Output Regulation of Invertible Nonlinear Systems via Robust Dynamic Feedback-Linearization

In this article, we address a problem of output regulation for a broad class of invertible multi-input–multi-output (MIMO) nonlinear systems. The system that we consider is assumed to possess a globally defined normal form, in which appropriate invertibility conditions are fulfilled, and to be strongly minimum phase. Asymptotic output regulation is achieved by means of a controller consisting of a preprocessing internal model and of a robust stabilizer. For the design of the latter, a recently developed method is proposed, consisting of interlaced design of dynamic extensions and extended observers that provides a robust version of standard stabilization methods based on feedback-linearization. The method does not presume the knowledge of an accurate model of the plant and only needs access to the regulated variables.