[MrForbes]

Might depend on what kind of motors you are using to drive the robot. If they are big motors like the CIM, then you really do need speed controllers. If they are quite a bit smaller, you might be able to get away with using relays, but robot control will be difficult. Or you can use smaller less expensive motor controllers if you use smaller motors.

We've built some robots using vEx control systems, but you could use an arduino or any other controller that has enough outputs.