Chapter 2 Linear System Representation
Xmath Control Design Module 2-12 ni.com
outputNames = "Velocity",
stateNames = ["Torque","Angle"]});
[,,stateNames] = names(sys5)?
statenames (a row vector of strings)=Torque Angle
Size and Indexing of Dynamic Systems
The size of a system object is defined by how many outputs, inputs, and
(in the case of a state-space system) states it has. You can use the size( )
function to find these dimensions.
You can index into a dynamic system to create a new dynamic system
which has a subset of the original inputs and outputs:
Sys = Sys1(i,j) is defined to be a system such that y=y1(i) and u=u1(j).
iand j can both be vectors as well, in which case multiple inputs and
outputs will be extracted.
The previous definition of indexing was designed with the traditional
definition of a transfer function in mind.
Using check( ) with System Objects
Several common attributes of systems can be easily determined using
Xmath’s ability to distinguish between object types and characteristics.
You can use the check( ) function with systems, as shown in
Example 2-8, to determine whether a system is in transfer function or
state-space form, discrete, continuous, or stable. In addition, you can use
check( ) with the convert keyword to change a system’s representation
between SISO state-space and transfer-function forms.
Example 2-8 Using check( ) with a System
a = [1.875,0;0,-0.26];
b = [1;0];
c = [0.5,1];
d = 0;
sys = system(a,b,c,d, {dt = 0.001});
Because this system is discrete and has a pole where magnitude exceeds 1,
it is not stable.
yq() Sys q() uq()×=