Annoying yaw movements Iris+ - how to tune them away

Posted by Christoph on October 23, 2015 at 8:00pm

I am using my Iris+ for about half a year now. Without any major issues. All is running smooth.

There is just one annoying issue that with a 2-axis gimbal (Tarot) I always need post video stabilization as there are strongly visible yaw movements.

I have seen other raw videos on youtube and it seems that some persons get much better yaw stability.

I tried tuning the PIDs with minor success. Basically I am able to tune down the amplitude of the yaw movements, change their frequency, but so far have not gotten them to a level which I found appropriate.

Anyone having good experiences with that?For me it's hard to accept that I would need a 3 axis gimbal. I still hope it can be fixed by a good tuning.

Currently my PIDs for yaw are like that:

rate P  0.7

rate D 0.008

rate i 0.03

stab P 10.0

Anyone having better values? Anyone having a good idea on the tuning strategy? Less stab P and tryin to solve it via the rate values?

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Replies

  • Justin H. October 23, 2015 at 8:58pm

    Hi Christoph,

    I think that's a fairly common problem. Most people I've asked about it (especially professional aerial photographers) recommend going at the controller rather than the PIDs at first. A 40%-50% expo curve on your yaw input should reduce the yaw twitches significantly, the remainder seems to be tuning and piloting skills. I had the same problem and managed to get rid of it with that combination.

    This is all assuming you're not flying in a mode that depends on the compass for heading, I've given up trying to get yaw-stable video in LTR or AUTO with a 2-axis gimbal.

    • Christoph > Justin H. October 24, 2015 at 4:46am

      Hi Justin,

      I did not know that the controller will have an influence on yaw stabilization even if I don't touch the stick. So the control loop depends on the controller settings?

    • Justin H. > Christoph October 24, 2015 at 7:10am

      No, I'm talking about the unintentional yaw that happens when the expo curve is flat. It's unforgiving, so even the slightest unintentional left-right movement on the stick when applying throttle will result in some yaw movement.

      If you are not touching the stick at all and the yaw is still twitching (not oscillating like a PID out of tune) the expo curve won't help. I thought I was pretty good at not giving those tiny unintentional yaw commands when on the throttle, but I was proven wrong when I changed the expo and things smoothed out.

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