飞行器静稳定裕度定义方法研究

Research on the definition of pitching static margin for flight vehicle

本文研究了对于飞行器如何更加合理地定义其静稳定裕度的问题。常用的静稳定裕度定义为无量纲化的质心位置与气动焦点之间的距离,这种定义对于常见的高升阻比的飞机导弹等飞行器是适用的,然而对于一些非常规飞行器,例如载人飞船返回舱这类大钝头大配平攻角阻力体,这种定义在反映其静稳定程度上存在一定的问题。本文举例说明了这个定义存在缺陷,指出定义静稳定裕度时不能只考虑升力变化的影响,而是应该根据气动合力的变化来进行综合考虑。提出了新的比较完备的静稳定裕度定义方法,指出常用的静稳定裕度定义方法是本文提出的定义方法在特定情况下的表述,并举例说明了本文定义具有更加广泛的适用性。

How to define the pitching static margin (PSM) more rational for almost all of flight vehicles was studied. Based on the detailed analysis of the problem, this paper indicates that, in the definition of PSM, we should not take into account of lift coefficient change only. Therefore, the total change of aerodynamic resultant force (ARF) vector should be taken into account. How to define the PSM better by the use of aerodynamic parameters in one of the two coordinates systems (wind axial system and body axial system) was studied, and new definitions of PSM in the two coordinates systems were proposed. The new definition is better than traditional definition, because in any case this definition shows the distance between a point (gravity center) and a line (incremental ARF vector) instead of the distance between two points (gravity center and aerodynamic neutral point) defined as the traditional PSM.