间隙非线性气动弹性系统的辨识

 间隙非线性气动弹性系统有非常丰富的动力学特征。由于工程实际中间隙不易准确测量甚至无法测量,通常需要通过辨识来建立其数学模型,其中间隙开关点位置是辨识问题中的难点。本文利用间隙开关点将间隙非线性系统区分为3个线性子系统,用Hammerstein模型表示其非线性部分,构造了开关点的迭代序列;并采用非迭代和迭代相结合的方法进行求解,从而成功获得包含间隙开关点在内的该系统所有模型参数;以间隙非线性的二元翼段为例,验证了该辨识方法的有效性。

Identification of a Nonlinear Aeroelastic System with Freeplay

There exist very rich dynamic features in a nonlinear aeroelastic system with freeplay. Since freeplay is no cinch to be correctly measured or just cannot be measured in engineering practice, a mathematic model of the system usually needs to be constructed by identification, in which the locations of the switching points are difficult to identify. In this paper a nonlinear aeroelastic system with freeplay is divided into three linear subsystems by using the switching points of the freeplay. Its nonlinear part is represented by a Hammerstein model. The iterative sequence of the switching points is structured, and solved by a method synthesized of the non-iterative and iterative algorithms. Then all model parameters of the system including the switching points of the freeplay are successfully obtained. The identification method is proved effective by an example of a two-dimensional airfoil with freeplay.