Copter: Dangerous flights when changed to ALT HOLD

[vmayoral]

Following from #1989 we changed to EKF but have been experiencing similar behaviors:

when taking off in ALT HOLD the copter suddenly gets height really aggressively:

Log available here.

Our guess so far is that the Kalman filter parameters are wrong or is not properly tuned.

[vmayoral]

@R-Lefebvre, @rmackay9, @tridge not sure how to diagnose this problem. Any thoughts on this matter are welcome.

[jschall]

Paul and I have patches that need to be pulled in to fix this sort of thing.
On Mar 30, 2015 6:23 AM, "Víctor Mayoral Vilches" notifications@github.com
wrote:

@R-Lefebvre https://github.com/R-Lefebvre, @rmackay9
https://github.com/rmackay9, @tridge https://github.com/tridge not
sure how to diagnose this problem. Any thoughts on this matter are welcome.

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Reply to this email directly or view it on GitHub
#2026 (comment)
.

[magicrub]

It may be worthwhile to note that #2010
#2010 was a recent bug that
@tridge just fixed that was causing the EKF to not initialize properly and
therefor were reverting to DCM.

On Mon, Mar 30, 2015 at 8:07 AM, jschall notifications@github.com wrote:

Paul and I have patches that need to be pulled in to fix this sort of
thing.
On Mar 30, 2015 6:23 AM, "Víctor Mayoral Vilches" <
notifications@github.com>
wrote:

@R-Lefebvre https://github.com/R-Lefebvre, @rmackay9
https://github.com/rmackay9, @tridge https://github.com/tridge not
sure how to diagnose this problem. Any thoughts on this matter are
welcome.

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Reply to this email directly or view it on GitHub
<
https://github.com/diydrones/ardupilot/issues/2026#issuecomment-87676911>

.

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#2026 (comment)
.

[vmayoral]

@jschall and @magicrub thanks for the comments.

We are flying with our code rebased on top of the latest commits. @jschall could you point out which are those commits?

Regards,

[vmayoral]

Update: The problem does not seem to be vibration-related.

Here is a flight with 2 imus enabled (MPU6000 and MPU9250) where the copter, as soon as it changes to ALT HOLD mode gets height aggresively. Can anyone make any sense of it?

(this seems to be a continuation of #1989)

[rmackay9]

This is really a duplicate of an existing issue so closing.
#1009