Dynamic Stability Control And Suspension Design Of Four-wheel Independent Driving Electric Vehicle With Variable Curvature Corner

With the increasing requirement of energy-conservation,safety and intelligence on vehicles,the electric vehicle driver assistant system is attracting more and more attention.In this paper,four-wheel independent electric vehicle as the research object,the study of different corners under the conditions of vehicle speed control methods,motion planning and path tracking control system,the main research includes the following aspects:(1)For the different corner conditions encountered,the design of a comprehensive integrated speed control strategy,and flexible selection of speed selection method.According to the calculation of anti-rollover and safe braking distance,the brake deceleration and driving acceleration of the curve are selected.(2)The kinematics model of the independent four-wheel drive electric vehicle and the dynamic model of the seven-degree-of-freedom vehicle are established.Simulink and CarSim model are simulated together.The simulation results show that Simulink mathematical model and CarSim model have similar kinematic characteristics and dynamic characteristics.(3)The four-wheel-independent vehicle speed tracking control system is designed,including fuzzy PID controller,torque identification and switching logic module and torque distribution module for calculating the expected torque.Through the joint simulation with CarSim,fuzzy PID speed tracking control system can accurately track the different speed signal,effectively avoid the brake and drive control frequent switching phenomenon,while the drive and braking torque can be flexibly distributed.(4)Based on the model predictive trajectory tracking control system,the prediction model,model constraint condition and optimization objective function are defined respectively,and Simulink and CarSim are used for joint simulation.Finally,the influence of different design parameters on the tracking accuracy and stability of the model predictive controller is analyzed.(5)Four-wheel independent drive electric vehicle rear suspension design,the suspension parameters to select the calculation,according to the results of component selection,the application of SolidWorks for suspension parts modeling and assembly;and then simplify the model,according to the three-dimensional model of hard point coordinates,The static model of the rear suspension of the electric vehicle is established.The finite element model of the column is established by ANSYS,and its deformation and stress cloud diagram under three kinds of working conditions(static,steering and braking)are analyzed to obtain the maximum stress and deformation.Column structure and materials meet the design requirements.