非定常大振幅振荡试验数据处理研究

Research on the data processing of unsteady large-amplitude-oscillation experiment

在大振幅振荡风洞试验过程中,去除测量数据信号中的噪声、对齐初读数和吹风数中的角度序列和力信号序列是获得准确大振幅试验数据的两个关键问题。文中介绍了全相位数字滤波原理和处理非定常试验数据方法,并推导了全相位处理数据理论计算公式,通过对天平各通道力信号进行频谱分析来确定滤波的截止频率。对移相位、插值拟合、移动最小二乘拟合3种对齐初读数和吹风数方法进行了详细介绍,并比较了3种方法处理试验数据结果。结果表明,在有噪声的信号中,全相位数字滤波能够减少滤波过程中信号相位和幅值失真,3种对齐数据方法处理试验数据结果比较一致、合理。

Removing the noise in the experimental data signals and aligning the angle and force signal sequences of the initial data and the test data are the two key issues that remain to be resolved in the large-amplitude-oscillation test.The basic principle of all-phase digital filtering and the method of processing unsteady experimental data are introduced.The theoretical formula of all-phase data processing is derived in detail.Spectrum analysis of each channel of the balance is used to choose the cutoff frequency in the digital filtering process.The three methods of moving phase,interpolating fitting and Moving Least Square（MLS）fitting are studied in detail for aligning the initial data with the test data.The experimental results obtained by the three methods are compared.The results show that all-phase digital filtering can remove the noise in the experimental signal data successfully and reduce the signal phase and amplitude distortion.The experimental results obtained by the three different methods are consistent and reasonable.