I need to create a simulation of a robot. The robot have 4 wheels, but moves like a tank, so right wheels, and left wheels. I need to simulate the wheel speed error so I need to move my vehicle basing on the motors speed. The problem is that the only way I know to move a vehicle is by **one **point/pivot. The actor have to simulate a rotation error, and have to correct it in the closest way possible to realtity. What is the class or the method i should use?