基于主动前轮独立转向系统的车辆稳定性控制研究

摘要

针对传统主动前轮转向(AFS)系统存在的问题,阐述了新近被提出的主动前轮独立转向(AIFS)系统结构和工作原理,建立了 AIFS 系统多体动力学模型,研究了 AIFS 系统的安装对悬架性能的影响；在MATLAB/Simulink 中建立了14自由度整车数学模型,设计了 AIFS 滑模控制器及附加转角分配模块,在阶跃、正弦等转向工况下,仿真计算了大侧向加速度工况下 AIFS 的控制效果。结果表明：AIFS 系统的安装增加了外侧车轮滑磨；高速转弯时,AIFS 系统较 AFS 系统可以更好地跟踪理想横摆角速度和理想运动轨迹,产生更大的转弯通过加速度,保证内外侧轮胎均在侧向力饱和之前区域工作,使左右轮胎工作负荷趋于相等,实现了“能力越大的轮胎贡献越大”的控制目标,提高了车辆极限转弯时的侧向稳定性。%The shortcomings of AFS system were indicated firstly,and then the structure and principles of the AIFS system proposed in recent years were introduced.A multi-body dynamics model of front suspension equipped with AIFS system was established to study the change of the steering geometry impact on vehicle suspension kinematics characteristics.A sliding mode control theory was employed to develop the AIFS con-troller and an allocation module was adopted to determine the split between the left and right tire angles.Nu-merical simulations were conducted to evaluate the proposed control algorithm using a 14-DOF vehicle model performed in MATLAB/Simulink environment.The simulation results show that the installation of AIFS sys-tem can aggravate the outer tire wear,however,the AIFS system can achieve a better effectiveness than that of the AFS system in tracking the ideal yaw rate and the ideal trajectory,and can generate a greater lateral accel-eration.The inner and outer tires of AIFS are guaranteed to work under the saturation region.Furthermore, the tire workloads tend to be equal so that the outer tire with heavier loads makes more contributions,enhan-cing the vehicle lateral stability.