The kobuki base on your own doesn't drift, so it is sensible the tilted inertia will cause the drift. Needless to say I can hack my URDF using a weightless superstructure, but I planned to deal with this in a far more practical way. I tried all I can take https://www.uk-exhibitionstands.co.uk/product-category/light-box-displays/casonara-light-box-walls/