Parameter Interval Uncertainty Analysis Of Suspension K&C Characteristics

With the rapid development of intelligent driving and new energy technology,the research and development of the chassis part of new energy vehicles has naturally attracted great attention from major companies in the industry.In terms of experience,the suspension performance is closely related to the comfort experience of passengers and drivers,and the K&C characteristics of suspension,as an important indicator of suspension performance evaluation,are related to the performance of the whole chassis and the whole vehicle.In this dissertation,a brand of McPherson front independent suspension is taken as the research object.Based on the interval analysis theory,the K&C characteristics of the target vehicle are studied by the way of experimental simulation.Firstly,based on the real vehicle parameter data of the target vehicle,the physical model of the suspension is established based on the virtual prototype Adams/car,which is selected as the specific evaluation standard of the K&C characteristics of the suspension.Based on the analysis of the test-bed and simulation data,the importance of different hard points on the suspension performance is shown.Then,based on insight,the DOE analysis of the hard points is carried out,and the hard points that have great influence on the evaluation criteria are selected as the subsequent optimization variables.Secondly,by analyzing the composition of the front suspension,the dissertation gives the schematic diagram of the suspension mechanism,verifies the correctness of the schematic diagram by the number of degrees of freedom,builds its mathematical model based on the schematic diagram and geometric knowledge of the mechanism,and gives the analytical method of each hard point coordinate and the calculation formula of the four-wheel positioning parameters.In order to ensure the accuracy of the mathematical model,it carries out the accuracy analysis and hard analysis Point adjustment.Finally,based on the interval analysis theory,K&C analysis is carried out on the suspension in the form of interval number for the design variables selected after sensitivity analysis.In view of the interval expansion phenomenon existing in interval calculation,the causes of interval expansion are analyzed in detail,the relationship between interval calculation and floating-point calculation is discussed,and the algorithm is modified based on the sub interval method of interval expansion Furthermore,the improved optimization algorithm is applied to the K&C analysis of suspension.It is verified by the test bench that the optimized camber angle is between-0.5deg and 1.8deg,and the toe angle is between-1.55deg and 0.75deg,both of which are in a reasonable range,indicating that the interval expansion phenomenon has been improved to some extent.It provides a practical reference value for the uncertain influence of suspension design and production due to positioning point,production and other factors.