飞机稳定尾旋的改出规律研究

Research on Recovery Rule from Airplane Steady Spin

研究稳定尾旋的改出方法，即寻求一种操纵规律，可以使飞机从一种稳定状态（稳定尾旋）跳到另一处非失速稳定状态。从系统的全局稳定性观点出发，构造了李雅普诺夫函数，根据输入操纵每一时刻该函数增长速度最大条件，保证尾旋改出过程中飞机振荡状态的频率接近其固有频率，从而求得飞机稳定尾旋的改出规律———振荡型改出操纵规律。本文用求解飞机运动的六自由度方程的方法计算出尾旋改出的时间历程，验证了用简单的三舵面回中难改出稳定尾旋或改出时间较长，而振荡型操纵规律可有效改出稳定尾旋。

The method is presented to recover from the steady spin,i.e. providing a control law, using which the airplane could jump from one steady state (steady spin) to another steady state (no stalling). From the view of the global stability of the system, Lyapunov function is constructed. According to the maximum increasing velocity of this function in every control input, it is asserted that the frequency of the airplane′s oscillatory state closes to its inhere frequency during the recovering process, so it is yielded that the recovery laws from the steady spin, i.e. the oscillatory type recovery laws. The time history curves are obtained by solving the six degrees motion equation. The results show that the oscillatory type recovery laws are effective for the recovery from the steady spin, but it is difficult to recovery from the steady spin or the recovery time is long by using the method of the three control surfaces returning to neutral position.