A reduction paradigm for output regulation

The goal of this paper is to provide a reduction paradigm for the design of output regulators which can be of interest for nonlinear as well as linear uncertain systems. The main motivation of the work is to provide a systematic design tool to deal with non-minimum-phase uncertain systems for which conventional high-gain stabilization paradigms are not effective. The contribution of the work is two-fold. First this work extends the nonlinear framework proposed in Marconi et al. (Systems & Control Letters 53 2004) to the case in which the so-called 'immersion into a linear system' does not hold. Furthermore, in the case the uncertain controlled dynamics are linear, we show how the proposed framework leads to a number of systematic design tools of interest in the case of non-minimum-phase linear systems affected by severe uncertainties.