A FEEDBACK CONTROL STRATEGY FOR TORQUE-VECTORING OF IWM VEHICLES

In last decades hybrid and electric vehicles have been one of the main object of study for automotive industry. Among the different layout of the electric power-train, four in-wheel motors appear to be one of the most attractive. This configuration in fact has several advantages in terms of inner room increase and mass distribution. Furthermore the possibility of independently distribute braking and driving torques on the wheels allows to generate a yaw moment able to improve vehicle handling (torque vectoring). In this paper a torque vectoring control strategy for an electric vehicle with four in-wheel motors is presented. The control strategy is constituted of a steady-state contribution to enhance vehicle handling performances and a transient contribution to increase vehicle lateral stability during limit manoeuvres. Performances of the control logic are evaluated by means of numerical simulations of open and closed loop manoeuvres. Robustness to friction coefficient changes is analysed.