Introduction to Uncertain Elements

Uncertain elements (also called uncertain Control Design Blocks (Control System Toolbox)) are the building blocks used to form uncertain matrix objects and uncertain system objects. There are 5 types of uncertain elements:

FunctionDescription

ureal

Uncertain real parameter

ultidyn

Uncertain, linear, time-invariant dynamics

ucomplex

Uncertain complex parameter

ucomplexm

Uncertain complex matrix

udyn

Uncertain dynamic system

All of the elements have properties, which are accessed through get and set methods. This get and set interface mimics the Control System Toolbox™ and MATLAB® Handle Graphics® behavior. For instance, get(a,'PropertyName') is the same as a.PropertyName, and set(b,'PropertyName',Value) is the same as b.PropertyName = value. Functionality also includes tab-completion and case-insensitive, partial name property matching.

For ureal, ucomplex and ucomplexm elements, the syntax is

p1 = ureal(name, NominalValue, Prop1, val1, Prop2, val2,...); 
p2 = ucomplex(name, NominalValue, Prop1, val1, Prop2, val2,...); 
p3 = ucomplexm(name, NominalValue, Prop1, val1, Prop2, val2,...); 

For ultidyn and udyn, the NominalValue is fixed, so the syntax is

p4 = ultidyn(name, ioSize,  Prop1, val1, Prop2, val2,...); 
p5 = udyn(name, ioSize,  Prop1, val1, Prop2, val2,...); 

For ureal, ultidyn, ucomplex and ucomplexm elements, the command usample will generate a random instance (i.e., not uncertain) of the element, within its modeled range. For example,

usample(p1) 

creates a random instance of the uncertain real parameter p1. With an integer argument, whole arrays of instances can be created. For instance

usample(p4,100) 

generates an array of 100 instances of the ultidyn object p4. See Generate Samples of Uncertain Systems to learn more about usample.

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