Design And Research On Active Front Steering System

With the improvement of people’living standards,the demands for driverflexibility,comfort,and vehicle handling stability is getting higher and higher. With thematurity and widespread use of the vehicle Electric Power Steering System, theActive Front Steering(AFS)system has become the hotspot of research anddevelopment. Through variable ratio and steering intervention control conducted byactive steering,ideal steering characteristics is realized.Aetive front steering systemcan meet the low-speed flexibility requirements and the demands of high-speedstability.Based on the analysis of the shortcoming of the traditional steering system, on thebasis of variable gear ratio system is put forward.All kinds of variable ratio of thesystem is introduced in this paper, and compared with BMW’s active steeringsystem.As an example, the structure and working modes of Active Front SteeringSystem and its double planetary gearmechanism of a BMW car are presented. Andthe implementation of variable gear ratio are discussed in detail.At the same time, thethree-dimensional model of the AFS is built with Solidworks software.And thedynamics modeling and kinematic simulation of AFS are realizaed based onADAMS.At last, the combination simulation of the control method with ADAMS andMATLAB is conducted, and verified by simulative experiment. Then, it wascompared with mechanical steering system. The experiment shows that the ActiveFront Steering System can commendably satisfy the request of handiness in lowspeed,stability and safety in high speed.