All motors perfectly level or FC level?

Discussion in 'Cinestar 6' started by Gary McCready, Sep 7, 2013.

  1. Gary McCready

    Gary McCready Active Member

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    Well guys it's raining so a nice evening to "revert". After about 20 flights I am convinced I've tried just about everything to get GPS hold to work as it did. I reverted to .90 (as I was running .88)
    Plugged the USB into the Nav board, and checked connection =ok
    Downloaded and updated to .90j: Got Error code 1 (FC not compatible)
    Downloaded the prior Nav update = .30h
    No Error = BUT got "MKTools not compatible" when I pushed the "settings" button.
    Please update to latest....well I have the latest? v2.00b
    Downloaded MKTools 1.80b into a separate folder =success! = "reverted"
    Comedy of errors!!!! lol A bit of a PIA but I got it done.
    Now I need to update all my settings (I have jpgs of all screens)
    And wait for the rain to stop!
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Colin:

    Good question. It could well be that Motor #6 has good bearings therefore is not having to work harder to spin, but Motor #5 has naffed up bearings that require more power -- but I'd be the first and second person to admit that I'm speculating.

    I've found that balancing the motors is a worthwhile thing to do, though (see the threads on the forum for motor balancing).

    Andy.
     
  3. Colin Snow

    Colin Snow Active Member

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    Got it. I think. I'll try replacing #5.

    I attempted balancing #6 but gave up after circumnavigating the motor two times (10 degrees each stop) with the tie wrap jig.

    Thanks

    Colin
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Motor #6 : vibrating but not capable of being balanced. I've not seen that problem before. Maybe the bearings are also bad enough to cause vibration but not bad enough to demand more power/create more heat? Guessing....

    Andy.
     
  5. Colin Snow

    Colin Snow Active Member

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    I ordered a set of bearings, the Bart tool, and a spare motor. I'll try the new motor on #5 and the bearings on #6.

    Colin
     
  6. Colin Snow

    Colin Snow Active Member

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    Well, that did nothing - other than get the vibration out of #6.

    Data:

    Motor1: 5.8 8.4 11.6 A Temp: 33 64 77 °C
    Motor2: 0.6 5.1 8.7 A Temp: 31 56 69 °C
    Motor3: 0.5 8.8 12.3 A Temp: 30 65 79 °C
    Motor4: 0.7 6.1 8.2 A Temp: 31 66 82 °C
    Motor5: 1.8 10.9 14.0 A Temp: 31 83 99 °C
    Motor6: 1.6 6.1 8.3 A Temp: 32 63 75 °C

    Odd motors pull more and #5 is still hot and averages double #2's. Kopter, gimbal, everything is in balance. Motors are straight, yada, yada.

    Now what?

    Colin
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    About now, I'd start to wonder whether Motor #5 is really truly running hot. I'd be tempted to take the props off, use MK Tool to spin up all the motors to full throttle for several minutes to try and get some kind of temperature rise, and then use an IR thermometer to compare the actual motor casing temperatures with those reported in the GPX file.

    If you can do the test outdoors (or where you can get a GPS lock indoors), believe it or not the MK board will think that the copter's "flying" -- the logic is to assume the copter's airborne when the throttle goes above 40% power. But you do need a GPS lock that's good enough to get the time and date otherwise the NC board doesn't know what to name the GPX file.

    People braver than I might also be tempted to tie the copter down securely and spin the motors up with the props on, but I'm too scared to do that. :)

    Andy
     
  8. Colin Snow

    Colin Snow Active Member

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    I'm not that brave either :) I don't have an IR thermometer, so I can only go by the GPX data and feel of the motor.

    I did test outdoors with props off and PH on for 4 min.

    Basic data:
    Motor1: 0.0 1.0 1.4 A Temp: 20 38 46 °C
    Motor2: 0.8 1.0 1.3 A Temp: 21 41 49 °C
    Motor3: 0.4 0.7 1.1 A Temp: 20 35 40 °C
    Motor4: 0.3 0.8 1.1 A Temp: 20 34 39 °C
    Motor5: 0.4 0.9 1.4 A Temp: 17 32 36 °C
    Motor6: 0.6 1.1 1.5 A Temp: 18 34 40 °C

    GPX file attached.

    I don't know what to make of this. Is it correct to deduce that this test shows there isn't and inherent motor problem? And the odd motor pull and #5 problem is a avionics hardware or software settings configuration problem? Again, the kopter itself is balanced and so is the gimbal with camera on it balanced.

    Colin
     

    Attached Files:

  9. Gary McCready

    Gary McCready Active Member

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  10. Colin Snow

    Colin Snow Active Member

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  11. Colin Snow

    Colin Snow Active Member

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    I still haven't solved this problem. I did a 3D flying test but cant interpret the results. The test here was done with AH and PH on.

