balance a brushless motor (EN/FR)

The motor case is not perfectly balanced, so you get always one side who has more weight than the other side. When it runs at high speed it makes some vibration. The sensors are very sensitive to the vibration and they can’t give the right data reading from ACC and GYRO to the Arduino. So the Arduino can’t control the motors accurately to make the multicopter stable in the air.

To balance a brushless motor with some tape you need to do only 2 things. Firstly you have to know where you put the tape to add some weight and secondly how much tape/weight you have to add.

You don’t need any special tool to make this done. Turn on your motor to balance and look the data read in the GUI(the Multiwii graphic interface on PC/Mac). Just remember how bad the curves you get. Now put anywhere a piece of tape on the motor case and turn on your motor again. You’ll see the curves are better if you are on the right side and they are worse if you are on the wrong side. If you are on the wrong side go to have a try on the other side. If you have better data read you should move the tape a little bit to right or to left and see if the data reading becomes better than better. if better than better just continue to move the tape further until the data reading becomes worse and than move back a little bit.

Now you need to know how much weight to add. You put some more or less tape on the place you found to see if the data reading gets better or worse. If it becomes worse go to the other way. If better, continue to do the same thing many more times to make sure that you can’t make it better than better.

My advise is to pass really 30 minutes on the motor balancing will make a bigger difference than to try finding the best PID settings to avoid the vibration. When you have less mechanical vibration you will be able to handling the PID settings easily.

French version :
La combinaison châssis alu DIYmulticopter + moteur X2212 n’a pas besoin de cette étape. Ils ne donnent pas beaucoup de vibration. Vous ne balancez que les hélices s’il le faut.

Si vous avez un multicopter qui n’est pas pilotable, s’il tremble énormément pendant le décollage, il faut balancer les moteurs avant de continuer à essayer.

Etape 1 : Trouver le bon endroit pour ajouter du poids
- Coller un morceau de scotch n’importe où sur l’extérieur du moteur à balancer.
- Comparer la lecture des données IMU par rapport à tout à l’heure. Si le résultat est pire il faudra changer de côté. Si le résultat est mieux, vous pourrez bouger un peu le scotch collé à gauche ou à droite en comparant les courbes pour trouver la meilleur position.

Etape 2 : Ajuster le poids ajouté
Dès que vous trouvez la bonne position pour ajouter du poids. Vous diminuez la taille de scotch ou coller plus de couches de scotch pour comparer si c’est mieux.