Research On Driving Torque Distribution Of Four Wheel Motor Electric Vehicle

Nowadays,automobiles are convenient for people to travel,but also bring a lot of burden to the society.Environmental pollution is serious,and energy is increasingly depleted.Therefore,the development of electric vehicles has become the focus of attention.The development of wheel motor electric vehicle has become the development of electric vehicles.The advantage of the automotive trend are that the four-wheel torque is independently controllable,the energy utilization is high,and the motor responds quickly.In order to ensure reliable and efficient driving of four-wheel motor electric vehicles,it is necessary to study the problem of control torque distribution.This paper focuses on the distribution of drive torque for in-wheel motors.The main research contents are as follows:A seven-degree-of-freedom vehicle model is established in Matlab/Simulink.The vehicle dynamics model,wheel model,slip rate model,tire model,and sideslip angle model are built respectively.The vehicle model can basically reflect the dynamic characteristics of a four-wheel motor electric vehicle.The simulation platform can realize the simulation and control verification of electric vehicles under various road conditions.In order to make full use of the road surface condition and achieve larger driving torque when driving an in-wheel motor vehicle on various road conditions,the maximum driving torque calculation module is designed to determine the maximum current road surface condition based on the six standard road surface curves.According to the coefficient of adhesion and the optimal slip ratio of the wheel,the maximum longitudinal force and the maximumlateral force are calculated,and the optimal slip rate of the wheel under the current road conditions optimized based on the moment balance formula and ?-?relationship.The calculated the optimal torque is assigned to the wheel.In addition,in order to ensure that the vehicle can be driven in a given direction by the driver,the lateral forces of the front and rear axle wheels should be opposite.Therefore,an additional steering angle is provided based on the fuzzy control principle to ensure the stability of the vehicle.Four-wheel driving torque distribution rules are formulated.Three situations are discussed: the driver's pedal opening is small,the driver's pedal opening is moderate,and the driver's pedal opening is large;when the driver's pedal opening is small,the desired torque are smaller and the four-wheel torque is evenly distributed;as the pedal opening increases,the desired torque increases.At this time,the wheel torque on one side of the smaller adhesion coefficient is preferentially distributed,and the remaining wheel distributes the remaining torque evenly;When the pedal opening is very large,the optimized driving torque is distributed to the four wheels to ensure the stable running of the vehicle.The feasibility of the maximum driving torque calculation module and torque distribution rules are verified.The corresponding model is established in Matlab/Simulink.The simulation results shows that the vehicle with additional steering angle can control the lateral slip angle and yaw rate of the vehicle.In a small range,the advantages of the four-wheel torque of the wheel motor electric vehicle can be fully utilized,and the four-wheel maximum torque can be achieved simultaneously,while the vehicle can run stably.