Mini CC3D Quad Wobbles
« on: December 11, 2019, 07:58:51 am »
Hey guys,

I built a quadcopter about 2 years ago using the (back then)Openpilot Mini CC3D Flight Control board and crashed it, but a few days ago tried to get my quad to start working again. I got it to successfully take off from the ground, but there has been a constant side-to-side rolling motion. I thought it was the self-level overcompensating, but I went into Rate mode and it still continues. When I am closer to the ground, it is more of a slight wobble, but the more throttle I give it the more severe it becomes until eventually I cut the power and the drone just flips over and falls to the ground.

Any suggestions to help me fix this?

Re: Mini CC3D Quad Wobbles
« Reply #1 on: December 11, 2019, 04:57:59 pm »
A video would help.  :)

Did this quad / this firmware version / these exact settings fly correctly before?

Are you still using the old OpenPilot stuff?  Nothing really wrong with that if it works for you.

If this used to fly well then it could be - Unmatched prop or weak motor, unbalanced props, loose motor or damaged quad arm with the same effect as loose motor, weak battery that can barely lift it (does it have plenty of power at full throttle?).

Re: Mini CC3D Quad Wobbles
« Reply #2 on: December 12, 2019, 01:17:08 am »
To answer your questions, it was flying perfectly fine 2 years ago before I stopped using it, but when I came back to it I reset the firmware on the board. And by old OpenPilot stuff do you mean the FC board, or the GCS software?
I just changed the props out for new ones and the rolling has decreased a lot. I think my main problem must be my bottom right motor, as it seems to spin slower than the others sometimes, and when I go to lift my quad off the ground, it is a lot slower to start up. I'll probably buy a new motor and put it on and hopefully the quad will fly stable.
Link to my Google Drive video (https://drive.google.com/file/d/1Lem6MeH-CC9uWDFOtc3TBt7wNWwtaE2Y/view?usp=sharing)
Another thing, I live in Southern California where there is a lot of dirt, and earlier I flew close to the ground in a field and now one of my motors has some dirt inside that won't come out when I spin the motor, any suggestions on the easiest way to get it out?

If you're curious here are my specs:
FliteTest Versacopter v2.0 frame
OpenPilot Mini CC3D flight controller
Emax MT2204-2300KV motors
Emax BLHeli 12A ESC
HQProp 6x4.5 props
Turnigy 3S 2200mAh 35C LiPo battery
Graupner MZ-10 transmitter and GR-12L receiver

Re: Mini CC3D Quad Wobbles
« Reply #3 on: December 12, 2019, 09:24:19 am »
To answer your questions, it was flying perfectly fine 2 years ago before I stopped using it, but when I came back to it I reset the firmware on the board. And by old OpenPilot stuff do you mean the FC board, or the GCS software?
The software / firmware.  So you basically set it up again...  So those settings were not previously flight tested.

Are you using LP now?  Or OP?  I was with OP back in the day, but I am rusty with the old code and basically just assume that it works the same as the new code.

I just changed the props out for new ones and the rolling has decreased a lot. I think my main problem must be my bottom right motor, as it seems to spin slower than the others sometimes, and when I go to lift my quad off the ground, it is a lot slower to start up. I'll probably buy a new motor and put it on and hopefully the quad will fly stable.
Brushless motors don't just start running slower.  You would generally need to change the windings for it to run slower.  ESC calibration and output page settings would make that motor run slower.  Output page is also where you tell it what ESC protocol to use.  All banks that refer to an output connected to a motor must run the same protocol, and that protocol should be either [email protected] or PwmSync.  If a single ESC calibration / output setting is wrong it will do it.  The instructions here will fix all of those possible issues.  It should work with OP, but I haven't tested it with OP.
https://librepilot.atlassian.net/wiki/spaces/LPDOC/pages/12058743/ESC+Calibration

Link to my Google Drive video (https://drive.google.com/file/d/1Lem6MeH-CC9uWDFOtc3TBt7wNWwtaE2Y/view?usp=sharing)
That looks like PIDs tuned too high yet quad is still mushy.  If you are using stock PIDs they should be OK, so it really starts to sound like you need to set your Output page ESC protocols to [email protected] or PwmSync as discussed before as that is probably the #1 reason for problems like I saw in that video.

Another thing, I live in Southern California where there is a lot of dirt, and earlier I flew close to the ground in a field and now one of my motors has some dirt inside that won't come out when I spin the motor, any suggestions on the easiest way to get it out?
For sand, I might just blow it out with compressed air.  If it was bad or finer gritty stuff I might wash it out with lots of water followed by compressed air to drive the water out (especially the bearings), followed by a thorough bearing dousing with WD-40 ("Water Displacing 40" FYI), followed by a small drop of motor oil on each bearing.

Re: Mini CC3D Quad Wobbles
« Reply #4 on: December 16, 2019, 06:48:51 am »
I bought the FC after OP was switched over to LP so I've only ever used LibrePilot. The ESCs PWM was set to 50Hz, and I switched them to 490Hz and now my quad flies smoothly without any problems.

Thanks for all the help.