The Effect Of Unsprung Mass On Vehicle Handling Stability

Due to the introduction of the In-wheel Motor,the weight of each wheel will be increased by 30~50kg,which will lead to the unsprung mass greatly increased.So the vehicle handling stability test and simulation were performed to study the unsprung mass' s influence on the vehicle handling stability.Details are as follows:(1)According to the classical vehicle dynamics theory,the vehicle dynamics models of 2 freedom degree and 3 freedom degree were established,which were as the theoretical basis of steady simulation exercise vehicle parameter optimization theory and vehicle.(2)Three test plans of the Polo original car,the original car plus 30 kg mass in each rear wheel and the original car plus 30 kg in each wheel were designed.Then the tests of the unsprung mass' s influence on the vehicle handling were performed according to the classic vehicle handling stability tests in the national standard.The test results show that an appropriate rear wheel mass will improve vehicle handling stability.(3)5 of the most important tests of the vehicle stability test were simulated using Carmaker software.According to the simulation results are basically consistent with experimental results,which verified the reliability of the simulation model and simulation method were turned out to be true.(4)The optimization of steady-state stability test was done and the results shown that if the front wheel and the rear wheel are respectively increased by 45 kg,the center of mass moves forward by 0.2m,center of mass rises up by 0.1m,front suspension stiffness increases to 75000N/m,after suspension stiffness reduced to 20000N/m,and a vehicle with high flat ratio tire,the understeer degree will increase twice.Thereby the vehicle handling stability will be improved.