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Gimbal starts humming and behaves strangely
  • summ
    Hey all,

    I think I have my DYS Eagle Eye with a 5D Mk III setup quite ok. I´ve mainly relied on the Autotune of my 32 bit Basecam with latest firmware and just tweaked it a bit here and there. But when I use my RC for YAW sometimes the whole gimbal starts "humming" and YAW wiggles back and forth. YAW input has no effect, or at least the gimbal does not rotate as before. After a while the whole thing settles back in and works fine until I rotate it via RC again. What could that be?
    Besides that ROLL seems to act just a little on its own when YAW is applied. It tends to lean into one direction depending on YAW.

    Any suggestions?

    Thanks for all you time and work you put in here!

    Chris
  • Garug
    It could be that you try to move via RC too fast. Set slower speed and you could try acceleration limit. Also make sure RClimits are not causing problems
  • summ
    Well ... actually it responds very good to speed. Right now it´s set to 40. But sometimes the whole thing starts hummin and shakin and after that its ok for while. I´ll see about the RC limits again.
    What could cause the Roll to have a life of its own?
  • Garug
    Do you get skipping motor steps indication on GUI when yawing with RC? If, then the acceleration/speed is to fast.
  • summ
    Yes it says motor is missing steps. Meanwhile I think the humming/vibration comes from the pitch motor. If I tilt the camera up or down the vibration goes away. Another strange thing is that even if the gimbal just sits there doing nothing it will start to vibrate at some point and come back to normal on its own ... I´ll recalibrate the whole thing tomorrow and if all else fails I´ll make a vid.
  • summ
    After fiddeling a bit I figured the humming is the pitch motor. I´ve turned off the others and played with the Frequence Filters, which eliminated 134Hz +/- 20.
    Still it reports missing steps, allthough the pitch is very responsive at higher speeds.
  • Garug
    Is the missing steps only when moved with RC? Try Attuning one axis at time, starting from Pitch axis and using good stability settings, or 1/4 up.

    Have you adaptive filtering activated. do not activate it before the PID and filtering is tuned.

    How is your power, are motor warm? if not you could try adding power and retuning yaw. For Pitch you could try to reduce Power.
  • summ
    Hey ... after recalibrating the IMUs and recentering them on the rig (it seems the sensor itself is a bit off inside the plastic casing) the Roll drift when pitch is applied is gone. One prob solved ;)
    What is definitely causing humming/vibration is the Roll motor. I´ve used a free spektrum analyzer and it gives me a frequency at about 3000something Hertz, which you obviously can´t input into the filter. The motor also gets warm, although power is at about 150. At about 130 it seems not sufficient.
    The vibration only occurs when the camera is level. As soon as I apply pitch in any direction it fades away and comes back when coming closer to level again.
    Missing steps are also still reported only when Roll motor is active. Pitch and Yaw now handle speeds at about 50 very well.
  • Garug
    Maybe you should check the Roll motor that it is ok. With spectrum analyser it is important to focus to the lowest frequencies that can be found. when those are filtered away, also the higher frequencies vill go away, thy are just harmonics of the original frequency.

    Set the spectrum analyser to 0 to 300 hz range. No need to care what happens above that.



    http://levitezer.com/styled-2/blog-2/files/archive-oct-2014.html
  • summ
    Only time I wish I had a Mac haha. Did not find a similar analyzer for Win. At least none of such simplicity. But I´ve checked against an analyzer app for Android and tried to filter 135Hz. Still not quite there. I still get a little of that vibration when camera is level. But I think it won´t be seen by the camera.
    What is still nagging is that the Roll motor gets warm. I have no means to measure, but it is definitly getting warm, although power is at about 135 now.
    What happens when the motor gets warm? I mean at least as it not become burning hot?
  • Garug
    Above 80 C it will destroy the magnets. General would be good to keep the power so that they do not get hot to touch.

    Is the roll motor different than other motors? Same motor with same Power should get equally hot not depending of axis. Different motor could require much different Power.
  • summ
    Pitch and roll are both DYS BGM5208-75 motors. I had the gimbal just sit there and do its humming for about 10 mins. the motor is warm, but you can still touch it ... ambient temp is about 20 C. So I think unless I go fly in the Sahara it won´t burn itself out. But just nags that I can´t get rid of that vibration frequency. I wonder why it only occurs when the camera is level. May I should balance it again, although the cam stays in every position I put it to. Balance should be close to perfect.
  • Garug
    Probably camera installation is less than perfect. Vibrations take place usually at some position. Try to autotune one axis at the time in the position it vibrates worst.
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