飞机的全局稳定性分析和非线性控制

现代军用飞机常设计为在大迎角下飞行。此时飞机是一个高度非线性系统，其稳定特性不能用线性方法求解。而实现控制，特别是在非线性不稳定性的情况下，更是十分困难的。本文介绍了一种综合的分析飞机非线性稳定性和控制的方法。即用分岐理论来决定飞机的全局稳定性。用四阶龙格－库塔积分来计算飞机运动的平衡面和分岐点，并构造运动状态的扰动传播矩阵，而此矩阵的特征值可用来预测稳定性的时变性。此外，还利用扰动传播矩阵来求得为满足规定的飞机反应特性（通常由频率和阻尼表示）所需的操纵，即各操纵面反馈回路的放大系数值。对典型飞机的算例计算结果表明，非线性控制是成功的。

Analysis of global stability and nonlinear control for a fighter configuration

The modern military aircraft are often designed to flight at very high A O A .As a highly nonlinear system, the stability characteristics obtained through the associated linear system becomes questionable. It could be very difficult to control the aircraft, especially in nonlinear unstable cases. A synthetic method for nonlinear analysis of flight stability and control is presented. In this method, the bifurcation analysis is used to predict the aircraft global stability. Motions from the bifurcate points or equilibrium surfaces are calculated with a fourth order Runge Kutta integration scheme which is also recast in the form of state disturbance propagation matrices .The eigenvalues of these matrices provide a mean to predict the variation of system stability with time .In addition, necessary control inputs to satisfied response characteristics in term of frequencies and dampings can also be estimated by using these state disturbance propagation matrices .Example calculations for typical fighter are presented, and shows that the nonlinear control is successful.