Computational modeling and analysis of an automotive suspension system response with nonlinear damping curves imported from a large external database

Bruno Haselein¹; Lucas Farias¹; Carlos Eduardo de Souza¹

¹ Universidade Federal de Santa Maria

doi:10.20906/CPS/CON-2016-1333

Resumo

The complexity of automotive racing cars improvement problems demands high financial investment and testing time in order enhance the overall prototype response. Regarding the suspension and cornering behavior of vehicles, the applicability of computational models to describe nonlinear systems with multiple degrees of freedom increasingly enables to predict the project final results, allowing the identification of the best setting for components and systems based on mathematical models. However, due the large number of variables related to an automotive suspension system, adaptations of a quarter car model to specific problems are usually applied on the decision-taking process in order to reduce number of inputs. This paper aims to determinate the best configuration set between several damper characteristic curves for a high performance automotive prototype through computational simulation in MATLAB. A numerical code was designed predicting a nonlinear behavior of the component, as well as to import automatically all the dynamometric data from an external database. Furthermore, due the high number of possible configurations, the code has to process the outputs information and identify automatically potential setups. The quarter car model was elaborated based on the equations of motion obtained from sprung and unsprung masses free-body diagram. The simulation uses an open loop processing in which a road pulse drives the unsprung motion, aiming to represent maneuvers in permanent and transient state. The code uses a mathematical loop to compute the outputs, which are calculated on an external function that defines the instantaneous damping constant and applies it on the differential equations. The output evaluation starts from in the graphical analysis of a limited number of damping curves, and then proceeds to an automatic analysis, in which the code scans the data and delivery desired outputs. The kinematic analysis begun from the suspension displacement in different road input and continues through its deriva

Palavras-chave: MATLAB; Vehicle dynamics; Nonlinear damping; Large database