K&C suspension parameters stability by production tolerances

Abstract

This paper considers a modern approach of K&C parameters stability analysis using the suspension MBS model of a short-wheelbase electric vehicle. According to the results of the work, even minor errors in suspension hardpoints positioning when overlaying can greatly affect the K&C parameters of car suspensions. Using MBS models, quasi-static K&C events have been simulated. In the same way the dependences of the suspension K&C parameters are numerically determined. Moreover, these calculations were made with different hardpoints positions for joints of wishbones fastening on a frame, and joint of a steering rod with a steering rack. The influence of suspension hardpoints displacement on the K&C parameters of the vehicle was estimated. As a result, recommendations are made for production positioning tolerances of suspension hardpoints in order to avoid deterioration of K&C parameters. Basically, the appearance of inaccuracies in the positioning of hardpoints leads to critical changes in anti-dive, anti-lift, kingpin inclination angle, bump camber and bump steer parameters.