Four-wheel independent drive electric vehicles have become the latest development trend of electric vehicles due to their simple structure and high control accuracy. Aiming at the sliding problem of four-wheel independent driving electric vehicles in the driving process, a driving anti-skid control strategy is designed. The strategy includes two contents: (1) a road recognition module that tracks the best slip rate in real time; (2) a slip rate control module that uses fuzzy PID control. Then, based on Carsim and MATLAB/Simulink, the vehicle dynamics model, tire model and driving anti-skid control model are established. A simulation of the driving anti-skid control algorithm is carried out to verify the feasibility of the control strategy. Finally, based on the built-up dSPACE semi-physical experimental simulation platform, the verification was carried out, and the test and simulation results were compared to verify the effective feasibility of the driving anti-skid control strategy.
In order to improve the stability of vehicle steering on low-adhesion road surfaces, this paper designed a hybrid robust control strategy, H2/H∞, for active front-wheel steering (AFS) based on robust control theory. Firstly, we analyzed the influence of the sidewall stiffness and road adhesion coefficient of the tires on vehicle stability, through which we can study the wheel deflection characteristics of low-adhesion roads. Secondly, the reference yaw velocity of the vehicle was calculated using the three-degrees-of-freedom model as the reference model, through which, taking the norm H∞ as the objective function and the norm H2 as the limit to control the output, the hybrid robust control strategy H2/H∞ of the AFS system on a low-adhesion road surface was developed. Finally, the simulation experiment was carried out by the Simulink/CarSim co-simulation platform and a hardware-in-the-loop (HIL) experiment. In this paper, the results show that the AFS control strategy can improve the vehicle handling stability on low-adhesion road surfaces, and the controller has good path tracking performance and robustness.