Robustness Based on the Internal Model Principle

Abstract

In this chapter conditions are derived such that asymptotic tracking and output regulation (or disturbance rejection) occurs in multivariable systems. The system in considered robust with respect to plant parameter perturbations as long as they do not affect system stability and the asymptotic behaviour mentioned above is guaranteed. The reference input and the disturbance are assumed to satisfy a certain differential equation. This problem is also known as the robust servomechanism problem. A servo-compensator is incorporated which consists of r unstable compensators with identical dynamics, corresponding to the class of reference/disturbance. The integer r is the dimension of the output signal y(t).