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data-science/bearing_snippets/more_features.R
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basedir <- "../bearing_IMS/1st_test/" | |
library(e1071) | |
# Helper functions | |
fft.spectrum <- function (d) | |
{ | |
fft.data <- fft(d) | |
# Ignore the 2nd half, which are complex conjugates of the 1st half, | |
# and calculate the Mod (magnitude of each complex number) | |
return (Mod(fft.data[1:(length(fft.data)/2)])) | |
} | |
freq2index <- function(freq) | |
{ | |
step <- 10000/10240 # 10kHz over 10240 bins | |
return (floor(freq/step)) | |
} | |
# Bearing data | |
Bd <- 0.331 # ball diameter, in inches | |
Pd <- 2.815 # pitch diameter, in inches | |
Nb <- 16 # number of rolling elements | |
a <- 15.17*pi/180 # contact angle, in radians | |
s <- 2000/60 # rotational frequency, in Hz | |
ratio <- Bd/Pd * cos(a) | |
ftf <- s/2 * (1 - ratio) | |
bpfi <- Nb/2 * s * (1 + ratio) | |
bpfo <- Nb/2 * s * (1 - ratio) | |
bsf <- Pd/Bd * s/2 * (1 - ratio**2) | |
all.features <- function(d) | |
{ | |
# Statistical features | |
features <- c(quantile(d, names=FALSE), mean(d), sd(d), skewness(d), kurtosis(d)) | |
# RMS | |
features <- append(features, sqrt(mean(d**2))) | |
# Key frequencies | |
fft.amps <- fft.spectrum(d) | |
features <- append(features, fft.amps[freq2index(ftf)]) | |
features <- append(features, fft.amps[freq2index(bpfi)]) | |
features <- append(features, fft.amps[freq2index(bpfo)]) | |
features <- append(features, fft.amps[freq2index(bsf)]) | |
# Strongest frequencies | |
n <- 5 | |
frequencies <- seq(0, 10000, length.out=length(fft.amps)) | |
sorted <- sort.int(fft.amps, decreasing=TRUE, index.return=TRUE) | |
top.ind <- sorted$ix[1:n] # indexes of the largest n components | |
features <- append(features, frequencies[top.ind]) # convert indexes to frequencies | |
# Power in frequency bands | |
vhf <- freq2index(6000):length(fft.amps) # 6kHz plus | |
hf <- freq2index(2600):(freq2index(6000)-1) # 2.6kHz to 6kHz | |
mf <- freq2index(1250):(freq2index(2600)-1) # 1.25kHz to 2.6kHz | |
lf <- 0:(freq2index(1250)-1) # forcing frequency band | |
powers <- c(sum(fft.amps[vhf]), sum(fft.amps[hf]), sum(fft.amps[mf]), sum(fft.amps[lf])) | |
features <- append(features, powers) | |
return(features) | |
} | |
# Set up storage for bearing-grouped data | |
b1m <- matrix(nrow=0, ncol=(2*23)) | |
b2m <- matrix(nrow=0, ncol=(2*23)) | |
b3m <- matrix(nrow=0, ncol=(2*23)) | |
b4m <- matrix(nrow=0, ncol=(2*23)) | |
# and for timestamps | |
timestamp <- vector() | |
for (filename in list.files(basedir)) | |
{ | |
cat("Processing file ", filename, "\n") | |
ts <- as.character(strptime(filename, format="%Y.%m.%d.%H.%M.%S")) | |
data <- read.table(paste0(basedir, filename), header=FALSE, sep="\t") | |
colnames(data) <- c("b1.x", "b1.y", "b2.x", "b2.y", "b3.x", "b3.y", "b4.x", "b4.y") | |
# Bind the new rows to the bearing matrices | |
b1m <- rbind(b1m, c(all.features(data$b1.x), all.features(data$b1.y))) | |
b2m <- rbind(b2m, c(all.features(data$b2.x), all.features(data$b2.y))) | |
b3m <- rbind(b3m, c(all.features(data$b3.x), all.features(data$b3.y))) | |
b4m <- rbind(b4m, c(all.features(data$b4.x), all.features(data$b4.y))) | |
timestamp <- c(timestamp, ts) | |
} | |
cnames <- c("Min.x", "Qu.1.x", "Median.x", "Qu.3.x", "Max.x", "Mean.x", "SD.x", "Skew.x", "Kurt.x", "RMS.x", "FTF.x", "BPFI.x", "BPFO.x", "BSF.x", "F1.x", "F2.x", "F3.x", "F4.x", "F5.x", "VHF.pow.x", "HF.pow.x", "MF.pow.x", "LF.pow.x", "Min.y", "Qu.1.y", "Median.y", "Qu.3.y", "Max.y", "Mean.y", "SD.y", "Skew.y", "Kurt.y", "RMS.y", "FTF.y", "BPFI.y", "BPFO.y", "BSF.y", "F1.y", "F2.y", "F3.y", "F4.y", "F5.y", "VHF.pow.y", "HF.pow.y", "MF.pow.y", "LF.pow.y") | |
colnames(b1m) <- cnames | |
colnames(b2m) <- cnames | |
colnames(b3m) <- cnames | |
colnames(b4m) <- cnames | |
b1 <- data.frame(timestamp, b1m) | |
b2 <- data.frame(timestamp, b2m) | |
b3 <- data.frame(timestamp, b3m) | |
b4 <- data.frame(timestamp, b4m) | |
write.table(b1, file=paste0(basedir, "../b1_all.csv"), sep=",", row.names=FALSE) | |
write.table(b2, file=paste0(basedir, "../b2_all.csv"), sep=",", row.names=FALSE) | |
write.table(b3, file=paste0(basedir, "../b3_all.csv"), sep=",", row.names=FALSE) | |
write.table(b4, file=paste0(basedir, "../b4_all.csv"), sep=",", row.names=FALSE) | |