Analysis and optimization of vehicle transient characteristics under sine-swept steering input with considering steering system stiffness and damping

This study focuses on the influence of steering system stiffness and damping on the vehicle transient characteristics at two different types of handling frequencies, and optimizes the vehicle transient characteristics with steering system stiffness and damping as optimization variables at both handling frequencies. The kinematic relationship between wheel angle and steering wheel angle is derived as well as a detailed analysis of the forces on the steering linkage. The differential equations of vehicle dynamics are developed to explain the influence of steering system stiffness and damping on the vehicle transient characteristics theoretically. The stiffness and damping, which have a significant influence on the vehicle transient characteristics, are selected by sensitivity analysis and used as variables for simulation verification. Simulation results show that the influence of steering system stiffness and damping on vehicle transient characteristics is different at high handling frequencies and low handling frequencies. The stiffness and damping are used as optimization variables and the objective evaluation indexes of vehicle transient characteristics at high handling frequencies and low handling frequencies are used as optimization targets for multi-objective optimization by the NSGA-II optimization algorithm. The optimization results show that: The yaw rate gain relative to steering wheel angle and the delay time of lateral acceleration relative to steering wheel angle are improved at both low and high frequencies.