Analysis of Steering Wheel Shimmy and It’s Affected Factors of a Coach

Considering nonlinear relationship between slip angle and lateral force,a steering wheel shimmy model of a coach with four degrees of freedom is constructed.Applying the nonlinear dynamical system theory,certain the Hopf bifurcation points of steering wheels occurring self-excited shimmy;Through MATLABSimulink software,a steering wheel shimmy simulative model of the coach is constructed.Check the theoretic analysis by the simulation,and acquire the curves,which about the relationship between velocity,steering gear stiffness and damping、tie-rod stiffness and damping,center of mass location,kingpin caster angle and amplitude,frequency of the shimmy.Find out sensitive parameters which affect shimmy and acquire the parameter ’s suitable values,being able to effectively reduce or eliminate self-excited shimmy of the coach.