System Identification Toolbox with Multiple Input Variables and one Output Variable

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Benjamin Pommer 2022-10-6

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评论： Benjamin Pommer 2022-11-1

采纳的回答： Star Strider

Hi Matlab community

Is there a way to conduct a system identification with multiple input parameters and one output parameter?

Thanks in advance

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Star Strider 2022-10-6

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If by ‘parameter’ you mean inputs and outputs respectively, yes.

See the iddata section on Input Arguments, then define the system appropriately using ssest or any other estimation procedure you want to use.

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Star Strider 2022-10-6

I would have to have the data and your code to respond appropriately.

It may be that since the system is optimising for more than one input with one output, that the input you are using with compare may not have the best overall system estimate. (I usually model SISO systems, so I would have to have more information about a MISO system.)

The order of the system could be another reason, so experiment with that. One way to determine it is to take the Fourier transforms of the input and output (fft), and construct the transfer function by dividing the Fourier transform of the output by the fourier transform of the inputs. Plot the one-sided imaginary part as a function of frequency. The number of peaks (singularities) will be the number of poles, characteristically defining the system order. It may require tweaking by ±1 or so to get the best fit, since there could be a pole at infinity that will not show up on the imaginary part of the transfer fucntion plot. It will also tell you something about the system single response to the two inputs.