Torque coordinated control of distributed drive electric vehicle based on nonlinear MPC

Here, in order to improve stability of distributed drive electric vehicles under limit conditions, a torque coordinated control strategy based on nonlinear model predictive control (NMPC) algorithm was proposed. The strategy was based on NMPC's overall optimization method of centralized system, it could consider the whole vehicle stability control and torque optimal distribution, improve the vehicle driving stability, ensure tire slip rate within a stable range, and improve the stability of vehicle drive/braking. Firstly, a whole vehicle dynamic model with 7-DOF was established using the software MATLAB, and the vehicle dynamic controller model was built based on the algorithm framework of predictive control. Then, according to handling stability control requirements, considering tire's longitudinal slip constraint, the system's objective function was designed. Combined with the obstacle function method, the boundary constraint of slip rate was realized based on the expected dynamic slip rate estimated. Finally, the expected value tracking control and sliding constraint control were converted into the constrained optimization problem to solve and obtain the optimal torque distribution on each wheel. The simulation results showed that the proposed torque coordinated control system can effectively improve vehicle stability, control tire slip rate within a stable range, and improve vehicle safety. © 2021, Editorial Office of Journal of Vibration and Shock. All right reserved.