Filtering Jerk from data
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I am having force data from an experimental setup. The experimental data is having jerk force being added due to inefficient mechanical design of the setup. Is there any way to remove the 'jerk' force from the data.
below is the figure of computational and experimental forces comparison.
you can find the jerk being found 0.1, 0.5. 1.1 and 1.5 cycle no.
I have plotted the computational data just as reference for showing where jerk occurs. I would not be able to use the computational data for filtering/reconstructing the data obtained from experiment.
A frequency dependent filter cannot be applied because the jerk happens almost at the fundamental frequency of experiment.
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Answers (2)
Image Analyst
on 23 Sep 2018
What you could do is to find the difference between the signals and replace the experimental signal with the computation signal wherever the difference is too great:
diffSignal = abs(experimental - computational);
mask = diffSignal > 10; % Or whatever you want.
experimental(mask) = computational(mask); % Replace bad values with computational signal.
Star Strider
on 23 Sep 2018
I would first do a Fourier transform (using the fft (link) function) to determine visually the frequency content of your signal, then use the lowpass (link) or related bandpass (linked to at the end of that page) functions to filter your data. (These were introduced in R2018a. You can design similar filters yourself with the ellipord and ellip functions.)
You will likely have to experiment to get the result you want. Your signal appears to be relatively ‘clean’ otherwise, and you can probably get good frequency separation with the elliptic filter.
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Star Strider
on 23 Sep 2018
Have you done the fft and then designed and used the filter?
It looks to me that the jerk consists of a higher-frequency signal added to the underlying low-frequency force signal. The filter should easily be able to separate them, producing a relatively ‘clean’ force signal.
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