Loss of Tilt Control During Flight

Discussion in 'Radian' started by Louis Wilsher, Sep 29, 2012.

  1. Louis Wilsher

    Louis Wilsher New Member

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    I have been having a problem with loosing control of the tilt slew during flight. We are running a duel system with a 2-axis gimbal. The problem is that after about 25 seconds of flight, my tilt radian makes a little jump similar to the one on start-up and then either the tilt slew control is totally dead, drifts down at neutral stick, slews up (with no down control/correction at all at the stick) or slews down (with no up control). I have to constantly turn it off and on during flight in an attempt to re-set, but most of the time this does not solve the problem (or the problem changes between one of the four listed above).

    This has happened with the spektrum satellite plugged directly in to the tilt or when running it from the roll.

    I am powering the Radian from the MK board, so could this be a power issue? Also, it is not consistent. Yesterday it happened once and today I got nothing but problems......
     
  2. Josh Lambeth

    Josh Lambeth Well-Known Member

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    Yes, my guess is your drawing to much power from the MK board and the system is going to brown-out... I too had this issue when running from the MK Board. Once I switched to the BEC I haven't had this issue at all.

    Josh
     
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  3. Jon Fredericks

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    Thanks Josh, very good to know you had the same challenges. We figured it was likely a power draw issue from the MK board. At first we thought it was somewhat peculiar because even when we are running (2) 5400's in parallel with plenty of juice, we still have the issue. But we suspected it is the MK's ability (or disability) to regulate proper amperage to the radian/servos. Time for a dedicated power source...

    Thanks!
    Jon
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Jon: Which "MK Board" are you (or were you) drawing power? If it was the Flight Control Board it's only got 5v at 1.0 Amp. Each Servo takes a max of 1.5A..... :(

    Andy.
     
  5. John Cunningham

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    Definitely sounds like a power issue. When the Radian comes back, it is trying to initialise its IMU but it can't because it is not stationary.

    The Radian will not reset until the voltage drops < 2.1 volts.
     
  6. Jon Fredericks

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    Andy - power is currently coming from MK FC board (not the dist. ring) to the Radian roll module. So that is definitely the problem, eh? I just ordered the BEC, and even though we are only running a 2-axis gimbal I think we will set it up with dedicated power instead of drawing from the motor batteries. We fly at high elevations, and have noticed a drop in our already short flight times since installing the Rad. I think a dedicated 3s lipo for the gimbal might be the way to go. What do you think?

    I appreciate the support.
     
  7. Steen Jensen

    Steen Jensen Member

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    I have the same problem, loosing tilt when flying, but I`m running on seperate power. I`ve got a 2200mah 3s through a bec that powers the 3axes stuff.
    I`m wondering if it is a power problem maybe my bec is too small. its a standard 3amp max 5, but I`m running the 3 radians- receiver - 800mw downlink transmitter and freefly hdmi converter.

    Also when I connect the power and initialise, I have to try 1-3 times before the radians all work. By that I mean that many times when I connect power, I end up with steady yellow and green (green not blinking), so I disconnect power again and power up again.

    What do you think ?

    regards bison
     
  8. John Cunningham

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    Bison,

    Are your units new or from the beta testing ?. The beta units have a problem where they sometimes enter the bootloader on power up. The fix is to have a jumper between the signal pin and Ground on port 5 of the radian. The problem is fixed on the production units.

    Digital servos can really spike the power supply so I suspect your BEC is too small considering the load you have on it. If you have another BEC, it might be a good idea to try powering the downlink and HDMI converter separately.
     
  9. Steen Jensen

    Steen Jensen Member

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    Hi JohnC Brand new production radian units from the official release. Have just ordered this sbec:

    DYMOND Switch-BEC 5A is useable to transform 8-42V from the battery to 5V or 6V for the receiver input. The system works with constant 5 Amp (peak 7,5A) and is useable for up to 6-10 normal servos.
    This might help on the loose of tilt control in flight.
    I`ll will use this only for the radians and receiver, and then use the other 3amp bec for the downlink and hdmi converter and see the results.

    regards
    Bison
     
  10. John Cunningham

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    Good plan : it should at least prove the cause.

