roll shake

Discussion in 'Radian' started by JY Air, Oct 17, 2012.

  1. MIke Magee

    MIke Magee Active Member

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    Hi Tabb. Thanks for the interest in this.

    The FC board is not loose at all - I checked and tightened it down a bit. AFA the FC settings. Here you go. Let me know what you think please. ALL opinions welcomed!
    GYRO
    • Gyro P - 100
    • Gyro I - 120
    • Gyro D - 27
    • Yaw P - 100
    • Yaw I - 120
    • Dynamic Stability - 70
    • Acc/Gyro Factor - 27
    • Acc/Gyro Comp - 32
    • MAin1 - 16
    • Drif Comp. - 0
    • Gyro Stability - 6
    • Motor Smooth - 0
    STICK (just as an FYI)
    • Nick/Roll P: 6
    • Nick/Roll D: 10
    • Yaw P: 4

    There does seem to be a bit of give on the plate that makes me think the wood support has legs, but I don't want to change too much at once.

    Thanks,m


     
  2. Tabb Firchau

    Tabb Firchau Administrator
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    Hi Mike,

    Just as a quick test can you try the following settings:

    Gyro P -100
    Gyro I - 100
    Gyro D - 15

    See if you can still hear the motor pulsing with these settings? The plate flexing is not causing this frequency of oscillation IMO.

    Thanks
     
    Kenny Chen likes this.
  3. MIke Magee

    MIke Magee Active Member

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    Tabb, I made the changes below. I noticed some improvement, but the vibration/oscillation is still vigorous.

    In this short side-by-side you can still see it on both cameras. I'm open to any and all suggestions and deeply appreciate your help and guidance. (I hope that does appear to be a distinct beg)

    I simply don't have the ear you do for motor issues, but it does look like 2 & 6 jump around from the MKGPXTool grab.



    Regards, Mike.


     
  4. Tabb Firchau

    Tabb Firchau Administrator
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    Hi Mike, Really nice video and very useful data. Let me watch this a few times and try and digest / come up with a few suggestions. The thing I am trying to nail down is what is starting the oscillation in the first place, with the Radians off the shake persists which tells me it isnt the Radians. We de-tuned the MK flight control loop to see if that helped and it did.

    Let me think for a minute and get back to you,

    -Tabb
     
  5. Tim Joy

    Tim Joy Active Member

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    Have you checked each motor and prop for vibes?
     
  6. Josh Lambeth

    Josh Lambeth Well-Known Member

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    I am playing around with strengthening the camera gimbal mount plate... from the first test i did in the dark it seems to have helped some... Ill be testing in the day this afternoon to know for sure.

    Josh
     
  7. Adam Paugh

    Adam Paugh Distributor

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    Hello Mike,

    We could send you the original MKTool FC settings for your Okto. It does sound and appear to be a tuning issue. Thanks for the diligence with posting the video

    Greetings,
    Adam
     
  8. MIke Magee

    MIke Magee Active Member

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    Tabb, I agree that the vibration is NOT caused by the radians, but I'm curiously wondering why it isn't corrected by them. I'll take any guidance you supply.

    Tim: I've put 2 new motors on that were "growling" a bit while using the MKTool to drive each motor, and installed new balanced props. I selected the motor replacement by ear and feel on the boom while testing each motor boom combo. Any suggestions on how to practically get quantitative on it? I'm open. I really need to get to the point where I can shoot smoothly with the full frame 5D.

    Adam: How are you? I'll take the original settings, however, other than the changes that Tabb suggested, I don't believe I've modified them.

    This is an interesting problem with vibration that occurs every number of seconds and then subsides.

    Thanks all.

     
  9. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Mike: is there any chance you could make an audio recording, please?

    1. Remove the props.
    2. Connect up to MK Tool and use the Motor Test.
    3. Put a microphone alongside each motor in turn (preferably the same distance away and with the audio gain set so that it doesn't peak above -6dB to avoid distortion.
    4. Run the motor up to about 25% of maximum -- and make a note of where the slider is, so you can kinda come close for all the motors.
    5. Record the sound of each motor -- annotate it with your voice so we know which motor's which.

    I'm working on a way to test bearings by analyzing a motor's sound.

    Thanks
    Andy
     
  10. MIke Magee

    MIke Magee Active Member

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    Andy, this is very interesting. Sure I will. I'll do it tonight!
    -m
     
  11. Howard Dapp

    Howard Dapp Active Member

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    Has anyone tried bracing in between the booms to make the setup more rigid? A guy using another CF frame used a thin steel wire to tightly link the boom ends to one another. Made a world of difference for him. Just a thought.
     
  12. Pavlos Antoniou

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    It seems to be the play from the dampers..
     
