The Study of Optimization and Matching to Spring and Antiroll Bar Stiffness of Suspension for Multiresponse Target of Whole Vehicle under Sine-Swept Steering Input

This article first leads from the specific double-wishbone suspension and multilink suspension structure form. And then systematically and detailedly analyse the change of spring's stiffness, and antiroll bar's stiffness causes the change of the side slip stiffness and rotation angle of tire, which will lead to the change of tire force, and then affect the dynamic characteristics of the whole vehicle. Based on this, the vehicle dynamics model considering the suspension is established, and the transfer function of the vehicle’s response index to steering wheel angle with coupling spring stiffness and antiroll bar stiffness is derived. Based on the dynamic theory analysis of the suspension and the whole vehicle, the multibody dynamics model of the whole vehicle with front double-wishbone suspension and rear multilink suspension was established. By calculating the frequency response characteristics of the vehicle under the sine-swept input, the frequency response index at the normal steering wheel operating frequency of 0.5 Hz was obtained. In addition, these frequency response indexes at 0.5 Hz were taken as optimization objectives, and the spring stiffness and antiroll bar stiffness of the front and rear suspension were taken as optimization variables, which were optimized by the NSGA-II algorithm. The results show that at 0.5 Hz, the gain value in the frequency response index is reduced, and the delay time is not significantly different from other group schemes, but it is not the worst; the value is within an acceptable range, and the dynamic characteristics of the car in the low frequency range have been improved.