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Brushless gimbals : AlexMos, Phobotic, Aligh vs Zenmuse combarison
  • stpfl
    I am playing since the Alex Mos Controllers came out with these kind of gimbals. If you invest a lot of time in PID Tuning these Gimbals can work really good but never perfect. In my experience you will never come to an end in tuning. You will always have this jerkiness and jitter in some situations. If more deflection more Error jitter occur. If moving slowly and carefully the frame you can get quit good results. If you do the same with Zenmuse Gimbals there a lot more resolution and the errors a a lot smaller i would say factor 10. But why?

    Last year the company Phobotic came up and tell us everything will getting better.
    They post some videos where their controller worked really good but most of the customer struggeling with their gimbals and the phobotic controllers.
    Some people meant its because of bad built gimbals.

    So lets have a look to the Align Gimbals. These Gimbals are nearly a exact copy of a zenmuse Gimbal, so lets say well built. With a solid full cage 2 point fixing mount for the camera with brushless Gimbal Motors. If you watch the Videos from Align the videos looking really good. But i guess there using a lens Stabilisator.
    With a lens stabilsator you can get quit good results but in 2 man operation its really annoying because OIS never doing that what you want. If you make a pan OIS will pan further or make movements in the wrong direction etc. So its not a goal to use Lens stabilisator.

    If you look the Customer videos using Align Gimbals the are really jerky and faulty and unusable. Its looks like the same as the videos with Phobotic and Alex Mos controllers.

    So its seems to me there is a correlation between not so good working gimbals like Alex MOS, Phobotic, Align and Zenmuse where the error is a lot smaller not only because of the Gimbal structure. Maybe they are using a more effective Algorithm. Zenmuse motors have a lot different resistance compared to brushless gimbal motors? Why?

    So what do you think what will bring the future? Will this brushless Gimbals be improved in the future?

    do you see the difference?

    http://youtu.be/aWTBGRG9960
    http://youtu.be/OGJbDueY-20
  • stpfl
    Cm3000 video looks good when hovering. if the speed increase the error increase as well.
    Not seen on the Zenmuse video. Why?
  • Constantin
    Hey stpfl,
    as an engineer and an gimbal developer myself I can explain you the difference.
    DJI producing the zenmuse series and Cinestar producing the Mövi Series are both using Encoders in their drives. This way they can control the torque of the drives. You will never see a Mövi or Zenmuse loosing steps. This is the key to less error and better performance.
  • Garug
    I think the biggest difference is that DJI has well integrated, tuned and tested the platform and gimbal (for a specific camera). Most of the BaseCam gimbal constructions are generic and not very solid and platform they are flown with are "under work" including the gimbal and tuning.

    I think BaseCam board can perform very well when used with good platform and gimbal and correctly set up.

    This is one of the best GoPro aerial videos I have made with a BaseCam board. The vibration dampening has been much improved since, on this video some vibrations are still present. (so the gimbal, platform and vibration dampening where all still "under work")



    Ps. BaseCam now have encoders too, I have been testing them for a while but not on flying platform yet. Yes the encoders provide many advantages.
  • stpfl
    do you think we could update one day our gimbals/motors with encoders?
    Especially for aerial shooting AM Gimbals are not accurate enough at the moment in my opinion.
    because i need something to work with at the moment i go with a zenmuse gh4 for now.
  • Garug
    On my experience so far the encoders do not really bring that much more accuracy, good gimbal construction, good camera installation, good balance, friction free movement and good tuning are important for accuracy.

    This is without encoders hand holding a gimbal at about effectively 1600 mm lens



    I think pretty accurate joystick control.

    This is walking with effectively 200 mm lens. There is some problems, the follow speed was not optimally tuned for they focal length but otherwise I think it is good considering it is handheld and walking with 200 mm focal length



    No lens stabilisation (IS) or post stabilisation was used on these videos and both of these videos where without encoders.

    The encoder provide maybe a bit more accuracy, maybe because Power setting is no more critical and PID tuning maybe a bit easier. But for me the accuracy was not the problem without encoders.

    Encoders provide much better return after disturbance. No matter how the gimbal is disturbed, it returns smoothly to the normal position and continues operation like nothing happened.

    But

    Encoders make the gimbal much more complicated to build and there is more tuning also as the encoders need to be tuned. I think it will take at least some time before the hobbyist gimbal builders will be able to use them, before there is gimbal constructions available that support the encoders.

    It is my opinion that GoPro sized camera does not really need a gimbal with encoders, though a potentiometer or encoder is really nice to have on Yaw axis.

    And for sure, encoders will not make a bad gimbal construction work good.


    Ps. normally Vimeo playback is smooth, but today I am experiencing some playback issues, I suggest downloading the files.
  • Garug
    This is BaseCam board with encoders. No IS or post stabilisation used, all handheld and walking.

  • stpfl
    looks good.
    Ronin is also using encoders ...
  • Constantin
    garug - what beatuful place you live in :)
  • Garug
    Thanks Stpfl and Constantin,

    There is plenty of nature and beautiful places in Finland. Without the long, gold and dark fall and winter it would be pretty perfect place to be.
  • Constantin
    Sorry OT:
    Very nice Garug
    last year it was the first time for me in Sweden/Stockholm and I liked it a lot. Some day I will come and visit Finland. Is it true that it is a kind of common sport to race with a car on frozen lakes in Finland? I would like to try this :D
  • stpfl
    i tested now zenmuse. You can not combare this with brushless gimbals :-(
    But for the price brushless gimbals are ok i think.
  • Constantin
    Yes you are right - at the moment you can not compare DJI or Cinestar with simpleBGC - these are two worlds. But it is possible to develop simpleBGC to the same level. I think some day it will come to this.
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