On-line references reshaping and control reconfiguration for non-minimum phase nonlinear fault tolerant control

Abstract

In this paper we consider the problem of graceful performance degradation, for affine non-minimum phase nonlinear systems. The method is an optimization based scheme, that gives a constructive way to re-shape on-line the output reference for the post-fault system, and explicitly take into account the actuators and states saturations. The on-line output reference reshaping is associated with an on-line, MPC-based, controller reconfiguration, that forces the post-fault system to track the new output reference. The effect of FDD uncertainties on the online controller reconfiguration stability are studied, to ensure at least boundeness of the closed-loop system's states. The reshaping and reconfiguration schemes are applied to the Caltech ducted fan numerical example, which is described by a non-minimum phase nonlinear model.