一种针对结构损伤的非线性容错飞行控制方法

A nonlinear fault tolerant flight control method against structural damage

飞机结构损伤会引起气动参数变化,进而影响系统的静稳定性和控制精度。针对具有多输入的非线性飞机模型,利用带有二阶命令滤波器的自适应反步控制方法在线估计飞机气动参数,补偿结构损伤导致的气动参数变化对控制系统的影响,以实现容错飞行控制功能;引入的命令滤波器可以避免反步控制中复杂的求导运算。从理论上分析证明了带有二阶命令滤波器的自适应反步控制的闭环系统稳定性,并给出了控制跟踪误差的理论上界和二阶命令滤波器频率参数选取的下界。通过一个大型客机垂直尾翼脱落场景的仿真实验,验证了所提容错控制方法的有效性。

Structural damage can affect system static stability and control precision by changing aircraft aerodynamic param- eters. A nonlinear fault tolerant flight control scheme against aircraft structural damage is presented, which implements the adaptive backstepping control method with a second-order command filter. The fault tolerant control is applied to a multi-in- put nonlinear aircraft model. In order to compensate the influence from structural damage, the aircraft aerodynamic parame- ters are estimated on-line and the controller is adaptively regulated. A command filter is employed to avoid the complex de- rivative computation in the backstepping method. The stability of the closed-loop system with the command filter is proved. The upper bounds of control tracking errors and the lower bounds of the frequency parameters in the command filters are also analytically presented. The proposed nonlinear fault tolerant control method is verified by a simulation of a large commercial aircraft with loss of the vertical tail.