特征值抽取—bp神经网络

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1、特征值抽取—bp神经网络1．时域时域特征值抽取程序：a=load('C:DocumentsandSettingsAdministrator桌面设备工况监测数据故障guzhang3cp10000zs30.txt');a0=(mean(a));b=std(a);c0=sqrt(mean(a.^2));c1=mean(((a-a0)/b).^4)-3;c2=mean(((a-a0)/b).^3);c3=(max(a(1:5000))-min(a(1:5000)))/2+(max(a(5001:10000))-min(a(5001:10000)))/2;c4=c3/c0;

2、c5=c3/a0;c6=c0/a0;c7=(mean((a-a0).^4))/(a0)^2;c8=abs(max(a))/((mean(sqrt(abs(a))))^2);shujuhuizong=[c0,c1,c2,c3,c4,c5,c6,c7,c8]2频域频域特征值抽取程序：fa=load('C:DocumentsandSettingsAdministrator桌面设备工况监测数据故障guzhang3cp10000zs30.tx');fa0=fa-mean(fa);[p,fi]=pwelch(fa0);fc=sum(fi.*p)/sum(p);vf=sum((

3、fi-fc).^2.*p)/sum(p);msf=sum(fi.^2.*p)/sum(p);shujuhuizong=[fc,vf,msf]时域，频域特征值：时域特征频域特征特征参数均方根值峰系数态偏态系数峰值峰值因子脉冲因子波形因子峭度裕度系数重心频率频率方差均方频率好的12.26518.3863-0.47504.9542.1871-2.2159-1.03310.03980.07160.78370.57801.192222.26477.9322-0.46863.87301.7102-1.72341.01120.02790.33100.47060.31480.536232.26

4、228.2939-0.39854.69952.0774-2.1014-1.01150.03050.30390.74660.55011.107542.26879.5105-0.53725.03902.2211-2.2498-1.01200.03600.04490.75400.55481.123352.26147.9689-0.54574.22201.8670-1.8996-1.01210.03240.15491.41340.63641.943662.26188.0407-0.45384.70202.0789-2.1017-101100.02710.16810.78370.5726

5、1.1869故障72.26371.0362-0.07882.94401.3005-1.3137-1.01020.00850.27270.64630.66121.078982.26141.0167-0.11262.44651.0818-1.0927-1.01010.00820.30800.64360.65081.065092.26351.1001-0.09503.0041.3272-1.3414-1.01070.00950.24780.64940.66571.0874102.25791.0721-0.11632.46951.0937-1.0015-1.01040.00900.20

6、650.63960.65151.0605112.26431.1281-0.11003.17251.4011-1.4153-1.01060.00860.25610.64700.66011.0787122.26330.9451-0.11572.77451.2259-1.2381-1.01000.00800.31850.64320.65681.06903，FFT变换FFT特征抽取程序：cleara=load('C:DocumentsandSettingsAdministrator桌面设备工况监测数据好的hao3cp10000zs20.txt');a=a-mean(a);

7、N=length(a);x=abs(fft(a));f=(1:N/2)/(N/10000);plot(f,x(1:N/2),'y')set(gca,'color','k');xlabel('频率(Hz)');ylabel('幅值');f1=(length(f)*450)/5000;f2=(length(f)*500)/5000;c1=max(x(fix(f1):fix(f2)))c2=mean(x(fix(f1):fix(f2)))FFT特征值：350-400HZ：好的：496.563348