Dynamic Delayed Controllers for Unstable Recycling Systems with Time Delays

In this work the problem of stabilization and control for recycling system is considered. Such class of systems is characterized by possessing two main paths named through this work as the direct (feedforward) and the recycling feedback) paths. This work considers recycling systems composed by a system of order n with one unstable pole at the direct path and a stable system of order m in the recycling path, both with different time delays. Two different dynamic delayed controllers are proposed in order to achieve a stable behavior of the closed-loop system. Stability conditions for the existence of these controllers are stated. The problems of step tracking and reject step disturbances are also addressed.