Research On The Driving System Construction And Yaw Stability Control Of The Rear Axle Independent Drive Electric Vehicle

Independent drive electric vehicle,which has simpler mechanical structure,stronger power and faster response compared to the internal combustion engine vehicle and the centralized drive electric vehicle,is one of the important directions for the development of pure electric vehicle.However,the driving force of independent drive electric vehicle comes from different driving motors,so it is easy to appear yaw instability during driving.This paper,starting with the structure design of the drive system of the independent drive electric vehicle,constructs the driving system of the rear axle independent drive electric vehicle.It gives full play to the advantages of independent driving wheel,accurate driving force control and quick response,and puts forward a direct yaw moment control strategy which takes the driving force of the driving wheel as the execution force to improve the stability of the vehicle yaw.It is specifically divided into the following aspects:(1)Based on the real vehicle platform of the National College Students' equation racing car,matching the parameters of the components to the structural design of the parts,reforming the single motor driving structure of the original electric vehicle,and designing and assembling the rear axle independent driving electric vehicle platform,finally obtaining the vehicle parameters.(2)Establishing the simplified vehicle dynamics models including the linear vehicle reference model and the nonlinear vehicle calculation model with the knowledge of vehicle dynamics.On the basis of the actual vehicle parameters obtained,establishing the actual vehicle control model of the actual operating state and control effect of the vehicle with the help of the Carsim software.Finally,building a joint simulation platform of Matlab/Simulink and Carsim.(3)Analyzing the factors affecting the stability of the vehicle yaw from three aspects,and taking the driving force of the driving wheel as the control variable by the yaw rate and the side angle of the centroid,which includes the direct yaw moment control strategy of the yaw moment decision layer and the torque distribution layer.The upper part of the control strategy uses the sliding mode variable structure control theory.The lower part adopts the optimal control theory.For the nonlinear system,it can ensure the control precision and the response speed.(4)Under the simulation platform,using the experiment conditions of the double shift test with the software,and building the snake test conditions in the software test environment,and verifying the strategy by two conditions.In the test environment,the test bench test of the hardware in the loop is carried out under the steady-state rotation condition,and the control strategy is further verified.The control strategy proposed in this paper,which taking the driving force as the execution force of the yaw moment,can ensure the yaw stability of the vehicle,and avoid the problem of driving safety caused by the reduction of the longitudinal speed when taking the braking force as the execution force of the yaw moment.