Matching And Optimization Design Of Suspension Main Parameters Of SUV Based On Handling Stability

SUV has been favored by more and more consumers of all ages because of its comfort,cross-country ability and large space.However,compared with cars,SUV has the disadvantages of great quality and high centroid,which leads to its weak capacity of antiroll and poor handling stability when turning.As one of the most important index of the vehicle performance,handling stability has direct impact on vehicle's control convenience and active safety.Besides,ride comfort determines the comfort level of passengers as well as the completeness of goods.The two are interrelated and interacted with each other.Suspension system is one of the key parts of automobile chassis,the performance of which is related to vehicle's handling stability and ride comfort.To solve the problem of the weak handling stability of SUV,this study has matched and optimized the suspension main parameters with the constraint of ride comfort,which provides a reference for improving the handling stability.Firstly,the influence of vehicle suspension on handling stability and ride comfort are respectively theoretically analyzed.From the respective of suspension,the impact of tire side slip angle,roll-steer angle and compliance steer angle on handling stability is studied.As for comfort,the two aspects of suspension stiffness and damper are discussed.After comprehensive analysis,the key parameters influenced vehicle handling stability and ride comfort are determined.Those theories have also proved that the two are interrelated and interacted with each other.Secondly,the multi-body dynamics model of suspension based on the vehicle is established in ADAMS/Car.The simulation of wheel parallel travel of front and rear suspension has been carried out and at the same time,three parameters of camber angle,toe angle and track base are chosen to verify the correctness of the full vehicle.By comparing the results of simulation with the experiment,the multi-body dynamics model of full vehicle is thought to be used for the next research.Then,according to the evaluation methods of handling stability and ride comfort of vehicle proposed by the national standard and based on the multi-body dynamics model of full vehicle,the handling stability has been evaluated.The main experiments are Constant Radius Cornering Test,Step Steer Test,Impulse Steer Test,Cornering with Steer Release Test,Steering Efforts Test and Fish Hook.Based on the B level road,the Random Input Running Test to evaluate ride comfort has been carried out.The results have shown that the value of index which is used to reflect the performance of Constant Radius Cornering Test is only 76.30,so it needs to be further optimized.Finally,based on Orthogonal Experimental Design,Kriging Model and NSGA-?algorithm,the spring stiffness,damper coefficient and anti-roll bar stiffness are chosen to be design variables,and the values of each evaluation indexes of Constant Radius Cornering Test are selected to be response function.At last,with the constraint of ride comfort,the value of index used to reflect the performance of Constant Radius Cornering Test has been improved from 76.30 to 81.49,which means the handling stability has also get some improvement.Meanwhile,the value of index related to ride comfort has changed from 0.4268 m/s~2 to 0.4273 m/s~2,which basically remains unchanged.