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System Identification fitness criterion (NRMSE vs NMSE)
A good model should have goodness of fit measure less than 1, indicating that the error (measured_data - model_reponse) is small...

5 years 前 | 1

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is it possible to convert iddata to cellstr
From iddata object "data", you can fetch the data arrays as cells using: y = pvget(data,'OutputData'); In your latest query, ...

5 years 前 | 0

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How to use a model generated from System Identification Toolbox in my work space?
The result of estimation is an object of IDTF class. It has properties containing numerical values of numerator and denominator....

5 years 前 | 0

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Import the dependence of experimental data on time in the System Identification Toolbox
It is possible to do so by specifying a time vector instead of a constant sample time, as in: data = iddata(y, u, 'SamplingInst...

5 years 前 | 0

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How can set initial conditions of a state space model obtained by data?
Is the temperature an output of the model? If so, what is the corresponding input? Supposing the input and outputs are known (...

5 years 前 | 1

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Nonlinear Greybox Object (idnlgrey) for Simulink realtime
idnlgrey block does not support code generation. But there are workarounds depending upon why you need to generate code. If you ...

5 years 前 | 0

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How to useParallel in system identification?
Currently there is no way to parallelize model estimation in System Identification Toolbox.

5 years 前 | 0

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Custom Regressor in Nonlinear Model created from Data
Could you describe the underlying physics here? Is the input some type of switch that turns a heat source on or off? Note that e...

5 years 前 | 0

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Following example using 'tfestimate' - Model has larger frequency range than data
The identififed model will have its behavior defined for all frequencies (0 to Inf). The identification algorithm is concerned w...

5 years 前 | 0

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How can I add contraints to a model ( non linear arx, arx, armax ...) ?
If the constraints can be expressed as lower or upper bounds on the model's parameters, the estimations routines will handle the...

5 years 前 | 0

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Linear Grey-Box system identification: idgrey()
The 'cd' option is to support the use case where you want to specify your own discretization formula (not use the standard c2d f...

5 years 前 | 0

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Autocorrelation of residuals Analysis
If the residue curve (solid green) is within the region defined by the dotted green lines, that indicates that any information ...

5 years 前 | 0

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Converting high order transfer functions model to discrete
If the identified model has complex poles, you can't wish them away by converting to zpk. Note that complex poles come in conjug...

5 years 前 | 0

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this is with regards to this article https://in.mathworks.com/help/ident/examples/estimating-transfer-function-models-for-a-boost-converter.html ....I have gone through the procedure and it has worked upto the frestimate only, error thereafter.
The data file "iddemo_boostconverter_data.mat" ships with System Identification Toolbox; stored under toolbox/ident/iddemos fold...

5 years 前 | 0

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How to convert a input and output arrays of complex numbers to iddata, idfrd or any other models in System Identification Toolbox?
If you have input-output signals, the data can be packed into an iddata object, using the syntax iddata(y,u,Ts), where y is the ...

5 years 前 | 0

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How to update MIMO Transfer Function from "tfest" with new data
Well, MIMO transfer function can't be split into a collection of SISO models for identification using input/output signals. You ...

5 years 前 | 0

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Optimization based on inputs and outputs (for online optimization)
Please look at Simulink Design Optimization product. You can run simulation based optimization of chosen parameters and states w...

5 years 前 | 0

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The system identification models I've exported to my work space do not match the results from the toolbox. Why is this happening?
What initial conditions are you using for simulation? Note that by default, the App estimates the initial conditions to maximize...

6 years 前 | 0

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Transfer function from ARX-model
Does the example on http://www.mathworks.com/help/ident/ref/idnlarxlinearize.html help?

9 years 前 | 0

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Suggestion for System id toolbox
How about: NoiseModel = noise2meas(IdentifiedModel); Then use NoiseModel as a regular LTI model in Simulink and run it wi...

11 years 前 | 0

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How do I model a time series in MATLAB using ARMA?
You should evaluate the quality of prediction results and perform some correlation analysis of the model residuals to verify how...

11 years 前 | 0

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Bump ---> Identification using invfreqs
Have you tried using the weight input argument? You can specify higher weights for the frequencies around which you are interest...

11 years 前 | 0

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how to create a state-space model without disturbance and how does the disturbance influence the solution
The difference between the output of the model and the actual (measured) output is, in general, not going to be zero. So, there ...

11 years 前 | 1

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How to use the under knees code of state space model "ident" toolbox in mfile
Double click on estimated model icon. A window containing information on the model is shown. This window offers commands that wi...

11 years 前 | 0

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Use N4sid for system identification (for new data estimation)
Computing response of a model to a given input is called simulation. Use the idParametric/sim command for that as in: Ud = i...

11 years 前 | 0

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How to define a polynomial orders ARX model [na nb nk], for a MISO system
Look up the documentation of delayest on how to put some limits on the values to be tested. Delay can also be determined by a st...

11 years 前 | 0

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improve the performance of system identification MISO
There are different types of choices to consider to get the most out of an identification: * Model orders: controlled by orde...

11 years 前 | 0

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initial state in n4sid
Note that N4SID always estimates initial states when using time domain data; the InitialState option does not really help here. ...

11 years 前 | 0

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Problem with ident GUI while predicting time-series
When predicting, the results depend upon the initial conditions. The GUI estimates the initial conditions to maximize the fit to...

11 years 前 | 0

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Prediction confidence intervals using a state-space model
For discrete-time systems, the forecasting model is same as the simulation (original) model. So you can use commands such as SIM...

11 years 前 | 1

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