CINESTAR 8 HL/MK FAILURE!! Help please

Discussion in 'Cinestar 8' started by Justin Marx, May 29, 2014.

  1. Adam Paugh

    Adam Paugh Distributor

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    Gentlemen,

    In attachment is a document that contains a preflight checklist and general in-flight standards for UAS operations. I drafted it some time ago and it is given to the attendees of our QC familiarizations. We are currently working on a reference version that will be laminated to keep in your Pelican cases.
    I thought it would be an appropriate time to share this with you all as we are speaking to both potential GPS irregularities and hardware issues.
    Looking forward to your feedback.

    Greetings,
    Adam
     

    Attached Files:

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  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I think it's more likely than not to be an issue with the GPS -- but whether it was a problem with the reception of the GPS satellite signals or an issue caused on the Nav board by the processing of the data is a harder call.

    One thing that is interesting that we've not discussed thus far is the target distance/bearing.

    My understanding -- I think we need to confirm this with Holger -- is that the "Target," if you are not flying waypoints, is actually the current "home" position. If that is correct, have a look at row 322 onwards. Up until then the target distance has been pretty rational, but it suddenly, within the space of 500 milliseconds it changes from 29.9 meters to 3.9.

    Here's a plot of the target distance (MK_GPXTOOL has a nice plot capability). I suspect this is related to the violent excursions on the GPS controls that I mentioned earlier.

    Andy.

    Justin\'s GPX file - target distance.png
     
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  3. Steve Maller

    Steve Maller UAV Grief Counselor

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    Justin, can you post a couple photos of your copter, specifically how you have your batteries and your GPS mounted?
     
  4. Steve Maller

    Steve Maller UAV Grief Counselor

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    Good find, Andy. Ever thought about doing forensics for a living?

    Nah, I didn’t think so. ;)

    There’s clearly a “chicken and egg” problem here. Those spikes (to my eye) correlate to the oscillations of the GPSSticks. But did one cause the other? Or are they both symptoms of something else?
     
  5. Gary Haynes

    Gary Haynes Administrator
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    Justin the flyaway rate of Phantoms is legendary. And that's just the ones where people post to youtube or something else that you hear about.
     
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  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Nah. There's no future to computers and the Internet. They're just fads like hula hoops and pet rocks.

    Good question. But let's imagine that the autopilot goes bonkers (technical term) and starts throwing in wild nick/roll maneuvers. Why would that affect the "home" position? The copter would spaz out in the air, but why would the target bearing/distance change?

    Conversely if the GPS/Nav board's "understanding" of where it was in three-space suddenly changes, then, to the Nav board (either in PH or CH), it would suddenly appear that the copter wasn't where it was supposed to be in three-space. Fortunately, the AH was on so it didn't suddenly climb or descend otherwise Justin's underwear would have been in really much worse shape.

    So, given my initial premise that the target bearing/distance is indeed "home," and given that the GPS position suddenly appeared to be roaming around the sky, what we see is consistent. The copter suddenly goes into "I urgently need to be elsewhere" mode.

    One other thing: you'll see that, even though the copter is in AH, the altitude does vary considerably -- but then check the RC sticks and you can see that (not at all unreasonably) Justin is making some quite large throttle movements as he fights to bring the copter home.

    That's my $0.02 anyway -- and it's probably worth even less than that.

    Dave/Steve: have you already emailed Holger to ask about target bearing/distance? If not, I will.

    Andy.
     
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  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Steve/Dave: I have already emailed Holger. He has requested the GPX file (which I just sent him). I'll let you know what he says.

    Andy.
     
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  8. Steve Maller

    Steve Maller UAV Grief Counselor

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    I believe that the exaggerated stick movements (either/or manual or GPS-induced) probably caused the copter to lose lift, which also might have contributed to what Justin was seeing. As we know, when the Cinestar banks at more than 20-30°, it needs significantly more thrust to stay in the air. I do see dramatically higher current draws, which are consistent with that issue.
     
  9. Justin Marx

    Justin Marx Active Member

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    Hey guys, so much information! Amazing!! I'm definitely learning a lot with this..

    I never lost lift via GPS, at the start I tried to bring it down myself, but as it kept acting erratic, I decided I'd like it higher so I could see it and not hit anything ..

    I definitely understand not to ever rely on GPS and that I should just use it when only needed.

    As far as it being bullet proof, I never really expected that.. I just expected that if I were to have issues that it would be in an area that close to something like a tower, or buildings, or something that looked like it was going to shoot GPS DEATH rays at me.. Not a residential neighborhood..

    I'm kind of glad it happened honestly.. Yea I ruined a pair of boxer shorts, and I gained some more gray hair, but I didn't do it at the expense of a human, property or the copter..

    Out of curiosity - Lets say a ribbon cable came loose from either the NAVI or the FLT Ctrl, and I switched to Manual, - what will/should happen?

    Pix attached..

    Cop image-3.jpeg image-2.jpeg image.jpeg image-4.jpeg
     
  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I believe this is a QC RTF -- so it looks like a nice clean build.

    Alternatively, use it when you need it, but, at the first sign of trouble revert to manual control.

    If you put on glasses that would show you radio frequencies, a residential neighborhood is buzzing with Wifi, Cell phones, microwave ovens, etc.

    Guess what frequencies Wifi and microwave ovens operate at? :)
    2.4Ghz.
    Guess what frequency your transmitter controlling the copter operates at.
    2.4Ghz.
    Some cell phones operate at 1.9Ghz and some at 2.5Ghz -- but get into a high powered beam from a transmitter and frequency doesn't matter -- it will over power your transmitter signal.


