Autotune - What's the definition of stability & precision?
  • I know their definition in the real world but struggling to work out from a gimbal perspective. For example if you were in handheld "mode" & walking & wanted take out the bumps when you took a step would you lean towards more stability or precision? Thanks in advance.
  • PID values have not much to do with the "taking out the bumps" The motors can correct only angular movement, to take out the bumps:

    1. Gimbal needs to be well balanced, otherwise the bumps will cause added imbalance and possibly angular movement.

    2. the gimbal needs to be solid. Otherwise the bumps will cause the gimbal flex and it needs to correct angular move movements.

    The bumps are not noticeable in long distance (when it is only up and down movement) See this video and compare the fence and the boat further away:

    Do a horizon test like on the above video. If horizon stays on the same place when walking, then there is no angular movements due bumps.

    Do a simple test, but your finger in front of you and close one eye at time. Notice how much your finger appears to move compared to background. The same happens when there is an object near the camera and the camera moves up/down or sideways. If also the object near the camera is moving, then this movement is not so visible.

    3. The best way really to filter bumps out is not to bump.

  • its clear that you cannot remove the up and down bumps but maybe he meant the vibrations occur because of your footsteps. you can also see this in your video you posted. look at the left or right edge you will see some oszillation.
  • Yes, as mentioned, balance and tuning are important, and no flex on gimbal or bumps will cause angular movement and that shows also on horizon.

    The above video was normal walking, so sharp hits when feet hits the deck and plenty of up and down movement as seen from the fence.

    If you look the 2 buildings at the middle of image and mask the rest of the video with hand etc. there is not much movement on those buildings. There is some yaw movement, but that is because of too sharply reacting follow yaw. i.e the follow yaw could have been better tuned and for this video it would had been better not to use follow mode at all.
  • Autotune - What's the definition of stability & precision?
  • My understanding is

    Stability: less prone for vibrations, keeps well its positions even in fast moves, smoother operation with the cost of the precision

    Presission: Angular error is small. Often makes the gimbal probe for vibrations etc.

    I suggest tuning first for stability and then moving towards precision if needed and if the gimbal can take it.
  • I like higher gains that make gimbal very precise, where angular error is less than 0.1 degree. But higher gains can result some vibrations, specially in some critical positions.

    As I can understand, precision means smaller angular error, that means holding horizon leveled.
    Stability means lower gains where angular error is larger but gimbals stay stable in every position.

    I would go for precision until I notice vibrations... then eliminate vibrations with notch filters. If filters don't help then autotune again with smaller precision.