Steady State and Transient Analysis of Ground Vehicle Handling

This paper presents simple linear and non-linear dynamic models and numerical procedures designed to permit efficient vehicle dynamics analysis on microcomputers. Vehicle dynamics are dominated by tire forces and their precursor input variables, and a few inertial and suspension properties. The steady state and dynamic models discussed herein include a comprehensive, unlimited maneuver tire model with relatively simple vehicle suspension kinematics and inertial dynamics to cover the full vehicle maneuvering range from straight running to combined limit cornering and braking or acceleration. An attempt was made to minimize the required tire and vehicle model parameter set and to include easily obtainable parameters. The computer analysis procedures include:

• A steady state model for determining perturbation side force coefficients, and a stability factor and maneuvering time constant for lateral/directional control.
• A linear perturbation model for analyzing dynamic modes and lateral/directional stability.
• A nonlinear time domain simulation for assessing large transient performance limits.

Both front and rear drive vehicles are analyzed as examples.