Creating and Manipulating Models    

Padé Approximation of Time Delays

The function pade computes rational approximations of time delays in continuous-time LTI models. The syntax is

where sys is a continuous-time model with delays, and the integer n specifies the Padé approximation order. The resulting LTI model sysx is of the same type as sys, but is delay free.

For models with multiple delays or a mix of input, output, and I/O delays, you can use the syntax

where the vectors ni and no, and the matrix nio specify independent approximation orders for each input, output, and I/O delay, respectively. Set ni=[] if there are no input delays, and similarly for no and nio.

For example, consider the Distillation Column Example. The two-input, two-output transfer function in this example is

To compute a Padé approximation of H(s) using:

type

where H is the TF representation of defined in the distillation column example. This command produces a rational transfer function.


  Retrieving Information About Delays Simulink Block for LTI Systems