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Flip before take-off (SOLVED)

PostPosted: Sun Dec 14, 2014 8:19 pm
by rput
Hi,

After many flights without issue, we suddenly have a problem occur. One of our partners is flying a system we have put together. They were doing some mapping missions successfully when suddenly on the next flight the system flipped before take-off.

I looked at the log and see some strange things in the UKF_Q1-4 happening. Does anyone have any ideas what this could be from?

I wonder if the parameters did not load correctly or something. Anyway we can check this?

UKF_Q_Screenshot.jpg


Log file:

https://www.dropbox.com/s/avsvf7ewcr7sr8b/025-AQL.LOG?dl=0

Re: Flip before take-off

PostPosted: Mon Dec 15, 2014 2:41 pm
by rput
We noticed that the system was sideways when they powered it on, could this explain such behaviour?

Re: Flip before take-off

PostPosted: Mon Dec 15, 2014 3:47 pm
by bn999
The board should be powered on in a near level attitude but more importantly, it should be left still and not moved until you get a green ready light. This might only take a second or two. Movement during initialization can cause poor initial GYO bias estimation. If this is difficult to achieve due to battery placement, I'd recommend hitting the reset button once the craft is sitting still.

Re: Flip before take-off

PostPosted: Mon Dec 15, 2014 6:13 pm
by rput
Thanks Bill,

I suspect this is the most likely cause for the issues. We will let them know how to avoid it in the future.


Richard

Re: Flip before take-off

PostPosted: Mon Dec 15, 2014 7:10 pm
by rput
We have successfully reproduced this issue with another system. It was indeed the initialization that Bill identified. We reproduced it by rotating the quad at power-up. First time I was relieved to see my system flip at take-off ;)

No worries, it was a soft landing without damage...

Cheers,
Richard

Re: Flip before take-off (SOLVED)

PostPosted: Tue Dec 16, 2014 4:31 am
by LordPikaChu
bn999 wrote:The board should be powered on in a near level attitude but more importantly, it should be left still and not moved until you get a green ready light. This might only take a second or two. Movement during initialization can cause poor initial GYO bias estimation. If this is difficult to achieve due to battery placement, I'd recommend hitting the reset button once the craft is sitting still.

How close to leveled it should be? I was always told that board's position during init didn't matter because the absolute level is determined during full sensor calibration, not during board init.

Re: Flip before take-off (SOLVED)

PostPosted: Tue Dec 16, 2014 1:55 pm
by bn999
Just don't start it upside-down or on its side.