轨道交通装备健康管理五次作业

Homework_1 Data Preprocessing --Wavelet Transform

题目：

Original raw signal is provided. Choose an appropriated wavelet function with levels. Then conduct signal preprocessing using wavelet de -noising. Post your Matlab code and plot a result figure such as:

Matlab 程序：

clear all clc

s = load('sta_ch1_1.txt'); % 加载原始信号

dn = length(s); % length of vector or largest array dimension

[C,L] = wavedec(s,6,'db5');% Help file, C: the wavelet decomposition vector , L: the bookkeeping vector

A6 = wrcoef('a', C, L,'db5',6); % a: approximation (基本信号)低频部分（尺度系数，逼近系数）

D1 = wrcoef('d', C, L, 'db5',1); % d: detail (细节信号)高频部分（小波系数，细节系数）

D2 = wrcoef('d', C, L, 'db5',2); D3 = wrcoef('d', C, L, 'db5',3); D4 = wrcoef('d', C, L, 'db5',4); D5 = wrcoef('d', C, L, 'db5',5);

D6 = wrcoef('d', C, L, 'db5',6);

subplot(811); plot(s,'k','LineWidth',1.5); ylabel('s','FontSize',12,'Fontweight','bold'); title('sta_ch1_1');

subplot(812); plot(A6(1:dn/2^1),'k','LineWidth',1.5); ylabel('a6','FontSize',12,'Fontweight','bold')

subplot(813); plot(D1(1:dn/2^1),'k','LineWidth',1.5);

s

sta c h1

1

a 1

d 1

d

2

d 3

d 4

d

5d 6

ylabel('d1','FontSize',12,'Fontweight','bold')

subplot(814); plot(D2(1:dn/2^2),'k','LineWidth',1.5); ylabel('d2','FontSize',12,'Fontweight','bold')

subplot(815); plot(D3(1:dn/2^3),'k','LineWidth',1.5); ylabel('d3','FontSize',12,'Fontweight','bold')

subplot(816); plot(D4(1:dn/2^4),'k','LineWidth',1.5); ylabel('d4','FontSize',12,'Fontweight','bold')

subplot(817); plot(D5(1:dn/2^5),'k','LineWidth',1.5); ylabel('d5','FontSize',12,'Fontweight','bold')

subplot(818); plot(D6(1:dn/2^6),'k','LineWidth',1.5); ylabel('d6','FontSize',12,'Fontweight','bold')

运行结果：

Homework_2 Batch data processing

题目：

1) Matlab code program to calculate at least 3 features from time -domain and frequency -domain respectively;

2) Project calculated features on figures of 2-D and 3-D with good discrimination looking like:

2-D Plot with one selected feature 3-D Plot with three selected features Key: Batch data processing and save

Matlab 程序：

clear all clc

na=dir('*_first_*.txt'); % lists the files N=size(na,1);

% plot3(m(:,1),m(:,2),m(:,3),'b.') for k=1:N

s(:,k) = load(na(k).name); % 加载原始信号 end

% s=decimalscaling(s);

% [s,ps]=mapminmax(s',0.1,.9); % s=s';

% s=mapminmax('reverse',s',ps); % s=s';

F1

F 3

Number of data

N o .7 f e a t u r e