基于相平面法的结冰飞机纵向非线性稳定域分析

结冰是威胁飞机飞行安全的重要因素之一,研究结冰后飞机稳定性及稳定域范围对飞机操纵安全和飞行安全极其重要。由于结冰后大飞机失速迎角提前,仅仅研究小迎角线性阶段的飞行稳定性显然不能满足要求。首先根据飞机迎角和升力曲线非线性关系建立了结冰条件下大迎角阶段飞机纵向非线性系统模型,然后通过相平面法刻画了迎角和俯仰角速度构成的不同飞行状态下飞机的纵向运动的稳定域,并探讨了迎角和俯仰角速度对纵向稳定性的影响规律,最后针对稳定域内外的不同初始状态,进行了零输入响应时域仿真,验证了相平面法确定的稳定域的有效性和准确性。研究结果可为飞机结冰后的稳定边界确定和边界保护提供一定的参考。

Longitudinal nonlinear stabilizing region for icing aircraft based on phase-plane method

Icing is one of the factors that could pose great threat to flight safety; therefore it is significant to conduct a research on stability and stabilizing region of aircraft for control and flight safety under icing conditions. Due to the early arrival of stalling angle of attack of icing large airplane, it is obvious that the research on the flight stability of a small angle of attack in the linear phase cannot meet the requirement. Firstly, the aircraft longitudinal nonlinear model for large angle of attack is proposed under icing conditions based on the nonlinear relation between the angle of attack and the lift. Then, the longitudinal stabilizing region of angle of attack and pitch angular velocity is depicted based on phase-plane method. At the same time, the influences of angle of attack and pitch angular velocity on longitudinal stability are analyzed. Finally, the stabilizing region based on phase-plane method is verified through the time domain simulation with zero input according to different initial conditions inside and outside of the stabilizing region. The results can provide a reference for stability envelope determination and envelope protection of icing aircraft.