr which is the angle of AF 
relative to BASELEG (http://en.wikipedia.org/wiki/Q_code)
>       <circle radius="nav_radius" until="NavCircleCount() > 0.5 " 
> wp="BASELEG"/>
Circle around BASELEG, at least half a turn
>       <circle radius="nav_radius" 
> until="NavQdrCloseTo(DegOfRad(baseleg_out_qdr)-10) && 10 > 
> fabs(estimator_z - WaypointAlt(WP_BASELEG))" wp="BASELEG"/>
Circle around BASELEG, until reaching AF _and_ 10m from the desired 
altitude.

To use this block:
 - set the TD waypoint where you want to touch, at the altitude of the 
ground
 - set the AF waypoint where (locate and altitude) you want to start 
your final descent, upwind of course (with a Funjet, about 200m from TD 
and 30m higher)
 - set the sign of nav_radius, positive to get a right-hand landing, 
negative to get a left-hand landing
 - switch to this block

"Land right" and "Land left" blocks are provided in the basic.xml flight 
plan. This block is followed by the actual final:

   <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>

This procedure do not take into accound the wind. The compute_TOD() 
function (from nav.c) can be called to compute a supplementary waypoint, 
TOD (Top Of Descent) which will be located between AF and TD, according 
to the wind speed (so you can set AF as far as you want). Example in 
mav07.xml

--Pascal

>     </block>
> Can someone explain this block. I noticed this in the mav07.xml flight 
> plan.
>
> On 1/15/08, * address@hidden 
> <mailto:address@hidden>* <address@hidden 
> <mailto:address@hidden>> wrote:
>
>     Code is in the CVS, its nothing special.  Look at the flight plans
>     in the folder in the CVS.  Possibly generic.xml
>
>         -------- Original Message --------
>         Subject: Re: [Paparazzi-devel] Auto landing
>         From: "Daniel Morgan" < address@hidden
>         <mailto:address@hidden>>
>         Date: Tue, January 15, 2008 12:11 pm
>         To: address@hidden <mailto:address@hidden>
>
>         Do you have the code you used for this faux auto landing. I
>         was speaking more in terms of the way marcus explained it.
>         More of using like a range finder and landing that way but i
>         would be very interesting to see how you did it
>
>         On 1/15/08, address@hidden
>         <mailto:address@hidden>* < address@hidden
>         <mailto:address@hidden> > wrote:
>
>             It depends on your definiton of auto landing.  Most of us
>             have done plenty of landings with our Airplanes that do
>             not have any landing gear.  I know Martin Mueller has done
>             a couple with his Twinstar 2 which has some wire gear on
>             them.  The way that we do landings is by shooting an
>             approach at an altitude, and then killing the engine while
>             adding some static elevator(the DragonSlayer doesnt
>             stall), which gives us a nice steep decent on target.  We
>             have messed with this a lot and using the Ublox I can say
>             you should get your airplane within 50 feet every time. 
>             But it does vary depending on the wind.  There is also a
>             function to fly a glide slope in paparazzi.  I could never
>             get the climb loop gains tuned well enough for this
>             function to work as designed.
>              
>             AJ
>
>                 -------- Original Message --------
>                 Subject: [Paparazzi-devel] Auto landing
>                 From: "Daniel Morgan" <
>                 address@hidden
>                 <mailto:address@hidden>>
>                 Date: Tue, January 15, 2008 9:38 am
>                 To: address@hidden
>                 <mailto:address@hidden>
>
>                 Has anyone been working on making the aircraft using
>                 paparazzi be able to auto land? Can you give me any
>                 info you have on this?
>                 
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