Specifications

c2d
16-27
16c2d
Purpose Discretize continuous-time systems
Syntax sysd = c2d(sys,Ts)
sysd = c2d(sys,Ts,method)
[sysd,G] = c2d(sys,Ts,method)
Description sysd = c2d(sys,Ts) discretizes the continuous-time LTI model sys using
zero-order hold on the inputs and a sample time of
Ts seconds.
sysd = c2d(sys,Ts,method) gives access to alternative discretization
schemes. The string
method selects the discretization method among the
following:
Refer to “Continuous/Discrete Conversions of LTI Models” in Chapter 3 for
more detail on these discretization methods.
c2d supports MIMO systems (except for the'matched' method) as wellas LTI
models with delays with some restrictions for
'matched' and 'tustin'
methods.
[sysd,G] = c2d(sys,Ts,method) returnsamatrixGthatmapsthecontinuous
initial conditions and to their discrete counterparts and
according to
'zoh'
Zero-order hold. The control inputs are assumed piecewise
constant over the sampling period
Ts.
'foh'
Triangle approximation (modified first-order hold, see [1], p.
151). The control inputs are assumed piecewise linear over
the sampling period
Ts.
'tustin'
Bilinear (Tustin) approximation.
'prewarp'
Tustin approximation with frequency prewarping.
'matched'
Matched pole-zero method. See [1], p. 147.
x
0
u
0
x 0
[]
u 0
[]
u 0[] u
0
=
x 0[] G
x
0
u
0
⋅=