Optimal torque distribution strategy of DDEV based on enhanced exponential sliding mode controller.

A novel direct yaw-moment control scheme is proposed to improve the lateral stability of distributed-drive electric vehicles (DDEV). The scheme adopts a hierarchical control structure that consists of an upper controller and a lower controller. An enhanced sliding mode controller (ESMC) with improved exponential reaching law is designed to calculate the additional yaw-moment to maintain the lateral stability of the vehicle in the upper controller. By adding the function about the sliding mode surface, the approach speed is increased when it is far away from the sliding mode surface, and the approach speed is reduced when it is close to the sliding mode surface, so as to suppress chattering. An optimized method of torque distribution is proposed in the lower controller, which uses a multi-verse optimizer (MVO) to minimize the tire utilization rate as the objective function to calculate the torque and optimally distribute it to each in-wheel motor. The co-simulation of Carsim and Simulink shows that under the conditions of high speed and high-adhesion road, the tracking error of the yaw rate is reduced from 6.4% to 2.7%, and the sideslip angle is within 0.018 rad; under the conditions of low speed and low-adhesion road, the tracking error of the yaw rate is reduced from 5.2% to 3.8%, and the sideslip angle is within 0.008 5 rad. The proposed strategy has better stability compared with the rule-based distribution strategy. [ABSTRACT FROM AUTHOR]