A Primer on Nonlinear, Steady-State Vehicle Turning Behavior

A simple, linear vehicle model is presented which incorporates the most important characteristics of contemporary passenger cars. It is a three mass model with a fixed, inclined roll axis and linear suspension geometric and compliance characteristics.

Basic concepts of understeer and oversteer are presented. Static and dynamic requirements are examined, yielding expressions relating the car's design to tire lateral load transfer, total lateral force, and turn radius. Turn kinematics give expressions for the front steer angle and sideslip angle. Suspension geometric and compliance effects describe the rear steer angle, tire inclination angles, and steering wheel angle divided by the overall steering ratio.