Open-Loop, Fixed-Control Simulation of a Vehicle Undergoing Steering and Acceleration Maneuvers

Recent interest in improving vehicle handling performance has concentrated not only upon achieving maximum acceleration or braking ability of the motor vehicle, but also upon maintenance of high lateral stability during acceleration or braking.

This study examines the influence of tire traction and vehicle characteristics on the directional behavior of an automobile undergoing maneuvers requiring combined longitudinal and lateral tire forces. The vehicle model considered in this analysis consists of ten degrees of freedom, including wheel rotational dynamics and steering system characteristics. The equations of motion for the sprung and unsprung masses have been derived using Lagrange's special equations for quasi-coordinates. The analysis includes nonlinear tire traction characteristics which expresses the longitudinal and lateral tire shear force components as analytical functions of several parameters. These parameters characterize both tire mechanical properties, and dynamic variables which describe tire/road contact patch kinematics.