Research On Dynamic Optimization For Commerical Vehicle Suspension Based On Traget Cascading & Systhesis Technology

Analytical Target Cascading(ATC), which is a hierarchical method for designing engineering product of complex large system, like commercial vehicle, it can make the R&D process more neatly and methodically arranged and more conveniently for quantification management.This thesis elaborates the process of forming main procedures of optimal design method based on ATC for commercial vehicle in detail. The main research contents are listed as follows:Modelling theory of three methods to build leafspring based on Virtual Prototyping Technology are studied and compared. A new improved method based on SAE three-link modeling is proposed. This new method is proved with more advantage such as requiring fewer parameters and with higher simulation accuracy.According to the theoretical system of ATC, performances of handling and ride characteristics of tri-axle commercial vehicle are optimized simultaneously. Modelling of each hierarchy in the optimization problem and its process of target cascading are dealt with specifically. Besides, method of improving the effectiveness of ATC is also presented.Although ATC has an enormous application potential to solve various engineering problems, there also exists a drawback of passing system targets down to the subsystem continuously. In order to widen the range of application, a new ATC method, ATC extended method is put forward. By the application of conceptual suspension and Three-Link Leafspring Model, input curves of full vehicle of conceptual suspension and K&C curves of multibody subsystem, stiffness curves of leafspring and its structure dimensions are related. Thus, design variable of the multibody subsystem can be cascaded down to the part level successfully, with the enhancement of simulation accuracy.Multibody models of full vehicle are built in ADAMS and the verification of the model is conducted with the test data. Objectives of the vehicle before and after the optimization are compared. It reveals that the performances of handling and ride characteristic of tri-axle commercial vehicle are improved to various extents after optimization using ATC extended method.According to the theoretical system of ATC as well as taking present status of research on commercial vehicle in China into consideration, this thesis rebuild a model system of commercial vehicle for research. This system can make the research process highly organized and standardized. Thus, quality and efficiency for research and development are enhanced to a great extent. This dissertation presents the development process for designing commercial vehicle based on Analytical Target Cascading method innovatively. This process is beneficial to enhance the efficiency of development. Besides, it greatly promotes the progress towards'target gate management' during the R&D process owing to the quantification performance targets of subsystems.