Welcome to PhantomPilots.com

Sign up for a weekly email of the latest drone news & information

Drift (with GPS) and squeaky rotor after fitting ImmersionRC and iOSD mini

Discussion in 'Phantom 2 Help' started by spengbab, Sep 8, 2015.

  1. spengbab

    Joined:
    Sep 8, 2015
    Messages:
    13
    Likes Received:
    1
    Hello everyone, apologies for my first post being a request for help, but I'm somewhat baffled by what's up with my Phantom 2, and I'm eager to get it up-and-running again. I miss flying :(

    Yesterday, I popped the top off my Phantom 2 and I performed a few upgrades:
    • Fitted a mini iOSD, which is taped to the front (inside) of the drone
    • Moved the anti-interference board, for the gimbal, from outside to the inside, removing and refitting two screws (attaching it to the main board) - I can't really describe where, but I can find out if it's significant.
    • Moved the CAN-bus from one of the legs to the inside (I attached it to the main board with a little bit of folded-over tape
    • Fitted an ImmersionRC 600mW transmitter to the underside of the Phantom 2 using velcro
    Today, I took the drone out to try the video and noticed a few things:
    • The drone appears to drift, definitely more than it used to (I can't remember if it always drifts in the same direction, relative to the direction the drone is facing)
    • There's a squeaky noise coming from the rear-left motor (I think it's that one...)
    • The rear-left arm appears to vibrate (upon which the motor which I suspect is squeaking is mounted)
    I cut a few cable-ties off to re-route cables and didn't put some new ones on, but I don't think (I'm not certain) that it'd cause the symptoms I'm seeing.

    I grabbed a video of the vibrating/squeaking sound...



    ...and one of the drifting...



    I've tried a few advanced IMU recalibrations, plus a swap of the propellers for a new set, but it didn't seem to make much difference. I think the squeaking stopped on one flight, but the drifting was still present. It's definitely doing it again now (before the second recalibration), though.

    I have a few questions:
    • Is there a chance I've misaligned the IMU, so I need to do the 'paper trick' whilst calibrating?
    • Could the squeaking be caused by compensation from the misalignment?
    • Could the motor be iffy and causing the drift? (I guess I'd need to check if it always drifts in a particular direction)
    • Could adding the iOSD mini and ImmersionRC require me to adjust the gains? (I didn't have to whilst adding the Gimbal, which was the bulk of the weight)
    Thanks, and apologies for the longer-than-I-expected first post! :)
     
  2. kenjancef

    Joined:
    Jul 20, 2015
    Messages:
    1,202
    Likes Received:
    236
    Location:
    East Providence, RI
    Definitely not an authority on IMU or balancing, yet, but last week I did the same mod, put the anti-interference board inside, and installed the iOSD mini and ImmersionRC 600.

    Just a thought: when you had the Phantom flipped over to remove the screws to take off the top, do you think you may have pressed too hard to remove the screws? I have workout-type floor pads in my basement, and I did my work on it, and noticed that the prop-less motors were digging a pretty deep hole in the pads, so thought I was pressing too hard.

    Probably not the cause, but made me think of it...
     
  3. noiseboy72

    Joined:
    Jul 13, 2014
    Messages:
    575
    Likes Received:
    17
    Location:
    Lincs, UK
    Check you have fitted the top back on the right way round - daft, but it can happen.

    If you removed any motor screws, ensure you did not over tighten them.

    Make sure the top cover is not catching on a motor.

    Some days, GPS is better than others, as it depends upon how many satellites are in view and how well they are spaced. You can sometimes end up with 8-12 hot, but all of them within the same quadrant, so the position lock is not brilliant.

    I doubt gains will alter the drift, although you may have altered the centre of gravity slightly. If the bird hovers level, you probably have little to worry about. My P1 has the gimbal moved forward 30mm and the track mounted on the front and still flies and hovers fine without anything more than a calibration of the IMU.
     
  4. spengbab

    Joined:
    Sep 8, 2015
    Messages:
    13
    Likes Received:
    1
    I assume this means you didn't do any recalibration or anything?

    I guess this isn't impossible! I did find the first set of screws very difficult to undo. The drone was upside down on a wooden floor, which I wouldn't want to mark, so I can't imagine I would've pushed down too hard. I gave the suspect one a spin this morning and it felt just like the other three.

    I worked out which way the top came off by aligning the GPS cable (it was already bent/weaving leading to the port). I don't think I could've accidentally put it on a different way around without leaving the GPS disconnected.

    As far as I'm aware, I didn't touch them.

    It doesn't appear to be. If I spin up the motors without taking off, there's no squeaking sound.

    Thanks, 'kenjancef' and 'noiseboy72', for your replies :)

    Perhaps I'll take the top back off, remove the parts I added and see if it goes back to normal.
     
  5. Beagler

    Joined:
    Jul 23, 2015
    Messages:
    14
    Likes Received:
    0
    Location:
    Uk

    There's thrust up and down on the motor spindles that isnt there without props on.
     
  6. spengbab

    Joined:
    Sep 8, 2015
    Messages:
    13
    Likes Received:
    1
    I had the propellers on but didn't apply enough power to take off.
     
