Optimization And Design Of Suspension Parameters Based On Handling Stability Of A Mini Passenger Car

The handling stability of the vehicle not only has an effect upon the vehicle's handling convenience, but also is a crucial factor for the high speed auto's safty and is called "the lifeline of the vehicle at high speed". With the demand for the high performance, the vehicle handling stability is regarded highly; at the same time, the growing of the types of virtual simulation software provides the possibility of multi-condition simulation for vehicle, thus the use of virtual prototyping technology to predict vehicle performance and optimize performance during the vehicle development phase has also been increasingly paid attention by the automobile manufacturers.With the combination of an automobile company's Minicar chassis development project, taking into the theory and the method of the multi-body dynamics, the virtual prototype model of a target vehicle is established with ADAMS software in this dissertation. And the main alignment parameters and the full vehicle dynamic simulations are performed separately. The sensitivity analysis and optimization design of front suspension performance as well as the full vehicle dynamic performance are finished.The content of research work in this paper mainly includes:1. The paper expounds the impact of the front wheel alignment, tread, suspension stiffness on vehicle handling and stability from theory.To solve the existence of tire wearthe of reference model, and the independent MacPherson front suspension model is built. Through sensitivity analysis, the key factors affecting the suspension characteristics are found and using response surface methodology to establish the regression model between the Suspension characteristics and key factors and optimize. It provides a reference for the rational arrangement of hardware of the suspension in the development process of suspension.2. The target vehicle uses front suspension and steering system model of the reference model completely.Therefore, on the base of optimization of suspension hard points, according to available vehicle parameters of every system,using ADAMS/Car to establish the target vehicle model, to verify the accuracy of the model and predict the target vehicle handling and stability performance through virtual experiments.the result is that the steady-state performance of the target vehicle model is worse reference car. 3. Combined with the parameters of steady-state response characteristics, factors are analyzed. The paper analyzes the factors which impact the redistribution of vertical load on both sides of the wheel when the vehicle roll occurs, identifies structural parameters of the vehicle affect the steady-state characteristics, and find that the reasonable matching between the front suspension roll rate and the rear suspension roll rate can significantly affect the steering characteristics.4. Driving under the car practical problems, the concept of robustness will be introduced. By using the comprehensive score in the steady circular test as evaluation index and considering the impact of the change of load and centroid position on the steering characteristics in the design condition, the paper optimizes the suspension parameters which affect the lateral stability of vechicle with Taguchi robust parameter design method and the robustness design of response surface method. And using Monte Carlo stochastic methods to verify the reliability of the optimization and achieved good results, this is innovation of this paper.