Study on intelligent control of yaw stability of electric vehicle with in-wheel motors

In order to improve yaw stability of electric vehicles with in-wheel motors, a yaw moment fuzzy control method based on yaw rate and side-slip angle is designed. A hierarchical control structure was set up. The upper layer is motion tracking layer, it obtains required additional yaw moment based on the fuzzy control theory according to current status feedback of vehicle and ideal status of reference model. The lower layer is a torque distribution layer that uses the weighted least squares method to optimise moment distribution by adopting an in-wheel motors/hydraulic brake system combined control strategy, with full consideration of all restraints. A rapid control prototype test bench is designed based on dSPACE system, simulation experiments were conducted under typical test work conditions. The simulation result shows that compared with even torque distribution and the optimal torque distribution involving the motor only, the optimal torque distribution control strategy of the combined in-wheel motor and the hydraulic braking system can effectively improve the stability of wheel-motor driven electric vehicles.