Suspension System Optimization And Study On Control Of The Electric Vehicle

The electric vehicle have the advantages of environmental protection,energy conservation and lower noise,they are widely used in daily life,the ride comfort and handling stability of electric vehicle are the basic performance of the vehicle.Compared with traditional fuel vehicle,the sprung mass and the unsprung mass are different,the quality of the whole vehicle is heavier,so it is necessary to optimize the suspension system.In addition,the control strategy is the key factor to affect the riding comfort and steering handling stability of the electric vehicle,based on the study about the different control strategies,improving the suspension performance and steering handling stability,enhancing the ride comfort and safety of the passengers.This paper mainly carries on the following researchs:(1)The hard point and the quality parameters,such as quality of the parts,the center of mass,centroid and rotational inertia were extracted from the suspension three-dimensional model,established the simulation model of the suspension according to the parameters.(2)The double wheel travelling in the same direction test were carried out by using ADAMS/Car,analyzed the suspension wheel alignment parameters,the roll center height and so on.The analysis matrix is created based on the DOE response surface method,the design matrix is created based on the full factorial method,optimized the wheel alignment parameters,the simulation experiment was carried out according to the optimized suspension model,analyzed the wheel alignment parameters of the optimized suspension.(3)The body vertical acceleration,suspension dynamic deflection and tyre deformation were selected as the evaluation standard about the suspension system performance,established the two-degree of freedom 1/4 suspension model,four degrees of freedom semi-vehicle suspension model and Seven degrees of freedom vehicle suspension model,the simulation modle is established by using the MATLAB program,analyzed the dynamic characteristics of the three kinds of suspension.(4)Based on the two-degree of freedom 1/4 suspension model,analyzed the semi-active suspension,which used the PID control strategy and sky-hook damper control,compared with passive suspension,analyzed the change of the suspension performance under different control strategies,and the advantages and disadvantages of the two kinds of the control strategies.(5)The lateral acceleration,yaw rate and side slip angle were selected as the objects,analyzed the steering characteristic of the four-wheel steering vehicle and two-wheel steering vehicle under the low speed and high speed.Finally,analyzed the steering handling stability of the traditional front wheel steering and the four-wheel steering with the proportional control and the LQR optimization control strategies.