i didnt get the hint what do you mean by
hint: you must use a software UART for the Arduino for it to work
To communicate with the VRbot, you need a UART to transfer serial data.
The Axon has four hardware UARTs, with one attached to USB. Hardware UARTs are very fast, reliable, and don't tie up your processor.
The Arduino has only one hardware UART, and it's already attached to USB. So you must use whats called a 'software UART' - they are slow, not so reliable, and waste processor time. WebbotLib does a good job handling software UARTs, but nothing can beat a hardware UART.