Unsteady aerodynamics, reduced-order modelling, and predictive control in linear and nonlinear aeroelasticity with arbitrary kinematics
Unsteady aerodynamics, reduced-order modelling, and predictive control in linear and nonlinear aeroelasticity with arbitrary kinematics
复制标题
任意运动学线性和非线性气动弹性的非定常空气动力学、降阶建模和预测控制
DOI：
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
R. Simpson
中科院分区：
文献类型：
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作者：
R. Simpson
本论文主要研究挠性飞机飞行动力学分析的计算方法。一个参数是层次结构的方法，提供预测能力的负载和稳定性分析，并能够创建低阶动态模型的控制系统综合。所提出的气动弹性模型是用三维非定常空气动力学以非定常涡格法的形式制定的，这种方法是为了模拟柔性飞机动力学中固有的相对复杂的运动学，特别是非定常诱导阻力。没有对流体-结构界面的运动学（输入）进行任何假设，并且使用三维Joukowski关系自然地解决了非定常气动力力（输出）的所有分量。一个一致的线性化，这种方法的任意参考状态产生无量纲（独立的自由流动压）离散时间状态空间模型，解决频率的空间-时间奈奎斯特限制定义的唤醒离散化，并有一个方便的形式与结构动力学模型耦合。飞机结构部件采用几何精确的复合材料梁公式进行建模，此外，在线性动力学的情况下，采用通用的模态描述。后者允许线性空气动力学被表示在一组减少的输入和输出，从而获得一个时域的替代经典的频域为基础的双重晶格方法。为这些模态自由度修改的模型被证明适合于平衡实现和截断，并在颤振分析中得到验证，其中收敛结果只需要10-100个平衡状态（与1000- 10，000个物理状态相比）。最后，预测控制器和线性二次型调节器的合成使用降阶气动弹性模型，并应用于阵风负载缓解的非线性仿真。
This thesis concerns the development of computational methods for efficient flexible-aircraft flight dynamics analyses. An argument is made for a hierarchy of methods that provide predictive capability for loads and stability analyses, and the ability to create low-order dynamic models for control system synthesis. The proposed aeroelastic models are formulated using three-dimensional unsteady aerodynamics in the form of an unsteady vortex-lattice method developed to model the relatively complex kinematics inherent in flexible-aircraft dynamics, and in particular the unsteady induced drag. No assumptions are made relating to the kinematics of the fluid-structure interface (inputs) and use of the three-dimensional Joukowski relation naturally resolves all components of the unsteady aerodynamic forcing (outputs). A consistent linearization of this method about an arbitrary reference state yields nondimensional (independent of free-stream dynamic pressure) discrete-time state-space models that resolve frequencies up to a spatio-temporal Nyquist limit defined by the wake discretization, and have a convenient form for coupling with structural dynamics models. Aircraft structural components are modelled using a geometrically-exact composite beam formulation, and, additionally, in the case of linear dynamics, a generic modal description. The latter allows the linear aerodynamics to be expressed in a reduced set of inputs and outputs, thus obtaining a time-domain alternative to the classical frequency-domain-based doublet-lattice method. The models modified for these modal degrees-of-freedom are shown to be amenable to balanced realization and truncation, and are verified in flutter analyses where only 10-100 balanced states are required (compared to 1000-10,000 physical states) for converged results. Finally, predictive controllers and linear-quadratic regulators are synthesized using reduced-order aeroelastic models, and are applied in nonlinear simulations for gust-load alleviation.
影响因子：
2.5
作者：
H. Hesse;R. Palacios
通讯作者：
H. Hesse;R. Palacios
影响因子：
4.7
作者：
Hesse, Henrik;Palacios, Rafael
通讯作者：
Palacios, Rafael