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Follow offset not consistent
  • eutico
    Has anyone else experienced problems similar to this on the follow offset? Set the offset using the GUI, get it all centered up perfectly, use it a bit and then turn it off. Move it around. Turn it back on. Comes back on as uncentered. Change the offset, get it centered up again. Turn it off, turn back on. Comes back as uncentered. Other than this one thing, the gimbal is operating perfectly. Definitely not skipping all the way to the next magnetic pole.

    I'm not going to use the phrase demon-possessed, but... :-)

    The thing is that I've seen this follow offset work fine at times, but many, many times I've seen it be very inconsistent. It is the only control in the whole GUI that seems to be inconsistent. Planning to upgrade firmware soon, but still on 2.43b6.

    Any experience/success at troubleshooting this?
  • Garug
    That is a feature. The only way to avoid it is to use encoders.

    A gimbal without encoders (or potentiometer) has no way of knowing how the handle/multicopter is related to the rest of the gimbal at startup.

    If it is oriented close enough to correct direction, then follow yaw offset is useful. Offset can correct the direction within one motor pole.

  • eutico
    Not sure we're communicating clearly. I completely agree that you have to be on the correct pole, but as I mentioned, it is definitely not skipping to the next pole. We're talking about moving it to the center position each time, so it knows what pole it is on. I'm saying that the OFFSET is not consistent.

    I'm using 22 pole motors at this point, and I can easily see the angular change caused by moving from one motor pole to the next by turning off the motor and moving it and turning it back on, etc. It's a significant angular change. The angular discrepancy I'm talking about it much less than that, maybe 5 degrees... and it's random. It isn't that the offset is such that the nearest poles are 8 degrees to one side of center and 8 degrees to the other, so that it doesn't know which way to go.
    I'm saying that it's set perfectly and then you turn it off, and turn it back on and it forgets the offset. The settings are still there in the GUI, but the gimbal can't repeat the position.

    I've wondered if deadband could affect this, but the deadband has always been set at 1 degree.

    If no one else has really ever had this problem, then I wonder about hardware, but I can't think of how it could be a hardware thing.
  • Garug
    If the mechanical center position is in between or close to middle of poles how does it know, to go left or right?... Turning the motor a bit could help.

    "If no one else has really ever had this problem" I think we all have it. For me it is not a problem on handheld where I have it, I correct it with joystick. On arial gimbal I use follow potentiometer, it removes the problem.

    It could be of course that there is some bug also, I have never relied on this functionality. Actually I keep the follow offset always zero, but yes I have tried it, with the same result you are having.
  • eutico
    Thanks Garug. It sounds like I'm not the only one here who sees this then. I was working with someone today with this problem, and it seemed like it would remember the offset if you just turned off the motors and didn't move anything, but if you shut off the whole thing and moved the motors around, it had problems.
  • Garug
    when the gimbal is on, it can track the movements based on IMUs if frame IMU is used and based on estimate angles from motors if that is used, and maybe something else too. When the power is off, it looses all this information.
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