高机动性飞机大迎角全局稳定性研究

 为了研究高机动性飞机大迎角时的全局稳定性,建立了飞机的非线性动力学方程和气动力模型。应用微分方程定性理论,通过对算例的分析,讨论了目前飞机设计中常用的稳定性判据(如(C_(nβ))_(dyn)和LCDP等)与平衡点处线化矩阵特征值之间的关系。结果表明这些判据可以从飞机在特定状态下的线化矩阵经简化得到。因此,它们只能预测大迎角的局部稳定性。若考虑全局稳定性则必须用本文所给的方法进行。最后,指出了平衡点和周期吸引子与机翼摇晃、偏离和尾旋之间的关系,并用时间过程作了验证。

A STUDY OF THE GLOBAL. STABILITY OF HIGH PERFORMANCE AIRCRAFTS AT HIGH ANGLE-OF-ATTACK

In order to study the global stability of high performance aircrafts at high angle-of-attack, we set up the nonlinear dynamical equations of an aircraft and the models of aerodynamic coefficients. The theory of stability of differential equations is used to calculate and analyse the aircraft. The relation between the stability criteria commonly used in aircraft design, such as （CnB）dyn and LCDP etc., and eigenvalues of the linearized matrices at the equilibrium points is discussed. It is believed that these criteria can be deduced from the linearized matrices of the aircraft nonlinear dynamic system at a specific flight state, therefore, they can predict the local stability of an aircraft at high angle-of-attack only. So the global stability of an aircraft must be analysed by the method presented in this paper. Finally, the relation between equilibrium point, periodic attractor etc. and some high angle-of-attack flight phenomena, such as wing rock, departure and spin etc. is pointed out and confirmed by the time history study.