Variable gain control-based acceleration slip regulation control algorithm for four-wheel independent drive electric vehicle

In order to improve the dynamic performance and stability of general acceleration slip regulation (ASR) control technology for four-wheel independent drive electric vehicle (4WID EV), an ASR control strategy based on variable gain controller (VGC) is proposed in this paper. First of all, a road identification strategy is designed to identify the current road surface and calculate the optimal slip ratio of the road. Then, the optimal slip ratio is taken as the control target, and the ASR control strategy based on VGC is designed to keeps slip ratio around the optimum slip ratio through controlling the driving torque output, so wheels can make the best of road adhesion to prevent vehicle from slipping. Meanwhile, we analyze the control system state space, and build a scalar function of the system, and prove that the system satisfies Lyapunov large scale asymptotic stability theorem, so the parameters of the VGC does not affect the system stability. Then, in order to meet the requirement of quick dynamic response and no overshoot, parameters selection of VGC is deduced by mathematics. Finally, the co-simulation of Matlab/Simulink and Carsim results show that the proposed control strategy is with the better dynamics and stability, and can better prevent wheel slipping on various roads.