主动前轮转向和直接横摆力矩集成控制

针对车辆操稳性控制中功能耦合的主动前轮转向（AFS）与直接横摆力矩控制（DYC）的任务协调问题，提出优化相平面法进行稳定区域划分. 基于所提方法建立轮胎侧向力特性协调准则，实现纵横向动力学系统操稳性集成控制. 以前、后轮侧偏角及两者之差作为车辆横向稳定的表征量，结合轮胎侧向力特性划分车辆横向状态为稳定、临界稳定和失稳状态区间. 建立AFS与DYC的协调准则. 考虑控制算法面向实际应用时状态量的获取问题，建立基于超螺旋算法的状态观测器估计车辆前后轮侧偏角. 分别设计基于自适应超螺旋高阶滑模算法的AFS和DYC控制器，在消除控制器抖振和避免频繁切换的基础上完成稳定性控制. 试验结果表明，所提协调准则和控制算法对协调AFS和DYC有积极作用，且操稳性控制效果良好.

Integrated control of active front steering and direct yaw moment

Aiming at the coordination problem of active front steering (AFS) and direct yaw moment control (DYC) in vehicle handling and stability control, an optimal phase plane method for stable region partition was proposed. In order to realize the integrated control of handling and stability on lateral and longitudinal dynamic system, a coordination criterion considering tire force characteristics was established based on the proposed method . Firstly, the side slip angle of front and rear tires and the difference between them were used as the characterization of vehicle lateral stability. Combined with the lateral force characteristics of the tires, the lateral state of the vehicle was divided into stable, critically stable and unstable regions. Thereby the coordination criterion between AFS and DYC was established. Secondly, considering the problem of obtaining the state variables when the control algorithm was oriented to practical applications, a state observer based on the super-twisting algorithm was established to estimate the vehicle front and rear wheel slip angle. Finally, the AFS and DYC higher-order sliding mode controller based on the adaptive super-twisting algorithm was designed to eliminate the chattering phenomenon and avoided frequent switching of the controllers during the process of stability control. Experimental results showed that the proposed coordination criteria and control method had positive effect on the coordination of AFS and DYC and obtained great effect on the control of handling and stability.