Crashed, fixed (thought so), test flight ... then wierd behavior! HELP!

Discussion in 'Cinestar 8' started by Sebastian Meredith, Dec 1, 2014.

  1. Gary Haynes

    Gary Haynes Administrator
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    It really looks like the behavior or a prop mounted on an incorrect motor (CW on a CCW motor) or one or more motors rotating in the incorrect direction. Have you carefully checked all rotations, both motor and props, checking them one at a time?
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Sebastian:
    Unfortunately, without seeing what was going on in the real world, I cannot tell whether the 3D copter was correctly depicting what was happening with the Cinestar. I'm afraid only you can know whether the 3D copter was moving proportionally to what you were doing with the Cinestar.

    The same is true with the GPX files -- the first one looks a bit weird for the motor currents. The second one is OK but the GPS Lost errors show up. However, not knowing what you were actually doing with the Cinestar makes it hard to make sense of the GPX file data.

    Sorry....wish I could be more help for those files and the videos.
    Andy.
     
  3. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Unfortunately, I cannot see the image to which you refer. But if you're pointing to the big capacitors on the BL-Ctrl, then use, they can cause major problems.

    You should see numbers in the low hundreds of ohms, increasing over a few seconds up to around, oh, 800 ohms or higher -- the important thing is the number should be low and increasing. If its 0 or unchanging then you have a problem.

    The pressure transducer might cause problems for altitude hold, but I don't think it would cause roll/tilt problems. It is only used for AH, I believe

    Andy.
     
  4. Sebastian Meredith

    Sebastian Meredith Active Member

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    Hi Andy.
    The ohm's reading climbs slowly to just under 900.
    Would the capacitors show any errors in MK Tools? I2C error etc?
    The 3D was behaving on-screen as per my physical motion. No random twitches etc. followed my physical action exactly.

    This is so frustrating! I'm in one of the most beautiful places on earth and having the most stressful moment ever!

    Thanks for all your assistance and suggestions.
     
  5. Sebastian Meredith

    Sebastian Meredith Active Member

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    Hey Gary.
    That's exactly what it looks like. It also resembles an accidental PH on during take off with a violent toilet bowl effect kicking in!
    I have rechecked props and rotation direction a million times. All that's left is the flight control board. Perhaps it's gone mental.

    Andy / Gary... Would a 2x BLs going up in smoke cause some sort of a inner melt down / fusing of bits within the PDB? Which could behave normally but as soon as its under load during throttle up it causes some magnetic interference or arcing? Reaching I know but at this moment in time I'm quite desperate for a solution no matter how far out!

    Shot for the help!
     
  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    OK. That's good.

    It may not. Can you check that you have all green LEDs on each BL-Ctrl?

    OK. That checks out.

    Yeah. I hear ya on that. But it's all just the Universe raising the finger of derision at you (it does it to me too).

    Andy.
     
  7. Steve Maller

    Steve Maller UAV Grief Counselor

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    Sebastian, how about when you're in MKTOOL and you bring up the simulated OSD? Do all your switches (CH/PH/AH) show their corresponding indicators? I know you probably don't use Carefree, but that's not showing up, right?

    I also wonder if maybe one of your motors got tweaked in the initial crash? If you have a bent shaft or other damage in one or more of them, that could also cause problems. I'm not sure how you'd test for that to eliminate that possibility without swapping out each motor and flying (scary given what's going on at the moment). But a good spin with your hand might indicate something making a different noise?
     
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  8. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Or you could try spinning the motors up one at a time with MK Tool and just listen for one or more that sound more like a power drill than a motor. If the shaft's bent, the odds are the bearing(s) is/are damaged as well.

    Andy.
     
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  9. Sebastian Meredith

    Sebastian Meredith Active Member

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    Hi Steve,
    Motors are all fine. I spun each one up and felt for any kind of vibration on the booms. Also when the props were on I did the same thing. All felt and sounded the same.

    I checked the OSD in MK Tools for the registering of the AH and PH. I don't even have carefree assigned to a switch but that was not activated. And all are responding to the switch commands.

    As a last resort given my limited resources on the island. I've got a spare PDB and I've just competed desoldering all the BL's and made up the new board. My thought is that perhaps some de lamination occurred in the first crash that is not visible to the eye and under load whe taking off the vibration is causing a separation and connection issue that is not evident when on the ground with less vibration.

    About the put it all back together and test. Will let you know what happens..

    Thanks for the input.
     
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  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Boy, this is a puzzler. Based on all the data there's nothing apparently wrong. I'm starting to think it relates to the high power/vibration/whatever of flight.

