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Uncertain Models

Uncertain state-space and frequency response models

Uncertain state-space (uss) models are linear systems with uncertain state-space matrices, uncertain linear dynamics, or both. Most functions that work on numeric LTI models also work on uss models. These include model interconnection functions such as connect and feedback, and linear analysis functions such as bode and stepinfo. Some functions that generate plots, such as bode and step, plot random samples of the uncertain model to give you a sense of the distribution of uncertain dynamics.

In addition, you can use functions such as robstab and wcgain to perform robustness and worst-case analysis of uncertain systems represented by uss models. You can also use tuning functions such as systune for robust controller tuning.


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ussUncertain state-space model
urealUncertain real parameter
ucomplexCreate uncertain complex parameter
ucomplexmCreate uncertain complex matrix
ultidynUncertain linear time-invariant dynamics
umarginModel gain and phase uncertainty (Since R2020a)
umatCreate uncertain matrix
ufrdUncertain frequency response data model
ucoverFit uncertain model to set of LTI responses
randatomGenerate random uncertain atom objects
randumatGenerate random uncertain umat objects
randussGenerate stable, random uss objects
diagDiagonal uncertain matrices; diagonals of an uncertain matrix
getNominalNominal value of uncertain model
uscaleScale uncertainty of block or system (Since R2020a)
plot (umargin)Visualize gain and phase uncertainty of a umargin block (Since R2020a)
actual2normalizedTransform actual values to normalized values
normalized2actualConvert value for atom in normalized coordinates to corresponding actual value
getLimitsValidity range for uncertain real (ureal) parameters
simplifySimplify representation of uncertain object
isuncertainCheck whether argument is uncertain class type
lftdataDecompose uncertain objects into fixed certain and normalized uncertain parts
ltiarray2ussCompute uncertain system bounding given LTI ss array


Uncertain Models

Model Object Basics