Research On Yaw Stability Control Method Of Distributed Drive Electric Vehicle

In order to solve the social problems such as environmental pollution,energy consumption,and traffic accidents caused by traditional vehicles,the lateral stability controller is designed for distributed drive electric vehicle to study the vehicle yaw stability control method to improve the vehicles driving stability under extreme conditions in this paper.Based on the software of Matlab/Simulink and CarSim,the distributed drive electric vehicle model is established as the actual model of the controller,the linear two-degree-of-freedom vehicle model as the reference model,and select the yaw rate and side slip angle as the control variables of the controller.The lateral stability controller is designed with the layered control structure in this paper,the upper controller uses the integral sliding mode control to calculate the additional yaw moment that can keep the vehicle running stably.The fuzzy control method is used to dynamically adjust the switching gain of the sliding mode system to weaken the system chatter.Combined the ?-? phase plane method with deviation of the yaw rate to judge the steady state of the vehicle,then set the controller interference threshold based on the steady state of the vehicle.The lower controller uses two torque distribution methods to allocate additional yaw torque,the first one is the hydraulic differential brake distribution method,it selects the optimal action wheel to adjust the braking force according to the single wheel brake rule.The other is an average distribution method of yaw moment based on the characteristics of the motor,it applies a pair of equal and opposite longitudinal moments on both sides of the vehicle to adjust the vehicle posture according to the steering characteristics of the vehicle.Constrained by road attachment condition and motor peak torque,when the torque capacity of the motor can't meet the additional yaw moment demand,the hydraulic differential brake compensation strategy is adopted.Based on Matlab/Simulink and CarSim simulation environment,the Fishhook condition and the double line change condition were selected to verify the vehicle yaw stability.The results show that the vehicle yaw rate follow the ideal value well and the side slip angle can be controlled within the allowable range under the controller is applied,the vehicle has better path tracking ability and yaw stability at the same time.Both torque distribution methods can achieve better control effect,and the average distribution performance is even better.