A practical solution for the control of time-delayed and delay-free systems with saturating actuators

This paper presents a predictor based structure that is suitable to deal with both time-delayed and delay-free systems with saturating actuators. Such condition, well known in the literature to cause the windup phenomenon, is usually coped within the control area by techniques that commonly lead to the controller augmentation. However, it seems to exist a lack of simple approaches to deal with the design of linear controllers for both systems with and without delay. Thus, this paper addresses the saturation problem by both proposing a linear controller design and an associated anti-windup compensator design. The controller tuning is realized in three distinct phases, initially considering set-point tracking adjustment, then robustness and disturbance rejection tuning, and finally the associated anti-windup compensator synthesis. Furthermore, linear matrix inequalities (LMIs) which include both performance and stability requirements are employed for the anti-windup synthesis. The proposed controller presents better results when compared with recently published anti-windup controllers as well as a constrained MPC algorithm. Experimental results on a neonatal intensive care unit are also presented in order to validate the usefulness of the proposed strategy.