It looks like it is from Justin. Nice job man.
@ NielsNL2 - Guilty as charged…thanks for the comment 
If all goes well this week v3 is going to have Quadrature encoders which should make all the difference - so cross your fingers and toes and hope it works 
What is v3 ?
@ Tzu Hsuan - Same thing but using Quadrature to read the encoders and move the wheels x mm to bring it to vertical rather than just ramping the motors up and down as now…
Quick and dirty test of the Quadrature module for v3…