The kobuki base alone isn't going to drift, so it is sensible that the tilted inertia triggers the drift. Naturally I'm able to hack my URDF that has a weightless superstructure, but I planned to resolve this in a far more sensible way. I tried all I can think about, https://www.uk-exhibitionstands.co.uk/product/pop-up-stand-3-x-3-bundle-straight/