Steering Maneuverability Control Of Distributed Drive Electric Vehicles Under Extreme Conditions

The control mode of distributed drive electric vehicle is more flexible,and the structure of drive system is more excellent,which will make it widely used in the future.The stability control method for vehicle is mainly to make the side slip angle within 6 ° to avoid the vehicle entering into extreme conditions.There is little research on the control of vehicle in extreme condition.Therefore,this paper explores the drift control method to maintain the control of the vehicle when the sideslip angle of the distributed drive vehicle is too large.Firstly,this paper builds vehicle dynamic model and state observer to provide the basis for the vehicle steady drift control under extreme conditions.The side slip angle is estimated by unscented Kalman filter.Secondly,this paper analyzes the vehicle drift equilibrium.Firstly,the equilibrium analysis of conventional steering and drift steering is carried out to compare the similarities and differences of the two steering modes.Then,according to the structural of the distributed drive vehicle,a three-wheel model is established to analyze the steady drift of the distributed drive vehicle.Compared with the centralized drive vehicle,the intuitive understanding of the state vector and input vector of the distributed drive vehicle drift control system is generated.The analysis results will be used as a reference for the design of vehicle steady drift control.After that,this paper proposes a steady drift control method based on longitudinal force pre-distribution.This method takes into account that there is a large range of lateral movement in the process of drift,which brings large load transfer.According to the proportion of vertical load,the longitudinal force of tire is pre-distributed.The feedback method uses LQR control and three-wheel model to design the control system.The effectiveness and reliability of the control method are verified by the joint simulation of CarSim and Simulink;the influence of control parameters on the control system effect is analyzed;the steady drift control is compared with DYC control to explore the advantages of steady drift control.Finally,the hardware in the loop test platform is built based on NI PXI,the steady drift algorithm is downloaded to the actual ECU,which verifies the real-time and effectiveness of the control algorithm.In order to further verify the control algorithm,a 1:5 proportional experimental vehicle is built.The test results show that the control algorithm is practical.