How to measure the steady state amplitude of a control system output

26 vues (au cours des 30 derniers jours)
Dear Matlab Answers,
Hello. I have included below an image concerning my problem
Here I have a sinusoidal weaveform that has an initial transient then settles to a steady state amplitude. It looks odd ebcause the plot is so dense, but the data is all sinsoidal with a transient offset. The data is represented as an array of time points and an array of ampltiude points. (tout and Y). How can I write an algorithm to detect when the transient is complete and return the final steady state amplitude? Technically, this is not only a MATLAB question, but a solution written in MATLAB code is preffered.
  5 commentaires
Pat Gipper
Pat Gipper le 8 Mar 2021
The frequency of the injected signal is under control of the app. If that is not the case then you would need to use some form of a spectrum analyzer.
Michael Sohnen
Michael Sohnen le 9 Mar 2021
@Paul Dear Paul, thank you for your comment. Thank you to other commenters as well. I need to be able to analyuze the data WITHOUT ACCESS TO THE INPUT SIGNAL, and WITHOUT ACCESS TO THE SIMULINK MODEL. I need to find a statistical approach. I am basically looking for an algorithm that can seperate the transient from the steady state component in ANY signal, knowing that the steady state is some sinusoid of a singe frequency.
I basically want to high pass filter my signal, then measure the amplitude using (max(data)-min(data))/2. How can I do a high pass filter on a signal in MATLAB given only data?

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Réponse acceptée

Michael Sohnen
Michael Sohnen le 9 Mar 2021
I figured it out. If you have some idea of what frequencies will be present in the signal, just use the highpass command. In my problem, I know the exact sampling rate, so it works. I highpass the data with a lower cutoff of 1 hertz and then measure the amplitude using max and min.
Thanks all.
Best,
Mike
  4 commentaires
Paul
Paul le 9 Mar 2021
If your system is "far from LTI" then there is no guarantee, in general, that the steady state output is a single sinusoid. So you have to have some idea about what's going on inside the system and what the output should be.
Good luck. Go Panthers!
Michael Sohnen
Michael Sohnen le 9 Mar 2021
Good luck to you too!

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Plus de réponses (1)

Pat Gipper
Pat Gipper le 8 Mar 2021
Try using this app. It injects a sine wave and measures the gain and phase after a number of cycles that you specify.
https://www.mathworks.com/matlabcentral/fileexchange/85448-frequency-response-analyzer
  1 commentaire
Michael Sohnen
Michael Sohnen le 8 Mar 2021
I was looking for something that worked exclusively on the output data, in the time domain.

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