旋翼桨叶的一阶摆振后退型模态是影响直升机地面共振稳定性的主要模态。为了识别装机状态下桨叶一阶摆振模态阻尼，本研究发展了基于FFT分析的移动矩形窗法、基于Fourier级数的移动矩形窗法、基于希尔伯特变换法和基于Wavelet小波变换等四种方法的无轴承旋翼一阶摆振模态阻尼识别技术，针对试验中测得的信号出现的频率成分密集和信噪比差等情况在阻尼识别过程中增加了数字滤波器，数值仿真和基于装机试验数据的识别均表明，基于Fourier级数的移动矩形窗和基于Wavelet小波变换两种阻尼识别技术可有效分离无轴承旋翼摆振模态，数字滤波器可有效提高桨叶摆振阻尼识别精度。
Abstract
Helicopter rotor blades’ first order lead-lag backward type mode is the main mode to affect its ground resonance stability.To identify the damping of this first order lead-lag mode, four different methods including FFT-based moving block (FFT-MB), Fourier series-based moving block (FSMB), Hilbert transform (HT) and Wavelet transform (WT) were proposed.Aiming at measured signals appearing dense frequency components and had signal-noise-ratio (SNR), a digital filter was added.Numerical simulation and recognition results based on test data indicated that both FSMB and WT methods can be used to effectively separate the first order lead-lag mode of helicopter bearingless rotor blades and the digital filter can be used to effectively improve the damping identification accuracy of this lead-lag mode.
关键词
旋翼 /
无轴承 /
阻尼识别 /
摆振 /
滤波
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Key words
Rotor /
Bearingless /
Damping Identification /
Lead-lag Motion /
Filter
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