Southpark:
So use one wheel as the reference, and make the other wheel try to lock onto the same velocity using a control algorithm.
But that only takes care of the first part (the motor speed) of the three issues PaulS pointed out in #1:
PaulS:
since the motor speeds will not be identical AND the wheel diameter is not identical AND the amount that each wheel slips is not identical (and they DO slip).
It will still need .....
PaulS:
some sort of "which way am I actually going" feedback,