I think that it's possible but a challenge, try to figure something out that gives your code a checkpoint each time so it can calibrate
If you don't want this and don't want sensors i thing you need some sort of encoders on the wheels (expensive) and even then
i doubt if you will be able to pull it of.
But i'm more in automation so maybe someone else will tell you a different story, but from my experience i know that i always need
a calibration point or something like encoders or sensors or so.