Re: [Paparazzi-devel] Autopilot crashing mid-flight

[Chris]

Hi.
First let me tell you that applying too much rudder in a turn is like 
using an air brake.
I can often airbrake nicely using the rudder and opposite roll
Maximum rudder and aileron movement should mechanically restricted to 
~20 degrees and the normal aileron to rudder mix should be no more than 
0.3 otherwise you will lower the stall speed and add a lot of drag.
As already noted when you turn you must increase throttle a bit, i don't 
know if there is a setting for that but you can use another airframe 
file mix to increase throttle a bit (say 10%) while banking
Chris


On 04/28/2014 07:53 AM, paparazzi_guy wrote:
> Hello everybody,
>
> The weirdest thing happened today during our test flight. The plane was
> flying perfectly in manual, fly by wire, and full auto. We wanted to
> increase the throttle during the rolls since it was always losing speed when
> turning. So we changed the gain AILERON_OF_THROTTLE from 0 to about 500. I
> thought this was a pretty reasonable amount since it gave me a range of 0 to
> 5000 with this value. However, once we committed this change the plane
> started spiralling and dove straight towards the ground. The pilot switched
> back to manual but had to land the plane because it had taken some damage. I
> took a picture of some of the logs and will provide the logs themselves in
> this message as well. The time that I committed the change was around 2125s
> and I reverted the change around the same time the pilot switched to manual
> at 2200s. It appears that the IMU and some other sensors died during this
> time for some reason, which is probably why it was starting to crash.
>
> Do you guys know why the plane would want to do this based on what happened
> and from these logs? Any input would be very helpful. We're going to try and
> repair the plane, but we leave for competition tomorrow. Luckily we have a
> backup, but it's not as nice.
>
> I will also include our airframe configuration if it would help.
>
> Thanks,
> Matthew
>
> 14_04_27__18_09_14.log
> <http://lists.paparazziuav.org/file/n15211/14_04_27__18_09_14.log>
> 14_04_27__18_09_14.data
> <http://lists.paparazziuav.org/file/n15211/14_04_27__18_09_14.data>
> Snitch2.xml <http://lists.paparazziuav.org/file/n15211/Snitch2.xml>
> Death_of_the_autopilot.png
> <http://lists.paparazziuav.org/file/n15211/Death_of_the_autopilot.png>
>
>
>
> --
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> http://lists.paparazziuav.org/Autopilot-crashing-mid-flight-tp15211.html
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>
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