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Start-up routine for gimbals using follow mode on the yaw axis
  • David_Hogg
    Hi everyone,

    I have never used a 3-axis gimbal in ernest before (but have a lot of experience with 2-axis ones), so forgive the slight newbie question! I will be using follow mode to keep my gimbal roughly pointing forward relative to my multi-rotor's chassis, smoothing out any slight left/right yaw wobbles as it flies.

    As there is no definitive reference for the yaw axis, I can understand that the gimbal controller can never truly know where the 'front' of a multi-rotor is. So is the best way to ensure the gimbal points 'forwards' to power the gimbal up, turn off the motors, move the gimbal in the yaw axis by hand until it's pointing straight forwards and then turn the motors back on again?

    I imagine if the yaw axis were to get disturbed strongly in flight (so the motors lose sync / grip) it will then forget where forwards is?

    Many thanks for your help (and patience with the simple question!),

    David
  • MdG_NL
    Is there a free radio channel left ?
    If yes, I will suggest to use this for the Gimbal Yaw-axis to turn it CW/CCW.
    Make sure you set the RC-control to the Speed option and set the Max-Angle and Min-Angle settings to 180/ -180 degrees.
    (this gives you a full 360 degree control)

    After the Gimbal start-up, you can change the position with your radio to the right place.

    A other option is to use two profiles.
    One profile is without the Follow-Mode and the second is with Follow-Mode on.
    After the Gimbal is ready to run, activate the profile without Follow-Mode and turn your MultiCopter until the position from your Gimbal is facing forwards.
    After this, activate the Profile with the Follow-Mode on.

    And yes, if the motor is lose sync/grip, it isn't come back to his original position.
    If you using a free radio channel, you always can correct this during your flight.
  • David_Hogg
    Hi MdG,

    Many thanks for your detailed reply, it's much appreciated.

    Unfortunately I don't have a free radio channel or your idea would have worked very well.

    I was test-flying the gimbal last week and found it quite satisfactory to unpower/power the gimbal to get it in the right position before flying ... or even just leave it powered and move the gimbal by hand.

    There were two things that left me a little disappointed with the follow mode though – these were:

    a) How far round I had to yaw the airframe before the camera would follow, and
    b) How long it took for the camera to catch-up after yawing.

    Is there any way to speed up / sharpen the response of the follow mode? It's probably nice and smooth for video mode, but most of my work is stills where I need to be able to quickly and accurately change the yaw of the platform to frame the shot.

    Many thanks for your help,

    David
  • Marian
    Those things are controlled by Speed and Expo. If you want to follow faster the yawing of the flying platform, increase the speed to about 60-80% of the range. In 32bit it would be around 170-190 from the range 0-255. You can go 250 in which case it should be locked and follow without delay.Play with expo. Increase to about 80 to soften the response or set it to 0 for fast and agressive response. Set the deadband to 1 degree or less. PID values do have effect too.
  • David_Hogg
    Ahh I knew there had to be a simple explanation! Thanks very much for your help Marian, I will report back with my findings :-)

    Thanks again,

    David
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