迭代学习控制在飞机全电刹车系统中的应用

飞机全电刹车系统具有传统的液压刹车系统不可比拟的优势,是未来飞机刹车系统的发展方向。针对现有液压刹车系统控制律的不足和全电刹车系统的特点,建立了以飞机纵向速度、滑移率为状态变量,滑移率为输出变量的刹车系统非线性状态方程。根据滑移率与结合系数的关系,在线辨识不同路面条件下的最大结合系数和最佳滑移率,提出了在常规PI控制器的基础上,施加一D型迭代学习前馈控制器的控制策略,以提高系统的快速跟随性,并将最佳滑移率作为迭代学习控制的期望输出。经过对干跑道状态下的仿真验证,表明加入迭代学习控制律后,可以满足飞机全电刹车系统的技术性能,在刹停时间、刹停距离及刹车效率等方面得到了改善,具有良好的收敛速度、稳定性和跟踪性。

Application of iterative learning control in aircraft all-electric braking system

Compared with hydraulic braking,aircraft all-electric braking system has some superior advantages,and becomes the development direction of aircraft braking system.Considering the disadvantages of controlling strategy of current hydraulic braking system and the characteristics of all-electric braking system,we built up the whole system's nonlinear state equation,whose state variables are longitudinal speed and slip ration and output variable is slip ration.According to the relationship between slip ratio and friction coefficient,the system can identify on line the largest friction coefficient and the optimal slip ratio under different road conditions.On the basis of classical PI controller,we introduced a D-type iterative learning feed-forward controller to improve system's rapid tracking performance,and used the optimal slip ration as the desired output of the iterative learning controlling.Through the simulation to dry runway state,we can conclude that the system with iterative learning control can satisfy the performance of aircraft all-electric braking system,which has great improvement on braking time,braking distance and braking efficient and also has excellent convergence speed,stability and tracking capability.