【正文】 小波在信號檢測中的應(yīng)用 畢業(yè)論文 誠 信 書 我謹(jǐn)在此保證：本人所寫的畢業(yè)論文 (設(shè)計 )，凡引用他人的研究成果均已在參考文獻(xiàn)或注釋中列出。論文 (設(shè)計 )主體均由本人獨立完成，沒有抄襲、剽竊他人已經(jīng)發(fā)表或未發(fā)表的研究成果行為。如出現(xiàn)以上違反知識產(chǎn)權(quán)的情況，本人愿意承擔(dān)相應(yīng)的責(zé)任。 聲明人 (簽名 )： 年 月 日 摘 要 小波分析作為最新的時 頻分析工具，在信號分析、圖像處理、特征提取、故障診斷等各領(lǐng)域得到了廣泛的應(yīng)用。小波變換具有表征信號局部特征的能力和多分辨 率的特征 ,因此，很適于探測信號中的瞬態(tài)和奇異現(xiàn)象 , 并可展示其成份。 本文在綜述小波變換的基本思想與具體性質(zhì)和原理的基礎(chǔ)上，重點介紹了小波在 滾動軸承 機械故障檢測中的應(yīng)用。 滾動軸承 機械故障信號分析中基函數(shù)的不同 將 導(dǎo)致對信號 的 觀測角度和觀測方法的不同， 在小波基函數(shù)的選取方面 Fourier 變換、短時 Fourier 變換和小波變換 各自的基函數(shù) 有著 的本質(zhì)區(qū)別。 本文 通過比較故障診斷中常用的各種小波基函數(shù) 的性能和特點，研究不同的故障信號特征與各種小波基函數(shù)的內(nèi)在聯(lián)系。 利用連續(xù)小波變換方法將滾動軸承振動信號的特征信息轉(zhuǎn)化 為能量譜與尺度的關(guān)系，進(jìn)而建立尺度 和 能量相對應(yīng)的特征向量，為滾動軸承的快速診斷提供了新方法。本文提出 一種 應(yīng)用 Daubechies 小波包多層分解、重構(gòu)提取滾動軸承各部件的故障特征頻率和能量特征 ，通過小波包多層分解確定滾 動軸承 機械 振動的奇異點的方法 , 實現(xiàn) 故障 的精確 診斷 。 關(guān)鍵詞： 小波分析 、 故障診斷 、 滾動軸承 、 多 層分解 Abstract Wavelet analysis as the latest time frequency analysis tool in signal analysis, image processing, feature extraction, fault diagnosis and other fields has been widely used. Characterization of the signal wavelet transform has the ability of local features and characteristics of multiresolution, therefore, it is very suitable for detection of transient signals and singular phenomenon, even to display its ponents. General speaking the summary of this paper, the basic ideas of wavelet transform and the specific nature, the most important of this paper is focusing on the wavelet applications of fault detection in the rolling machine. In the mechanical failure of the rolling bearing signal analysis, the different basis functions lead to a difference of signal point of observing views and observing methods, which are the essential differences among wavelet transform Fourier transform, shorttime Fourier transform. In this paper, by paring the performances and characteristics of a variety of mon used smallwavelet fonctions in fault diagnosis, I research on the internal relations between different characteristics of the fault signal and wavelet fonctions. Making using of continuous wavelet transform method, this paper changes the characteristics of rolling bearing vibration signal information into the relationship of energy spectrum and measure, ing to the establishment a feature vector corresponding to energy and scale, creats the new method for the rapid diagnosis of rolling bearings. In order to accurately diagnosis of fault type, this paper proposes the application of multideposition of Daubechies wavelet packet, reconfiguration of the extraction of fault characteristic frequency and energy feature in ponents rolling bearing ponents, by analysing multideposition of Daubechies wavelet packet, we can clearly see the failure point of mechanical vibration in rolling bearing. Key words： Wavelet analysis, fault diagnosis, rolling bearing, multideposition 目 錄 摘 要 Abstract 第 1 章 緒 論 .............................................................................................................. 1 論文選題背景和意義 ........................................................................................... 1 論文研究現(xiàn)狀 ..................................................................................................... 1 ：小波分析現(xiàn)狀 ......................................................................................... 1 ：機械故障診斷現(xiàn)狀 .................................................................................. 3 論文研究方法和內(nèi)容 ........................................................................................... 6 第 2 章 小波分析的理論 基礎(chǔ) ...................................................................................... 7 傅立葉分析及其優(yōu)缺點 ....................................................................................... 7 傅立葉變換 (Fourier Transform) ................................................................. 7 傅立葉變換 的優(yōu)點與缺點 .......................................................................... 7 小波分析 ............................................................................................................. 9 小波基性能研究 ..................................................................................................11 針對故障診斷處理的小波分類 ............................................................................ 13 小波變換對信號奇異性檢測的基本原理 .............................................................. 14 . 1 奇異性的定義 ......................................................................................... 14 . 2 小波變換的卷積表達(dá)形式 ....................................................................... 14 . 3 小波變換的極值點 、過零點與信號奇異性的聯(lián)系 .................................... 15 小波基的選擇 ................................................................................................... 16 最佳小波基的選取 ............................................................................................ 17 Daubechies 小波 ................................................................................................. 18 小波分解與尺度選擇 ......................................................................................... 19 第 3 章 滾動軸承的故障及診斷技術(shù) ........................................................................ 20 滾動軸承的結(jié)構(gòu) ................................................................................................. 21 滾動軸承失效的基本形式 ................................................................................... 21 滾動軸承故障的振動診斷 ................................................................................... 22 滾動軸承的振動機理及故障特征頻率 ................................................................ 23 滾動軸承的振動機理 ............................................................................... 23 滾動軸承各元件單一缺陷的特征頻率 ....................................................... 24 由滾動軸承構(gòu)造所引起的振動 ................................................................. 25 滾動軸承的非線性引發(fā)的振動 ..............................................................