Abstract As is well known, gust responses of an elastic aircraft can be predicted by both time-domain and frequency-domain methods. The frequency-domain method can produce accurate predictions as long as the obtained aerodynamic data in frequency-domain is accurate. The time-domain method might involve the problem of degraded accuracy due to the modeling errors resulting from the rational function approximation (RFA) of the frequency-domain aerodynamic forces. However, the state-space time-domain model can efficiently deal with a large number of calculations needed for determining the worst-case gust loads, and is very convenient for the design of an aeroelastic controller. In view of the disadvantages of traditional RFA, this paper proposes an aerodynamic subsystem realization technique, which is used to build time-domain aeroservoelastic state-space model with a high precision. Firstly, the Loewner framework is introduced to generate an accurate descriptor system using frequency-domain aerodynamic data. Then, model decomposition and reduction are applied to the descriptor system in order to generate a reduced order system with guaranteed stability. Finally, the aerodynamic subsystem is expressed in state-space form after extracting the additional direct term. The proposed modeling method of the aerodynamic subsystem does not need iterative calculations and artificial selection of aerodynamic poles, and has the advantages in accuracy, efficiency and numerical stability. The proposed method is verified by an example of a transport aircraft flying into the fields of discrete and continuous gusts. The simulation results demonstrate that the developed state-space aerodynamic model is sufficiently accurate, and the time-domain method established in this paper can achieve the same accuracy as the frequency-domain method.

中文翻译：

---

一种用于状态空间阵风分析的改进气动伺服弹性建模方法

摘要 众所周知，弹性飞行器的阵风响应可以通过时域和频域方法进行预测。只要获得的频域气动数据是准确的，频域方法就可以产生准确的预测。由于频域气动力的有理函数逼近 (RFA) 会导致建模误差，时域方法可能会涉及精度下降的问题。然而，状态空间时域模型可以有效地处理确定最坏情况突风载荷所需的大量计算，并且非常方便气动弹性控制器的设计。针对传统RFA的不足，本文提出了一种气动子系统实现技术，用于建立高精度的时域气动伺服弹性状态空间模型。首先，引入 Loewner 框架以使用频域空气动力学数据生成准确的描述符系统。然后，将模型分解和约简应用于描述符系统，以生成具有保证稳定性的降阶系统。最后，空气动力学子系统在提取附加直接项后以状态空间形式表示。所提出的气动子系统建模方法不需要迭代计算和人工选择气动极点，在精度、效率和数值稳定性方面具有优势。以运输机飞入离散和连续阵风场为例验证了所提出的方法。