Repetitive control for Lur'e-type systems: application to mechanical ventilation

Overview & Synopsis

Repetitive control (RC) has shown to achieve superior rejection of periodic disturbances. Many nonlinear systems are subject to repeating disturbances. The aim of this paper is to develop a continuous-time RC design with stability guarantees for nonlinear Lur'e-type systems. Approximate output tracking is achieved by combining an internal model, consisting of a finite number of linear oscillators with frequencies at the reference frequency and at its multiples, with a stabilizer that guarantees a convergence property of the closed-loop system. The developed RC approach is applied to a nonlinear mechanical ventilation system for Intensive Care Units (ICUs), which can be modeled as a Lur'e-type system. The experimental study confirms that the repetitive control scheme is able to successfully follow the desired target pressure profile to properly support the ventilation needs of an adult patient.