Suspension Optimization And Vehicle Handling Stability Analysis Based On Sensitivity Analysis And Improved Genetic Algorithm

Suspension system as an important part of vehicle's chassis which has enormous influence on the performance of vehicle.The main external characteristic of the suspension is the K&C characteristic of suspension.The indexes of suspension K&C are the core paramenters of the suspension system which also has some influence on the handling stability of the vehicle.This paper base on a certain electric SUV development project.Based on sensitivity analysis and improved genetic algorithm to do research on suspension optimization,and compared optimizational simulation analysis of multi-body dynamic vehicle model with rigid and flexible coupling with original simulation analysis.It's further verified that suspension optimization has an important influence on vehicle's handling stability performance.The main research work and results are as follows:1.Establish a rigid and flexible multi-body dynamic model.The Catia models of subframe,longitudinal arm,lower control arm are imported into the Hypermesh for discretization.The modal neutral files of parts,namely the MNF files,are obtained by Optistruct solver.By replacing the rigid-body parts in ADAMS/Car with the MNF file,a more precise and flexible multi-body dynamic model is established.2.The K&C bench test is carried out to determine the target value of the suspension K&C optimization.It provides references for optimization direction.The optimization indexes of the kinematic characteristics of the rear suspension are:Roll center location,Bounce steer change,Bounce camber change,Bounce lateral displacement change of the wheel center;3.The main optimization variables are determined and the interference of independent variables is eliminated,and the optimized efficiency is improved,Based on the method of sensitivity analysis.The optimization process of suspension in this paper is multi-objective and multi-variable optimization.Traditional optimization methods,experience methods,and trial and error methods can not find the optimal variables that affect the optimal targets quickly,accurately and efficiently.Therefore,this paper adopts the method of experimental design to the iterative calculation,design variable and the response function of data through the response surface method ofmathematical regression analysis,and finally got all variables for the sensitivity of different optimization objectives,greatly improving the efficiency of optimization.4.The improved genetic algorithm(NSGA-II)is used to optimize the multi-objective of the higher sensitivity.The improved genetic algorithm has been added to the traditional genetic algorithm to maintain the strategy of the elite,and to eliminate the repetition of the individual,and to improve the efficiency of the algorithm.5.The stability evaluation and comparison of the rigid-flexible coupled multibody dynamics model of the vehicle before and after optimization were conducted.The pitch characteristics roll characteristics?the degree of understeerofthe vehicle have been improved,It's further explained that the kinematic optimization of suspension has an important influence on the improvement of vehicle steering stability.