Control system classes
The classes listed below are used to represent models of input/output
systems (both linear timeinvariant and nonlinear). They are usually
created from factory functions such as tf()
and ss()
, so the
user should normally not need to instantiate these directly.

A class for representing input/output systems. 

LTI is a parent class to linear timeinvariant (LTI) system objects. 

A class for representing statespace models. 

A class for representing transfer functions. 

A class for models defined by frequency response data (FRD). 

Nonlinear I/O system. 

Interconnection of a set of input/output systems. 

Interconnection of a set of linear input/output systems. 
The following figure illustrates the relationship between the classes and some of the functions that can be used to convert objects from one class to another:
Additional classes
Base class for nonlinear systems with a describing function. 

Results of describing function analysis. 

Base class for implementing basis functions for flat systems. 

Base class for representing a differentially flat system. 

Base class for a linear, differentially flat system. 

Polynomial basis functions. 

Class representing a trajectory for a flat system. 

Description of a finite horizon, optimal control problem. 

Result from solving an optimal control problem. 

Description of a finite horizon, optimal estimation problem. 

Result from solving an optimal estimationproblem. 
The use of these classes is described in more detail in the Differentially flat systems module and the Optimizationbased control module