振动与冲击
振動與遲擊
진동여충격
JOURNAL OF VIBRATION AND SHOCK
2015年
16期
135-140
,共6页
胥永刚%赵国亮%马朝永%张建宇
胥永剛%趙國亮%馬朝永%張建宇
서영강%조국량%마조영%장건우
双树复小波变换%非线性时间序列%软阈值%降噪
雙樹複小波變換%非線性時間序列%軟閾值%降譟
쌍수복소파변환%비선성시간서렬%연역치%강조
dual-tree complex wavelet transform (DT-CWT)%nonlinear time series%soft threshold%denoising
针对双树复小波变换传统软阈值降噪方法对实、虚部树系数分别进行阈值处理时提取的强背景噪声下轴承故障特征信号效果不理想,且实、虚部分离的阈值处理方法会引起局部相位失真问题,利用故障信号小波变换系数具有周期性与双树复小波系数模震荡小等特点,提出双树复小波变换与非线性时间序列方法相结合的强背景噪声下轴承故障特征提取方法。对故障信号进行双树复小波变换,获得各层小波系数并求模,选择系数模周期性较强层系数进行非线性时间序列处理,增强系数中周期性成分,抑制随机噪声;对增强后系数进行软阈值处理消除直流成分对提取结果的影响;将处理后系数还原为复数形式进行双树复小波重构,可成功提取弱故障特征信号。仿真、试验信号处理结果表明,该方法能有效提取强背景噪声下的故障特征信号。
針對雙樹複小波變換傳統軟閾值降譟方法對實、虛部樹繫數分彆進行閾值處理時提取的彊揹景譟聲下軸承故障特徵信號效果不理想,且實、虛部分離的閾值處理方法會引起跼部相位失真問題,利用故障信號小波變換繫數具有週期性與雙樹複小波繫數模震盪小等特點,提齣雙樹複小波變換與非線性時間序列方法相結閤的彊揹景譟聲下軸承故障特徵提取方法。對故障信號進行雙樹複小波變換,穫得各層小波繫數併求模,選擇繫數模週期性較彊層繫數進行非線性時間序列處理,增彊繫數中週期性成分,抑製隨機譟聲;對增彊後繫數進行軟閾值處理消除直流成分對提取結果的影響;將處理後繫數還原為複數形式進行雙樹複小波重構,可成功提取弱故障特徵信號。倣真、試驗信號處理結果錶明,該方法能有效提取彊揹景譟聲下的故障特徵信號。
침대쌍수복소파변환전통연역치강조방법대실、허부수계수분별진행역치처리시제취적강배경조성하축승고장특정신호효과불이상,차실、허부분리적역치처리방법회인기국부상위실진문제,이용고장신호소파변환계수구유주기성여쌍수복소파계수모진탕소등특점,제출쌍수복소파변환여비선성시간서렬방법상결합적강배경조성하축승고장특정제취방법。대고장신호진행쌍수복소파변환,획득각층소파계수병구모,선택계수모주기성교강층계수진행비선성시간서렬처리,증강계수중주기성성분,억제수궤조성;대증강후계수진행연역치처리소제직류성분대제취결과적영향;장처리후계수환원위복수형식진행쌍수복소파중구,가성공제취약고장특정신호。방진、시험신호처리결과표명,해방법능유효제취강배경조성하적고장특정신호。
A new denoising method based on dual-tree complex wavelet transform and nonlinear time series was proposed,considering the weakness,such as the phase distortion,of the wavelet soft-threshold denoising method,in which the real and image parts of the coefficient are processed individually.The new method process the magnitude of the complex coefficients instead,taking into account the fact that the magnitude does not oscillate in positive and negative directions which is more suitable for threshold denoising and the fact that the coefficients of the fault signal are always periodic.The nonlinear time series method can be used to strengthen the periodicity of the coefficients caused by the fault signal and to restrain the noise meanwhile.In the method proposed,the fault signal was decomposed by dual-tree complex wavelet transform to obtain the coefficients of different layers,the nonlinear time series method was used to strengthen the periodicity of the coefficient,and then the soft-threshold denoising was carried out to remove the DC component.Finally, the fault characteristic signal was obtained by coefficient reconstruction.The simulation and experimental results show the effectiveness of the method,and a new efficient denoising method was provided.