CS8 HL Mikrocopter FC acting up, and can you watch this and give me suggestions

Discussion in 'Cinestar 8' started by Steven Flynn, Oct 8, 2015.

  1. Steven Flynn

    Steven Flynn Member

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    Hi all. I'm hoping maybe someone super technical can answer this query. I'm on a job flying an alexa mini with a zeiss lens, follow focus and movi m10. And the rig has started to behave badly in the nic axis and the gps is just too unreliable for some of the holding that is required. And with that amount of money in the air it's just too stressful. so...

    Essentially, it seems like the NIC response can be really SNAPPY even in manual mode. roll is fine, but when I put even the smallest input into a forward or backward movement it can snap quickly which makes me react and I end up with a pilot induced oscillation. IN this video, the nic access is pointing away from the camera. The first test is with gps on, and then it seems like in this case when gps is off it moves better. Also, toward the end of the video, the copter starts to toilet bowl (my term). Wind is still. And I don't know why it's washing around. Also in this gps mode (dynamic position hold is enabled), when I push forward or backward, it is like it can't just move smoothly, it moves and then slows, moves then slows without any change in stick input.

    The hold time in my gps is set to 1 second.... And gps gain is at 90%. Motor currents are really even across all motors so I believe it is balanced well. It only took a couple bumps to trim it to neutral without gps.

    If anyone can help me today I'd be so grateful. IF I can't smooth out the reactions I'll probably leave the gig. Just too stressful. Let me know if I can offer you more information. Thanks again.

    here is the vimeo link: https://vimeo.com/user13706159/review/141763340/eb6fbf74bc

    Steve
     
  2. Bryan Monarch

    Bryan Monarch New Member

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    Link password?
     
  3. Steven Flynn

    Steven Flynn Member

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    well that was silly. I just removed the password. Sorry

    I just tried another fix on set and thank goodness we did it before we put a camera on it. Empty heli and it pitched right over on the nic access right into the grassy field. Very small stick input and bam. Here is the gpx file below. seems to be going from bad to worse. thanks for any suggestions.
     

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  4. Howard Dapp

    Howard Dapp Active Member

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    Are your frame vibrations at a minimum? Any nicks on any of your props that would affect prop balance? Are you using really stiff rubber standoffs for your flight control? Heavy vibrations hitting the flight board could cause similar issues.
     
  5. Jason Smoker

    Jason Smoker Active Member

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    What firmware are you using? For fc and navi? Post some pics of your setup sometimes someone can spot
    Something that u might not see
     
  6. Gary Haynes

    Gary Haynes Administrator
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    Also check all of the connections to the electronics. You video looked good but obviously if it pitched over something is wrong.
    Also check for a loose prop.
     
  7. Steven Flynn

    Steven Flynn Member

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    I'll upload some better data on my hardware/firmware in a little bit. Have to eat after this one. Here is a gpx file from my last flight of the day. I took a look at the last gpx file and noticed a current peak twice the others. so I figured maybe my last effort would be to change the motor to another spare in case the motor had gone weird. Took copter apart, changed motor. Put it back together. Went to field, started great... got it in the air, and it decided to flip itself upside down and fly straight into the ground. A bit like a dog that just said "I'm not going anywhere". In 3.5 years of building and working this rig, I've never ever seen anything like it. So here is the gpx file from my new tractor/plowing machine. I'll take some pics after I eat. :(
     

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  8. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hmmm. The GPX file 15100807.GPX shows that even at takeoff the copter had a -5.0 degree roll angle -- that suggests that the problem is with the Accelerometers, ACC. You will need to recalibrate the ACC with the aircraft completely level and then moving the left stick to the top right-hand corner (full throttle, full right yaw).

    Is there a chance that you might have accidentally done that stick movement when the copter was not level and thus mis-calibrated the ACC?

    The first GPX file 15100805 also shows some significant non-zero Nick and Roll angles even though it looks like the copter was one the ground -- and then just getting airborne (there are only 9 rows of data in the file).

    Hope this helps.
    Andy
     
  9. Steven Flynn

    Steven Flynn Member

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    thanks andy. I'm going through all of it and updating all firmware first. Just curious, is it best practice to redo the ACC every time it reboots? I read somewhere a while ago that maybe it wasn't. I always calibrate the compass, but I don't always do the ACC. I don't believe I did any major inputs. It was an 8 second flight (or less). Really fast and kinda shocking to watch it go inverted. All we could do was laugh at it because it was just so extreme. But it did land flat upside down in the soft grass. Phew.
     
  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Steven:
    I would only re-calibrate the ACC when:
    1. I update the firmware.
    2. I dismount/remount the Flight Controller (which has the ACC's on it).
    3. After a hard landing or uncontrolled flight into terrain (aka "crash").
    4. The copter appears to be drifting in flight (which suggests a possible accidental re-calibration).

