Study On The Optimization Of Suspension And Wheel Alignment Parameters Of In-wheel Motor Drive Electrical Vehicle

In-wheel motor(IWM)drive electric vehicle conforming to the requirements of the national energy development plan,it has the advantage of low emission and energy diversification,high efficiency and so on,and it also has a great advantage in the vehicle arrangement,vehicle control and convenient operation and so on,which is an important research direction of new energy vehicles.But the IWM is introduced,so that the vehicle unsprung mass increases,causing the vehicle ride comfort deterioration.Besides,due to the the motor air gap generated unbalanced magnetic force(UMF)wave may have impact on the wheel alignment parameters and ride comfort,may also cause the vibration of suspension system.Previous studies have focused on the single excitation source,the study on road surface roughness and the electromagnetic force of the motor as the common excitation is less.In this paper,the National Natural Science Foundation of China(Grant No.51575001),'Research on Vertical Electromechanical-coupling Vibration Mechanism and Its Suppression Method of Electric Vehicle Driven by in-wheel Motor'as the basis,the electric vehicle prototype of the four-wheel motor is used as the research object,and the optimization of the wheel drive electric vehicle suspension and wheel alignment parameters is studied by theoretical analysis,modeling simulation and simulation verification.The main research work includes:(1)Aiming at the kinematic characteristics of the IWM drive electric vehicle suspension,the influence of the non-sprung mass and the UMF impact on the vehicle ride comfort,Adams/Car was used to construct a reasonable analysis model of the IWM drive electric vehicle.Combined with the actual operating conditions of vehicle and motor,given the road surface excitation model and UMF analysis expression.The kinematic characteristics of the suspension under the single-wheel beating excitation and the influence of the UMF fluctuation on the wheel alignment parameters are analyzed.The influence of the quality of the IWM on the acceleration of the vehicle body,the dynamic deflection of the suspension and the root mean square(RMS)value of the dynamic load of the wheel are studied.The variation of vehicle body acceleration,suspension dynamic deflection and dynamic load of the wheel is considered or without considered the UMF of the motor.(2)In order to verify the accuracy of the multi-body dynamic model of the IWM electric vehicle,the dual-mass vibration system model and the differential equation of motion are established by using the vehicle dynamics method.The influence of the IWM quality and UMF on vehicle ride comfort correlation evaluation index is analyzed by using Matlab/simulink,and the results of the multi-body dynamics model of Adams/Car software were verified.(3)The optimization of multi-objective linear weighting method for IWM drive electric vehicle suspension and wheel alignment parameters is carried out.Proposed the optimization method of combinating the experimental design and sensitivity analysis.The Adams/SQP quadratic programming method is used to solve the multi-objective function,and the aim of improving the vehicle ride comfort is achieved by optimizing the coordinates,stiffness,damping and wheel alignment parameters of the suspension.The optimal model is used to reconstruct the simulation model to verify the accuracy of the optimization results.The results show that the optimization of the wheel parameters can be controlled reasonably by the optimization method,and the vehicle ride comfort is improved by the reasonable match the stiffness and damping of the suspension.