跨声速风洞测力模型的降阶及H_∞减振控制

Model Reduction and Active Vibration Suppression of a Wind Tunnel Test Model by H_∞ Control

在风洞测力试验中,尾部支撑是一种广泛采用的模型安装方式。以该方式安装的风洞测力模型中,总体呈现低刚度特性。在试验进入大攻角状态时,低频气流脉动压力极易引起模型低频大幅俯仰振动,导致测试精度降低,甚至以疲劳方式破坏试验设备。针对一种采用尾部支撑方式的跨声速风洞测力模型,建立其有限元模型,结合模态截断及平衡降阶两种方法,对高维有限元模型进行降阶;基于低维的降阶模型及柔性结构的特点,采用简化的混合灵敏度优化方法,实现对测试中模型低频俯仰振动的主动抑制。仿真分析表明该主动减振方案有效且易于实现,对于大型复杂结构具有重要的实用价值。

In wind tunnel testing, the test model is usually mounted by an axially supported beam inserted at the rear.The whole structure of the test model and the support is flexible with low natural frequencies. In transonic testing with alarge angle of attack, the low-frequency pulsating pressure by airflow can easily cause the pitching vibration of the modelwith low frequency and large amplitude, which can lead to poor accuracy of measurement and fatigue damage of the testdevice. In this article, a FEM model is established for the transonic wind-tunnel testing model with its rear supported by abeam. Using balancing and modal truncation methods, the order of the model can be reduced. According to the feature oflow- dimension, low- order and flexible structure of the model, an H∞ robust control method is used to fulfill the activevibration suppression of the low- frequency pitching vibration of the model. Simulation and analysis show that this activevibration suppression strategy is applicable and efficient, and has practical significance for the analysis of large complexflexible structures.