1. After being tightened, the wheels shake when running, why?

This may be caused by the gap in the motor shafts. The shaking may be more obvious when extended shafts are used.

Since the four Mecanum wheels are required to fully come in contact with the ground when they move,  you need to keep a certain movement space for the wheels in the vertical direction.

2. Why do I need to put nylon washers when installing electronic modules? 

If the metal parts of an electronic module are in direct contact with the metal shell of mBot Mega, a short circuit may be caused and the electronic module may be damaged.

3. A deviation occurs when mBot Mega moves in a straight line, why? 

The possible causes are described as follows:

• The TT motors are common DC motors without encoder sensors. The four motors are not consistent with each other and therefore run at different speeds.
• The ground is rough and therefore the areas of the four wheels that come in contact with the ground are different, thus the friction between the wheels and the ground is different and a deviation is caused.

4. Noise is made when mBot Mega is moving, why?

There are 9 rollers on each Mecanum wheel. When moving at high speed, each roller makes noise when it comes in contact with the ground.