分析了轮胎侧偏角与操纵稳定性的关系,提出根据前、后轮胎侧偏角及其角速度来定义判断车辆稳定性的因子。采用层次化的模糊逻辑监督控制协调各相对独立的子功能控制器,以实现主动转向、主动驱动/制动的集成控制。下层的各子功能控制器根据上层监督控制分配的权重,实现各自的横摆角速度跟踪或者稳定性控制目标。通过仿真研究了这种层次化集成控制策略和算法在极限工况下的性能。结果表明,相比传统的一些独立或联合的底盘控制方法,该集成控制避免了控制器间的冲突,在极限工况下能更好地实现车辆状态跟踪和稳定操纵,并可减小控制能量消耗。
The vehicle stability characteristic was represented by coupling of state variables,the front or rear tyre side slip angle and its angular velocity.To improve the maneuverability and stability of vehicle,a fuzzy supervisory control based on integrated control algorithm was implemented to coordinate the subsystems of the vehicle chassis control system.According to the control weights assigned by the upper supervisory controller,the subsystems including active steering control,active driveline control and active brake control were proposed to achieve their performance targets independently.An 8-degree-of-freedom nonlinear vehicle model was used in simulation to verify the integrated algorithm through critical test maneuvers.Simulation results confirm that,compared with the conventional stand-alone or combined controllers,the proposed hierarchical control algorithm provides vehicle with better performance of maneuverability and stability,while avoiding conflicts among the subsystems and decreasing consumption of the control.