A Robust Asymptotic Observer for Systems That Converge to Unobservable States—A Batch Reactor Case Study

In this paper, we propose an observer for a dynamical system for which the states on the frontier of its domain are not observable, and all trajectories converge to the frontier. The proposed case study, a bioreactor in batch operating conditions with a single microbial reaction and gas production, is standard and largely encountered in practical situations. We also show how to extend this observer to obtain an observer in higher dimension that is robust with respect to unbiased noise.