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Yaw axis calibration
  • I am close to finishing my handheld gimbal (Lumix GH3 camera).

    I have no other experience with gimbals so there has been a lot of head scratching. The balance is good on all three axises and I think I am close with the PID settings but My power settings of 120 for all of them are a total guess (5208-200T). Is there such a thing as a rough guide to starting points for different camera weights? My gimbal seems to work well except at extreme angles of pitch or roll, when I get oscillations. I probably won't ever go to this e angles in the real world but it would be good to fix it.

    The thing that is really stressing me is that I can't work out the yaw calibration at all. How do I tell the board which way is forward? My camera insists on pointing in one of two useless 30 degree angles. Surely this is something simple? I have tried six point calibration with the IMU aligned precisely with the frame. I have set up a joystick and I can use that to straighten it but I have to do it every time I switch the gimbal on. What am I missing? Any help would be greatly appreciated.

  • I have the same initial Yaw angle problem. I go to normal mode, rotate the outer frame to correct it and go back to follow mode. This works, but is really a annoying startup procedure.
  • To adjust initial angle of YAW, use Offset setting in the "Follow mode" tab. You may noticed that motor may switch between a fixed angles by hand, but can not be adjusted by hand inside this set of angles. "Offset" parameter is dedicated to help in this case.
  • Great, thanks Alexei. I thought that was one of the things I had tried but maybe not. I seem to remember applying a lot of offset but only seeing small results when I wrote it to the board. I spent quite a bit of time trying different things.

    Is there a way of getting it closer during the calibration process? Where does the board get it's information about which way the IMU is facing on the yaw axis? Looking at the GUI I was wondering if it was magnetic, from a 3 axis compass chip.
  • Chriscotech. There is one thing you have to do. Before disconnecting the radio you have to set the gimbal back to its original position...otherwise even power cycling it it will memorize last radio position even with radio off.
  • Actually, There is no radio in my setup but I do have a joystick which I can use to centre it. I am not sure if that is applying an offset that will confuse the home position though.

    I have my setup stabilising well on all three axes but I am finding that the yaw can break synchronisation fairly easily, despite a very good balance and fairly high power. For some reason it is much worse when I set the gimbal to follow pitch. When the synchronisation breaks three things happen: The frames go out of alignment, the gimbal oscillates and the pitch becomes linked to the yaw somehow. i.e. when I tilt down it also yaws one way and up yaws in the opposite direction. I need to find a way to prevent this from happening, or at the very least work out a quick and accurate way of resetting it without a computer for when I am on a shoot. Any ideas?
  • You have to make it work first in follow mode. Then you try the other modes. Use the offset AUTO to center the gimbal. Then you´ll have a starting point
  • Hi, I always use joystick on power on to set YAW and PITCH, then switch to FOLLOW. Seems to keep the last joystick setting and then go. If angles get too off, I just repeat.
  • Thanks dbeaty2, that is good advise. I will try it. I know how to fix it with a laptop but what is important to me is getting my gimbal back under control quickly in the middle of a shoot. I am refining the button and joystick buttons to do this. By the time I have connected it to a PC via USB, even if it is booted and running the GUI, it is game over. My first goal is to get the PIDs as robust as possible.
  • Chriscotech...your yaw will be always centered at startup if you tune the offset.
  • Chriscotech...your yaw will be always centered at startup if you tune the offset.
  • i have the same problem. but initial angle can be fixed pretty easily. i;m also experiencing yaw drift. is this normal? even if i rock my gimbal side to side, my yaw ends up at a completely different place. i have to push it back to place. everything works fine at slow speed and not too extreme angles. help? this is my first gimbal. i;m not sure how well yaw is suppose to work. but on you tube even the 8bit versions seem to work better than my 32bit with 2 imu
  • I am having this issue as well. Whenever I power up the gimbal, the yaw axis aligns about 30 degrees to the right, or sometime to the left. I find that if I turn the motors off in the software, reset the alignment manually, then turn the motors back on, it does much better. Powering down the gimbal and then powering it back up does not have the same effect. Also, as soon as turn Follow Yaw on, it get even worse.

    I'm wondering what factors can contribute to this? Could it be bad balance on the yaw axis? Or bad IMU calibration?

    Any advice would be appreciated.
  • Hello,
    ptaylor999, try re-calibrate IMU. What board version are you using?
  • Hi Andrew.

    I'm using V 2.5b2 firmware.
    I've re calibrated the IMUs multiple times
    I've tuned and re-tunes all axis.
    Just flew today and this is still happening.
    After using the gimbal for a bit, returning to home position, by flipping a switch I have setup, resets the gimbal yaw position about 30° off.
    Follow mode is on, if that even makes a difference.
    I'm at my wits end on this.
    Any advice would be appreciated.
  • Hello,
    ptaylor999, when your problem appeared, try to directly connect GUI to the board and see any errors.
  • Andrew - I've done that there are no errors. As soon I yaw my copter around, and then hit the home position switch, the gimbal either goes to a bad position, or starts spinning! I'm beginning to wonder if I have a bad yaw motor?

    Also, I have encoders on this AM gimbal as well. I would think the presence of encoders would help the situation, but who knows.