Hi,
The following is programmed in MATLAB:
I have a system or structure which are exited by a shaker, i obtain the response in the form of time domain accelerations using Newmark-time integration.
My problem is that i now want to change the the reponse(accelerations) from time to laplace domain in MATLAB. But i cant get it to work properly.
I hope someone can help, mi with this problem,
Michael
follow this link use of laplace(f)
http://in.mathworks.com/help/symbolic/laplace.html
If you have a known input and a measured output then you are doing system identification. Anyway, I bet you are using sampled signals, so you should be using the z-transform, not the Laplace transform. See the answers to this recent question for some guidance ...
https://www.researchgate.net/post/Finding_z-transform_coefficients_from_real_data_series
But if you are just dealing with the output signal, then the Discrete Fourier Transform (DFT) may be more appropriate.
However, for some systems/signals there may be no need to transform the data and staying in the time domain may be better.
Hi thanks for all the answers, i think Hugh might have the answer to the problem.
I am now tying to use the method to transform my accelerations into the Laplace domain.
I think you want to get transfer function of your system just like system identification problem. But the Lapalace transform has both real and imaginary part. So you put real part zero and get the frequency response only. In Matlab you can do this by DFT function. Find the DFT of excitation and its response.
Hope this will solve your problem.
I think you want to know the command to use for conversion through Matlab.
syms t;
laplace(t^5) returns 120/s^6
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