Auto tunes issues on large X8, near rollover.

Posted by Shaun Bell on September 21, 2016 at 7:31am

I saw this has popped up in another post, but didn't want to hijack the conversation as it may be related to a fence breach.  Started the autotune and everything seemed normal.  Starting with roll axis.  Twitch left, twitch right and on it goes.  Until it starts rolling from one side completely to the other.  No stopping in the middle.  At 6min I terminated the autotune, before rolling right over.  This is a big unit, but I've done other AT this last week on a 960mm HEX and X8 that worked great.  AGGR is .1, filt is 10hz with voltage scaling.  30mm booms with 5mm carbon top and bottom bracing, so it's pretty stiff.  By no means a flexy frame.  I'm running 3.4rc5 (which has run flawless in the two 960's).  Here's the basics of my setup:  

Tmotor U8 170kv motors, 2880 props, 80a foxtech esc's (no sync issues), 8s44ah battery and a weight of 16kg.  The log: https://www.dropbox.com/s/emer3e1hsamix6w/2016-09-20%2018-37-27.bin?dl=0

3691318180?profile=original

You need to be a member of diydrones to add comments!

Join diydrones

Email me when people reply –
Follow

Replies

  • Gregmaan September 23, 2016 at 6:23am

    I am also very interested in autotune with the T960s. With 3.3.3 I had problems with much to high Ps and Ds from Autotune 10Hz filters did a much better job aggr. was 0.05. If there are recommendations for Autotune with large heavy props (18")on 3.4 I would like to switch to 3.4 RC5 or later.

    Cheers

    Gregor

    Shaun Bell said:



    You think those provisions are the actual AT process, or additional parameters that can be use set?  I know the filter rate made a big difference in the 960mm units giving better results.

  • Shaun Bell September 21, 2016 at 10:35am



    You think those provisions are the actual AT process, or additional parameters that can be use set?  I know the filter rate made a big difference in the 960mm units giving better results.

  • DG September 21, 2016 at 9:38am

    I thought the latest beta fw had additional provisions for doing AT on large craft?

  • Marco C September 21, 2016 at 9:24am

    I just want to add my experience, in the image below you can see roll and pitch tune on my copter and the values are not so different from yours...

    3702302705?profile=original

  • Marco C September 21, 2016 at 8:59am

    Hi Shaun,

    for what I can tell from your log it is that for the whole roll tuning process it goes from -30 to 30 degrees and it is quite constant during this process, I can see that before rolling on the other direction it waits half second (more or less), very short time. 

    I don't know if this is normal because I don't have experiences in large copter, my experience goes up to 3 kg max. 

    3702302735?profile=original

This reply was deleted.