Research On Torque Coordination Allocation Strategy Of Electric Wheel Vehicle Based On Driver Behavior Identification

At present,electric vehicle has become an important direction of automobile development because of the advantages of low carbon,energy saving and simple structure.In recent years,electric-wheel vehicle has been a research hotspot in the control technology field of electric vehicle.Because it has many advantages,such as higher integration,independent and controllable four-wheel torque.In this paper,a coordinated torque allocation strategy based on driver behavior identification for electric wheel vehicle is studied in depth,and the main contents are as follows:(1)First,a seven-degree-of-freedom dynamic model of electric wheel vehicle through system dynamics is established,and then a mathematical model of the Pacejka tire is set up by analyzing the mechanical properties of the tire,at last,a road surface recognition model is finished based on fuzzy control algorithm,all the work is the foundation for the study of control strategies.(2)According to the power and stability of the vehicle,the driver’s behavior intention is divided into power demand,steering sensitivity demand and trajectory maintenance demand.The fuzzy rules corresponding to the three requirements are determined,and the parameters are adjusted adaptively according to the driver’s state,and the driver’s intentions are identified by variable universe adaptive fuzzy control algorithm.(3)Firstly,the influence of steering sensitivity requirement and trajectory maintenance requirement is added to the lateral stability control algorithm.The switching surface is constructed by using the yaw angular velocity and the sideslip angle of the center of mass as the joint control variables based on the driver’s requirement.The lateral stability of the vehicle is controlled by the dynamic sliding mode variable structure control algorithm.Secondly,Four-wheel drive force is optimized by grey particle swarm optimizationalgorithm which aims at improving the dynamic and stability of vehicles,and takes yaw moment,dynamic demand,road adhesion limit as constraints.Finally,the four-wheel motor torque is controlled by dynamic sliding mode variable structure control algorithm which takes wheel angular acceleration as the control objective and combines the optimal distribution of four-wheel driving forces.(4)The co-simulation model about coordinated torque allocation strategy based on driver behavior identification for electric wheeled vehicle is realized,with the conjunction of the MATLAB/Simulink and Carsim software.Three driving conditions about high-speed small turning,medium-speed turning and low-speed large turning are respectively simulated in the co-simulation model.In summary,this strategy provides theoretical and technical support for the development of EV driving force distribution technology and the application of hub motor in EV.