Research On Yaw Stability Control Strategy Of Distributed Drive Electric Vehicles

With the development of electric vehicles,distributed drive electric vehicles have become one of the key research to universities and enterprises.Drive motors are distributed to four wheels in a distributed drive electric vehicle.This kind of structure has the advantages of short transmission chain,high efficiency and compact structure.The driving motor of each wheel can realize the independent control.This paper researches the yaw stability control strategy of distributed drive electric vehicles.Firstly,each subsystem of the vehicle is modeled.Vehicle body system,air dynamic system,steering system,transmission system,suspension system,braking system,and tire system are established in Carsim.Driver model,wheel model and motor model are established in Matlab/Simulink.A complete distributed driving vehicle dynamics model is built through the interface of the two software.Second,in order to obtain the accurate vehicle state parameters,the parameters of the vehicle is estimated based on the Extended Kalman Filter and Unscented Kalman Filter.The estimated results are compared with the parameters of the whole vehicle model.Simulation results show that the two kinds of filtering algorithms can estimate the vehicle state parameters effectively.Besides,the estimation accuracy of the Unscented Kalman Filter is higher than that of the Extended Kalman Filter.In the estimation of sideslip angle,the estimation error of the Unscented Kalman Filter is 31% lower than that of the Extended Kalman Filter.In the estimation of yaw rate,The error has been reduced by 5%.Third,based on the fuzzy control system,the measurement noise R is adjusted adaptively.The simulation results show that the adaptive Unscented Kalman Filter is more accurate than the Unscented Kalman Filter to estimate the parameters of the vehicle.The accuracy of the sideslip angle estimation and the yaw rate in double lane condition is improved by 7.1% and 4.6% respectively.The accuracy of the sideslip angle estimation and the yaw rate in serpentine condition is improved by6.7% and 4.7% respectively.Fourth,the yaw stability algorithm is studied.Using the hierarchical control strategy,the upper layer motion tracking layer is based on the sliding mode control algorithm,and the distribution of the lower torque is distributed evenly.Simulation results show that the yaw stability control algorithm can greatly improve the yaw stability of distributed drive electric vehicles under extreme conditions.Finally,Hardware in the loop simulation is established to verify the effectiveness of the control algorithm.Results show that through control algorithm,in double lane conditions side slip angle decreased by 40.5%,the yaw rate decreased by 52%,in serpentine condition,sideslip angle decreased by 32.3%,the yaw rate decreased by 36.7%.