考虑非线性因素的飞机防滑刹车系统控制

飞机的刹车过程存在较强的非线性,目前广泛应用的速度差加压力偏调式(PBM)控制律难以实现对飞机刹车的高性能控制.本文提出了一种考虑飞机刹车过程中非线性因素的滑模控制律.首先建立考虑轮胎跑道非线性和刹车盘摩擦系数非线性的的飞机防滑刹车系统非线性模型,然后设计了滑模观测器对飞机速度进行估计,并在此基础上设计了一种滑模变结构控制律,最后基于模糊理论对滑模控制律进行优化,从而抑制控制器的抖振.仿真结果表明,基于模糊指数趋近律的滑模变结构控制律控制效果优于传统“PD+PBM”控制律,抑制控制器输出抖振效果良好,能够很好的适应刹车过程中的复杂非线性因素,刹车效率高,控制方法合理有效.

Control of aircraft anti-skid braking system considering nonlinear factors

The braking process of aircraft has strong nonlinearity, the widely used pressure-bias-modulated (PBM) control law is difficult to achieve high performance control of aircraft brake. In this study, a sliding mode control law considering nonlinear factors in aircraft braking process is proposed. Firstly, the nonlinear model of aircraft anti-skid braking system is established for considering the nonlinear tire-runway and the nonlinear friction coefficient of brake disc; Then a sliding mode observer is designed to estimate the aircraft speed, and on the basis, a sliding mode variable structure control law is designed; Finally, the sliding mode control law is optimized based on fuzzy theory to suppress chattering of the controller. The simulation results show that the control effect of the sliding mode variable structure control law based on the fuzzy exponential reaching law is better than the traditional PD+PBM control law, the chattering effect of the controller output is obviously suppressed, it can adapt to the complex nonlinear factors in the braking process, and the control method is reasonable and effective.