Optinoal Arguments for idnlgrey

Hi guys,

I'm using the grey-box estimation methods of the System Identification Toolbox to estimate the parameters of lateral motion of an aircraft. My model has several parameters to estimate and also a few parameters that are known but cannot be hard-coded in the model function. So the header of my model function looks like this:

function [ dx, y ] = AC_lat_model_nl(t, x, u, param1, param2, optional_args)

Before I can start the estimation process I have to use idnlgrey to get the grey-box object. So far my function call looks like this:

AC_lat_nlgrey    = idnlgrey('AC_lat_model_nl', Order, parameters, InitialStates, 0);

The question is how do I hand over those 'optional_args'? For the linear version idgrey I can hand them over after the sample time but this doesn't seem to work for the nonlinear version idnlgrey.

Thanks for your help!

Kevin

[Shaoyi Zhou]

Hello, have you solved your problem? For me I don't know exactly what does 'optional_args' mean, even in linear case. Dose it mean the initial values of state vector?

Answer 1

[Walter Roberson]

Let optional_args be a cell array, and use

AC_lat_nlgrey    = idnlgrey('AC_lat_model_nl', Order, parameters, InitialStates, 0, optional_args{:});

Answer 2

[Josiah Wai]

In case anyone else has this issue, I had to use the 'FileArgument' property of idnlgrey. Let optional_args be a cell array

sys = idnlgrey(FileName,Order,Parameters,InitialStates,Ts, 'FileArgument', optional_args)