roll shake

Discussion in 'Radian' started by JY Air, Oct 17, 2012.

  1. Gustavo Rios

    Gustavo Rios Member

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    Hi Brad, my setting gyros P 100, I 100, D 15, the gyro stab. in 4, I will try the gyro D 10 as you suggest and make the flight with and without radians.

    thanks,

    Gustavo.
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Thanks, Mike. It will be very helpful to know. I'm not seeing a clear enough pattern emerging on the forum to really have a sure-fire strategy that's generally applicable. Certainly no "one size, fits all." :)
    Andy.
     
  3. Brad McGiveron

    Brad McGiveron Active Member

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    Gustavo... and you are using FreeFly Servo's or Savox ?
     
  4. Gustavo Rios

    Gustavo Rios Member

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  5. Gustavo Rios

    Gustavo Rios Member

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    Hi Brad, I did what you said and have noticed that the vibrations are not going to radians disconnected, at least that's what I can see. I'm about to upload the video, but I can get ahead something, I made the flight with Gyro P 100, I 100, D 10 and 120 roll gain. This indicate something ?

    Gustavo.
     
  6. Philip Ellerbroek

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    Brad,

    VERY interesting input on Gyro D needing to be below 20. Do you mind explaining more? Did this come from Tabb, or your own evaluations? What do you base this on? I'm at 27 now and will consider lowering based on your input. If I do, should I alter any other MK settings due to this Gyro D adjustment? Why does a setting of 20 or higher cause this issue?

    Phil
     
  7. Philip Ellerbroek

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    Gustavo,

    Have you strengthened the gimbal plate? Perhaps the vibrations are coming down into the gimbal through a vibrating/flexing plate? There are several posts of modifications online. I posted one myself of doing so with a 2-3mm carbon fiber plate.

    Phil
     
  8. Brad McGiveron

    Brad McGiveron Active Member

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    It comes from the MK wiki as well as evaluations I have found with different setups. http://www.mikrokopter.de/ucwiki/en/MK-Parameter/Gyro

    With the stock Cinestar 6/8 and the QC's you can get the gyro D fairly high. Even around 30 or more in the summer. But also it can cause shaking (more like vibrating) and in particularly in cooler weather with power on in a climb. It absolutely will happen with larger motors and you have to keep it below 15 or so. You can really see it if you power upwards... so getting it as high as you can and dial it back seems the best plan. It does seem to be affected by temperature but that might be more to do with the stiffness of everything at a certain temperature.

    I was running around 23 on my stock CS8 and as high as 28 but every once and awhile it would get the shakes. The I2C converter test that I did I used the MT 3515's and I had it at 10 in the end as it shook badly on 20 just hovering. I put the QC's on as a last test and I got them to 28 before it started to get the grumbles. So it is affected by power output it seems.
    Josh turned his down if I remember and it improved for him as well, so ya there is some data there of what happens. So with that if your are having issues I would look into lowering it. Turn it way up and you'll see what it does :)
     
  9. Philip Ellerbroek

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    Brad,

    WOW! Perfect. That helps soooo much. I've noticed vibrations during take off here in the cold desert now that we've dropped 40 degrees.

    Would this affect the horizon roll left and right? I still can't get past this dang horizon roll when I bank left and right after all the tweaks and mod's.

    And now I have toilet-bowl with PH. I'm hoping that is just a simple compass reset.

    Phil
     
  10. Brad McGiveron

    Brad McGiveron Active Member

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    hehe... well take everything with a grain of salt as they say and test it, because if I followed what I have heard on some other forums about various things ( I2C converter, CC esc's, WKM and wind, and the list goes on ) I would have just past over stuff that works very well.


    Not sure about the horizon and how this affects it. I always try major major tweaks to a setting so I understand what it does and then start to make minor adjustments. Most advice I have seen say make minor tweaks but you never really know what it does that way. It may have something to do with the TB though.
    Just a thought.
     
  11. Gustavo Rios

    Gustavo Rios Member

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    Hi Philip, I not have strengthened the gimbal plate, but I think that these oscillations are of small play that has the roll servo.

    Gustavo
     
  12. Bo Tornvig

    Bo Tornvig Member

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    I think your right. I just stiffen the gimbal plate with a 2mm alu plate and I still have the same vibration as before...
    The play in in the servo gear set and the belt creates a little but very annoying roll shake. If I didn't have the fantastic stab in the CX 730, my Ariel footage was useless.
    Can anyone come up with a success story? I´m running out of options...

    Good luck to you all
    Bo
     
  13. Peter Eriksson

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    My shake dissapered with roll gain @80, still performs good when it comes to stab
     
  14. Bo Tornvig

    Bo Tornvig Member

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    Interesting - I´m having 128 as the best performance on the roll. 80 is what I have on the tilt.
     
  15. Peter Eriksson

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    Even moore interesting is that i have 170 in tilt and it is rock solid.
     
  16. Bo Tornvig

    Bo Tornvig Member

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    Hmm.. What camera are you flying? Ill try out your setting when it stops blowing..
    Thanks for sharing :)
     
  17. Peter Eriksson

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    I have the Gh2, it just got me thinking, i hope it is not my high tilt gain that has caused the shake? and not the roll, maybe eyes are tricked when looking at video

    However i have seen moore than med having tilt adjusted that way.....
     
  18. Peter Eriksson

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    well, back to square one, still have that annoying roll shake. When i remove roll radian it is gone.

    I have stiffened up my mount, tension on belt is good, Versin 1.03.

    I have tried gain down to 40 but still the same, maybe change to savox and try?. My ff servos are brand spanking new
     
  19. Jim Swanson

    Jim Swanson Member

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    Numbers, numbers, numbers.

    Shaky video has so many variables. If the belts are tight, the servos are slop-free, and the gimbal is balanced, the radian numbers are not as important IMHO as the copter itself. Once you mount the camera and give it the tap test, you should be fine.

    Brad above writes about playing with the Gyro numbers. Those numbers are super critical to smooth video in terms of ascending and descending without a lot of vibration. I'm chasing those numbers now to find the right balance between no wind and light wind conditions. Some people swear by Gyro D at 15, some at 28. I'm pushing 40 and getting good video results (better than 15) on my ascends and descend with my GH 2. It seems every copter is different because of camera weight, battery placement, MK setup, and copter center of gravity...to name a few.:)

    Anyway, if you want smooth video, take off and hover at 15 feet or so. Watch the rear landing leg closely. If the leg shakes even a tiny bit when you move the left, right, up, down...your video will shake no matter what Radian numbers you use.

    jim
     
  20. Peter Eriksson

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    It dosent shake but i can feel the vibes in it, and it is moore vides on the legs than on the booms. I guess they are self vibrating.

    The funny thing is that without the radians on roll i dont have thoose small tvitches. Somehow the vibes maybe go through the o-rings of the mount and into the radians?
     

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