运输机超低空空投重物动力学分析与H∞鲁棒控制设计

摘要

运输机超低空空投重型货物是一个对控制精度要求较高的复杂技术过程.本文针对飞机-货物间约束力的理想特性,采用拉格朗日分析力学的第二类方程,建立了机-货两体系统的耦合动力学方程,比起牛顿矢量力学方法,受力分析和建模过程简洁方便.在定义飞机及货物状态变量的基础上,将上述方程组转化为状态空间描述.为了有效抵抗货物移动对运输机姿态的影响,基于现代鲁棒控制理论,设计了状态反馈H∞最优控制律.最后,对空投过程进行了无拉和闭环控制两种条件下的数值仿真对比.结果显示,本文设计的H∞最优控制能有效抑制货物移动对运输机姿态的影响,改善了飞行品质,且控制量在工程允许的范围内,该控制律是有效的.%Transport airdropping heavy cargo at super-low-altitude is a complex technical procedure demanding high precision control. The second class equations of Lagrange analytical mechanics are used for establishing the dynamics model for transport-cargo-two-body systems. The model is simpler than Newtonian mechanics since the constraint force between transport and cargo is ideal. State space description is obtained then and state feedback H∞ flight control law is designed in order to suppress transport's attitude response to heavy cargo's moving in airdropping procedure. Numerical simulation is carried out in the conditions of open-loop and closed-loop respectively and the results show that the proposed H∞ closed-loop flight control law is effective.