MATLAB: System Identification model validation failure!

system identificationSystem Identification Toolbox

Hello, I am using the system identification tool in Matlab R2012a. I have a data set imported in the GUI, used the State space estimation method. I got a 95% best fit on the model output window. The estimated model is now imported to the workspace to get the state variables. The problem is when I use these stat variables in simulink to observe its response to a step input, i get constant 0. What could the problem be? If the estimation gives us 95% match, why would the model always give zero?

Best Answer

What initial conditions did you use in Simulink block? The GUI estimates the initial states to maximize the fit to data. If you want, you can use the same initial states in the Simulink block by using the FINDSTATES command to compute the fit-maximizing values.

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