Now I think that the load on the wheel is determined by the force with which the tire presses on the road. Changing the load at a given time: (Kt+Ct*D)*(Xu-Xr). And we must find the maximum value of this expression.DaveW wrote: ↑Mon Mar 05, 2018 3:31 pmI believe you have forgotten the inertia force acting on the wheel. If I simply rewrite your equation:
Load on the wheel = Wst+(Ks+ Cs*D)*(Xs-Xu) + (Kt+Ct*D)*(Xu-Xr), where D is the operator d/dt.
Then dyamically, Mu*D*D(Xu) = (Ks+Cs*D)*(Xs-Xu) + (Kt+Ct*D)*(Xu-Xr). Here D*D(Xu) is the acceleration of the wheel, and Mu is the wheel (unsprung) mass. Wst disappears because it is balanced by static offsets of the springs. A similar equation can be written for the acceleration of the sprung mass, and the two can be solved together to compute the various responses of the vehicle per unit road input.
It is a little more than that, because the sprung mass connects the front & rear suspensions (so the sprung mass has "heave" & "pitch" inertias).
I hope this helps...