Control system classes

The classes listed below are used to represent models of input/output systems (both linear time-invariant 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.

InputOutputSystem([name, inputs, outputs, ...])

A class for representing input/output systems.

LTI([inputs, outputs, states, name])

LTI is a parent class to linear time-invariant (LTI) system objects.

StateSpace(A, B, C, D[, dt])

A class for representing state-space models.

TransferFunction(num, den[, dt])

A class for representing transfer functions.

FrequencyResponseData(d, w[, smooth])

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

NonlinearIOSystem(updfcn[, outfcn, params])

Nonlinear I/O system.

InterconnectedSystem(syslist[, connections, ...])

Interconnection of a set of input/output systems.

LinearICSystem(io_sys[, ss_sys, connection_type])

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:

_images/classes.pdf

Additional classes

DescribingFunctionNonlinearity

Base class for nonlinear systems with a describing function.

DescribingFunctionResponse

Results of describing function analysis.

flatsys.BasisFamily

Base class for implementing basis functions for flat systems.

flatsys.FlatSystem

Base class for representing a differentially flat system.

flatsys.LinearFlatSystem

Base class for a linear, differentially flat system.

flatsys.PolyFamily

Polynomial basis functions.

flatsys.SystemTrajectory

Class representing a trajectory for a flat system.

optimal.OptimalControlProblem

Description of a finite horizon, optimal control problem.

optimal.OptimalControlResult

Result from solving an optimal control problem.

optimal.OptimalEstimationProblem

Description of a finite horizon, optimal estimation problem.

optimal.OptimalEstimationResult

Result from solving an optimal estimationproblem.

The use of these classes is described in more detail in the Differentially flat systems module and the Optimization-based control module