Analysis And Method Research Of Explosion Separation Shock Data

Explosive separation test is an indispensable part of space system test.The shock acceleration data measured in the test do not return to zero at baseline,which leads to the lack of reliability of data information.In order to analyze the influence of sensor selection on the measured data of explosion separation test and the correction of baseline non-return zero data,the following work has been done in this paper.According to the requirement and purpose of explosive separation test,a scheme of explosive separation test is put forward.The protective recovery platform,free falling body and separation process,cable wiring scheme and parameters of measurement and control system are described in detail.Ensure the feasibility and reliability of the test scheme.In order to verify the reliability of measurement data of charge-output piezoelectric accelerometer and voltage-output piezoelectric accelerometer in explosion separation test,the characteristics and advantages and disadvantages of the two sensors were analyzed,and three explosion separation tests were carried out.Two types of sensors were installed at the same measuring point,and the output signals of the two sensors were analyzed and compared.Based on the national military standard,a quantitative criterion is proposed for the interpretation of explosion separation test data,which is more intuitive for signal interpretation.Aiming at the problem that the baseline does not return to zero in the measured data,a data processing scheme is adopted to correct the signal and extract part of the signal.Wavelet analysis and empirical mode decomposition are commonly used data processing methods.Selection of wavelet basis function,optimization of threshold function,determination of decomposition level and threshold optimization are the core issues of wavelet analysis.By analyzing the shock data of explosion separation and the characteristics of wavelet analysis,the criterion entropy energy ratio of wavelet basis function selection is proposed and verified numerically;the threshold value is optimized and the threshold function is improved;and the scheme of determining the decomposition level range is proposed.In empirical mode decomposition(EMD),the selection of reconstructed components does not specify the index.In order to extract more effective decomposition components,the correlation coefficient between the decomposition components and the original function is proposed as the judgment basis.By comparing the reconstructed signals of wavelet analysis and empirical mode decomposition,an improved data processing scheme based on aggregated empirical mode decomposition and wavelet analysis is proposed.It can be concluded that the charge-output piezoelectric accelerometer should be selected as the accelerometer for explosive separation shock test,and the aggregated empirical mode decomposition combined with wavelet analysis scheme proposed in this paper can be used to modify and extract some effective signals for the measured data in this test.