Global modeling and simulation of vehicle to analyze the inertial parameters effects

This paper mainly studies the comparison of the global vehicle models and the effects of the inertial parameters due to the center of gravity (CG) positions when we consider that the vehicle has only one CG. This paper proposes a new nonlinear model vehicle model which considers both unsprung mass and sprung mass CG. The CG positions and inertial parameters effects are analyzed in terms of the published vehicle dynamics models. To this end, two 14 degree-of-freedom (DOF) vehicle models are developed and compared to investigate the vehicle dynamics responses due to the different CG height and inertial parameters concepts. The proposed models describe simultaneously the vehicle motion in longitudinal, lateral and vertical directions as well as roll, pitch and yaw of the vehicle about corresponding axis. The passive and active moments and the forces acting on the vehicle are also described and they are considered as a direct consequence of acceleration, braking and steering maneuvers. The proposed model M-1 takes both the CG of sprung mass, unsprung mass and total vehicle mass into account. The second model M-2 assumes that the vehicle is one solid body which has a single CG as reported in majority of literature. The two vehicle models are compared and analyzed to evaluate vehicle ride and handling dynamic responses under braking/acceleration and cornering maneuvers. Simulation results show that the proposed model M-1 could offer analytically some abilities and driving performances, as well as improved roll and pitch in a very flexible manner compared to the second model M-2.