为提高多输入多输出(Multiple input multiple output,MIMO)线性随机振动试验系统中具有相关特性的多路驱动信号生成精度,基于驱动谱非负定Hermite特性及矩阵分解理论提出了一种CD(Cholesky decomposi-tion)白噪声滤波信号生成方法.构造具有特定"频响特性"的传递系统,将一系列独立白噪声通过该系统得到具有预期相干特性、相位差以及自谱的平稳随机信号.建立悬臂梁两输入两输出线性振动系统仿真模型,将传统傅里叶逆变换时频转换方法与CD滤波法生成的驱动信号进行对比分析.结果表明新方法精度与参考值误差不足1 dB.两轴振动试验验证结果表明,应用CD法既满足工程实际标准需求,又为振动环境试验提供理论依据.%To improve the generating precision of driving signal in multiple-input multiple-out (MIMO) linear random vibration test system ,a new method called Cholesky decomposition (CD) filter based on w hite noise is proposed according to the matrix decomposition theory in view of the nonnegative definite Hermite characteristic of driving powr spectral density (PSD) .The lower triangular matrix with particu-lar frequency response transfer characteristics is constructed .A series of independent w hite noises are passed through the system ,and the multiple stationary random signals with articipative coherence per-formance ,phases and self-PSD are obtained .A two-input two-output simulation system based on a can-tilever beam is established to verify the effectiveness of the proposed method .The mixed reference spec-trum including board and narrow random signals is set and the results between the traditional time-fre-quency transformation method based on Fourier transform and the new method are compared .The re-sults show that the new method has high accuracy in the self-spectrum and cross-spectrum ,and can meet the technical requirements of engineering application ,thus improving the effect of random vibra-tion environment test control .
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