Abstract: A novel active steering system with force and displacement coupled control(the novel active front steering(AFS)system) is introduced, and it has the functions of both active steering and electric power steering. The novel AFS system can not only achieve perfect combination of steering road feel and steering portable, but also realize harmonization of automotive safety and flexibility. Therefore, it is an ideal technology of automotive power steering. Based on the model of the novel AFS and the vehicle three-freedom system, the concept and quantitative formulas of the novel AFS system steering performance are proposed. The novel AFS system can be optimized based on collaborative optimization, with steering road feel as the system-level optimizing target, and the ergonomics, vehicle safety and steering economy as the subsystems. The simulation results show that based on the collaborative optimization, the novel AFS system can improve the steering road feel and can also guarantee the steering stability, steering portability and steering energy consumption, thus the collaborative optimization method can provide a theoretical basis for the design and optimization of the novel AFS system.

Key words: Active steering, Collaborative optimization, Force and displacement, Vehicle engineering