The design of discrete IMCs is similar to that of the continuous IMC design procedure detailed in Chapter 8. The primary difference is that the factorization is performed on a discrete-time (Z-domain) model.
Factorize into good stuff and bad stuff the discrete model
where contains zeros outside the unit circle and zeros inside the unit circle that negative. The reason for this is that negative zeros inside the unit circle cause oscillatory poles in the controller if not removed. Make certain that the numerator ...