A lot of time has passed since my last update. I have since learned a lot and this version of the robot base reflects that.
I completely reviewed the chassi, with meccanum wheels, real DC9V motors with reduction and an acceptable speed.
I redesign the box and made a complete review of the electrical system.
The communication mode has also been revised, and it is now in series via the TX and RX pins.
Now i'm programming the RPi and the arduino to work together.
Thank you !