Problem with CC3D, Descend with no control after flip
« on: August 28, 2016, 09:27:23 am »
Hello,
I have  a strange problem. I built a Robo-Cat 270 with the KINGKONG Force 200 4 x 2204-2300kv Set. The controller is a Micro CC3D (Atom like). I updated to Librepilot. The receiver is connected via PPM. Battery is 3S, 1400mAh, 65C. The controller is suppled by a 5V/3A BEC.

The copter flies quite well with the standard settings. However, in 3 of 8 attempts to fly a flip, the controller seems to switch into some kind of failsafe mode. It does the flip, than it stabilizes the copter and descends with around 2m/s. I always tried in 10m height. That is why I had time to observe. During the descend there is no control on throttle.

After each crash I disarmed the motors (by low throttle, left yaw). The motors always were disarmed when I reached the copter. I can not tell if this is the reaction to my disarm TX-command or any kind of self disarm. Anyway after picking it up it is ready to fly again.

What can be the reason for this?


Thanks
Stefan

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Re: Problem with CC3D, Descend with no control after flip
« Reply #1 on: August 28, 2016, 01:31:16 pm »
Hi, Welcome.

This issue is strange, can be some bad wiring that cause issues with hard turns.
After the crash you can check if board rebooted or not, connecting board to the computer and checking the time value displayed in PFD.

What receiver do you use ?

Re: Problem with CC3D, Descend with no control after flip
« Reply #2 on: August 28, 2016, 02:48:01 pm »
One thing I'll add: when my CC3D goes into failsafe, it cuts all power to all motors immediately - which is the default setting.    Im not sure that what you're describing is failsafe mode.

Sorry i don't have any solutions to suggest.

Sent from my VS986 using Tapatalk


Re: Problem with CC3D, Descend with no control after flip
« Reply #3 on: August 28, 2016, 03:16:00 pm »
What receiver do you use ?

receiver: FS-iA10 in PPM

Bad wiring: The only connection that may cause behavior like this is the connection between receiver and controller.  The descend is quite controlled.

What happens in default configuration if connection to the receiver is lost? Failsafe and cut of power to all motors? (like written)

Re: Problem with CC3D, Descend with no control after flip
« Reply #4 on: August 28, 2016, 10:00:46 pm »
My experience was that my aux channel was intermittently losing connection due to a damaged cable between the reciever and the CC3D.

If the connection was lost mid-flight, the CC3D would immediatly cut power to all motors and disarm.

I found the issue by connecting the CC3D to my computer and watching the inputs as i physically moved the quad around. As i recall, the aux input would ocassionally go to 0 instread of being at whatever the transmitter was sending at the time.

I would think if it isnt cutting all power immediatly, it likely isnt going into failsafe.

Sent from my VS986 using Tapatalk


f5soh

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Re: Problem with CC3D, Descend with no control after flip
« Reply #5 on: August 28, 2016, 10:30:38 pm »
Is the FS-iA10 capable of PPM output ?

PPM input means only one cable between receiver and board, maybe you are using the PWM input with all cables connected, one cable per stick/switch function ?
If one connection/channel fails, the board go into failsafe.

Re: Problem with CC3D, Descend with no control after flip
« Reply #6 on: August 29, 2016, 10:37:11 pm »
Yes, it is PPM capable. I only use one cable (actually I use two, one for power and one for the signal)

I more and more believe that it is really caused by a bad connection. The flight controller does not cut the power in case of signal loss. I have the option "spin at the neutral speed when armed" enabled.

I prepared a video (no permanent link). The motors continues to run at the neutral speed when I remove the signal cable:
https://dl.dropboxusercontent.com/u/42732628/2016-08-29%2018.43.02.mp4

Stefan