Pb with octo coax with quatos (Solved)

[plexus]

Hi,
The firm is R445.
My X8 is in X coax and fly very well without quatos.
But with quatos it cannot take off , it flip.
My config is this one given by Max:
<craft id="octo_coax_x" config="custom" motors="8" configId="33">
<geometry>
<motor rotation="+1" port="1">1,-1</motor>
<motor rotation="-1" port="2">1,-1</motor>
<motor rotation="-1" port="3">1,1</motor>
<motor rotation="+1" port="4">1,1</motor>
<motor rotation="+1" port="5">-1,1</motor>
<motor rotation="-1" port="6">-1,1</motor>
<motor rotation="-1" port="7">-1,-1</motor>
<motor rotation="+1" port="8">-1,-1</motor>
</geometry>
These curves are very strange:
Mot Roll and pitch are in saturation:

Strange curves of the MOT0 to 7:

Thanks for the help;
alain

[Max]

Alain, post your full XML file and your onboard params.

-Max

[plexus]

Hi max,
thanks again for your help, you are very kind.
The Mot value scale has been changed : 950 to 6800 to see. The esc are calibrate at 6800.

testX.xml

(1.57 KiB) Downloaded 921 times

PARAMS.txt

(15.27 KiB) Downloaded 841 times

Alain

[Max]

Not sure what is going on, Alain, sorry... the settings seem OK. You might be the first to try Quatos on a coax config. Hopefully someone with more Quatos experience will chime in.

-Max

[LPR]

Alain

I looked at your PARAMS and I think you have the wrong value in for MOT_SCALE with 2800.

The MOT_SCALE value should be the Maximum RPM of your motor and prop combination. My guess that you should be around 9000 RPM. The MOT_SCALE value also has to used in the ESC32 settings.

Larry

[plexus]

Hi Larry,
As said the rpm tested was the same that is in the esc: 6800, and write in the motor scale. I tested other value from 950 to 6800, but the x8 dont like!!!!
I hope to not to be alone with that config.

Alain

[drone-controls]

Hi Alain

Your MOT_VALUE_SCAL 2800 is definitely wrong, if your motors can go upto 6800 rpm
Your value of
MOT_VALUE2T_A2 0.001258639968 seems rather high! Please recheck
Edit:
Something is very wrong with your thrust calibration numbers
Max thrust in gms = A1*MAX_RPM + A2*MAX_RPM*MAX_RPM
If you substitute your numbers, you will get a max thrust of 57480gms of per prop!
Looks like you are planning to take off into space

Before we look at the other params, please sketch out how you have numbered the motors and give them directions (cw or ccw).
Generally this is the first place to look for problems and especially if the port numbers have got mixed up

[plexus]

Hi drone-controls,

Many thanks to try to help me.
1) the mot value scal 2800 has been changed by 6800. That was jusy a test.
2) The trust of the motors has been computed by the help in the wiki :
http://autoquad.org/wiki/wiki/quatos-ad ... rpolation/
and the values A1 and A2 added in section MOT, Mot_value2T_A1 and A2.
That all.
The result is a big saturation of all the motors and mot yaw and roll.
3) the order of the motors is that one in QGC "octo coax X (X8)".
I have no error in number of the ports neither direction, that is correct.

As you said,I think the error is in the values of A1 A2. But I dont understand why the computed value is wrong.
There is, may be a problem in the XML file.

testXsans gopro.xml

(1.26 KiB) Downloaded 931 times

Alain

[plexus]

I believe that my config is wrong: mistake between n° of the port and real position of the motors.
Could you have a look on my drawing.
Alain

[drone-controls]

Hi Alain

Your configuration xml seems to match your sketch
Can't find any obvious errors in it.

Could you post your thrust vs rpm numbers?