    Bad Things happen. It may crash, or you may see sporadic "glitches" in the flight characteristics.

    How many flight hours do you have with this copter, out of curiosity? EDIT: I'm just curious as to whether the flight hours were high enough to have caused loose cables.

    Andy.
     
  11. Justin Marx

    Justin Marx Active Member

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    Very true about all the wireless in neighborhoods..

    I'd say I have about 20 flights on this copter..
     
  12. Chris Fox

    Chris Fox Active Member

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    G'Day Justin,

    I'll put money on the erratic behaviour being that XBee ribbon cable slowly working loose ... the flight behaviour is nearly identical the incident that I experienced. Nobody has to be viewing data, the xbee when connected is still forming the electrical circuit and if the connection gets flakey it messes with your nav controller and hence GPS Stick inputs.

    Cheers
    Chris
     
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  13. Chris Fox

    Chris Fox Active Member

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    I've had plenty of problems with PH performance that have had to be worked through, including the ribbon cables separating from the NC board during flight .... which is on the copter I bought RTF (thankfully that is in the deep dark past, which was something less than a stellar build (it was not a Quadrocopter build)

    So, in order of ribbon cable disconnect undesirables

    1. Ribbon cable from Xbee or MK(equivalent) to NC - Bad things happen when you remain in GPS PH, CF, or CH ... switch GPS off, and copter settles down and flies straight and normal, with no GPS/NAV contributions. This does not register as a failure mode in the NC or FC, the copter is receiving incomplete commands, and the failure mode is not graceful.
    2. 6 Pin ribbon cable FC to NC - You loose position hold, bad things don't happen but warnings start beeping away about no connection to NC, or NC failure. The failure mode is graceful
    3. 10 pin ribbon cable FC to NC - Haven't experienced this one yet ... and probably won't (fingers crossed) to much hot glue in use when I use MK electronics, and the other electronics don't have ribbon cables.

    Cheers

    Chris
     
  14. Justin Marx

    Justin Marx Active Member

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    Chri
    Chris!! This is the most interesting thing yet! If this is true then I can see this being the problem.. I had no idea that the Xbee being connected/disconnected could actually effect the the GPS..... Verrrrrrry interesting!!!!!
     
  15. Chris Fox

    Chris Fox Active Member

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    The radio connection is used for monitoring, but also for programming way points in flight. So if something goes screwy in in the communications from the xbee to the NC, you don't really know what the NC is being told to do.

    Just have a look at some of the waypoint videos from Holger on programming waypoints and then flying them, you can update things such as the next way point to fly to and the home position. And when waypoints are loaded into the NC, the trigger to make the copter fly to a waypoint is to engage CH

    The loose connection can be at either end of the ribbon cable i.e. the NC end or the Xbee end, and result is the same problem, you can even do some pretty horrible things inflight with the Xbee connected if you make a change and write a change to the FC, the copter FC will reboot. So for a good couple of seconds the copter becomes a rock, and will make a straight line for the centre of the planet.

    My 2 cents on flying with an Xbee of MK equivalent attached. Don't, unless you are trying to monitor something specific, or you need to watch the progress of the copter when flying waypoints (but you get a lot of WP info on the transmitter itself if you are using a MC20 or MC32 and don't really need it on the computer screen)

    The Xbee or MK thingy, can present this problem, even if you don't have a computer on with the other end of the connection running.
     
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  16. Dave King

    Dave King Well-Known Member

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    Justin

    I never keep the Xbee hooked up unless I need it. For one it can interfer with GPS signals and cause issues. I only hook it up when I need to reconfirm balance.
     
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  17. Dave King

    Dave King Well-Known Member

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    This has nothing to do with your issues you posted but I also notice that you are mounting your FPV transmitter on the hub and having the antenna point up. You might find that if you mount it on the boom and have it point down you will have better luck especially if you are using a 5.8 transmitter.
     
  18. Justin Marx

    Justin Marx Active Member

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    Great information in the Xbee! Thank you! I really think that could be one really big factor.

    Dave, the only reason it's pointed up is pointing down interferes with the panning of the MoVI. Pretty sure it works both ways well', just not straight..

    Thank you!!

    Going to fly today with Jose and Leo.. Will keep you guys updated..
     
  19. Steve Maller

    Steve Maller UAV Grief Counselor

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    As if the deities were watching, I encountered this today.

    When I landed after an uneventful flight (no warnings, no alerts), I looked down at the Graupner and noticed an error (GPS FIX LOST). Curious. I used PH quite a bit for testing the gimbal, and didn’t notice anything untoward. And I flew again afterwards and gingerly used my GPS again, and it worked fine.

    When I got home, I looked at my GPX file, and sure enough, saw this:
    Errors / warnings:
    Error "ERR: GPS lost" (21) occured 6 times!
    And confirmed in the list view that there were several exceptions thrown.
    I find it interesting that these were right around when I disabled the MK.
    My landing was fine, although it was on uneven ground, but otherwise nominal.
    I wonder if there was something like a large power line underground, or what.
    Solar weather wasn’t particularly alarming.
    Double checked all connections, and, like I said, flew another pair of batteries on a long flight (almost 10 minutes) right afterwards with no errors whatsoever.

    Parallels Desktop-snap001.jpg
     
  20. Justin Marx

    Justin Marx Active Member

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    Hey guys, quick update.. Not sure if this is the cause of the problem, but after 2 flights I noticed the ribbon cable came out of the NAVI a tiny bit. Enough where I could push it back in and notice that it actually did move..

    Otherwise the flights went well.. Definitely not flying again without hot gluing these in.. Honestly it should be mandatory to fly with them hot glued or secured in some way.

    Thanks for all the help and will keep you posted!
     

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