@anaskh Please post in threads any old person can respond to: https://vexforum.com/t/modular-robot/33877/1
Here’s a commercial robot that does exactly what you are looking for.
http://www.helicalrobotics.com/FerroTanker-20
Here’s a DIY instruction set for a robot.
However I don’t see where you can buy these wheels
http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=6696363&url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel7%2F6679723%2F6696319%2F06696363.pdf%3Farnumber%3D6696363