Simulation Analysis Of Handling Stability And Suspension Optimization Of A Medium Sized Bus Based On ADAMS

In modern vehicle design,the performance requirements of buses are getting higher and higher.As an important part of vehicle,suspension performance directly affects the comprehensive score of buses.In this paper,based on Adams/Car and Motion Solve software,a rigid-flexible coupling dynamic model of suspension and vehicle is established according to the vehicle data of a medium-sized bus,and the influence of non-independent suspension structure parameters on suspension kinematics characteristics and vehicle handling stability is analyzed.Firstly,based on the air suspension of a medium bus,the research status of suspension kinematics and elastic kinematics(K&C),rigid-flexible coupling and bus handling stability are discussed.Based on the multi-rigid-body dynamics theory and the Multi-flexible-body dynamics theory,the flexible anti-roll bar model and the rigid model including suspension system,steering system and tire system are established,and the vehicle assembly and parameter debugging are completed.Then,K&C of the suspension is carried out under the condition of parallel wheel jump,and three sub-objectives are selected to be optimized: front wheel toe,longitudinal displacement of wheel center and lateral displacement of wheel center.Insight module is used to analyze the sensitivity of front points of upper thrust rod,front points of lower thrust rod,left point of the anti-sway bar and the outer point of the steering tie rod by using the full factor method.Finding out the hard point coordinates of the top six of the optimal target contribution as the design variables.The response surface model is established,and the objective function is optimized by weighting method.The simulation results of the optimized suspensionshow that the change range of left front toe is reduced by 27%,the change range of right front toe is reduced by 26%,the longitudinal displacement of wheel center is reduced by 32%,and the lateral displacement of wheel center is reduced by 31%.The optimized suspension is put into the vehicle for simulation analysis.The results show that the optimized suspension makes the vehicle run more steady when encountering obstacles and curved road surface,reduces tire wear and enhances the handling stability.Therefore,the correctness of the optimization process is verified.Finally,the evaluation method of bus operation stability is expounded,and whole vehicle stability analysis is carried out.The three items of steering reversal,constant radius cornering and steering portability are simulated under the requirement of national standard and compared the results with the actual vehicle.According to the Criterion thresholds and evaluation of controllability and stability for automobiles,the relevant evaluation indexes are scored.The scoring errors of evaluation parameters and items in simulation and real vehicle test are less than 12%.The results verify the accuracy of modeling and simulation and the feasibility of optimization.It is proposed for the following evaluation system and technical improvement of the medium-sized bus handling and stability.