【正文】
n the BP neural network technology application in the problem.The rolling bearing vibration data of three fault patterns (innerrace fault, outrace fault and rolling element fault) are chosen in this paper, and it is adopted that taking eight energy ponents deposed by wavelet packet as the ANN (artificial neural network) input vector. Then, according to the ANN theory, set hidden layer and output layer parameters of the BP neural network and design the structure of the neural network model for rolling bearing fault diagnosis. At last, train the network on Matlab and get the training error curve, then test and simulate the network and calculate the correct rate of the simulation results.Through a series of training, testing and simulation process, it can be seen that the BP neural network method, which is applied to the rolling bearing fault diagnosis, can get different training error curves, bined with different set of parameters of the neurons in the hidden layer. All the curves have good convergence. In the test and diagnostic procedures, the network can identify different fault patterns quickly and accurately depending on the input data, at the same time it has a higher accuracy rate. The BP neural network method is more accurate, practical and it has a higher diagnostic accuracy rate pared with ordinary methods. So it surely has broad application prospects.Key Words:Rolling bear, Fault diagnosis, BP neural network, Energy ponents III 目 錄摘 要 IAbstract II目 錄 III1 緒論 1 論文背景與意義 1 論文研究現(xiàn)狀 1 論文的研究內容與目標 12 滾動軸承故障特征 2 滾動軸承的基本結構 2 滾動軸承的失效形式和故障類型 23 BP神經(jīng)網(wǎng)絡 3 人工神經(jīng)網(wǎng)絡概述 3 BP神經(jīng)網(wǎng)絡 3 BP算法的缺陷及其改進算法 4 BP算法的缺陷 4 BP算法的改進算法 44 基于BP神經(jīng)網(wǎng)絡的滾動軸承故障診斷 6 小波包分解與故障數(shù)據(jù)篩選 6 小波包分解方法 6 故障數(shù)據(jù)篩選 8 滾動軸承故障診斷神經(jīng)網(wǎng)絡的設計及參數(shù)設置 9 Matlab神經(jīng)網(wǎng)絡工具箱 9 BP神經(jīng)網(wǎng)絡的建立及參數(shù)設置 10 BP神經(jīng)網(wǎng)絡的訓練 11 BP神經(jīng)網(wǎng)絡的測試仿真 15結 論 16致 謝 17參考文獻 18蘭州交通大學畢業(yè)設計(論文)1 緒論 論文背景與意義滾動軸承一直是各種機械中應用最廣泛的通用部件,其運行狀態(tài)直接影響整臺機器的性能、壽命、功能和效率,由于軸承的疲勞損傷、磨損、腐蝕及操作不當而產(chǎn)生的故障,輕則影響機械設備的正常運行,重則帶來巨大的生命和財產(chǎn)損失。選取滾動軸承三種故障類型(內圈故障、外圈故障、滾動體故障)下的軸承振動數(shù)據(jù),經(jīng)小波包三層分解后得到8組能量特征值,作為人工神經(jīng)網(wǎng)絡的輸入層的輸入,然后根據(jù)神經(jīng)網(wǎng)絡的原理,設置BP神經(jīng)網(wǎng)絡隱含層、輸出層的相關參數(shù),設計完成神經(jīng)網(wǎng)絡的結構模型。蘭州交通大學畢業(yè)設計(論文) 摘 要滾動軸承是機械設備中最常見、應用最廣泛的零部件之一,其運行狀態(tài)對整個設備的工作狀態(tài)、生產(chǎn)過程都有直接影響。最后在Matlab軟件平臺上對所構建的網(wǎng)絡進行訓練,得到訓練誤差曲線,再在訓練完成的神經(jīng)網(wǎng)絡上進行測試和仿真,得出仿真結果正確率。因此,隨著工業(yè)社會的高速發(fā)展和進步,及時發(fā)現(xiàn)并排除軸承故障責任重大。近年來,隨著信號檢測技術、計算機技術、數(shù)字信號處理技術、人工智能技術的發(fā)展,滾動軸承故障診斷的主要發(fā)展方向主要體現(xiàn)在小波變換、專家系統(tǒng)、模糊診斷、神經(jīng)網(wǎng)絡等方面。收集滾動軸承三種故障狀態(tài)(內圈故障、外圈故障、滾動體故障)下的振動數(shù)據(jù),經(jīng)小波包三層分解得到8組能量特征值作為神經(jīng)網(wǎng)絡的輸入層的輸入,然后根據(jù)神經(jīng)網(wǎng)絡的原理和相關參數(shù)設置原則,對BP神經(jīng)網(wǎng)絡隱含層、輸出層的相關參數(shù)進行設置,設計出所需BP神經(jīng)網(wǎng)絡的結構。內圈外表面上有供鋼球或滾子滾動的溝槽,稱內溝或內滾道。(3) 滾動體(鋼球或滾子)在內圈和外圈的滾道之間滾動,它的大小和數(shù)量決定著軸承的承載能力。有的軸承中還有鉚釘、防塵蓋、密封蓋以及安裝調整時用的止動墊圈、緊定套和螺母等零件。(2) 疲勞失效。(4) 斷裂失效。壓痕是指滾道和滾動體表面上產(chǎn)生局部變形而出現(xiàn)的凹坑,主要由裝配敲擊或異物落入滾道形成,也有可能是由于過載和撞擊引起。主要由裝配工藝不當引起,保持架發(fā)生變形,增加其與滾動體之間的摩擦,甚至造成某些滾動體卡死不能滾動。軸承滾動表面損傷的形態(tài)和旋轉速度,決定了激振力的頻譜;軸承和外殼,決定了振動系統(tǒng)的傳遞特性。通常,軸的旋轉速度越高,損傷越嚴重;其振動的