Re: [Paparazzi-devel] automated landing

[Aka]

Hi Chris,

in theory there is nothing wrong in controlling the descent rate like this. I 
just think that by the way the control is implemented in the normal way in 
Paparazzi descent rate will be controlled by throttle which will not work since 
you force throttle to 0 :-)

So you would have to switch altitude control to elevator which could be 
critical without an airspeed sensor...

Probably somebody could comment but I think the way it is in the examples was 
choosen to be able to land without airspeed sensor. But even with airspeed 
sensor you can´t control speed and descent rate without activating the motor 
since they are coupled by the total energy of the plane.

My experience is that as long as your plane is able to do a constant flare with 
motor off it works quite well. Thats true for planes with moderate wing 
loading. For me it worked with the "Multiplex fleet" (EG,ES, Funjet, Mentor).

Cheers

Marc


-------- Original-Nachricht --------
> Datum: Sat, 02 Jul 2011 14:33:51 +0300
> Von: Chris <address@hidden>
> An: address@hidden
> Betreff: [Paparazzi-devel] automated landing

> Hi.
> I have been thinking to ask this question for a long time but i was 
> always distracted by something else.
> What is wrong with controlling the final approach using the "climb" mode 
> like this:
> 
> <block name="land_north_wind" strip_button="Land (North wind) " 
> strip_icon="land-right.png">
> <exception cond="pprz_mode == PPRZ_MODE_MANUAL || pprz_mode == 
> PPRZ_MODE_AUTO1" deroute="standby"/>
> <call fun="Set_Min_Groundspeed(14.)"/>
> <set value="CAM_MODE_OFF" var="cam_mode"/>
> <call fun="nav_compute_baseleg(WP_AF_SOUTH, WP_RNW_END_SOUTH, 
> WP_BASELEG, nav_radius)"/>
> <circle radius="nav_radius" until="NavCircleCount() > 0.5" wp="BASELEG"/>
> <circle radius="nav_radius" 
> until="And(NavQdrCloseTo(DegOfRad(baseleg_out_qdr)-(nav_radius/fabs(nav_radius))*20),
>                        10 > fabs(estimator_z - 
> WaypointAlt(WP_BASELEG)))" wp="BASELEG"/>
> </block>
> <block name="final_north">
> <exception cond="pprz_mode == PPRZ_MODE_MANUAL || pprz_mode == 
> PPRZ_MODE_AUTO1" deroute="standby"/>
> <exception cond="(ground_alt + 5) > estimator_z" deroute="flare_north"/>
> <call fun="Set_Min_Groundspeed(0)"/>
> <go approaching_time="0" from="AF_SOUTH" hmode="route" vmode="glide" 
> wp="RNW_END_SOUTH"/>
> </block>
> <block name="flare_north">
> <exception cond="pprz_mode == PPRZ_MODE_MANUAL || pprz_mode == 
> PPRZ_MODE_AUTO1" deroute="standby"/>
> <go approaching_time="0" climb="-1.0" from="RNW_END_SOUTH" hmode="route" 
> vmode="climb" wp="TD"/>
> <attitude roll="0.0" throttle="0.0" until="FALSE" vmode="throttle"/>
> </block>
> 
> Thank you all for your time and help.
> Chris
> 
> 
> _______________________________________________
> Paparazzi-devel mailing list
> address@hidden
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