基于調制隨機共振的轉子故障早期檢測

噪聲是影響旋轉機械早期故障檢測的主要因素。只有抑制噪聲增強信號、提高信噪比，才能從噪聲中提取故障特征信息，為故障診斷特別是早期故障檢測提供可靠的依據。文中根據非線性雙穩系統在噪聲和弱周期信號作用下的周期響應特性，將調制技術與隨機共振原理相結合，提出了調制隨機共振方法，實現了在較寬的頻率范圍內從強噪聲中檢測微弱周期信號。理論分析、數值仿真和實驗結果表明，對信號進行調制產生的差頻分量可形成低頻信號，該低頻信號通過雙穩系統易產生隨機共振，從而使隨機共振發生在具有優良頻率特性的低頻區，能使微弱的故障信號特征突出、明顯而易于捕捉。該方法靈活、可靠，在轉子系統早期故障檢測方面的應用是可行的。

Noise is the main factor influencing incipient rotor machine failure detection. Only when the noise is suppressed and SNR is improved, the failure characteristic information can be picked up from noise supplying the reliable basis for failure detection especially the incipient failure detection. The modulated stochastic resonance method is proposed according to the period response characteristics in nonlinear bistable system caused by noise and weak period signal. The weak periodic signals can be distinguished from strong noise in broaden frequency range with this method. The theoretical analysis, numerical simulation and experiment results manifest that differential frequency component generated by signal modulation can form low frequency signal. The stochastic resonance is easily generated when the low frequency signal acts on the bistable system. The frequency of stochastic resonance is on low frequency range making the characteristics of weak fault signal obviously and easily to capture. The method is flexible, reliable and effective in application of the incipient fault detection in rotor system.