Research On Torque Distribution Control Of Distributed Drive Electric Vehicle Based On Road Identification

Distributed drive electric vehicle(DDEV)has eliminated the whole complex power transmission system,and outputs torque directly through the wheels,which can increase utilization of chassis space,and reduces the energy consumption.In addition,due to the characteristics of fast response and high control precision of in-wheel motor,DDEV is very suitable for active control and intelligent control.Based on the research of DDEV,this thesis studies above road identification method,wheel anti-slip control and torque coordinated distribution control.According to the actual test vehicle parameters,the DDEV dynamics simulation model is established in Car Sim.After finishing the modeling of in-wheel motor in Simulink,a complete co-simulation of Car Sim and Simulink is established.In view of the fact that the wheels are prone to severe slip in the acceleration stage of vehicle starting,a road identification method is designed based on Burckhardt tire model.The optimal slip rate and peak value of vehicle driving road are estimated by using adhesion coefficient,so as to improve the adaptability of driving anti-slip control algorithm.Then,the effectiveness of the identification method for single road,splicing road and open road surface is verified.Considering that the torque fluctuation of the motor output and the external interference will affect the control system,an ADRC controller is designed to improve the robustness of the system,which can lower the difference of wheel speed between current values and expected values by controlling the output torque of the in-wheel motor.Simulation results show that the slip rate control can effectively reduce the wheel slip during starting acceleration,and reduce steady state error of motor output.To achieve the requirements of reducing wheel slip in low speed steering condition and improving vehicle stability of high speed steering under the low adhesion conditions,a coordinated torque distribution control strategy is proposed.In low-speed steering conditions,DDEV use electronic differential to reduce slip ratio;in high-speed steering conditions,DDEV use quadratic programming to redistribute output torque,which can improve vehicle stability.In order to adapt to complex speed conditions,a control strategy is developed to coordinates output torque.The simulation results show that the torque coordinated control can effectively improve trajectory tracking and steering stability.Based on the existing experimental platform of dual-in-wheel motor in laboratory,using HIL to verify the control effect of driving anti slip on split mu road is carried out.The simulation results shows that the anti-slip control can effectively reduce the possibility of vehicle sideslip,and make good use of the road conditions in the process of acceleration Then,another HIL simulation of the coordinated torque distribution control is carried out,and the effectiveness of the torque redistribution control based on quadratic programming is verified by the high-speed double line change condition.