    The production Radians will have a solid green + yellow once they are initialised and have sbus/ppm/Spektrum data valid - but they will flash for a second or two at first while it initialises. When it goes into bootloader, they are solid from power-up.
     
  11. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Jon: Sorry for my late $0.02, but yes, a separate 3S Lipo would be a good thing. You might want to equip it with it's own low voltage alarm so that you don't accidentally over-discharge it.

    Andy.
     
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  12. Adam Paugh

    Adam Paugh Distributor

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    Hello Jon F.
    +1 with Andy. A dedicated power supply is a good idea. This way the Flight control will be unaffected in the unlikely event of a gimbal stall.
    Greetings,
    Adam
     
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  13. Louis Wilsher

    Louis Wilsher New Member

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    Thanks for all the input. Going to try the BEC with a 3c battery and hopefully that works!
     
  14. Louis Wilsher

    Louis Wilsher New Member

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    Revisiting this issue again.....So I got a dedicated 3s battery to power the Radians and a Castle BEC outputting 5.1 volts w/10 amp peak. The Radians are the only thing powered by this battery.

    I am having issues with the roll going haywire - it rolls hard just before take-off and then sometimes while flying. Here is a video that shows what I mean:



    Password: radianroll

    Is anyone else having this problem? I need to figure out how to make it stop ASAP!
     
  15. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    ??? indeed. It looks like it's quite happy to roll left or right.

    Could you post a screen shot of how you have the roll Radian sensor programmed please, Mr. Bill.
    Also can you confirm the wiring going into each port of the roll Radian sensor.

    It's more a case of trying to eliminate anything obvious before concluding that the Radian sensor is bonkers.

    Thanks
    Andy.
     
  16. Tabb Firchau

    Tabb Firchau Administrator
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    How do you have things wired up? Also did you update to latest FW1.02?

    Thanks!

    Tabb
     
  17. Louis Wilsher

    Louis Wilsher New Member

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    Andy - will have to get you that screen shot tomorrow....

    Tabb, I am wired as follows: power from BEC into roll Port 1, S.BUS out of Port 3 (to Port 1 on tilt module), Port 4 to servo. I am not running 1.02, but I guess I will update tomorrow.....
     
  18. Tabb Firchau

    Tabb Firchau Administrator
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    Hey Bill,

    Plug power into another port besides port 1, that should fix you right up.

    Best,

    Tabb
     
  19. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Mr. Bill: No need to send the screen shot if Tabb's advice solves the problem!

    Andy.
     
  20. Steen Jensen

    Steen Jensen Member

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    Hi I`ve got the same issue and worse - total loss of control over the gimbal.

    when operating the gimbal jumps from time to time

    Here you can see it on a video in the air (stabi is horrible)

    http://www.kameratest.dk/radian_control_error2.mp4


    Other times you suddenly loose control over the whole gimbal, as you can see on the video here...

    http://www.kameratest.dk/radian_control_error1.mp4

    if you give full left stick you can get the pan to stop, and if you give full right it just pans quicker in the same direction..

    when you flip the mode switch to stabilize roll and tilt it goes to to that position. Going back to full mode, it continue the strange behaviour

    when you flip the switch to "gimbal off" and back to full control, it works for a while again..

    Radian Firmware 1.02
    Radians got its own 5amp (7.5amt) BEC
    Transmitter is MX 20
    Receiver is GR-24

    Wiring is from BEC to GR-24 receiver and from ppm out to the pan port1

    PAN
    ---
    ppm from receiver to port 1 on the pan.
    port 3 to Roll port 1
    servo on port 4

    Roll
    ----
    ppm from pan to port 1 on the roll.
    port 3 to tilt port 1
    servo on port 4

    Tilt
    ----
    ppm from roll to port 1 on the tilt.
    servo on port 4

    Regards
    Bison
     

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