Accelerating the pace of engineering and science

# dss

Create descriptor state-space models

## Syntax

sys = dss(A,B,C,D,E)
sys = dss(A,B,C,D,E,Ts)
sys = dss(A,B,C,D,E,ltisys)

## Description

sys = dss(A,B,C,D,E) creates the continuous-time descriptor state-space model

$\begin{array}{c}E\frac{dx}{dt}=Ax+Bu\\ y=Cx+Du\end{array}$

The output sys is an SS model storing the model data (see State-Space Models ). Note that ss produces the same type of object. If the matrix D = 0, you can simply set d to the scalar 0 (zero).

sys = dss(A,B,C,D,E,Ts) creates the discrete-time descriptor model

$\begin{array}{c}Ex\left[n+1\right]=Ax\text{\hspace{0.17em}}\left[n\right]+Bu\text{\hspace{0.17em}}\left[n\right]\\ y\text{\hspace{0.17em}}\left[n\right]=Cx\text{\hspace{0.17em}}\left[n\right]+Du\text{\hspace{0.17em}}\left[n\right]\end{array}$

with sample time Ts (in seconds).

sys = dss(A,B,C,D,E,ltisys) creates a descriptor model with properties inherited from the LTI model ltisys (including the sample time).

Any of the previous syntaxes can be followed by property name/property value pairs

```'Property',Value
```

Each pair specifies a particular LTI property of the model, for example, the input names or some notes on the model history. See set and the example below for details.

## Examples

The command

```sys = dss(1,2,3,4,5,'inputdelay',0.1,'inputname','voltage',...
'notes','Just an example');
```

creates the model

$\begin{array}{c}5\stackrel{˙}{x}=x+2u\\ y=3x+4u\end{array}$

with a 0.1 second input delay. The input is labeled 'voltage', and a note is attached to tell you that this is just an example.