[Bongle]

I think a pure hovercraft would be a silly idea. Throwing away the traction that you ARE allowed from your wheels and opting instead for an even harder to implement and control drive system doesn't seem like the right idea.

However, using a fan to augment your acceleration and deceleration might work. The wheels can only give you a maximum of about 26.7N of acceleration¹ force. If you build a fan that's good for a few newtons of thrust², then that can be a substantial increase in your robots straight-line handling, allowing you to outrun someone intent on dropping rocks in your trailer (and maybe even causing a bit of aerodynamic drag against them).

¹: Maximum mass of robot: 54.54kg. Weight = 54.54 * 9.81 = 535N. Maximum traction: ff = uFn -> ff = 0.05 * 535N = 26.7N

²I know nothing about fans. This may very well be outside of the possibilities for a 12V fan, but it would be worth running numbers on.