  13. Philip Ellerbroek

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    Mike,

    Watching you issues in your video, I'd thought I'd share. I have the exact setup as you, running a CS8/3axis, Mark3 w/ 28mm is. I had a tip over and prop shock last week, causing my #3 motor to not only make noise but excessive vibration. Turns out the bearings were damaged during the prop strike, causing the vibrations to radiate from the motor to boom. As Tabb said, it doesn't seem radian-sourced. Tim Joy suggested the same above.

    I posted a crude recording here: http://forum.freeflysystems.com/index.php?threads/really-dusty-motors.331/page-2#post-6392

    I was seeing noticeable vibration on the boom shaft of the damaged motor prior to changing the motor out. Have you done a motor test and worked through motors 1-8 individually? I'd take the props off motor test in and in addition to check for oddities in a motor also grip each boom when testing its coorespondin motor.

    Phil
     
  14. MIke Magee

    MIke Magee Active Member

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    Thanks Phil. All of my motors "Seem" OK. I have replaced 2 that had a bit of a bearing growl. On the bench (no props) the motors seem to run smoothly and identically. The shafts aren't bent or wobbly. The booms appear to vibrate about the same (very very slightly). GPXTool shows motor draw that looks OK, but still 2 motors a bit suspect, so I'll test with them some more.

    I just ordered another new motor today (Hey - they are on sale, why not)

    Speaking with Casey yesterday, (I hope I explain this correctly) he mentioned that they have seen motors that look, smell, sound, feel, benchtest etc.. good, but when they get up under load at decent RPM will "choke" or stutter.

    NEXT, I'm going to install some blue o-rings, and take that "new out of the box" motor, put it on a spare boom and methodically test fly and analyze the GPX data as well as visually monitor the shake on each boom to see if I can corral the problem by moving the boom around the clock.

    AND, I agree it's not radian sources, but the radians don't correct it either. I need to mitigate the shake and get on with working.

    I'm open to all suggestions, comments and prayers.

    Best,m



     
  15. Bo Tornvig

    Bo Tornvig Member

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    Hi Andy,
    It looks like there is a lot of wind. I guess you have to live with the shaky shoots... or fly in calm weather.

    I live in a windy country and I have tried everything. 3 different sets of props - replacing motors - played around with the MK settings/radian settings - balanced props over and over again - turned the roll belt inside out - balanced the camera gimbal over and over again - changed the servos - played with different O-rings (2-4-6 rings). I dont think I have many options left. 3 months later (full time) I´m still at square one...

    I´m hooking up with some people now and we will test the maxon motors. They have direct drive and will eliminate the play, coming from the FF servos and the gimbal - like the zenmuse... the big task with the Maxon is the control. But that we will overcome, as there is some really pro experts around here...

    Cheers
    Bo
     
  16. Philip Ellerbroek

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    Bo

    What about strengthening you star shaped gimbal plate? Perhaps it's flexing and causing issues.

    Ps what size and weight is your lens?

    Phil
     
  17. Bo Tornvig

    Bo Tornvig Member

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    Hi Phillip,

    Currently I´m trying to stabilize the Sony cx730 on a cinestar 8. My plan is to fly 5D lll with a 24mm IS, before summer. When a can make a nice steady shot Ill move om to something bigger ending up with the RED.

    Strengthening the gimbal plate could be a interesting task. Thinking to make one out of aluminum.
    Have you done that? Any experience?

    Bo
     
  18. Brad Meier

    Brad Meier Active Member
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    Mike,

    To answer your question to Tabb about the radians not eliminating vibration...

    The high frequency bumps and vibrations caused by motors, props, turbulence etc. are dampened but cannot be eliminated by the Radians due to limitations of the servos.

    It's amazing how I can still pick apart my own video results with radians but when I go back and look at pre radian video, I'm surprised I could get usable video. I'll have to post a short clip from 30 mph winds. I had to use post stabilization but it was still usable for broadcast tv. Now, with the Radians, I only use minimal if any rotational stabilization in post.
     
  19. Philip Ellerbroek

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    Josh,

    Did it help?

    Phil
     
  20. Jim Swanson

    Jim Swanson Member

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    Hey All,
    I've been trying to get rid of a little camera shake like many in this post. Today I ran my Cinestar Hexacopter/two axis gimbal and my GH2 camera with 2 lipos to see if I could get longer flight times. To my surprise, with the extra weight, most of the picture shaking was gone. The weight was not added to the gimbal, just an extra 4s lipo on the battery tray. I then flew with just one lipo and the occasional little shake was back. HMMMM?

    I've always thought the shake or little vibration was in the gimbal. Even with the blue rings it still feels a bit sloppy.

    Is it possible that the extra battery weight could steady the Hexacopter and ultimately the shots?

    Confused,

    Jim
     

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