Research on the Stability of Vehicle Suspension Excited by the Road Surface Profile

A research on the motion stability of nonlinear vehicle suspension system with two degrees of freedom is proposed, under the conditions that forced vibration of road surface profile with single frequency excitation is present. According to the experimental results of dynamic response of the magneto-rheological fluid damper, the software Matlab is implemented to fit the modified Bouc-Wen model, and it then deduces a quarter suspension model based on the experiment results of the magneto-rheological damper. The frequency response characteristics of the nonlinear model including hysteretic loop are analyzed subsequently. We studied the vibration statuses by the phase portrait, Poincare¿ diagram and bifurcate diagram, which are gained by using the Runge-Kutta method. The vibration statuses of these systems with different excitations are finally illustrated by the continuously change of system parameters.