Simulation on multifunction steering system of wheel drive electric vehicle
                                  WANG Yanan, YAN Shirong, LU Bingbing, YANG Jiancui, ZHOU Hailin, LIU Zhan
                          (School of Mechanical Engineering and Automation, Fuzhou University, Fuzhou 350108, China)

Abstract: Aimed at solving the steering differential problem of fourwheel independent driven electric vehicle, the electronic differential control strategy of the distributed driven electric vehicle was studied and simulated. The traditional method that first, the same target torque was allocated and then compensated of each wheel was improved. A more active objective torque allocation method was proposed and a road surface recognition controller was added to achieve a better steering of vehicle. First, according to the current feedback signal of the vehicle, the ratio between vertical load and vehicle mass of each driving wheel was calculated, and then the target torque of each wheel was preallocated. Then, according to the slip rate of each wheel, the driving torque of each wheel was compensated and reallocated. Finally, the whole vehicle dynamics model with 7 degrees of freedom, road surface recognition controller, the Dogoff tire model and torque distributor model and so on were established based on Simulink, and then these models were simulated and analyzed. The simulation results show that the controller can better realize the electronic differential control of the vehicle, reduce the fluctuation of torque and slip ratio, and improve the steering performance, stability and comfort of the vehicle.

Key words: fourwheel independent driven; electric vehicle; electronic differential speed; slip rate; torque distribution