Dynamics of the vehicle rear suspension system with electric motors mounted in wheels

The dynamics analysis of the rear suspension system of the Fiat Panda III with electric motors mounted in wheels is presented in the paper. The simplified model of this system modeled using the multibody system dynamics method and the MSC. Adams package is proposed. In order to validate the proposed numerical model, the road tests were carried out consisting on passing the vehicle without motors in wheels at constant speed through the obstacle. The vertical displacement of the center of the vehicle wheel was measured during the tests. During the validation, parameters of the wheel-to-road contact, stiffness coefficients of springs and shock absorber damping coefficients of the suspension of the simulation model were modified so that the numerical results were consistent with the experiment. Further, such a tuned model was used to simulate the motion of suspension with the motors mounted into the wheels. The obtained results were validated, obtaining the accepted compatibility. In the following, a series of calculations was carried out in order to analyze the influence of stiffness coefficients of springs and shock absorber damping coefficients on the dynamic response of the suspension.