Multidisciplinary Design Method Research Of Automotive Steering And Suspension Integrated System

Optimization of the steering system can improve the handling stability of vehicles andoptimization of suspension system can improve the riding comfort of vehicle. But the simplesuperposition of the optimization of the steering system and suspension system can not guarantee thevehicle get the satisfied performances of handling stability and riding comfort. Therefore, it isnecessary to consider the coupling factor between the vehicle and chassis subsystem, and between thechassis subsystems. It is urgent to seek a highly efficient multidisciplinary optimization method forthe integrated system of steering and suspension, which can guide the design of the chassis andimprove the comprehensive performance of the vehicle.Active steering system can reconcile the road feeling and vehicle active safety perfectly withvariable transmission ratio control and active steering intervention control, and it is a kind of idealpower steering technology. The semi-active suspension can not only overcome the shortcoming offixed performance parameters of traditional passive suspension, and also solve the technology andcost problems of active suspension in practical application. It can coordinate the differentrequirements of both riding comfort and automotive safety. Therefore, with active steering andsemi-active suspension as the research object, considering the coupling factor between systems andsubjects, the multidisciplinary optimization method of steering and suspension integrated systems isresearched. First of all, the dynamics models of steering and suspension integrated system areestablished, which include vehicle model, steering system model, suspension system model, tiremodel and pavement input model. The performance evaluation index of integrated steering are putforwarded, including steering road feel, steering sensitivity and riding comfort, then the quantitativeformula for the evaluation index are deduced. Based on the theory of multidisciplinary collaborativeoptimization, a collaborative optimization model for the integrated system is established, and amultidisciplinary collaborative optimization method for the active steering and semi-active suspensionintegrated system is put forward. Then the genetic algorithm and multi-island genetic algorithm areapplied for the integrated system parameter optimization, and the Pareto optimal solution set and thesystem performance index are obtained. Based on the target cascading theory, an analytical targetcascading method is researched. Considering the coupling factors of integrated system, the targetcascading optimization model for the integrated system is established, and the target cascadingoptimization method for the integrated system is put forward. Applying the multi-island genetic algorithm, the parameters of the integrated system are optimized, and the results are compared withthe collaborative optimization. To sum up, studying the multi-disciplinary optimization method of theintegrated system, can provide the theoretical foundation and technical support for the integrationdesign of the automotive chassis.