Re: [Paparazzi-devel] Vibration issues (?) on a quadrotor

[Loic Drumettaz]

Hi,

I've made some test with the quad fixed on a table. With 43% throttle, i have the following results:

GYROMETER
voie	min	max	moy	stdev
p	-15.1073	20.6046	0.99363	6.3917
q	-12.3935	11.5403	-0.69831	4.3985
r	-36.1035	48.0075	1.7297	16.4202
ACCELEROMETER
voie	min	max	moy	stdev
ax	-13.6587	10.9194	0.15068	4.3117
ay	-8.347	6.8557	-0.16339	2.8296
az	-15.4049	-2.4464	-9.7606	2.1168
MAGNETOMETER
voie	min	max	moy	stdev
mx	-0.94291	-0.7847	-0.86101	0.032067
my	0.092289	0.19825	0.14064	0.020364
mz	0.146	0.44435	0.27401	0.05397

I don't know if this test is relevant, since the landing gear does introduce additionnal vibrations. Nevertheless, i find it easier to compare different damping arrangements.

I'll try to balance the motor/propeller and the rubber screws on the IMU. Is it also efficient to add some mass on the IMU, in order to lower the natural frequency? I've checked that the motor and frame are well fixed and stiff enough.

Can anyone confirm my guess that the issues I had with RC climb mode comes from vibrations ? (see my previous message)

Thanks

Loïc

Hi,

a vibration level of 20% full scale of the rate sensor  is  normal.
The best way is to damp vibrations and to balance the propeller   together with  with the  motor rotors.
You can try rubber screws   like on this page: https://www.mikrocontroller.com/index.php?main_page=index&cPath=77&zenid=f3cc9c70489e257d4d4e04552f0e1343
If the damping is to soft the quadcopter will became unstable.
Is your motor mounting, your frame, wiring and the PCBs  fix?
Can you sense  the vibrations  with  your hands if you hold the quadcopter?

Heinrich Warmers