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30.1 m/s decent rate ...

Discussion in 'General Discussion' started by datincan, May 31, 2016.

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  1. datincan

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    So, this could apply to any phantom I guess, mine, a P2 with HD3 and Go Pro, with boscam downlink.

    Flying fine as normal yesterday, after the 2nd flight just coming into the LZ at about 50m the phantom starts to drop on it's on accord. No low battery, no loss of signal, no obvious anything. It came down slowly and wouldn't respond to stick up. It only bounced very slightly on the dirt road, nothing broken, back two props went into the grass verge only a tiny chip in a back prop. The gimbal even stayed fully attached.

    Since yesterday, it won't hold position, taking off and hovering it drifts left or right and after about 30sec it will loose altitude and drop. The motors seem fine, no obvious overheating, pressurised air run through the motors - no strange noise like something in the motor, the emu has been calibrated advanced. After reading a few posts here and other forums, I've taken out the Naza and given it a good beating on its side to free up something that may be jammed.

    The onscreen display shows even when the phantom is on the deck that it has a forward V of about 0.4m/s and the vertical swings kind of around -0.2, to 0.5 m/s.....?
    Just now I've come in from another failed attempt to diagnose, this while the phantom had again uncontrolled landed in the soft grass, and it sitting upside down, I spotted that the decent velocity was 30.1m/s..even while the thing was turtled and stationary - this v speed gradually slowed to zero by the time I walked 15 sec over to pick it up again....

    Is a new naza the most likely fix? Just before I splash out on one I'd love to hear any other maybe fixes....
    Thanks
     
    #1 datincan, May 31, 2016
    Last edited: May 31, 2016
  2. Mako79

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    When was the last time you recalibrated the gyro and accelerometer??
    Find a level place. Don't fly your phantom for an hour and keep it in a cool place.
    Have you Phantom assist ready. Find the Calibrate Adv IMU screen. Plug your phantom into the USB and do the IMU adv calibration the moment the button allows you to. The quicker you do the calibration, the better the calibration. Just don't let your phantom warm up.
     
  3. datincan

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    Hi ya, thanks for the advice, unfortunately I've recalibrate the IMU lots today, I had an error 34 , (an imu cal required error) at one stage after banging the naza hard on the bench to free any jammed sensor. The cal completed and the error went away.
    Thanks all the same )
     
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  4. Mako79

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    Sounds like you had a stuck IMU value. Its like a value of +/-16. And yes, the bang will release the stuck value and fix the IMU. I assume you this has resolved your problem.
     
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  5. datincan

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    Ah no it's still the same, it did seem to behave for about 30 seconds, and then went crazy again, dropped altitude, still wouldn't respond to stick up while in its own decent, and soft landed into the grass. It that's the point when it was turtled I noticed the totally false 30.1m/s decent rate coming from the imu as it lay stationary.
    I guess I'll be taking it out again to give it another beating...It would be great if there was a way to open it up so only to shock the necessary parts and not potentially destroy the casing.
    Thanks again, appreciated )
     
  6. Mako79

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    Can you plug into your PC and have a look at the IMU status. You might still have a stuck IMU value.
     
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  7. datincan

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    Hi ya, Nope the IMU status seems ok the value is about 1400. I'm going to take out the naza for more banging around and see if it changes anything...
    I can't remember from before but when the phantom is on the deck before take off, the measurements for forward and vertical speed should be zero obviously, I'm getting small changes, forward speed about 0.4m/s and vertical about the same, is this normal?
     
  8. datincan

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    I've now taken the naza out again and this time really bashed it hard against the ground. The phantom came back on with a code 34 error, that cleared after a calibration, but it is still flying out of control..
    I'm lucky that I have a large soft grass area where I can take off and not be too worried of a crash land.
    Here is a video of the last normal flight, @ 7.06 mins something seems to happen to the phantom, it descends but with some yaw input still having effect.

    d HD 720p
     
    #8 datincan, Jun 1, 2016
    Last edited: Jun 1, 2016
  9. Mako79

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    1400??? That's not the Gyro/Accelerometer. That looks more like compass values. Your IMU should have a mod value of 0 and 1.
     
  10. datincan

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    Hi ya, yes you are right, that is the compass value, my mistake...) the Gyro/Accelerometer values are normal, at about 0.6 and 1.
    Still scratching my head as they seem to be ok.
    I don't know heater to start replacing esc's and motors, or the naza...thanks for the advice )
     
  11. datincan

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    Here is a screen shot of from the P2 software...just tried another take off....I take it up a meter or two, it keeps drifting to port at about 5kph then it won't respond to stick up, and comes down by itself...
    Screen Shot 2016-06-02 at 02.14.03.png
     
  12. Mako79

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    Your IMU looks fine.

    You need to recalibrate both your sticks again in BOTH software
    Download the RC12 assist and recalibrate your sticks AND sliders.
    Then recalibrate the sticks again in the Phantom assist.

    Then goto and open field free of metallic interference and do the compass dance.

    Also, it going down by itself could be low voltage - battery could be on the way out. Do you have telemetry? can you see a steep drop in battery percentage???
     
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  13. datincan

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    Hi, thanks again,
    I've just had a look around for that software, I can find on the Dji site, the phantom 2 is not listed a model in the support page! I google searched for the software, a dji forum post that talks about the same software does have a manual method of calibration Updated controller firmware--gimbal thumbwheel erratic and can't recalibrate. ...I wonder if this would work? or maybe you might know here I could get it...If not I'll try the manual method.

    The battery is fine, I have 5 of the 2 stock and 3 good quality aftermarket 5400mAh, I've cycled through all the batteries at this stage, it's the same flying experience with each one...
    It's that sudden bump in the video at 7.06 sec, I'd love to know what it was ...
    Screen Shot 2016-06-02 at 03.15.10.png
     
  14. datincan

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    So I've done the above calibrations, both types of radio, manual, which worked like the above data sheet, and then through the P2 programme, advance cal'd the IMU, no errors, and did the compass dance. All figures were normal. I took it out up to about 2 metres, still is drifting sideways and after about 30 sec is coming down with no stick input having effect..
    I have 4 T-motors sitting here that I was at some stage going to use on new build. I'm now going to install these and report back what happens.
     
  15. datincan

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    So, I found the RC software thanks, I was looking in the wrong place....I got 4 new T-mmotors on last night, went through the radio calibration again,....There was out of difference at resting of 13 on the R channel....I re-calibrated it, that seemed to work...I noticed there was firmware upgrade...did this...during the upgrade, a warning message came up as upgrade failed...the radio now seems to be bricked....searching the forums for a solution...


    edit...reconnected to the RC software this morning...the upgrade succeeded...
     
    #15 datincan, Jun 3, 2016
    Last edited: Jun 3, 2016
  16. datincan

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    Update... new motors, seem to have solved this....thanks for the advice...