inconsistent roll axis going from off to fix/stabilized on mode switch

Discussion in 'Radian' started by Rick Marcus, Oct 4, 2012.

  1. Rick Marcus

    Rick Marcus New Member

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    Does anyone know why I would be getting inconsistent results with my mode switch going from off to fix/stabalized. After I have initialized on the ground, each time I go from the off position to fixed/stabalized on my mode switch I am getting a slightly different angle on my roll axis, and usually not level.
     
  2. Tabb Firchau

    Tabb Firchau Administrator
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    Hi Rick, Just to understand you are initializing on the ground, then hanging the multi rotor and going from off to stabilized?

    If the multi rotor is swinging around at all the Radian will try and bring the roll axis level. Are you sure that you have the Radian square to the roll axis and / or have adjusted the angle trim to acheive a perfectly level roll axis?

    A video would be helpful if you can manage!

    Tabb
     
  3. Rick Marcus

    Rick Marcus New Member

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    Hey Tabb. Here is a video showing my roll axis results. Camera is perfectly balanced on all axis. Please let me know your thoughts. I am still getting some shaky footage and am trying to troubleshoot.

     
  4. John Cunningham

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    Rick,

    It looks like you might be going from 'Off' directly into 'stabilised' mode. This will run the Radian through the motor initialisation then into stabilised mode. The motor initialisation moves the mount a few degrees to verify it is driving properly. If you have a slew channel allocated to the roll, it will then be under command from the radio.

    You need to either go into 'fixed position' before you go into 'slew' mode so that the axis is driven to 'zero' or remove the slew control channel and it will be in 'fixed position' all the time (unless it is 'off' of course).
     
  5. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    JohnC : would going from off to stabilised [sic] mode happen if you use a two position switch to control the mode and thus you move from the Red part of the mode bar directly into the green?

    Rick: Are you using a two position or three position switch please?

    Thanks
    Andy
     
  6. Rick Marcus

    Rick Marcus New Member

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    Hey guys. I am using a three position switch, using the Spectrum dx8. I am going from the off, red position of the bar, to the middle - yellow position of the mode bar. For the example above I have not entered the green, slew mode. Each time I go from red to yellow, I end up with a slightly different position, only level some of the time randomly.

    Thanks,
    Rick
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Thanks, Rick.
    So you're going from Off to Fixed Position Stabilized. Hmm.

    Next things to check (sorry to make you do all this, but obviously we cannot see your set up):

    1. Are you using the Spektrum Satellite or main receiver?

    2. For each of the six ports on the roll Radian servo, can you tell us what you have plugged in?

    3. Could you post a screen shot of the current settings you have for the roll Radian servo?

    4. Also, what do you see happening in the Current Angle/Demand window for the roll Radian servo as you cycle the switch? Does it reflect this jumping to new angle behavior?

    Thanks
    Andy
     
  8. Rick Marcus

    Rick Marcus New Member

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    1. I am using the Spektrum Satellite
    2. Port 1- coming from port 3 on pan radian. Port 2-empty. Port 3-going to port 1 on tilt radian. Port 4 -going to roll servo. Port 5 & 6 - empty.
    3. See attachment
    4. Yes, the Current Angle/Demand is reflecting the change each time.

    I am noticing that after I initialize it snaps to position and then creeps back a degree or 2. It does this whether my gain is set to 30 or 120.

    Thanks,
    Rick
     

    Attached Files:

  9. John Cunningham

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    Hey Rick,

    It looks like it has quite a large offset to the servo at null (+22%) : what resistors do you have for the servo motor (which replace the pot) ?.

    Can you swap the resistor pack for the tilt and roll servos and see if you get the same symptoms ?.
     
  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Thanks, Rick.
    Looks like the Radian is wired up correctly (but then you probably double checked that! :) )

    There are couple of oddities I notice in the screen shots:

    Edit: Disregard item 1. I'm wrong. They're checkboxes, but not user selectable and the Radians use S.bus for the daisy chain from one servo to another. (Thanks for the clarification, Tabb.)
    1. Diagnostic window: You have the Sbus checkbox checked and I suspect you might need to have Spektrum checked.

    2. Configuration window: The Slew Rate is set to 0. On my set up (and as shown in the documentation) it's set to 60. I'm not sure quite what effect that would have. Did you set it to zero or was that set when you turned Slew off?

    Beyond those, I think I'll need to defer to JohnC and/or Tabb's superior knowledge at this point, I'm afraid.

    Andy.
     
  11. Arthur Vieira

    Arthur Vieira Flight Squad

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    Rick,
    Just a very, very, very wild guess.... Are you sure you don't have any kind of mixer / Dual Rate / Flight Condition set to the same DX8 Switch? Also, are you using a hacked DX8 with Sexpander? If you are, please turn it off and test again.
    Good luck.
     

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