Chapter 5 - Steering System and Vehicle Dynamics

Abstract

The equations of two degree-of-freedom rotational motions of steering wheel and front wheels equivalently around kingpin are introduced. Using the steering system equations of motions together with the equations of vehicle motion introduced in Chapter 3, the effects of the steering system parameters on the fundamental vehicle handling dynamics are investigated in this chapter. When the steering wheel angle is regarded to be given, it is shown that the overall torsional stiffness of the steering system has predominant effects of equivalently reducing cornering stiffness of the front tires on vehicle handling dynamics. This is called compliance steer effects. When the steering angle is regarded having a motion degree-of-freedom, it is shown that the vehicle motion becomes the oscillatory unstable at high speed if the natural frequency of the steering system is smaller than some specific value.