Vibration analysis using wavelet transform
Vibration analysis using wavelet transform
(OP)
Hi everyone!
I'm making a system that will detect all different kinds of fault on different machinery like bearing, misalignment etc. I understand the concept on wavelet transforms and its advantages over the regular FFT for these kind of signals but I can't see how to compare and analyse the values of the wavelet transform to in fact detect any faults (automatically, of course). If anyone have any knowledge or know where I can find some information in this area it would be deeply appreciated!
Sincerely
Axel
I'm making a system that will detect all different kinds of fault on different machinery like bearing, misalignment etc. I understand the concept on wavelet transforms and its advantages over the regular FFT for these kind of signals but I can't see how to compare and analyse the values of the wavelet transform to in fact detect any faults (automatically, of course). If anyone have any knowledge or know where I can find some information in this area it would be deeply appreciated!
Sincerely
Axel





RE: Vibration analysis using wavelet transform
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(2B)+(2B)' ?
RE: Vibration analysis using wavelet transform
Thanks for the hint, but I've done some serious research for quite some time now without any real success so far. The thing is, that there's a lot of papers of this topic showing that wavelet is able to detect faults and showing different kinds of wavelet plots for different faults. And while I obviously can see that there's a difference, I cannot find any good reliable relationship between faults and the plot (like in the fft analysis, where bearing faults shows at x times the rotational frequency).
RE: Vibration analysis using wavelet transform
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Vibration analysis using wavelet transform
Tricky it is for sure, and it doesn't get easier since you need different wavelets for different applications. But maybe identifying the fault isn't the right approach here, maybe it's better to find just that something is wrong and then use something like fft to find what's actually wrong (or use manual inspection).
But Greg, is there anything special you're looking for in your wavelet plot or is it just that something has changed? And what wavelets algorithms are you using the most?
RE: Vibration analysis using wavelet transform
It's important to have a smart approach when using wavelets.
The choice of the kind of wavelet to use is very very important.
To do this, you have to look at your time-history signal and see precisely the shape of the curve where appears the default.
Then, the idea is to select the wavelet that matches the best the shape of the default.
Then the wavelet spectrogram gonna amplify the default, even though it can scarcely be seen on the time history signal.
RE: Vibration analysis using wavelet transform
Or are wavelet uneccesarry complicated? The problem I have are large and fast variations on the RPM as well as load of the machines so I assume Wavelet and STFT is a good approach to this. But maybe there are better methods?
RE: Vibration analysis using wavelet transform
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Vibration analysis using wavelet transform