Optimal torque distribution strategy for a four motorized wheels electric vehicle

Electric vehicles (EV) with four motorized wheels allow for an independent and accurate torque control of each wheel. This offers many possibilities for the development of effective new dynamic stability control systems. Furthermore, EV should be developed with respect to energy saving. In this paper, an optimal torque distribution strategy (OTD) for EV with a four motorized wheels is investigated. OTD combines improved vehicle stability performance with low energy consumption. Objective functions for both vehicle stability and economy are established with different weighting coefficients. They are determined from the vehicle body sideslip angle through use of fuzzy logic rules aimed at improving vehicle economy under stable driving conditions. The solutions to these objective functions are derived under the constraints of direct yaw moment, desired driving torque and friction coefficient. The effectiveness of this proposed control approach is tested and confirmed with a suitable simulation model.