The Kobuki base on your own won't drift, so it is sensible that the tilted inertia causes the drift. Naturally I'm able to hack my URDF which has a weightless superstructure, but I needed to correct this in a far more sensible way. I tried all I can think about, https://www.uk-exhibitionstands.co.uk/product/casonara-seg-light-box-display-4ft/