how to use RMS alogrithm in MATLAB for acceraltion analysis

i have recently done a two wheeler testing on different test tracks and by using accerlerometers
i have tapped the acceration data
i need to analysis to justify my suspension design
can some on help with the analysis of this data (acceralations)
by rms method in matlab

RMS, as in root-mean-square? That should simply return the average amplitude of a time-varying signal. You should be able to call rms(data) in Matlab, assuming that "data" is a 1D array taken at a constant sample rate. It will spit out a single number.

If you find the RMS value of a set of values that are all positive values, it will return the same as mean() or average(). RMS can be thought of like the average function, but it looks at the signal's magnitude, regardless of if it's positive or negative.

To calculate RMS manually, take the square root of the mean (average) of the square of each value. So, if you have x1, x2, x3, x4...
Square each term: x1^2, x2^2, x3^2, x4^2... xn^2
Take the average: (x1^2 + x2^2 + x3^2 + x4^2 +... +xn^2) / n
Take the square root: sqrt( (x1^2 + x2^2 + x3^2 + x4^2 +... +xn^2) / n ) = RMS value

If RMS stands for something else in this case, then I can't help you :wink:

dear enjunear

i was parellely doing some findings towards my question and the points indicated above
are clear to me thnkxx alot for ur response
one more addition i would like to do to my question as RMS seems to be simple analysis in time domain
could you help me with the analysis of the same question in frequency domain ..so that i could extend this to power spectral density concept
as i am lost in matlab codes and alogrithm regarding

please help me out with the frequency analysis !!!!


regards
ashu

I'd start out with a simple FFT, so you can look at your frequency content. If you have a "before" and "after" test-set, you can show that some of the high-amplitude frequencies have been reduced... or whatever story you're trying to tell w/ your data.

www.ele.uri.edu/~hansenj/projects/ele436/fft.pdf

This file has a nice write-up with basic FFT examples. The most relevant is right at the end, but I'd work through the whole thing (6 pages, including plots) to help you understand what the FFT and FFTshift functions are doing.

dear enjunear
i tried to run the rms alogrithm as indicated and from math works
but it dint wrk out for me tht well
could u share ur email so tht i can give u a sampel of dat so tht u can try the rms on the data

please