How to resolve tilt gitters?

Discussion in 'Radian' started by Chris Babiana, Jan 22, 2013.

  1. Chris Babiana

    Chris Babiana Member

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    Keep getting this gitter on the tilt axis (CS8, two axis gimbal, radians). This happens when I activate tilt from my 3 position switch and while in flight with radinas. Camera -5DMKII. Center of gravity is pretty much spot on, (centered with belts off...see video). Adjust tilt settings? Radian issues? Roll is perfect...smooth as silk!

    Balanced with belts off:
    3 position switch gitters:
    Radian gitters...notice roll is fine:
    Has anyone had the same issue? :confused:
    Thanks!
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Reduce the Radian tilt gain a bit Chris. See if that helps.
    Thanks for posting video. Man, it makes it sooo much easier to see the problem...

    Andy.
     
  3. Chris Babiana

    Chris Babiana Member

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    Thanks for the quick reply Andy...I'll try that and post my results!
    No problemo on the videos.
    Regards!
     
  4. Brad Meier

    Brad Meier Active Member
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    In the first video the camera is not quite balanced, very close but not right on. When your camera is level without the belts on it wants to pitch forward. With the belt connected you can tell its working harder to lift the camera than it is to let the camera down. The slightly forward balance of the camera.. coupled with gravity is probably what's causing those jitters.. IMO
     
  5. Chris Babiana

    Chris Babiana Member

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    Thanks Brad...I'll re-adjust and give it another go.
    Question...I assume that most people while in the field (and I could be totally wrong here) don't take the belt off to balance the camera for every flight. I have a small mark on the bottom of the camera that I line up with the end of the mounting plate...predetermined balance point. Would it be safe to say that there is a small margin or error where the pan would not gitter if it were off a hair. And being off just a hair will affect prefect balance.
    Just my thought...
     
  6. Brad Meier

    Brad Meier Active Member
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    I would also assume that no one balances in the field. I arranged my gimbal so that the camera balances perfectly when the camera is mounted against the back of the camera mount plate. No marks to make or guess on.
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I certainly use Brad's approach. Balance in the comfort of your shop and use reference marks, alignment aids, whatever, just in case you need to re-set to that mark in the field with a DP breathing down your neck ("Are you ready yet?") ;)

    Andy.
     
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  8. Arthur Vieira

    Arthur Vieira Flight Squad

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    Hi Chris,
    Just got you PM.
    As Andy and Brad already pointed, balance is a must, the best you get it the best result you will have.
    With the belts off the camera should stay in the position you point it, if it tries to level out by itself the hole gimbal is too low. Take the time and balance in your office, then mark the hole gimbal and camera so you can readjust it quickly on the field.
    But.... if you want another ideas also.... here they come ;)
    1 - Check if the gimbal is moving smoothly without the belt or camera, sometimes it gets a little misaligned and the bearings get less smother. The less friction you get the more power to move the camera you have.
    2 - Check the belt tension, a loose belt creates gitter and a too tight also creates undesirable results.
    3 - I'll assume you are using MK electronics and 1 operator camera. If this is true, I'll guess you have connected the gimbal servos/Radian to the FlightCTRL. This works for light cameras, for DSLR the MK FlightCTRL can't supply enough Amps for the FreeFly servos/Radian. My suggestion is to install a BEC for the servos/radian. To do this, connect the negative (-)(comming from the Radian) to both FlightCTRL and the BEC, connect the plus (+) to the BEC only and the servo signals to the FlightCTRL only. By doing this you will keep the command coming from the FlightCTRL but with a much stronger power source coming from a separate BEC.
    3.1 - Another approach is to change the RECON on the FlightCTRL from a 5v to a 6.5v, I did this but this voids the FF Servo voltage limit. It is possible but I don't recommend.

    Good Luck and keep us informed ;)
     
  9. Chris Babiana

    Chris Babiana Member

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    Thanks for the reply Arthur.
    I did have a minor crash the other day...no damage but a hard landing the CS flipped over (sorry...forgot to mention that in previous posts). The gimbal was tweaked to the right a bit (realigned it) so possibly this is a realigning of the entire gimbal and balancing issue. I also noticed that the belt on the tilt axis was a bit loose...when pinched, it had about an 1/8 of an inch of play. Before the crash everything was working perfectly with the 5D mounted. I'll start there with the process of elimination.
    Regards!
     
  10. Chris Babiana

    Chris Babiana Member

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    Well...problem solved. (wheres the emoticon with two hands over the face...)
    Slightly (barely visible) misaligned gimbal from the flip which also resulted in a loose belt! Once again, running smooth as silk.
    Lesson? Check alignment, camera balance and belt tension first...oh, and try to land it on the landing gear...that helps! :cool:
    Thanks for all the guidance everyone, I'm sure it will come in handy in the future!
    Regards!
     
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  11. Colin

    Colin Member

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    Chris,
    Whatever you do, do not put anymore than 5V into the FF servos. Radian can take more. The servos cannot handle more than that. Our CC BEC was set by the dealer at 6.2v, we have gone through three servos in as many flights.
     
  12. Chris Babiana

    Chris Babiana Member

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    Thanks for the tip Colin!
     

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