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PID problem on my 3axis steadi with 32bit alexmos...
  • hello to everyone! i have build my personal 3 axis gimbal brushless for canon 5d markIII ... this it's the configuration :

    Control board alexmos 32 bit with 2.41fw and 2 imu
    Yaw motor 5208 200T
    Pitch and roll motor 5208 75 T

    i have tried many combination of pid but nothing working good for me... the gimbal it's good balanced. the best problem it's on pitch axis... i have made a video :
  • to weak motors for that camera/lens combo
  • which motor recommendations ???
  • I am running the same motors with a 5D MkII. No problems. I noticed your lens seems to be in auto, it must be in manual otherwise it will go out of balance very quickly.
    See below from a previous post of mine.

    "
    RC Timer legacy hand held gimbal
    Canon 5D MkII 35mm manual lens
    4S 1300mAh battery
    All up weight 2.5kg
    RC Timer 32 bit running 2.41b5 dual IMU
    Joystick connected
    Follow yaw

    PID's
    Roll 10 .07 12
    Pitch 10 .09 15
    Yaw 15 .07 26

    Power
    R 150
    P 100
    Y 150

    Gyro trust 70
    Gyro high sens ON

    No serious problems, need to keep tweaking to perfect.
    No roll on yaw (previous problem, nothing specific that I can pinpoint solved this).
    This result after a very meticulous mechanical balancing period, it is now perfectly balanced, I can't emphasize how important this is, when you turn off the motors it must not move more than a few mm's!
  • GB85 is excellent, though expensive.

    One note, on the video your pitch axis is not on balance after the Zoom slides out.

    What are your Power and PID settings? does the motor get hot? if not you could add power.
  • Zeb, why do you have gyro high sens on? your PIDs are very low. Nothing wrong on this if it works good, just curious.

    Though I would recommend loading the just released 2.42 b6 and give the PID auto tuning a try with high sense off and the adaptive PID tuning is nice for removing remaining vibrations in other than handle in level position.

  • I had problems with high freq oscillation that I couldn't seem to tune out, once I had selected high sens it went away, I know it could indicate something else isn't set up correctly. I will load the new software and retune. I'm juggling all sorts of projects and work at the moment so I tend to dip in and out of this stuff. Cheers
  • I have suspected also that the high sens does something else too than just multiply the P and D by 2 as the user manual suggest. Would be good to actally know what it does.
  • Ok, I've just uploaded new software and carried out autotuning, it has radically changed my PID's, very high numbers, Roll is 205 0.12 103, Pitch is 202 0.22 86, Yaw is 205 0.08 167!!!
    Never seen such high numbers. My camera and lens are heavy but I don't understand why these numbers are so high. I will do some experimentation. Gyro high sens is now not selected. The system performs ok apart from a slight high freq vibration if I move quickly, this quickly dissipates so I can probably get rid of it. With the high numbers the gimbal is quick and responsive. Motors remain cool thankfully!
  • Yes, quite a difference. I have tuned manually high PID, but even for my gimbal the Auto tune gets bigger numbers. I think a bit too big.

    What I do is move the gimbal to position where it starts vibrating and then perform the auto tune again on that position. Usually it results lower PID and better overall result. I tune using close to the good stability setting. To Finnish the tuning I do some final manual tuning, but I think the Auto tune is great support tool for the tuning.

    The adaptive PID tuning is good for killing starting vibrations and filtering can help even more.
  • Hello to everyone! i have solved my problem (problems) the first problem it's my pid too big... i have used the pid of user zeb and it's a good start point for me... need only small change ... the 2 problem it's the plate where i put the camera.. it's 2mm of carbon fiber and i have changed with 3mm carbon fiber , now all Ok! thanks all !!!