  7. Beagler

    Joined:
    Jul 23, 2015
    Messages:
    14
    Likes Received:
    0
    Location:
    Uk
    Apologies I thought you'd tried it without props just spooling the motors up.
     
  8. Marlin009

    Joined:
    Dec 31, 2014
    Messages:
    1,091
    Likes Received:
    515
    Location:
    West Coast of Florida
    You don't mention having done a compass calibration after the install. Did you?
     
  9. spengbab

    Joined:
    Sep 8, 2015
    Messages:
    13
    Likes Received:
    1
    No problem, thanks for contributing!

    Assuming that you mean the spinney GPS dance, yep! I do that before each flight :)
     
  10. jason

    Joined:
    Oct 12, 2014
    Messages:
    4,104
    Likes Received:
    404
    Location:
    Commerce Twp,MI
    I can tell you one thing that the equipment you installed inside your P2 have nothing to do with drifting problem you experiencing.

    When you preform an advanced IMU it should be done on a completely level surface as it effects all three axis of the gyroscope, acceleration and the compass all three of which control stability.

    If you have noise coming from one of the motors there is a possibility that there might have been some foreign substance in it causing the noise and after the flight it's no longer there. The other possibility could be a worn bearing.To check for worn bearings put on prop and see if there is any lateral or up/down movement in the motor.

    Remember you came here asking for help with a problem you were having and those of us who answered were only trying to help.

    One more thing that I noticed in the video is how you have the antenna pointed on your P2 it should be point straight down and not straight out.
     
  11. Marlin009

    Joined:
    Dec 31, 2014
    Messages:
    1,091
    Likes Received:
    515
    Location:
    West Coast of Florida
    You do turn the Phantom when you calibrate the compass. It has nothing to do with the GPS.

    Also, it is not necessary to do it every flight.
     
  12. spengbab

    Joined:
    Sep 8, 2015
    Messages:
    13
    Likes Received:
    1
    Thanks, I'll check this out :)

    Useful tip - I'll be sure to do that!

    I'm not quite sure what prompted you to say that? I've been extremely grateful for the tips and advice I've received.

    Ah, I've been calibrating the compass each time then :(
     
  13. jason

    Joined:
    Oct 12, 2014
    Messages:
    4,104
    Likes Received:
    404
    Location:
    Commerce Twp,MI
    I'd quit a bit of time if I were to calibrate the compass each time I changed location. Compass calibration is not necessary every time you go out to fly. The only time I do it is if I have made modification to the P2, driven across state or taken a trip out of the country. If there is a problem with the compass the rear LED's will indicate there is a problem or iOSD has a warning diamond icon which will be displayed at the bottom of the FPV monitor screen.
     
  14. spengbab

    Joined:
    Sep 8, 2015
    Messages:
    13
    Likes Received:
    1
    I've grabbed another video of the vibrating/squeaking, in daylight, just incase it demonstrates the problem better:



    Based on kenjancef's post, does anyone have any tips on how to diagnose a faulty motor?

    Perhaps I should contact DJI? Other than adjusting the gains, which jason suggests wouldn't make a difference, I'm out of ideas :(
     
  15. jason

    Joined:
    Oct 12, 2014
    Messages:
    4,104
    Likes Received:
    404
    Location:
    Commerce Twp,MI
    Well I see you removed all the equipment which I told you removing it would make no difference. I never suggested that adjusting gains wouldn't have any effect on the drifting which of course it will not solve the drifting problem. What will effect drifting is not doing an advanced IMU on completely level surface which should be done when ever you make modification to the P2 or after a crash followed by a compass calibration..

    It would be a total waste of time contacting DJI.
     
  16. spengbab

    Joined:
    Sep 8, 2015
    Messages:
    13
    Likes Received:
    1
    Yes, because I'm getting desperate/running out of ideas. You seem to have taken it personally. It wasn't intended to be a deliberate attempt to ignore you :)

    Yes, that was my mistake - I mixed you up with noiseboy72's thoughts on altering the gains...

    I've done multiple advanced IMU calibrations, all on level surfaces, to no avail - hence my last-ditch attempt by removing everything I added to the P2.
     
  17. jason

    Joined:
    Oct 12, 2014
    Messages:
    4,104
    Likes Received:
    404
    Location:
    Commerce Twp,MI
    If removing everything is going to make you happy so be it but I do not think it will resolve your problem.
    There are a great number of us flying with the same equipment both inside and outside the shell and have no problem whatsoever.
     
  18. spengbab

    Joined:
    Sep 8, 2015
    Messages:
    13
    Likes Received:
    1
    Quite the opposite. I'd rather everything be in there. But, as I said, it was a last-ditch attempt to diagnose what's wrong because nothing else has resolved my issues just yet.
     
  19. jason

    Joined:
    Oct 12, 2014
    Messages:
    4,104
    Likes Received:
    404
    Location:
    Commerce Twp,MI
    May the issue isn't the phantom.
     
  20. spengbab

    Joined:
    Sep 8, 2015
    Messages:
    13
    Likes Received:
    1
    What?

    I don't think this is really going to go much further. Thanks for your suggestions and prompt responses, Jason :)

    If I manage to get to the bottom of it, I'll report back, in-case it helps another person with mystery squeaking.