Optimization Designs Of Vehicle Suspension System Based On The Response Surface Methodology

In this paper, the virtual prototype of certain heavy vehicle for special services was established in the adams/car software, and then the simulations on the controllability and stability and on the ride comfort were carried through . Further more, the performance of whole car was evaluated according to the evaluation index and evaluation score calculation system, both of which were transformed from the national standard. Based on the finished tasks,the optimization design of front suspension was finished with the characteristic and structural parameters of the front suspension being design variables, and the evaluation index being optimization objectives.For all the work presented in this paper, a modernization method for whole car performance (in this paper ,the whole car performance only include the controllability and stability and the ride comfort)evaluation and optimization design of suspension system was provided.The content of research work in this paper mainly includes:(1) According to the national standards, the values of whole car performance evaluation index were acquired ,which were relative to the virual experiments.Based on this ,the evaluation net of whole car performance was charted,a new method of evaluating whole car performance offered;(2) Integrating with the knowledge of auto theory, auto design and three-dimensional mechanism kinematics, the virtual prototype was established based on the basic data of certain heavy car for special service;(3) According to the demands of the current national standards on the controllability and stability as well as the ride comfort, the control document for each virtual experiment was programmed, and the virtual experiments were carried through utilizing the virtual prototype;(4) With the structural parameters of the front suspension being design variables, and the evaluation index being response objectives, the sensitivity of the front suspension structural parameters was analysed, the structural design variables ascertained by finding out the main structural parameters which affected the whole car performance mostly; (5) With the spring stiffness of suspension system and the structural parameters being the input design variables,and the evaluation indexs of whole car performance in each virtual experiment being output response objectives, the models were constructed which represented the relation between the design variables and the response objectives utilizing the Response SurfaceMethodology;(6) With the whole car evaluation indexs being the optimization objectives, the optimization design on front suspension was accomplished with the multi-objective optimization method.Then the contrast analysis between the whole car performances before and after the front suspension optimizated was made;The following achievements and innovations have been accomplished:(1) A new evaluation system has been adopted in evaluating the whole car performance. This system has taken all the experiments related to whole car controllability and stability as well as ride comfort into consideration, and chose a proper evaluation calculation method to score the evaluation index.Further more, the evaluation of whole car performance was fulfilled by adopting proper calculation method to score the evaluation index, the evaluation net charted which presented the whole car performance directly;(2) The Response Surface Methodology was applied into the optimization design process of auto suspension system. The Response Surface Methodology was adopt to simplify the complex relationship between front suspension spring stiffness and structural parameters and whole car performance evaluation indexs into response surface model,which was introduced into the iteration format to complete the optimization design process.