| 摘要: |
| 运载火箭截面动载荷难以直接测量，利用飞行过载、低频振动等遥测数据进行反向辨识是一种有效方法。针对在火箭低频模态较为密集时小波分解和HHT变换存在的频率混叠和模态混叠等问题，提出一种结合小波分解和HHT变换的识别方法。首先根据运载火箭模态计算结果，利用小波分解将振动信号分解到火箭低阶振动的频率范围；然后利用经验模态分解（Empirical Mode Decomposition ，EMD）对小波分解后信号进行经验模态分解，通过希尔伯特变换计算每个分量的瞬时频率，对某一阶箭体振动，考虑一定频率偏差，将在此阶火箭固有频率附近的分量进行叠加，得到火箭在不同阶模态下的振动；最后利用模态叠加原理得到箭体各截面动载荷。对遥测数据进行了动载荷识别，识别结果约为设计值的30%，具有重要的工程应用价值。 |
| 关键词: 运载火箭 动载荷识别 小波分解 HHT变换 遥测数据 |
| DOI： |
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| 基金项目:国家自然科学基金（U23B6009） |
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| Dynamic Load Identification of Launch Vehicle Section Based on Wavelet Decomposition and HHT Transform |
| WANG Lei,JIANG Renwei,HU Pengxiang,GAO Yihang,WANG Mingjie |
| (Beijing Institute of Astronautical Systems Engineering, Beijing 100076, China) |
| Abstract: |
| It is difficult to directly measure the dynamic load of the launch vehicle cross-section, and reverse identification using telemetry data such as flight overload and low-frequency vibration is an effective method. A recognition method combining wavelet decomposition and HHT transform is proposed to address the frequency and mode aliasing issues that exist when the low-frequency modes of rockets are relatively dense. Firstly, based on the modal calculation results of the launch vehicle, wavelet decomposition is used to decompose the vibration signal into the frequency range of the lower order vibration of the rocket; then EMD is used to carry out empirical mode decomposition of the signal after wavelet decomposition, and the instantaneous frequency of each component is calculated through Hilbert transform，for a certain order of rocket body vibration, considering a certain frequency deviation, the components near the natural frequency of this order of rocket are superimposed to obtain the rocket vibration under different orders of modes; finally, the dynamic loads of each section of the rocket body are obtained by using the modal superposition principle. The identification result is about 30% of the design value, laying the foundation for the refined design of dynamic loads and has important engineering application value. |
| Key words: Launch vehicle Dynamic load identification Wavelet decomposition HHT transformation Telemetry data |