利用气液协调控制的车辆稳定性控制系统设计
Development of vehicle stability control system with the coordinated control of active aerodynamic system and hydraulic brake system

针对高速工况下轮胎易饱和并导致车辆失稳的问题，提出基于主动气动控制与液压差动制动控制相协调的车辆稳定性控制方法. 在车辆顶部安装一对主动风翼板并分析其气动特性，通过独立控制两风翼板的攻角以主动控制车辆所受的气动力/力矩. 控制器采用分层控制架构，顶层根据车辆运动状态和道路附着情况计算期望横摆角速度，中层采用模糊控制算法实时计算实现车辆稳定性控制所需的辅助横摆力矩，底层则协调主动气动控制和差动制动控制产生辅助横摆力矩. 在Casim/Simulink 联合仿真平台上对所提方法进行仿真验证，结果表明，该方法能使车辆的动力学响应较好地跟踪期望值，且能降低轮胎工作负荷，达到避免车辆失稳的目的.
Under critical condition，tyres are easily saturated and might cause the unstability of the vehicle. A new control method for vehicle stability control was presented，which was applied additional yaw moment to intervene the state of the vehicle by means of active aerodynamic control and differential braking control. Two airfoils are properly placed on the roof of the vehicle，and those angle of attack can be modulated separately. The aerodynamics of the vehicle were analyzed by CFD method. The control architecture for the stability system is hierarchical. In the upper layer，the desired yaw rate was calculated with the consideration of vehicle dynamics and tyre adhesive limit．In the middle layer，a fuzzy controller was designed to determine the additional yaw moment in real time. In the lower layer，a new control stratage was proposed to coordinate active aerodynamic control and differential braking control. The proposed method was evaluated via Carsim/Simulink. The results show that the proposed method can make the vehicle yaw response track the desired value，and can effectively reduce the tyre work load