A two-degree-of-freedom quarter-car model is shown in Fig. 1. In this model, the sprung and
unsprung masses corresponding to the one corner of the vehicle are denoted respectively by ms
and mu: The suspension system is represented by a linear spring of stiffness Ks and a linear damper
with a damping rate Cs; while the tire is modeled by a linear spring of stiffness KT: Since damping
in the tire is typically very small, it is neglected in this study. The parameter values chosen for this
study are shown in Table 1. They are typical for a lightly damped passenger car.