Function Reference 

Functions  By Category
LTI Models
Function Name

Description

drss

Generate random discrete statespace model

dss

Create descriptor statespace model

filt

Create discrete filter with DSP convention

frd

Create a frequency response data (FRD) model

frdata

Retrieve data from an FRD model

get

Query LTI model properties

rss

Generate random continuous statespace model

set

Set LTI model properties

ss

Create statespace model

ssdata , dssdata

Retrieve statespace data

tf

Create transfer function

tfdata

Retrieve transfer function data

totaldelay

Provide the aggregate delay for an LTI model

zpk

Create zeropolegain model

zpkdata

Retrieve zeropolegain data

Model Characteristics
Function Name

Description

class

Display model type ('tf' , 'zpk' , 'ss', or 'frd' )

hasdelay

Test true if LTI model has any type of delay

isa

Test true if LTI model is of specified type

isct

Test true for continuoustime models

isdt

Test true for discretetime models

isempty

Test true for empty LTI models

isproper

Test true for proper LTI models

issiso

Test true for SISO models

ndims

Display the number of model/array dimensions

size

Display output/input/array dimensions

Model Conversions
Function Name

Description

c2d

Convert from continuous to discretetime models

chgunits

Convert the units property for FRD models

d2c

Convert from discrete to continuoustime models

d2d

Resample discretetime models

delay2z

Convert delays in discretetime models or FRD models

frd

Convert to a frequency response data model

pade

Compute the Padé approximation of delays

reshape

Change the shape of an LTI array

residue

Provide partial fraction expansion

ss

Convert to a state space model

tf

Convert to a transfer function model

zpk

Convert to a zeropolegain model

Model Order Reduction
Function Name

Description

balreal

Calculate an I/O balanced realization

minreal

Calculate minimal realization or eliminate pole/zero pairs

modred

Delete states in I/O balanced realization

sminreal

Calculate structured model reduction

StateSpace Realizations
Function Name

Description

canon

Canonical statespace realizations

ctrb

Controllability matrix

ctrbf

Controllability staircase form

gram

Controllability and observability grammians

obsv

Observability matrix

obsvf

Observability staircase form

ss2ss

State coordinate transformation

ssbal

Diagonal balancing of statespace realizations

Model Dynamics
Function Name

Description

bandwidth

Calculate the bandwidth of SISO models

damp

Calculate natural frequency and damping

dcgain

Calculate lowfrequency (DC) gain

covar

Calculate covariance of response to white noise

dsort

Sort discretetime poles by magnitude

esort

Sort continuoustime poles by real part

iopzmap

Plot the pole/zero map for I/O pairs of an LTI model

norm

Calculate norms of LTI models ( and )

pole , eig

Calculate the poles of an LTI model

pzmap

Plot the pole/zero map of an LTI model

rlocus

Calculate and plot root locus

roots

Calculate roots of polynomial

sgrid ,zgrid

Superimpose s and zplane grids for root locus or pole/zero maps

zero

Calculate zeros of an LTI model

Model Interconnections
Function Name

Description

append

Append models in a block diagonal configuration

augstate

Augment output by appending states

connect

Connect the subsystems of a blockdiagonal model according to an interconnection scheme of your choice

feedback

Calculate the feedback connection of models

lft

Form the LFT interconnection (star product)

ord2

Generate secondorder model

parallel

Create a generalized parallel connection

series

Create a generalized series connection

stack

Stack LTI models into a model array

Time Responses
Function Name

Description

gensig

Generate an input signal

impulse

Calculate and plot impulse response

initial

Calculate and plot initial condition response

lsim

Simulate response of LTI model to arbitrary inputs

ltiview

Open the LTI Viewer for linear response analysis

step

Calculate step response

Time Delays
Function Name

Description

delay2z

Convert delays in discretetime models or FRD models

pade

Compute the Padé approximation of delays

totaldelay

Provide the aggregate delay for an LTI model

Frequency Response
Function Name

Description

allmargin

Calculate all crossover frequencies and associated gain, phase, and delay margins

bode

Calculate and plot Bode response

bodemag

Calculate and plot Bode magnitude only

evalfr

Evaluate response at single complex frequency

freqresp

Evaluate frequency response for selected frequencies

interp

Interpolate FRD model between frequency points

linspace

Create a vector of evenly spaced frequencies

logspace

Create a vector of logarithmically spaced frequencies

ltiview

Open the LTI Viewer for linear response analysis

margin

Calculate gain and phase margins

ngrid

Superimpose grid lines on a Nichols plot

nichols

Calculate Nichols plot

nyquist

Calculate Nyquist plot

sigma

Calculate singular value plot

Pole Placement
Function Name

Description

acker

Calculate SISO pole placement design

place

Calculate MIMO pole placement design

estim

Form state estimator given estimator gain

reg

Form outputfeedback compensator given statefeedback and estimator gains

LQG Design
Function Name

Description

lqr

Calculate the LQoptimal gain for continuous models

dlqr

Calculate the LQoptimal gain for discrete models

lqry

Calculate the LQoptimal gain with output weighting

lqrd

Calculate the discrete LQ gain for continuous models

kalman

Calculate the Kalman estimator

kalmd

Calculate the discrete Kalman estimator for continuous models

lqgreg

Form LQG regulator given LQ gain and Kalman filter

Equation Solvers
Function Name

Description

care

Solve continuoustime algebraic Riccati equations

dare

Solve discretetime algebraic Riccati equations

lyap

Solve continuoustime Lyapunov equations

dlyap

Solve discretetime Lyapunov equations

Graphical User Interfaces for
Control System Analysis and Design
Function Name

Description

ltiview

Open the LTI Viewer for linear response analysis

sisotool

Open the SISO Design GUI

 Functions  Alphabetical List  