MATLAB: Contious time model – linear analysis toolbox

Question

I've been using the linear analysis toolbox quite a bit lately for generating linear models within simulink. >> Tools / control design / linear analysis..

For some reason the models generated are generally discrete. I appreciate that their are a few functions for shifting between discrete and continuous time however is their a way of defining the output when generating the linear model? There doesn't appear to be any obvious options within the GUI. Generally I get a discrete model but now and again the toolbox spits out the desired continuous time model..

Cheers,

Jamie

Answer 1

Linear Analysis Tool is part of Simulink Control Design.

Here is an excerpt from the doc:

By default, the software chooses the slowest sample time of the multirate model. If the default sampling time is not appropriate, specify a different linearization sample time and repeat.

So the sampling time of the resulting linear model depends on the model you are linearizing. If that model has discrete-time components, than the tool (with default options) will return a discrete-time model.

If you want a continuous-time model, specify "Sample Time" value in "Options" to be 0, as described in the section of the doc linked to above.

Regarding your comment that generated code does not tend to run: could you provide an example of that?

Thanks.

Arkadiy