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Hiccups!

Discussion in 'Phantom 2 Vision Discussion' started by wincrasher, Jan 12, 2014.

  1. wincrasher

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    Mostly my Phantom 2 Vision works as advertised and I'm really having fun with it.

    But occasionally, it gets what my nephew called hiccups.

    You are traveling forward, at full throttle, and it pauses in hover mode for just a split second, and then continues on again forward.

    My first thoughts are that this is radio interference - it happens so quickly, that I can't see any message on the phone display.

    I am on the latest firmware. Should I recalibrate IMU and the compass? Any other things to check?

    I fly in a suburban environment, so plenty of radio interference sources is a given.
     
  2. amrflyingdude

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    I think this is an indiction that should should look further in to this before keep on going. Definitely not a normal behavior.

    I have a quick question. Have you flown your P2V somewhere else? did the same happen? that would be in my opinion your next test. If that happens again I would ground it.

    Definitely re calibrate compass and IMU's, also open a ticket with DJI, I know they are not responsive but if something else were to happen (hopefully not) at leas you have written documentation that you reported this issue.

    Hope this helps.
     
  3. wincrasher

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    yes it does happen at another location a few miles down the road.
     
  4. iDrone

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    If you can upload a video we might be able to better determine. Other info: Any low battery warnings? How many bars on the battery remaining? How many % battery in the app remaining? Does this only happen when throttling full power? What distance & approx altitude? Has your Vision ever had prop guards on it?

    iDrone
     
  5. wincrasher

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    On video, all you see if the image bounce violently up and down - just a blip.

    I haven't seen any correlation with % battery level. Certainly can't say it's only at low level, as it's happened at beginnings of flight, and fairly well into it. Distance is usually a few hundred feet away, but it has done it passing directly overhead. Altitude is usually 150 to 200 feet high. I've never noticed it at really low altitudes, probably because I slow down at really low elevations.

    The only thing constant is that I've only experienced it at full throttle. I will do some runs a partial throttle and see if I can reproduce it.

    Never had prop guards.
     
  6. Seandyt

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    Check colin vid, i think its has been explained in it as a flyaway prevention algorithm....if p2v go in 1 direction more than 10 sec....it will hover to detirmen if its gonna be fly away or not, so you must respond by move your stick to any direction to regain control
     
  7. wincrasher

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    You may be on to something - I'll have to check if the amount of time I'm holding the throttle down is related to this behavior, but I have my doubts, as I think it's done it during long sweeping turns.

    I can say that it didn't do this before I upgraded from 1.05 to 1.08.
     
  8. gunslinger

    gunslinger Moderator
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    I've seen this as well. I was trying to get mine to go over 40MPH a week or so ago and, naturally, this entailed full throttle for an extended period of time. I saw a short interference with forward progress at one point in every run. A blip!

    It would make sense that this is the algorithm that Colin was alluding to. It's just making sure that it's actually us going full throttle on purpose and not some outside interference...

    -slinger
     
  9. iDrone

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    If you're noticing this behavior starting on v1.08 and not v1.05 I'd say it's not related to continuous-stick receiver confusion issues. I'm starting to see more & more reports of anomalies with erroneous battery % remaining vrs battery led's, auto-landings, and loss of power... and they all appear to be connected with throttle-up's ever since v1.08 was released. Here's what v1.05 was supposed to remedy (in part):

    In previous receiver firmware (before v1.05) the receiver could misconstrue another signal on the same channel as being yours -if- you transmitted the same command & value constantly for several seconds. Taking a stick all the way to its limit and holding it there w/o moving it will satisfy this condition and cause the Phantom to continue flying in that direction.


    iDrone
     
  10. gunslinger

    gunslinger Moderator
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    I can't say for sure, iDrone, as I never noticed this issue pre-v1.08... By the same token, I never really had it going this fast for this length of time until after the v1.08 upgrade...

    -slinger
     
  11. gunslinger

    gunslinger Moderator
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    I was just looking at the video http://www.youtube.com/watch?v=R8v6LFM2wNg and at the 19 second mark, you can see it distinctly. This is almost exactly 10 seconds into a high speed run... Coincidence? Maybe...

    -slinger
     
  12. iDrone

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    Sorry slinger we cross-posted as I edited to add the 2nd paragraph about what older firmware was prone too. But none of this excludes their making a mistake and creating another glitch while thy tried to fix that bug. All these things seem to be continuous-stick or power-throttle related, and might explain the blips, wierd battery readings & warnings, and auto-landings. BTW in Vision mode if you flip S1 in & out of Up position it'll cause it to buck. So I wonder if the NAZA autopilot is dropping out & back into GPS mode (blip) because of battery reading issues?

    iDrone
     
  13. gunslinger

    gunslinger Moderator
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    Oh... NP on the cross post. I was just curious as to when I saw that blip in my vid and was kind of surprised to see it at the 10 second mark. Frankly I didn't even notice the blip until I was editing. At first I thought it was me, releasing the throttle, but that happened a few seconds later. It does seem that something is going on with a "continuous stick" condition... Good point...

    -slinger
     
  14. garygid

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    Under high power usage, the battery voltage will sag down, and the new code that
    no longer "requires" the battery data connection might be sensing a too-low
    battery condition, and be preparing to do a low-battery failsafe, where the P2V
    would go into a hover mode. But then, finding that the battery voltage recovers
    in the lower power hover, it aborts (or does not actually enter) the failsafe, and
    continues the high-speed flight?
     
  15. iDrone

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    I knew I shouldn't have clicked on that videolink, I didn't realize it was your video. (I've been avoiding looking at Flytrex videos for fear my wallet might get thinner). Wow! So that's what it looks like, I'm so seriously in trouble. I guess I'm going to have to join the throng. I won't hijack this thread, but I see I have some homework to do. Back to the topic...

    Yeah I see the blip in your run @19sec (Gawd I love that overlay!) Shot in the dark here, but if my suspicions are correct anyone on v1.08 will be able to duplicate this after pulling a 10sec sustained pegged-throttle...

    :idea: I think they may have patched a watchdog timer into the last TX upgrade which breaks-off the transmission for a few milliseconds if the stick value doesn't change (blip!) then resumes sending the command / signal. This would allow Vision's receiver to know its you and not some other stray continuous signal on 5.8Ghz.

    :idea: The workaround would be to not peg the stick, but to hold it near the edge of the rim so the stick position value is constantly wavering a little.

    As for the other problem: sudden throttle-up (<10sec) causes low-battery alarm, red outline screen, klaxon, etc... this is probably more about the firmware changes they made to the CB/PMU which monitors battery capacity, or a defective battery.

    iDrone
     
  16. iDrone

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    Slinger, according to your Flytrex clock it looks like around 8secs to the blip. Wincrasher, have a look at your videos and tell us if you see a similar pattern: how many seconds between throttle-up and the blip?

    iDrone
     
  17. wincrasher

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    Flew a little today - not much as it's pretty cold.

    Kept the throttle below full and it behaved normally the whole time. So definitely think the problem is tied to full throttle.