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本文分析研究一在线飞行双引擎喷气客机飞行性能。基于快速存取记录器(QAR)记录的飞行数据,先采用兼容性分析进行滤波,进而从中提取出计入动态地面影响的纵向和横向气动力模型,建立模型时考虑了飞机雷达高度及其沉降率的影响。进一步地,通过模糊逻辑算法,提炼出预先不做光滑处理的气动力数学模型。这些模型描述了飞机的非线性、非定常气动特性,并用于非线性飞行动力学模拟。研究表明该客机飞行中遭遇的横侧风相当大,容易诱发出荷兰滚运动。通过各瞬时的线性分析,发现这里的荷兰滚处于没有明显幅值阻尼的非线性振荡中。研究还表明,所有稳定性导数都随时间变化,是状态变量的非线性函数。尽管飞行中全时段采用偏航阻尼器,但荷兰滚模态并没有阻尼掉,这表明,偏航阻尼器设计相关数据仍不够真实,今后侧滑角时间导数对阻尼的贡献应予以考虑。最后,非线性飞行模拟表明,着陆前作用于飞机上的垂直风,其作用是将飞机往下拉拽并且沿其飞行轨迹有所变化。不断变化的上升气流似乎使飞机保持一定速率下降变得比较困难,招致着陆时出现更高的过载。
This paper analyzes the flight performance of an online flying twin-engine jet airliner. Based on the QAR recorded flight data, firstly the compatibility analysis is used to filter and then the vertical and horizontal aerodynamic models which are included in the dynamic ground influence are extracted. The model is built with the radar altitude and its settlement Rate of impact. Further, the aerodynamic mathematical model that is not smoothed in advance is extracted through the fuzzy logic algorithm. These models describe the aircraft’s non-linear, unsteady aerodynamic characteristics and are used in nonlinear aerodynamic simulations. Studies have shown that the cross-wind encountered in the flight of this airliner is quite large and tends to induce the Dutch rolling movement. Through the instantaneous linear analysis, it is found that the Holland roll is in non-linear oscillation with no significant amplitude damping. The study also shows that all stability derivatives change over time and are non-linear functions of state variables. Although the yaw damper is used during the flight, the Dutch roll mode is not damped, which shows that the yaw damper design-related data are still not real enough and the contribution of the slip-angle time derivative to damping should be taken into account. Finally, non-linear flight simulations show that the vertical wind acting on the aircraft before landfall acts to pull the airplane downwards and vary along its trajectory. The changing ascent currents seem to make it more difficult for the aircraft to maintain a certain rate of descent, resulting in higher overloads on landing.