Problem with convert acceleration to velocity and displacement

Hi everyone,

I used DAQ to get acceleration, however, when I convert accleration to velocity and displacement (using 'cumtrapz' function) is not OK like the picture below:

Problem is that the velocity and displacement is increase with time. What i need to do make the velocity and displacement stable around 0.

Answer 1

[Jos (10584)]

Apparently there is an offset in your acceleration data. You can subtract a running mean

A(k) = ValueFromDaq - mean(A(1:k-1))

[vu ngothanh]

Dear Mr Job,

Your method not work properly. It still have a little offset. Do you have any other way to solve it.

Thank you.

[Star Strider]

Try subtracting the median instead of the mean.

[vu ngothanh]

Dear Mr Star Strider,

Thank you for your help. your way much better.

Thank you very much.

[Star Strider]

As always, my pleasure.

The median is the value at which 50% of the values are above and 50% are below. The mean is significantly affected by extremes of the values, since it is the least-squared-error estimate of the centroid of a particular distribution. The median is not affected by the extremes.

[Jos (10584)]

Good suggestion, Star Strider, to use the median.

[vu ngothanh]

Dear Mr Jos and Star Strider,

at last, I found "detrend" function. I think that is the best solution for this situation.

Thank you for you all for helping me.

Answer 2

[Bora Eryilmaz]

The new convertVibration function in MATLAB R2024a release of the Predictive Maintenance Toolbox lets you compute baseline-corrected and filtered acceleration, velocity, and displacement signals from vibration measurements using a single sensor output from either an accelerometer, velocity sensor, or displacement sensor.