The Optimization of Automotive Suspension System Considering Multidisciplinary Design Requirements

This paper presents the optimization of bushing stiffness curves and suspension tuning parameters for enhancing the handling performance as well as the kinematic and compliance characteristics of the automotive suspension system. The optimization process consists of two steps. In the first step, the trailing arm bushing curves are optimized to satisfy the Kinematic and Compliance (K&C) characteristics of rear suspension. In this case, bushing stiffness curves are described as three parameters (linear gradient, non-linear gradient, transition position between linear range and non-linear range). The four optimization cases are executed to compare the design alternatives and choose the best one. In the second step, the handling performances are added to design requirements. In order to execute an automatic analysis process, K&C analysis and handling simulation are sequentially integrated using by Process Integration and Design Optimization (PIDO) technology. The spring rate, damping curve, boost value parameters are set as additional design variables. The dynamic responses are noisy so that the conventional gradient-based optimizer may not be converged. In order to obtain an optimal design in dynamic problem, the Progressive Quadratic Response Surface Method (PQRSM), it is one of function-based approximate optimization technique, is utilized. The optimizations for enhancing K&C characteristics are successfully executed in 19~31 hours and those for enhancing K&C and handling characteristics takes about 96 hours. In this study, the various tuning parameters of automotive suspension can be optimized and multidisciplinary design requirements can be simultaneously considered.