Discussions

EKF on ArduCopter 3.2 - Any news?

Posted by Andrea Zamuner Cervi on January 30, 2015 at 11:58am

In the last 2 days I started some test on the EKF.

In my opinion It looks very interesting =)

I have some question:

1) I found very little web pages or forum discussions that talk about EKF. I have read all the copter wiki about EKF, but I wonder: there are some other relevant information sources?

2) Actually, after some tuning, it seems that my copter is more stable with legacy algorithm. With EKF the altitude is a little "twitchy" (is this the correct word? Sorry for my bad English =P).

3)My main issue In the EKF mode is the altitude. Can anyone help me with some suggestion?

4)Does anyone fly usually with EKF on? If yes, how is your copter?

Thanks everyone,

Andrea from Italy

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Replies

Krzysztof February 5, 2015 at 12:30pm

Can/Should we do the autotuning when the EKF is on?
Andrea Zamuner Cervi February 4, 2015 at 11:16pm

It acted twitchy only after takeoff in guided mode?

If yes then I and 3 other users have detected a problem in EKF that regard only the first 10-20 second after take off.

Have you open any issues on GitHub?
- DG > Andrea Zamuner Cervi February 5, 2015 at 9:35am
  
  I had twitching last weekend. Taking off in stab it was fine, then switched to poshold and had fairly severe twitching, then drifted for a few seconds before landing.
  
  A time before that it yawed quickly about 30-45 degrees just before landing.
  
  EKF enabled
  
  Logging set for 'All plus disarm' (forget the exact term.
  
  The cause is not known at this time, but only appears to occur in GPS flight modes. Have any of you used Auto Analysis since running on AC3.2? I'm getting speed errors (looping) in every log. Randy seems to think it's a red herring, but I'm interested if others are seeing these errors.
Richard Kennedy February 4, 2015 at 5:34pm

I have been flying with EKF on for many months. However a couple weeks ago with 3.2.1 I noticed in guided mode it acted 'twitchy'. Just for the heck of it I used ch 7 to turn it on and off and sure enough the twitchy went way when I turned EKF off. I haven't turned it back on since. There's no doubt at that moment EKF wasn't as stable feeling.
CyberCrash February 1, 2015 at 5:26am

What is EKF?
- Admin
  
  Thomas J Coyle III > CyberCrash February 1, 2015 at 5:31am
  
  @CyberCrash,
  
  EKF: Extended Kalman Filter Link
  
  Regards,
  
  TCIII AVD
Rob_Lefebvre February 1, 2015 at 5:17am

I use EKF exclusively on all my copters. Even, or I should say, especially on the big expensive ones. Simply put, it is more reliable and accurate than DCM. There's not a lot to know about it. I just enable it, and that's it, I've never touched any settings.
- Andrea Zamuner Cervi > Rob_Lefebvre February 1, 2015 at 1:08pm
  
  Thank you very much for your reply (=
  
  Another question: Do you have any video about one of yours copter in Loiter mode with EKF engaged?
Andre K. February 1, 2015 at 4:50am

I did a lot of testing of EKF, but got stock with this issue: feel free to reproduce and see if you get the same results.

; https://github.com/diydrones/ardupilot/issues/1713

Other than that, it flies fine. I did not do any side-by-side comparsion between EKF enabled and disabled.
- Andrea Zamuner Cervi > Andre K. February 1, 2015 at 1:07pm
  
  Thank you very much for your reply (=
  
  If I can I try to do the test to reproduce the issues. And if I notice something I write about it ;)
  
  Everything depends If I can finish to setup my EKF succesfully: actually I do not have a stable altitude in EKF, so before doing auto I need to fix this.
  
  Another question: Do you have any video of your copter in Loiter mode with EKF actived?