中文摘要：

针对大型运输机侧风环境下超低空空投重型货物的瞬间受到三维突变和不确定干扰问题,提出一种基于四级复合控制的运输机三维控制律设计方法.在考虑侧风和地效不确定因素的基础上,建立了空投过程的不确定突变模型;为了保证飞行安全,采用四级复合方法设计了三维控制律：先逐层设计位置回路的虚拟指令,使位置、航迹和姿态的偏差向内逐层传递,再设计舵面和油门控制量消除位置和空速回路的偏差.在弱不确定性条件下,证明了控制系统的闭环稳定性.仿真结果表明,所提控制律可保证运输机侧风环境下超低空重装空投的安全性.

英文摘要：

Large transport aircraft suffer from catastrophes and uncertainties in both longitudinal and lateral directions at the moment of airdropping heavy cargos at extremely low-altitude under a crosswind. A three dimensional nonlinear controller for transport aircraft airdropping cargos is investigated. Taking the crosswind and the ground effect into account, the airdropping dynamics including catastrophes and uncertainties is established. To ensure flight safety, a three dimensional controller is proposed by a fourth-order compound approach. The virtual commands for the position loop are given gradually to cause the errors of the position, the flight path and the attitude to propagate toward the inner loop. Subsequently, the control surface and the throttle setting are designed to eliminate the errors of both the position and air speed loops. The closed loop stability of the control system under weak uncertainties is analyzed. Simulations show that the proposed controller can ensure the flight safety for transport aircraft airdropping heavy cargos at extremely low-altitudes under a crosswind.