Simulation Analysis And Optimization Research Of Ride Comfort For Wheel Drive Electric Vehicle

With the depletion of petroleum energy and the increasingly prominent environmental problems caused by emissions,electric vehicle is an important direction of future automobile development.Because of the unique advantages of wheel drive electric vehicle in the aspects of vehicle structure and dynamic control,it has been paid close attention by many scholars and enterprises in the field of electric vehicle.However,due to the vertical vibration caused by the increase of unsprung mass,the ride comfort of the vehicle becomes worse,which limits the future application of wheel drive electric vehicles.For this problem,this paper does the following research:First of all,based on the quarter vehicle dynamics simulation model,in different road conditions,the ride comfort simulation experiments of centralized motor drive system,traditional wheel drive system and wheel drive system with vibration-absorbing are carried out respectively,and their vertical vibration performance is analyzed and studied.The simulation results show that compared with the centralized motor drive system,the vertical vibration of the traditional wheel side drive system is stronger,and the vertical vibration of the wheel side drive system with vibration-absorbing is relatively gentle,and its ride performance is optimal.Therefore,the wheel damping wheel side drive system is selected as the research object of the follow-up optimization work.Secondly,for the negative impact of the increase of the unsprung mass of the wheel drive system on the vehicle ride comfort,the single factor parameter influence analysis of the wheel damping wheel drive system is carried out from the amplitude frequency characteristics and root mean square response.The results show that the performance evaluation indexes of the vehicle can be improved by increasing the damping of the motor suspension,and the performance evaluation indexes of the vehicle can be deteriorated by increasing the stiffness of the vehicle suspension,but the influence of the damping of the vehicle suspension and the stiffness of the motor suspension on the performance evaluation indexes is not completely consistent in the amplitude frequency characteristic analysis and the root mean square value analysis.Based on the single factor parameter influence analysis,the orthogonal test design method is used to optimize the parameters that affect the ride performance of the vehicle,and the optimal scheme combination that can improve the ride performance of the vehicle is selected.Then,in order to better improve the ride comfort of the wheel drive electric vehicle,different active suspension layout and parameter optimization design are carried out for the wheel damping wheel drive system.Based on the quarter vehicle dynamics model,the ride comfort simulation test and analysis are carried out for the wheel damping wheel drive system before and after the optimization design.The test results show that the two kinds of active suspension arrangement schemes can improve the ride performance of the wheel damping type wheel side drive system,of which the effect of the second scheme is better;and the ride performance of the wheel damping type wheel side drive system optimized by FMINCON function(function optimization)is better than the two schemes.Then,the ride performance of the wheel damping type wheel side drive system is compared between the active suspension layout scheme and the orthogonal test optimization design in the third chapter.Finally,it is found that the improvement effect of orthogonal test optimization design method is better than that of active suspension layout design.Finally,in order to select the best optimal design method of ride performance more accurately,a 9-DOF wheel damping type rear wheel drive electric vehicle dynamic model with more comprehensive vehicle information is built in SIMULINK.The system suspension parameters after orthogonal test optimization design and function optimization design are applied to the vehicle dynamic model,and the ride performance is carried out under different road inputs Simulation analysis of sex test.The simulation results show that the vehicle ride performance after the function optimization design is improved under some road inputs,while the vehicle ride performance after the orthogonal test optimization design can be improved under all road inputs,effectively improving the ride performance of the wheel drive electric vehicle.