How to tell if an object is an Uncertain state-space (USS) model?

I have a function that is overloaded, and takes both standard state space, and uncertain (uss) state space as inputs.

Since c2d() doesn't work for uss, i need to do a different process depending on which type I pass in.

How can I tell programatically if an object is an Uncertain state-space (USS) model, vs a normal state space model?

I tried isempty(), isfield(), etc, but none of these commands are accepted on both uss and normal state space objects.

Answer 1

[Paul]

Hi @John

Looks like isuncertain can be used to query if the input is uncertain.

Also, there is a function isStateSpace that can handle the other part, though it might be undocumented.

p = ureal('p',1);
usys = tf(p,[1 p]);
usys

Uncertain continuous-time state-space model with 1 outputs, 1 inputs, 1 states.
The model uncertainty consists of the following blocks:
  p: Uncertain real, nominal = 1, variability = [-1,1], 1 occurrences

Type "usys.NominalValue" to see the nominal value and "usys.Uncertainty" to interact with the uncertain elements.

isuncertain(usys)

ans = logical
   1

isStateSpace(usys)

ans = logical
   1

[John]

Ah, great. Thanks @Paul, that solves it. I searched the documentation but didn't find this. Still not sure how else to find this type of thing in the future :)