【摘要】 随机子空间识别算法是一种基于环境激励的模态参数识别方法,仅需要响应时程便可识别模态参数。其中,协方差驱动随机子空间方法中Toeplitz矩阵行数的选取直接影响识别精度。通过构造相关矩阵,研究了Toeplitz矩阵行数i对协方差驱动随机子空间方法中奇异值分解去噪能力的影响。引入Toeplitz矩阵条件数,根据i与Toeplitz矩阵条件数的关系再次证明了i对识别精度的影响。研究了Toeplitz矩阵行数i的选择方法。采用两自由度弹簧振子系统和切尖三角翼模型两个仿真算例研究了Toeplitz矩阵行数i的选择方法。结果表明:在确定合适的系统阶数的前提下,Toeplitz矩阵的条件数越小识别精度越高。更多还原

【Abstract】 Stochastic Subspace Identification is a parameter identification method,which can effectively obtain modal parameters from the structural signal under ambient excitation. The choice of Toeplitz matrix row number directly influences the accuracy of identification. By constructing a correlation matrix,the influence of the dimension of Toeplitz matrix i on the denoising ability via SVD was derived. The concept of condition number was introduced in solving the system matrix. According to the relationship between i and condition number of Toeplitz matrix,it is proved once again that i has influence on identification accuracy. Then the selection method of Toeplitz matrix row number i was studied.Two examplic simulations in regard to a two-degree spring mass vibration system and a cropped delta wing model were presented to show the method in the selection of i. The results show that on the premise of determining a suitable system order,the smaller the Toeplitz matrix condition number is,the higher the identification accuracy is.更多还原