    I recalibrate the compass when I move to a new location that's more than a few tens of miles from where I last re-calibrated it.

    The problem with re-calibrations is that they also present an opportunity to "bake in" an error -- eg. re-cal the ACC when the copter's not level.

    You might want to check out the state of the ACC with MK Tool -- just to display the Nick and Roll angles when you *know* the copter really is level -- I use the battery plate as "proxy" for the flight controller on the belief that if the battery plate is level, so's the FC. But I check that this was true on my copter using MK Tool to display the ACC outputs when the battery plate was level.

    Glad to hear that your copter "face plant" didn't damage anything other than, possibly, your underwear.
    Time for a Guinness or two, I'd say! :)

    Andy.
     
  11. Jason Smoker

    Jason Smoker Active Member

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  12. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Jason: I could be wrong, but if Steven's already experiencing FOD (flips of death), I wouldn't dare get airborne again until I'd done a ground-based ACC re-cal! :)

    Andy.
     
  13. Jason Smoker

    Jason Smoker Active Member

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    Yeah true that I also wonder if the fc is not facing the right way that can cause FOD also. I shouldn't say but I gonna "don't ask me how I know"
     
  14. Howard Dapp

    Howard Dapp Active Member

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    Steven, because your last post is mostly based on a job you were already in the process of shooting but was unable to complete due to equipment failure while on set please allow me to add my 2 coins...

    Some directors can be very demanding, it's ultimately your determination whether or not a set is safe to fly and if you feel a set is hazardous you have the final say whether or not you'll fly (this should be in your contract). Share your concerns with the AD, tell him you'll be grounded until your hazard concerns are met...usually this is all it takes.

    A scenario: suppose you actually captured the waterfall shot that they were after, the director was pleased and you recieved praise for pulling off a tricky shot? Would you be here venting about all the onset demands and hazards mentioned in your post?

    Conclusion: The reason you were unable to get the shot is because of equipment failure. Your client relied on you, trusted your abilities and equipment....where is your backup? You can't be upset with the client in this case, Sorry, they have every right to hold back your remaining 50% or so balance.

    That flight board should be ground and sent in for repairs. Me personally, I'm crazy about that stuff, if the issue is hardware related i'd just replace it and forget about it.

     
  15. Steven Flynn

    Steven Flynn Member

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    Howard, Fair enough. I think most of what you say is accurate, without the details in there it doesn't really get the nuance of it. But I appreciate your feedback from a cold hard viewpoint. I think sometimes getting caught between making the business work and figuring out how or when to leave a set is sometimes the hardest thing for me personally. When we arrive we always walk clients through how we need to operate, actually have a form we both sign to prove we talked through and both agree and understand protocols. and it almost always goes exactly the way we need. Everyone works together toward a positive outcome. In some cases, it turns into a slow decent into a very disorganized arrangement where suddenly I find things have slipped out of control around us. Like the frog in boiling water... it creeps up and then there are issues. I think that is the part that irks me. At the end of that there isn't enough ownership from some clients over how they contribute to a result that was below expectation. Anyway, thanks for honest feedback. I appreciate it. S.
     
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  16. Howard Dapp

    Howard Dapp Active Member

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    I've been here many times and totally understand how that can happen. It's definitely a balancing act...pleasing the client while trying to keep yourself, crew, and more importantly your equipment :) safe when dealing with that director who thinks he is Scorsese!
     
  17. Steven Flynn

    Steven Flynn Member

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    ok so back to my hardware. I've updated all my firmware in fc, navi, and bl. I'm now running FC 2.10c, Bl v 1.10, navi 2.10c. Everything seems to power up fine, but I can't make the ACC calibrate. It worked before I upgraded to the 2.10c. Any ideas why stick up and right won't calibrate the acc?
     
  18. Steven Flynn

    Steven Flynn Member

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    ok, so now I've figured out why it wouldn't calibrate the acc. System thinks my stick position on nic and roll is not centered. If I put the left stick up and right, and then just pull back the nic and bank slightly right it calibrates. So now i have to find where to reset my center point. I'll keep digging, any directions would be brilliant! steve
     
  19. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Check the trim tabs on your transmitter, Steven. They can produce that effect.
    You can also use MK Tool's Channels window to see what deflections you're getting viewed from the Receiver's point of view.

    EDIT: Oh....I forgot one thing (which happened to me), check to Expo and Dual Rate settings on the transmitter -- you can also induce the "unable to send full scale deflection of sticks" problem if you have those set to extreme values as I recall

    Andy
     
  20. Dave King

    Dave King Well-Known Member

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    Steven

    Did you see this in the wiki? This started with 2.10 versions.

    To calibrate the ACC (throttle up + yaw right) you must activate this function now for longer then 5 seconds.
    Only then you will hear the "beeping" and the ACC is calibrated.
     

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