CC3D All Motors Randomly Cut Out - Related to TxPID?
« on: August 06, 2016, 10:00:56 pm »
Looking for some guidance on this one:

I have a quad with a CC3D board.  The other day I setup the TxPID option using the guide and ever since my quad hasn't responded correctly.  When I was flying it after enabling TxPID, it was about 30 or so seconds into the flight when suddenly all motors stopped and it fell from the sky.  I've since disabled the TxPID option, but it has issues arming and randomly dropping power to all motors at once.

Today I was looking into it more and I feel like maybe my CC3D is bad, but I want to know if anyone else has advice before I start randomly purchasing hardware.

Symptoms while attached to GCS:

- Very often will not arm, even though channel values in the GCS input screen are stable and show correct values when moving sticks on the transmitter. Verified arming settings are correct.
-- I was only able to get it to arm 3 times today regardless if it was attached to GCS or not.  It now no longer arms at all.
-- Will not arm/respond to throttle even if set to "Always Armed"
- When it did arm and motors responded to throttle, they would all cut out at once and this seemed to relate to me tilting the quad at angles around 20-40 degrees.  If I continued tilting and moving the quad, they would occasionally start again.
- Using Output > Live Testing feature, all motors spin and no amount of tilting/shaking/etc causes them to stop.
- Going through the Vehicle Setup Wizard along with re-downloading firmware and clearing all settings doesn't solve the issue.

So to me, it seems like my CC3D is having some sort of software issue when its trying to stabilize itself.  Since GCS can display flight data and the channel values from my controller, I know the CC3D is getting good data in from all sources and communicating OK through USB.  Since GCS can manually control the motors, I know that all hardware from the motor to the CC3D is good.  That really just seems to leave the CC3D as the problem with understanding when to arm and then understanding what to do when at certain angles (you know, like to level yourself, add throttle to 2 motors instead of cutting power from all motors  ::) ).


Any thoughts on possible fixes?  I'm strongly leaning toward just ordering a new flight controller.

Thanks in advance!

3dprintingwa

Re: CC3D All Motors Randomly Cut Out - Related to TxPID?
« Reply #1 on: August 07, 2016, 12:44:21 pm »
Hi just  responding on a hunch as I had a similar issue- quad was flying fine, next time I want to launch on a new battery it just drops out of the sky, then flies fine for the rest of the day, or cut out randomly.

Turned out to be a sparked out battery connector on the quad ( could only see the damage under a  microscope )
Anyway, maybe you're lucky

Cheers Phil
 

Re: CC3D All Motors Randomly Cut Out - Related to TxPID?
« Reply #2 on: August 07, 2016, 06:22:22 pm »
Sooooooooooo, I'm an idiot - But I did figure out the problem!

In short, I have a bad connection from my accessory channel to the CC3D.  When it loses connection, the controller goes into failsafe....and there isn't much 'safe' about failsafe: it immediately disarms and cuts all power to motors and drops from the sky.

I didn't know this was an issue earlier because before I was trying out the TxPID feature, my accessory channel was unassigned and so it wasn't causing a failsafe state.  I'll have to fix that connection.

Is there a way to change the behavior of the failsafe/signal lost state while armed?  Maybe something more like slow decrease in power to 0%?  I certainly don't want to fly while it doesn't have signal on a channel, but dropping out of the sky in self sacrifice due to signal loss on a accessory channel seems a bit extreme.

-EDIT-
I looked at a topic about failsafes and they made extreamly good arguments about why dropping out of the sky is almost always the best setting for the safety of everyone and I will keep it that way.  Guess that's yet another reason its always best to never fly over people or property! :)

https://forum.librepilot.org/index.php?topic=1677.15
« Last Edit: August 07, 2016, 07:15:25 pm by crof2003 »