User`s guide

modred
11-144
The reduced-order model hdel is clearly a better frequency-domain
approximation of . Now compare the step responses.
step(h,'-',hmdc,'-.',hdel,'--')
While hdel accura tely reflects the transient behavior, only hmdc gives the true
steady-state response.
Algorithm The algorithm for the matched DC gain method is as follows. For
continuous-time models
the state vector is partitioned into , to b e kept, and , to be eliminated.
hs
()
Time (sec.)
Amplitude
Step Response
0 0.5 1 1.5 2 2.5 3
−0.05
0
0.05
0.1
0.15
0.2
0.25
0.3
x
·
Ax Bu+=
yCxDu+=
x
1
x
2