基于 NDO 的飞机轨迹跟踪抗干扰控制律设计

摘要

A robust sliding mode control law of trajectory tracking is described and demonstrated for the coupled and under-actuated aircraft longitudinal dynamic model.Firstly,by introducing a virtual state variable, the state counterchange is applied to realize the control decoupling.Secondly,a nonlinear disturbance observer (NDO)is proposed for the compensation of system uncertainty which consists of modeling error and atmosphere disturbance.Thirdly,the curves of angle of attack (AOA)and the virtual state variable during extremely short takeoff and landing (ESTOL)are set up,which are treated as the tracking trajectories of the designed sliding mode control law.Finally,the simulation results are given,which demonstrates that the proposed NDO can re-alize accurate estimation and compensation of system uncertainty,as well as that the designed control law can be effectively applied to longitudinal trajectory tracking of AOA against system modeling error and atmosphere dis-turbance.%针对飞机纵向欠驱动耦合动力学模型设计鲁棒轨迹跟踪滑模控制律。首先，通过引入虚拟状态变量进行状态变换实现模型控制解耦。其次，考虑由系统建模误差和大气干扰组成的复合不确定性，设计非线性干扰观测器（nonlinear disturbance observer，NDO）进行观测补偿。然后，建立飞机极短距起降中攻角变化轨迹曲线，设计滑模控制律实现对虚拟状态变量和攻角轨迹指令的稳定跟踪。仿真结果表明，NDO 可以实现对系统不确定性的精确观测和补偿，滑模控制律具有对系统建模误差和大气风切变的鲁棒性和抗干扰性。