Once the traditional electric vehicle was refitted with distributed drive (4WID) system

the increasing of vehicle's unspring mass would significantly increase the steering resistance

as a result of that

the efficiency and accuracy of the original car's steer-by-wire (SBW) system will be reduced. In order to solve this problem

taking BAIC-EV150 for example

this paper introduced a design of SBW controller for 4WID vehicles

and the corresponding refitting work of real vehicle were completed. The refitted vehicle adopted dual-motor

dual-controller to coordinate control. The difference value between the auxiliary torque and the resistance moment were token as the input of the controller. An adaptive fuzzy PID controller was used to calculate the compensation torque

aiming at controlling the additional motor output compensation torque to offset the increased steering resistance. Based on the joint simulation of CARSIM and MATLAB

the real vehicle test was carried out consequently

during which the response speed and precision of ordinary PID control and adaptive fuzzy PID control are compared. Simulation and experimental results show that the controller can meet the requirements of 4WID vehicle steering

and the dual-motor steering system based on fuzzy PID control is more responsive and more accurate than the single-motor steering system which under ordinary PID control.