Re: [Paparazzi-devel] another fatal crash

[Reto Büttner]

Hi Eduardo

Sorry to hear about your next crash.

Why weren't you able to recover manually? How high did you fly? How
far did you fly? Is your flying wing not able to recover from a stall?

In your airframe parameters I still see a lot of igains. Did you try
to set them to zero and fly with pgains only?

What tuning method were you following?

Have you tuned an aircraft before or is this you first experience? For
beginners to learn paparazzi and control tuning I recommend to start
out with standard paparazzi configuration without airspeed control.
This simplifies the system, you have one element less to debug. I have
experienced some troubles with the ets airspeed sensor. Once you
master standard paparazzi control that you can add an airspeed
control.

Good luck and happy landings!
Reto

2012/6/1 Eduardo lavratti <address@hidden>:
> wow .. more friends with same problema.
> well, i simulated this problem and re-checked all my config.
>
> i changed some parameter in V_CTL and the simulation are working very well
> for now.
>
> try change your v_ctl with this parameters and publish the result here :
>
>
>    <section name="VERTICAL CONTROL" prefix="V_CTL_">
>     <define name="POWER_CTL_BAT_NOMINAL" value="16.0" unit="volt"/>
>     <!-- outer loop -->
>  <define name="ALTITUDE_PGAIN" value="0.05"/>
> <!--    <define name="ALTITUDE_PGAIN" value="0.0869999974966"
> unit="(m/s)/m"/>-->
>     <define name="ALTITUDE_MAX_CLIMB" value="4." unit="m/s"/>
>     <!-- auto throttle inner loop -->
>     <define name="AUTO_THROTTLE_NOMINAL_CRUISE_THROTTLE" value="0.5"/>
>     <define name="AUTO_THROTTLE_MIN_CRUISE_THROTTLE" value="0.4"/>
>     <define name="AUTO_THROTTLE_MAX_CRUISE_THROTTLE" value="0.9"/>
>     <define name="AUTO_THROTTLE_LOITER_TRIM" value="2000" unit="pprz_t"/>
> <!-- elevador trim para voo loiter (lento) -->
>     <define name="AUTO_THROTTLE_DASH_TRIM" value="-1500" unit="pprz_t"/>
> <!-- elevador trim para voo dash (rapido) -->
>     <define name="AUTO_THROTTLE_CLIMB_THROTTLE_INCREMENT" value="0.15"
> unit="%/(m/s)"/> <!-- 0.1 -->
>     <define name="AUTO_THROTTLE_PGAIN" value="0.008" unit="%/(m/s)"/>
> <!--0.02-->
>     <define name="AUTO_THROTTLE_IGAIN" value="0.25"/>
>     <define name="AUTO_THROTTLE_PITCH_OF_VZ_PGAIN" value="0.14"/>  <!-- 0.05
> pitch devido a erro altitude -->
>     <!-- auto airspeed and altitude inner loop -->
>     <define name="AUTO_GROUNDSPEED_SETPOINT" value="15.0" unit="m/s"/>
>     <define name="AUTO_GROUNDSPEED_PGAIN" value="0.75"/>
>     <define name="AUTO_GROUNDSPEED_IGAIN" value="0.25"/>
>     <define name="AUTO_PITCH_PGAIN" value="0.145"/>
>     <define name="AUTO_PITCH_IGAIN" value="0.025"/>
>     <define name="AUTO_PITCH_MAX_PITCH" value="RadOfDeg(25)"/>
>     <define name="AUTO_PITCH_MIN_PITCH" value="RadOfDeg(-25)"/>
>  <define name="THROTTLE_SLEW_LIMITER" value="2" unit="s"/>
>   </section>
>
> ________________________________
> Date: Fri, 1 Jun 2012 09:22:40 +0530
> From: address@hidden
> To: address@hidden
> Subject: Re: [Paparazzi-devel] another fatal crash
>
>
> Hi all,
>    I am also using the latest repository, yesterday I found when i engage
> AUTO2 throttle stops completely. In Manual I could fly well but moment I
> engage AUTO2 throttle gets cut and aircraft starts falling down. Anybody
> please suggest how to rectify this problem? I am also trying to find the
> reason for the throttle cut, but nothing clicked yet.
>
> Another problem I faced was during flight In Auto2 Iam unable to change the
> gains from the Ground control station? When on Ground I tried this exercise
> of changing gains in AUTO2 it works well. Are there any  altitude
> limitations? or I should ensure Aircraft is level? or any other settings
> that needs to be done?
>
> Kindly help
> --
> Thanks and Regards
> R.Guruganesh
>
> On Fri, Jun 1, 2012 at 9:03 AM, Eduardo lavratti <address@hidden>
> wrote:
>
> Whell, one more time the ppz fizedwing set throttle to 0 (zero) when i
> engaged AUTO2 mode.
> the flywing stalled and crashed.
>
> i think fixedwing ppz have a bug in throttle code.
> i am using airspeed_ets.
> when i engaged auto2 the altitude is greater than desired.
>
> i will search and put a minimul throttle value in the ppz code.
>
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