EN CN
pitch problem
  • anaka
    Hi people i'm working on a 32bit platform with blacmagic pocket and quadframe gimbal
    all is going well but once i remote the gimbal with RC_PWM i start to have problems on pitch axis

    whrn i tild down the pitc around 30degrees the pitch motor starts to have hi-frequency vibrations

    is there anyone that had the same problem?
    any solution?

    please help me!

    thanks in advance

    Augusto
  • Garug
    That is pretty normal and there is several different causes for that.

    1. is it with frame IMU, if not try using estimate angles from motor (follow tab)
    2. often this could be just not optimal PID tuning. Try to autotune it in position where it vibrates.
    3. Filtering can help, but wrong filtering will make it worse.
    4. adaptive filtering can help.
    5. it could be mechanical imperfection
    6. it could be bad balansing
    7. it could be something loose.
  • anaka


    here you can see what i mean

    it's with frame IMU
    PID it's ok i think...i spent a lot of time balancing all the weights and finding the optimal PID

    where are the filtering parameters that you are talking about?
  • anaka
    you have to watch the video with audio cause of the vibration is not visible but you can clearly ear it

    thanks for your help Garug
  • Garug
    The video is private.

    PID tuning, if you tune well on level position, it might vibrate on other position. Often tuning the axis that vibrate on the position it vibrates helps.

    About filters http://www.levitezer.com/styled-2/blog-2/files/archive-oct-2014.html

  • anaka
    thanks Garug i'll follow the tutorial on filters, i think it is exactly what i need

    now my video should be visible
  • Garug
    The IMU installation looks flexing. there is a big hole on the construction making it weak. I would try to instal the IMU to bottom plate.
  • anaka
    hi garug i fixed my problem... filters was the solution

    thanks for your help!
  • anaka
    well...these settings are good for an hand gimbal

    in my case i'm using a drone so when all i s off the gimbal looks perfect but when i start to fly the gimbal goes crazy...it looks like that the frame vibrations from the motors influence a lot the gimbal

    i'm going crazy....
  • Garug
    Yes, it requires good vibration dampening and retuning, and flight controller tuning and retuning...and lot of patience.
  • anaka
    it looks like all the issues come from the YAW axis

    before to add the yaw the gimbal was working really good, also with 8bit board
    but once i added the yaw i had no more rest
  • Garug
    Yaw is usually the most difficult axis for many reasons:

    1. On aerial gimbals there is often not much mass above yaw, so yaw has difficulties to work (as vibration dampers usually flex a lot on yaw direction)

    2. Yaw must handle the biggest inertia.

    3. there is 3 axis between yaw and camera IMU and all of them have some free-play and mechanical binding (no matter how good they are, they alway have some and yaw always has more than the other 2 axis).

    4. often the yaw axis is not that well supported and it is quite common that yaw balancing is not good. it must be balanced just as the 2 other axis.

    5. not well working yaw can cause problems also on other axis.
  • anaka
    i totally agree...

    i already balanced well all the axis and i noticed that more power i assign to the yaw and more unstable it becomes

    it looks like the yaw generates so much noise that all the other axis go crazy and the result is a dancing gimbal
    so the pitch issue wasn't pitch...it was yaw that keeps influencing all the axis
  • anaka
    thank you Garug

    i rearranged the cables in the way to make the motors work as clean as possible
    i rebalanced perfectly all the axis with even more attention to YAW
    i made the vibration absorption system a bit more stiff to better hold the YAW
    i powered the gimbal with a separate battery

    and finally i got a stable gimbal flight!!

    thanks again!

    Augusto
  • Garug
    Good to hear you got it working.
Add a Comment