Specifications

2 LTI Models
2-14
K = [–1 3;2 0];
H = zpk(Z,P,K)
creates the two-input/two-output zero-pole-gain model
Notice that you use
[] as a place-holder in Z (or P) when the corresponding
entry of has no zeros (or poles).
State-Space Models
State-space models rely on linear differential or difference equations to
describe the system dynamics. Continuous-time models are of the form
where x is the state vector and u and y are the input and output vectors. Such
models may arise from the equations of physics, from state-space
identification, or by state-space realization of the system transfer function.
Use the command
ss to create state-space models
sys = ss(A,B,C,D)
For a model with Nx states, Ny outputs, and Nu inputs
•
A is an Nx-by-Nx real-valued matrix.
•
B is an Nx-by-Nu real-valued matrix.
•
C is an Ny-by-Nx real-valued matrix.
•
D is an Ny-by-Nu real-valued matrix.
This produces an SS object
sys that stores the state-space matrices
. For models with a zero D matrix, you can use
D = 0 (zero) as a
shorthand for a zero matrix of the appropriate dimensions.
Hs
()
1–
s
------
3 s 5+
()
s 1+
()
2
--------------------
2 s
2
2s– 2+
()
s 1–
()
s 2–
()
s 3–
()
---------------------------------------------------
0
=
Hs
()
xd
td
------
Ax Bu+=
yCxDu+=
ABCand D,,,