Optimal design of steering trapezoid considering multiple performances of the whole vehicle

Abstract

As an important component of the steering system, steering trapezoids should be designed to satisfy multiple performances of the vehicle. In this study, theoretical and simulation analysis has been conducted focusing on the influence of the steering tie rod on the Ackermann error, bump steer, forces at the tie rod joints, and frequency characteristics of the whole vehicle. The results show that the Ackermann error is mainly influenced by the position of the outer point of the steering tie rod. The bump steer is mainly influenced by the Z coordinate of the outer point. The impact force at the joint and the frequency characteristics are mainly influenced by the X and Z coordinates of the outer point of the tie rod. The trends of the evaluation indexes for each performance to the hard point coordinates are not completely consistent and some are conflicting. To integrate the vehicle performance, multi-objective optimization is carried out with Archival Micro Genetic Algorithm, Neighborhood Cultivation Genetic Algorithm, and Non-Dominated Sorting Genetic Algorithm-II algorithms considering the hard point coordinates as variables and the evaluation indexes as optimization objectives. The optimization results show that the relative optimal solutions obtained by the three optimization algorithms provide a significant improvement to the Ackermann error, while other performance indexes have differences. In the practical application of steering trapezoid optimization, it is possible to choose the appropriate optimization algorithm based on the focus of the vehicle performance requirements.