ABSTRACT
The development of Four-Wheel Independent Drive (4 WID) Electric Vehicles (EVs) has led to significant changes in modern vehicles. The introduction of an In-Wheel Motor (IWM), which increases the unsprung mass of the vehicle, deteriorates the comfort and the contact condition between tires and road. Besides, it also increases the coupling effect of the vertical vibration of the suspension and the shimmy of the steering system. In this paper, a dynamics model of the wheel shimmy with 5DOFs is established base on Lagrange’s equation. The tire model uses a nonlinear magic formula, taking into account the suspension system shock absorber damping. Based on the bifurcation theory in nonlinear dynamics, the influence of the characteristics of the suspension damper system on the limit cycle in the self—excited pendulum is analyzed systematically and its numerical characteristics are analyzed. It provides a new theoretical basis for the suppression and control of wheel shimmy of 4 WID EVs.
