Structural Topology and Dynamic Response Analysis of an Electric Torque Vectoring Drive-Axle for Electric Vehicles

In-wheel motor-drive electric vehicles have the advantage of independently controllable wheel torque and the disadvantages of unsprung mass rise and power restriction. To address the disadvantages, a centralized layout electric torque vectoring drive-axle system (E-TVDS) with dual motors is proposed, which can realize arbitrary distribution of driving torque between the left and right wheels. First, the speed and torque distribution principle of E-TVDS based on velocity diagram are analyzed, and a virtual prototype of the whole vehicle with basic gear ratio relation model of the E-TVDS is built for simulation to verify the theoretical results and the basic effect of E-TVDS on the steering performance of the vehicle. Second, the characteristics of 36 types of the novel E-TVDS topology structure are compared and analyzed, and the optimal structure scheme is selected. Third, the accurate multiple degrees of freedom dynamic model for the optimal structure is established by using the bond graph method, and its dynamic response characteristics are analyzed. The results show that the vehicle equipped with the proposed E-TVDS can distribute the driving torque with the almost identical amount but opposite sign between the left and right wheels in any direction, and varying amount according to different chassis dynamics control requirements, and the torque response performance is great with little delay and overshoot. The function and dynamic response of the proposed E-TVDS show that it has potential application value for various performance improvements of electric vehicles.