Mini quad 250 - something horribly going wrong

[Hood49]

Hi Guys,

I am a but stuck here. I hope you can help me.

Over the last few weeks I have been building my Mini quad.


Chinese carbon frame
Emax 12 amp ESC
RCX 2400 kv motors (1804)
3S Lipo
CC3D board
Graupner GR-12 receiver (6 channel)

Made my own wire harness and there is juice in all wires.


With the configuration wizard I have been going through the configuration of the CC3D board. Everything works well:
=>motors are spinning in the right direction
=>Calibrated the motors and ESC's
=>Sequence of the motors are setup well
=>Setup PIBank
=>Attitude set

Radio is setup and all sticks are in the good direction.

PROBLEM:
Before taking off the motors spin well. When adding some throttle it wants to take off. But as soon as it lifts off it goes crazy and flips over (I am speaking about 10cm from the ground)
Look like something serious is going wrong here.

When I want to start again I can see that intermittently one motor does not turn, only when I add more throttle it starts turning. But I can see that it is not going as fast as the others. (I have calibrated them with the Openpilot Wizard). When I disconnect the battery (and reset the CC3D) all motors seem to start up together again (weird)

So I am thinking of these possible problems:

1. Motors are crap
2. ESC is not working as they should
3. Wiring issue? (would be surprised, I checked everything)

Any idea what I can check? Did one of your experience this before.

Many thanks in advance fro your input!

 

[kloner]

have you either loaded a known setup for PID gains? if not, have you turned them up at all? if i remember right there default is 0.... and they all need to be set.

 

[Hood49]

I have used the gains of a tutorial on the web.

Roll: 50 - Pitch 50 - Yaw 50

Rate Stabilization:
Proportional: Roll: 0.00230 - Pitch 0.00250 - Yaw: 0.00350
Integral: Roll: 0.00500 - Pitch 0.00500 - Yaw: 0.00700

Sometimes one motor turn slowly or not - other times it is another. Weird.

 

[kloner]

my cc3d does that too, if you move the roll, pitch or yaw you'll see a different response or other motors should stop as well....

the instability is most likely a gain setting. I don't know exact numbers to tell you to try, but i'd start there...

 

[Hood49]

Thanks for your answer!

Wow, I guess I need to do some tweaking.

I have another quad with Naza and never had any problems. Just a bit of oscillation that I could tweak.

But never that it when completely crazy when 10 cm of the ground (it does not even take off)

Thanks

 

[kloner]

yea, they aint easy to setup like a naza.... you might hitup the open pilot forums

 

[Hood49]

Looks like maybe I have got the orientation wrong. I will test that out...