Analysis And Tuning Of An Electric Vehicle Chassis

The car is an omplex multi-body coupling system,and with external input,make the working conditions of the car during use are very complicated and varied,therefore,vehicle dynamics research has always been a hot and difficult issue.The emergence of virtual prototyping technology makes it possible to simulate various driving conditions by Modeling through software,greatly facilitates the study of automotive dynamics.However,because of the difference between the simulation analysis and the actual vehicle state,and taking into account the uncertainty of the driver,Objective test and subjective evaluation are also used in automotive dynamics research.This paper combines the research and development project of an electric vehicle,for vehicle handling stability and ride comfort,to analysis and optimize the comprehensive performance of the chassis system by simulation,objective test and subjective evaluation.Based on the 3D model of the development vehicle and the parameters provided by the company,the vehicle dynamics model is built by ADAMS/Car.For the problem of insufficient precision of the rigid model,three flexible processing methods were compared.Perform meshing and modal calculation of the anti-roll bar,the lower control arm and the subframe by Hypermesh,then generating MNF files into ADAMS to build a flexible model.The contribution of the hard points of the suspension to the four-wheel alignment parameters is obtained by using the model to perform a sensitivity analysis.Through the K&C characteristic simulation analysis and the simulation of the vehicle handling stability,it was found the problem that the Ackerman percent was small,the pitch gradient and the steering sensitivity were a little large.Combined with the results of simulation analysis and enterprise requirements,Design the test process according to the principle and method of K&C characteristic test and the objective test of vehicle handling stability,and did the objective test with the mule car.Compare and analyze the data from the objective test,simulation and the test data of the benchmark vehicle,it is concluded the risk point that the development vehicle has a mismatch between the front and rear roll center heights,the brake pitch gradient is too large,and the Ackerman percentage is small.According to the existing risk points,three schemes are proposed and compared from the optimization of the hard point of the suspension system,effectively improved the risk points that exist by choose one scheme to do the optimization analysis of K&C characteristics and handing stability.Next compare the two modeling methods of the anti-roll bar,and for the McPherson suspension structure from the bias frequency and roll stiffness,three matching schemes for springs and anti-roll bar are proposed for comparison to provide the basis for the selection of key parts of the chassis.Select and tuning key parts of the chassis such as springs,dampers,stabilizer bars,buffer blocks and bushings,and subjective evaluation scores,the results show that the improved overall performance of the vehicle chassis has been significantly improved...