基于阶次分析的无人机挂飞振动正弦分量幅值准确提取技术

Accurate Amplitude Extraction Technique for the Sine Component of UAV Flying Signal Based on Order Analysis

传统的快速傅里叶变换分析装备在变转速工况下的振动信号出现"频率模糊"现象,针对此问题提出一种无键相阶次分析方法。首先通过控制系统或其它途径预估转速变化范围,确定窄带滤波频带;然后对信号进行窄带滤波;之后利用Hilbert变换计算滤波后信号的瞬时频率;最后根据瞬时频率对信号进行重采样得到角度域平稳信号,对角度域信号傅里叶变换得到阶次谱。通过信号仿真验证了该阶次分析方法有效、准确,并应用到装备在无人机的挂飞振动信号分析中,用于准确提取变转速工况下振动信号中正弦分量的幅值,为准确制定装备的振动环境试验条件奠定基础。该方法是对阶次分析方法的有效补充,对于相似装备的动力学环境试验条件制定也具有参考和借鉴价值。

In order to overcome the "frequency ambiguity" phenomenon by using the traditional Fast Fourier Transform to analyze signals of equipment under the condition of varying rotating speed,this paper presents an order analysis method without phase signal.Firstly,the variation range of rotation speed is estimated by equipment control system or other ways to confirm the filter range;secondly,narrow band filtering is filtered off from the signals;Thirdly,the instantaneous frequency is calculated by Hilbert Transform;Finally,the stationary signal in angular domain is obtained by re-sampling the time-domain signal according to instantaneous frequency,and then the order spectrum is made by Fast Fourier Transform.The validity and accuracy of the order analysis method are verified by the simulation signal.Then,the method used to extract the amplitude of sinusoidal component of signal under variable rotating speed condition is applied in analyzing equipment signals in UAV,laying a foundation for accurately setting up the environment condition of equipment.The method in this paper is an effective supplement to the signal order analysis,and its application has reference value for the evaluation of dynamic environment of similar equipment.