The kobuki foundation by yourself does not drift, so it makes sense that the tilted inertia leads to the drift. Certainly I am able to hack my URDF with a weightless superstructure, but I wanted to deal with this in a more realistic way. I attempted all I can give https://www.uk-exhibitionstands.co.uk/3-trade-show-mistakes-to-avoid-and-how-to-fix-them/