Application And Research On Expert System In MacPherson Suspension Design

Suspension system is an important part for cars, and has a decisive effect on car drivability and stability. Because of its characteristics of simple structure,low cost and space economy,nowadays MacPherson suspension has become one of the most popular independent suspension.This paper introduced the some concepts of expert system. By collecting the knowledge of MacPherson suspension, the content of knowledge base was summarized. Based on the knowledge of MacPherson suspension,the article built the front suspension system simulation model with the ADAMS/CAR software and simulated the parallel wheel analysis,then analyzed the changes of front wheel alignment parameters in the simulation results. Using the ADAMS/Insight, the kinematics analysis of the MacPherson suspension was carried out and the main influenced factor of the wheel was found out. Through the optimum design using ADAMS/Insight, the optimized suspension was obtained.The whole article includes five chapters:In chapter one, we described the content and significance of MacPherson suspension research, reviewed the suspension growing history, and prospected the trend of vehicle at first. Then the paper simply summarized the characters of MacPherson suspension and introduced the some concepts and construction of expert system. Chapter one also introduced the research method—the theory of multi-body system dynamic, the thorough introduction to the modules and theory of ADAMS, one of the most popular multi-body system dynamics software. ADAMS(Automatic Dynamic Analysis of Mechanical Systems) is developed by American Mechanical Dynamics Inc, and is one of the best mechanical simulation software .It is the most authoritative and most widely-used simulation software of mechanical system .In chapter two, the content of knowledge base was summarized by collecting the knowledge of MacPherson suspension. Then the knowledge system of knowledge base was built. The knowledge system included kinematic analysis, suspension design, structure analysis and optimization design.In the third chapter, we simplified and abstracted the kinematic structure of MacPherson suspension. The dimensional positions of points on the left Macpherson suspension are calculated with the method of dimensional coordinate transformation. According to the construction and parameters, the article built the simulation model of MacPherson independent front suspension system with the ADAMS/CAR software and the summarized knowledge system. We simulated the parallel wheel analysis,then analyzed the changes of front wheel alignment parameters in the simulation results.In chapter four we used ADAMS/Insight to design a series of experiments and analyze results for the front suspension assembly. Some hardpoints were observed carefully in this article. We fit our data to determine which factor most affected performance of the assembly. After analysis the optimum design was made by ADAMS/Insight, the optimized front wheel alignment parameters was obtained.Chapter five is the summarization of the article. In this chapter we depicted the main works, researching result and the future research direction. In conclusion, we summarized the basic suspension knowledge of expert system successfully, built parametric model by ADAMS/CAR, analyzed the changes of front wheel alignment parameters in the simulation results and made the optimum design in this article.