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acceleration integration

acceleration integration

acceleration integration

(OP)
Hello,
I am currently working on a project where I need to find a digital integration for acceleration data.  I believe I have found a sufficient integration filter that I have tested in matlab but after the first integration there is a dc offset that makes the second integration to get displacement data impossible.  It would be ideal to find another type of filter to remove the dc offset for my project.  I have tried basic high pass filters with no luck.  Is it possible to do such a thing?  and if so could someone advise me on a sufficient high pass filter?

RE: acceleration integration

You can remove the DC offset from the signal with just about any correctly calculated HP filter, so I don't know what you are doing wrong.

Anyway, another method is to subtract the straight line joining the dfirst and last points in the integrated data - this is nice from apractical point of view, but is analyitically treacherous.

Or you can remove the average level from the original data.

This is less dangerous.

Cheers

Greg Locock

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RE: acceleration integration

Don't forget to perform high-pass filtering (dc offset removal) both before and after integration.

There are many ways to do high pass filtering.  A small twist on Greg's method is to subtract a rolling average.

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RE: acceleration integration

Subtracting a moving average is a very nice way to do it, and is mathematically equivalent to a high pass filter, tho I can't remember which shape it is.

Of course, 5 minutes in MathCad would tell me.

 

Cheers

Greg Locock

Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.

RE: acceleration integration

Below is one author's recomendation for a high pass filter to remove DC bias.  I don't know if there is anything unique about this.

OUT(n) = IN(n)-IN(n-1)+ [alpha x OUT(n-1)]

Where alpha is the decay constant between 0 and 1

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