主动四轮转向车辆的分数阶滑模控制
Fractional Order Sliding Mode Control of Active Four-Wheel Steering Vehicle

考虑到模型跟踪控制时的车辆状态误差主要来自于初始状态和车辆参数的差异，针对仅存在初始状态差异的主动四轮转向车辆设计了最优控制，该控制策略能让其很快地跟踪上参考模型。针对两种差异同时存在的主动四轮转向车辆，采用最优控制设计了滑模面以消除因初始状态差异所导致的车辆状态误差，并在此基础上设计了分数阶滑模控制器以进一步消除因车辆参数差异所导致的状态误差。仿真结果表明：当主动四轮转向车辆和参考模型的参数不匹配时，也能很快地让控制车辆跟踪上参考模型。可见，采用最优控制设计滑模面的分数阶滑模控制是有效的。
Considering that the vehicle state error derives from the different initial states and parameters between the real vehicle and the reference model, we propose the optimal control for the active four-wheel steering vehicle with only the initial state difference, which can make the 4WS to follow the reference model very quickly. And for the 4WS with the two differences, optimal control is adopted to design the sliding mode in order to eliminate the state error caused by the initial state difference. On this basis, the fractional sliding mode control is designed to eliminate the state error caused by the parameter difference. And the simulation results show that the fractional sliding mode control can make the 4WS to track the reference model very quickly, although the parameters between the 4WS model and the reference model are mismatched. It is proved that the fractional sliding mode control is effective