    Does it look like it's trying to yaw against itself? What else does this test show?



    Appreciate your insights.

    Colin
     
  12. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Do you have a GPX file from the flight, Colin? It certainly looks like the copter's feeding in yaw corrections, but it's hard to know whether this anomalous or just normal. The GPX file will show autopilot inputs.

    Andy.
     
  13. Colin Snow

    Colin Snow Active Member

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    Hi Andy - Here is the GPX file for this flight. Where does it show that?

    Colin
     

    Attached Files:

  14. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Colin:
    Sorry for the delay in responding.
    The GPX files contain data values for "GPS Sticks" -- basically these values show what the autopilot is doing. There are also data values for "RC Sticks" -- which are what you are doing with the RC controller.

    You can see the values in a program like MK_GPXTOOL, and play back the flight to see what the autopilot is doing. You can get MK_GPXTOOL from http://www.mikrokopter.de/ucwiki/en/MKGPXTool

    Every 500 milliseconds (on recent firmware, older versions every 1,000 milliseconds), the Navi-Ctrl board writes out data for a so-called "trackpoint." You can see the meaning of this data at http://www.mikrokopter.de/ucwiki/GPX -- and can thus figure out what the autopilot is doing.

    For your specific GPX file, I don't see that the autopilot is fighting a yaw -- at least not using GPS sticks -- it might be doing it just by differential motor speed.

    Hope this helps.
    Andy.
     
  15. Colin Snow

    Colin Snow Active Member

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    Thanks for looking at this Andy. I appreciate your time.

    I have had the GPX Tool but didn't have the wiki to understand the metadata and values. Yes, I see in the GridView that GPSSticks Yaw value is always zero.

    Well, this problem with the odd motors -especially #5 - is just vexing. I am getting lower than average flight times using a wide range of batteries. The frustrating part is trying to fix this problem is taking up 100% of my free time and as a result I am not doing any subject matter filming - and wont until I have confidence in this thing.

    Any ideas on what to check next? I see the posts on firmware 2.01 but I am hesitant still to try it.

    Colin
     
  16. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Colin:
    Yeah, it can be very frustrating, I'm afraid. These copters and their avionics are pretty complex systems -- as you are discovering.

    Was that GPX file you posted a typical flight for you?

    The reason I ask is that you landed with a voltage of 14.6 volts which is pretty conservative.

    I have my low voltage alarm set to 14.4 volts, which is the point where I will bring the copter home. I usually arrive back home either at 14.3 or 14.2 and that gives me some spare capacity for emergency dog/children/spectator avoidance.

    Motors #1 and #5 certainly seem to be working harder that the others on that flight in terms of peak current, but not in terms of temperature. I suspect those higher currents are just part of normal flight manouvering.

    Motor1: 1.1 7.2 10.1 A Temp: 25 63 77 °C
    Motor2: 1.3 5.7 7.7 A Temp: 25 59 75 °C
    Motor3: 1.0 7.5 9.7 A Temp: 26 66 78 °C
    Motor4: 0.0 5.4 7.3 A Temp: 30 67 80 °C
    Motor5: 0.0 7.2 10.8 A Temp: 31 72 89 °C
    Motor6: 0.0 5.7 8.7 A Temp: 28 61 73 °C

    Motor #5 is still running hotter than all of the other motors.

    Forgive me: I've forgotten all the things you've tried....but have you tried swapping motor's #3 and #5 -- did you find that the motor on the number 5 boom always runs hotter (in which case the issue is the #5 BL-Ctrl board)?

    Andy.
     
  17. Colin Snow

    Colin Snow Active Member

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    No, not typical. It was only enough flight to record the 3D simulation. I normally fly to the point of the alarm which is set at 14.4V.

    I have replaced motor #5 with a new one and put a new bearing in #6. I have not tried swapping #3 and #5. Even so, if it is the #5 BL-Ctrl board, what are the steps to remedy?

    Colin
     
  18. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    You would need to replace the #5 BL-Control on the power distribution board. If you're experienced with soldering, you can do it yourself (Dave King has done a training video showing how to do the replacement.)

    If you're not comfortable doing soldering, then you would probably be best served by sending the power distribution board back to Quadrocopter (presuming that it is from whom you purchased it).

    Andy.
     
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  19. Steve Maller

    Steve Maller UAV Grief Counselor

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    You could also change the address jumpers on two of the BLs and swap their wires, right? That'd be way simpler than disassembling the entire PDB. Especially if it's just to test this theory.
     
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  20. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Sure, if the wires are long enough to reach, that would work. The addressing pads are numbered 1-2-3 on the underside of the Power Distribution Board on each BL-Ctrl, just to the left of the silk-screening that says "BL-Ctrl."

    The addressing scheme is explained here: http://www.mikrokopter.de/ucwiki/en/BL-Ctrl_2.0#Address_selection

    Andy.
     

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