    I'm starting to ponder how you could perform some kind of tethered "flight" -- e.g. with four booms tied down to the ground and the aircraft only capable of lifting off about 24" above ground and not able to tip over -- just to see if you can hover at, say, 12" without Bad Things happening. The idea of the short tether is to prevent a tip-over (you would be in ground effect but that's OK as what you're looking for is the sudden nick or roll motion). If I remember correctly, Steve Maller once tied his Cinestar to his vehicle's roof-rack, but I don't think it actually got airborne -- or if it did that would explain why he's got a new vehicle. :confused:

    Your idea of changing out the PDB is a good one. It's hard to know just what damage has or has not occurred. My gut feel is that it's the flight controller for two reasons: 1) that's the board the controls nick and roll, and 2) that's the board you don't have a spare one of.

    I would certainly go over both surfaces of the Flight Controller with a magnifying glass looking for any signs of damage, missing components, components that have lifted up, whiskers of solder etc.

    I didn't see any signs of I2C bus errors, so that would seem to eliminate the inter-board wiring. I'm wondering whether G-forces of the crash did something bad to the the ACC or the gyros? Both of those are required for stable flight.

    I wish I was on the Ile du Nord -- also for two reasons, 1) this would be a lot easier to diagnose, and 2) it looks pretty cool -- but I would need a least a couple of weeks to diagnose the problem. :rolleyes:

    Andy,
     
  11. Sebastian Meredith

    Sebastian Meredith Active Member

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    Whoooooohoooooo!!!! :D

    Good news ...

    My plan to move all the BLs to the other board work a charm!! Initial test are all looking great. First flight loolks really stable and no issues noted. AH workd perfectly. PH worked perfectly. SO I can only gather that my wild guess on the PDB perhaps delaminating could perhaps make some sense ... or else the resoldering ofall the components re-aligned themselves and the starts and my luck!

    Attached is the GPX from the test flight. Please have a look. All loooked ok. Motor currents wern't all over the place as before.

    Thanks again for all the suggestions and input!! Much appreciated as always.

    Cheers.
     

    Attached Files:

  12. Ozkan Erden

    Ozkan Erden Distributor

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    Very glad to see you airborne. I was about to buy a ticket with a Cinestar8 set :)
     
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  13. Sebastian Meredith

    Sebastian Meredith Active Member

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    I would have paid you for that ticket! It was getting close to desperate times! Further test all good. Off to finaly do some flying. Weather is perfect today.

    Cheers.
     
  14. Steve Maller

    Steve Maller UAV Grief Counselor

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  15. Sebastian Meredith

    Sebastian Meredith Active Member

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    Oh crap ... spoke too soon!

    So! It takes off fine ... but its seems to be reacting in a super sensitve way to the point that its not quite controllable.
    Scenario ... take off, hover at about 2 meters (fine), it starts drifting towards me due the breeze pushing it, I give a little stick to move it away and it reacts like I gave it a full stick movement (not fine), which obviously then results in a violent to-and-fro as I try an get it under control and put it on the ground with as little impact as possible.

    I am at the point of giving up and tossing the thing in the bin. :mad: Travelling back home will be alot lighter and easier!
     
  16. Sebastian Meredith

    Sebastian Meredith Active Member

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    Forgot to mention. The test flight that went 100% was with no gimbal attached. Just landing gear. The odd bevahing flights thereafter had the full CS 3Axis gimbal on it ... and only the gopro4 for test flights. Its like the extra weight over exagerates the sensitivity. Perhaps it was doing a similar thing with the no gimbal flight but was not as severe due to the lack of weight under?!?

    Oh hum ...
     
  17. Howard Dapp

    Howard Dapp Active Member

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    Disconnect all cabling for gps, AH or any autopilot functions. Disable them in MKTOOLS as well and fly completely manual. Let us know how that test goes. Also blow/brush off any dirt, dust or any fine particles that may be acting as gremlins on that naked stack of electronics you're flying around with.
     
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  18. Sebastian Meredith

    Sebastian Meredith Active Member

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    Like it .. will def. try it.
    I had unplugged the navi and gps stack, but had not disabled it in MK Tools. Will let you know!
     
  19. Steve Maller

    Steve Maller UAV Grief Counselor

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    Dammit. This IMHO points toward a bad FC, unfortunately (I know you don't have a spare). If the addition of the gimbal (and it's attendant shift in CG) make the copter unstable, it's almost certainly a gyro or something that's gone bad on the flight control board.
     
  20. Adam Paugh

    Adam Paugh Distributor

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    Hey Sebastian,

    Are you still in setting3=easy? When you calibrate the gyro does the kopter respond with "3 beeps"?

    A hasty compass cal. sometimes inadvertently bumps you into setting2 or setting1, which are sport modes.

    Greetings,
    Adam
     

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