Effect of Sitting Occupancy on Lateral Dynamics and Trajectory of a Passenger Car

In the current work, the effects of sitting locations and combinations of occupants on handling performance of a four-wheeled passenger car have been investigated. A new multi-occupant nonlinear lumped parameter model (LPM) is developed by coupling 1-DOF longitudinal vehicle model, 2-DOF lateral vehicle model, 13-DOF nonlinear vehicle ride model including seats, 6-DOF nonlinear human occupant model, and 1-DOF tire model. The combined model with a maximum of 50 degrees-of-freedom (in case of all five seats occupied) is simulated in MATLAB/SIMULINK environment. Model subsystems i.e. occupant and vehicle models including tires are validated independently by comparing biodynamic responses of seated occupants, vehicle vertical response and handling behavior with published results. The coupled model can facilitate the study of vehicle dynamics considering the combined effects of road inputs, vehicle maneuvering and seat occupancy while taking into account the nonlinear behavior of vehicle suspension. Further the yaw rate and vehicle trajectories are compared and studied for various cases of sitting occupancies at a given vehicle velocity with a road input representing harsh and abrupt scenario. The current study shows that appreciable changes in yaw rate and vehicle trajectory can be caused due to varying sitting occupancies and vehicle velocities.