Target Driven Bushing Design for Wheel Suspension Concept Development

Bushing elasticity is one of the most important compliance factors that significantly influence driving behavior. The deformations of the bushings change the wheel orientations under external forces. Another important factor of bushing compliance is to provide a comfortable driving experience by isolating the vibrations from road irregularities. However, the driving comfort and driving dynamics are often in conflict and need to be balanced in terms of bushing compliance design. Specifically, lateral force steer and brake force steer are closely related to safety and stability and comprises must be minimized. The sensitivity analysis helps engineers to understand the critical bushing for certain compliance attributes, but optimal balancing is complicated to understand. The combination of individual bushing stiffness must be carefully set to achieve an acceptable level of all the attributes. Traditional bushing tuning method involves an optimization process in Adams Car or any other multi-body simulation software. Though they provide reliable results, it is a time-consuming process to build models for the complete Kinematic and Compliance analysis. Therefore, a method to set the bushing specifications automatically according to the compliance targets is proposed by the author. The method makes sure the instant motion of the wheel meets the targets. The bushing stiffness values are calculated according to force distribution and motion ratios between the wheel and each bushing. The method decouples the axial stiffness and radial stiffness. It provides a method to set up the radial stiffness automatically. The new method will reverse the traditional trial-and-error approach, to avoid extensive iterations and significantly reduce the development time.